All EyeLink Publications
All 12,000+ peer-reviewed EyeLink research publications up until 2023 (with some early 2024s) are listed below by year. You can search the publications library using keywords such as Visual Search, Smooth Pursuit, Parkinson’s, etc. You can also search for individual author names. Eye-tracking studies grouped by research area can be found on the solutions pages. If we missed any EyeLink eye-tracking papers, please email us!
2016 |
Judith Degen; Michael K. Tanenhaus Availability of alternatives and the processing of scalar implicatures: A visual world eye-tracking study Journal Article In: Cognitive Science, vol. 40, no. 1, pp. 172–201, 2016. @article{Degen2016, Two visual world experiments investigated the processing of the implicature associated with some using a “gumball paradigm.” On each trial, participants saw an image of a gumball machine with an upper chamber with orange and blue gumballs and an empty lower chamber. Gumballs dropped to the lower chamber, creating a contrast between a partitioned set of gumballs of one color and an unpartitioned set of the other. Participants then evaluated spoken statements, such as “You got some of the blue gumballs.” Experiment 1 investigated the time course of the pragmatic enrichment from some to not all when the only utterance alternatives available to refer to the dif- ferent sets were some and all. In Experiment 2, the number terms two, three, four, and five were also included in the set of alternatives. Scalar implicatures were delayed relative to the interpreta- tion of literal statements with all only when number terms were available. The results are inter- preted as evidence for a constraint-based account of scalar implicature processing. |
Louis F. Dell'Osso; Faruk H. Orge; Jonathan B. Jacobs Effects of augmented tenotomy and reattachment in the infantile nystagmus syndrome Journal Article In: Digital Journal of Opthalmology, vol. 22, no. 1, pp. 12–24, 2016. @article{DellOsso2016, PURPOSE: To test the hypothesis that augmented tenotomy and reattachment surgery (AT-R), which involves placing an additional suture in each distal tendon during the 4-muscle tenotomy and reattachment (T-R) or other infantile nystagmus syndrome (INS) procedures, could increase the beneficial effects of many types of extraocular muscle (EOM) surgery to treat INS. METHODS: Both infrared reflection and high-speed digital video systems were used to record the eye movements in 4 patients with INS before and after AT-R surgery. Data were analyzed using the eXpanded Nystagmus Acuity Function (NAFX) that is part of the OMtools software. RESULTS: Placement of the augmentation suture did not interfere with Kestenbaum, Anderson, bilateral medial rectus muscle recession, or T-R surgeries. The therapeutic effects of AT-R were similar to but not equal to those from the traditional single-suture surgeries (ie, broadening longest foveation domain [LFD] but no improvement of NAFX peak). The average of the NAFX percent improvements after AT-R was within 31% of those estimated from NAFX values before T-R; the average of the percent broadenings of the LFD values after AT-R was within 16%. CONCLUSIONS: The AT-R does not improve the foveation quality in INS above the traditional T-R surgery. It is not improved by an additional suture; indeed, some improvements may be diminished by the added suture. The hypothesized augmented-tendon suture technique (sans tenotomy) has been modified and remains to be tested. |
Vera Demberg; Asad Sayeed The frequency of rapid pupil dilations as a measure of linguistic processing difficulty Journal Article In: PLoS ONE, vol. 11, no. 1, pp. e0146194, 2016. @article{Demberg2016, While it has long been known that the pupil reacts to cognitive load, pupil size has received little attention in cognitive research because of its long latency and the difficulty of separating effects of cognitive load from the light reflex or effects due to eye movements. A novel measure, the Index of Cognitive Activity (ICA), relates cognitive effort to the frequency of small rapid dilations of the pupil. We report here on a total of seven experiments which test whether the ICA reliably indexes linguistically induced cognitive load: three experiments in reading (a manipulation of grammatical gender match / mismatch, an experiment of semantic fit, and an experiment comparing locally ambiguous subject versus object relative clauses, all in German), three dual-task experiments with simultaneous driving and spoken language comprehension (using the same manipulations as in the single-task reading experiments), and a visual world experiment comparing the processing of causal versus concessive discourse markers. These experiments are the first to investigate the effect and time course of the ICA in language processing. All of our experiments support the idea that the ICA indexes linguistic processing difficulty. The effects of our linguistic manipulations on the ICA are consistent for reading and auditory presentation. Furthermore, our experiments show that the ICA allows for usage within a multi-task paradigm. Its robustness with respect to eye movements means that it is a valid measure of processing difficulty for usage within the visual world paradigm, which will allow researchers to assess both visual attention and processing difficulty at the same time, using an eye-tracker. We argue that the ICA is indicative of activity in the locus caeruleus area of the brain stem, which has recently also been linked to P600 effects observed in psycholinguistic EEG experiments. |
Shujie Deng; Jian Chang; Julie A. Kirkby; Jian J. Zhang Gaze–mouse coordinated movements and dependency with coordination demands in tracing Journal Article In: Behaviour & Information Technology, vol. 35, no. 8, pp. 665–679, 2016. @article{Deng2016, Eye movements have been shown to lead hand movements in tracing tasks where subjects have to move their fingers along a predefined trace. The question remained, whether the leading relationship was similar when tracing with a pointing device, such as a mouse; more importantly, whether tasks that required more or less gaze–mouse coordination would introduce variation in this pattern of behaviour, in terms of both spatial and temporal leading of gaze position to mouse movement. A three-level gaze–mouse coordination demand paradigm was developed to address these questions. A substantial dataset of 1350 trials was collected and analysed. The linear correlation of gaze–mouse movements, the statistical distribution of the lead time, as well as the lead distance between gaze and mouse cursor positions were all considered, and we proposed a new method to quantify lead time in gaze–mouse coordination. The results supported and extended previous empirical findings that gaze often led mouse movements. We found that the gaze–mouse coordination demands of the task were positively correlated to the gaze lead, both spatially and temporally. However, the mouse movements were synchronised with or led gaze in the simple straight line condition, which demanded the least gaze–mouse coordination. |
Tao Deng; Kaifu Yang; Yongjie Li; Hongmei Yan Where does the driver look? Top-down-based saliency detection in a traffic driving environment Journal Article In: IEEE Transactions on Intelligent Transportation Systems, vol. 17, no. 7, pp. 2051–2062, 2016. @article{Deng2016a, A traffic driving environment is a complex and dynamically changing scene. When driving, drivers always allocate their attention to the most important and salient areas or targets. Traffic saliency detection, which computes the salient and prior areas or targets in a specific driving environment, is an indispensable part of intelligent transportation systems and could be useful in supporting autonomous driving, traffic sign detection, driving training, car collision warning, and other tasks. Recently, advances in visual attention models have provided substantial progress in describing eye movements over simple stimuli and tasks such as free viewing or visual search. However, to date, there exists no computational framework that can accurately mimic a driver's gaze behavior and saliency detection in a complex traffic driving environment. In this paper, we analyzed the eye-tracking data of 40 subjects consisted of nondrivers and experienced drivers when viewing 100 traffic images. We found that a driver's attention was mostly concentrated on the end of the road in front of the vehicle. We proposed that the vanishing point of the road can be regarded as valuable top-down guidance in a traffic saliency detection model. Subsequently, we build a framework of a classic bottom-up and top-down combined traffic saliency detection model. The results show that our proposed vanishing-point-based top-down model can effectively simulate a driver's attention areas in a driving environment. |
Rutvik H. Desai; Wonil Choi; Vicky T. Lai; John M. Henderson Toward semantics in the wild: Activation to manipulable nouns in naturalistic reading Journal Article In: Journal of Neuroscience, vol. 36, no. 14, pp. 4050–4055, 2016. @article{Desai2016, The neural basis of language processing, in the context of naturalistic reading of connected text, is a crucial but largely unexplored area. Here we combined functional MRI and eye tracking to examine the reading of text presented as whole paragraphs in two experiments with human subjects. We registered high-temporal resolution eye-tracking data to a low-temporal resolution BOLD signal to extract responses to single words during naturalistic reading where two to four words are typically processed per second. As a test case of a lexical variable, we examined the response to noun manipulability. In both experiments, signal in the left anterior inferior parietal lobule and posterior inferior temporal gyrus and sulcus was positively correlated with noun manipulability. These regions are associated with both action performance and action semantics, and their activation is consistent with a number of previous studies involving tool words and physical tool use. The results show that even during rapid reading of connected text, where semantics of words may be activated only partially, the meaning of manipulable nouns is grounded in action performance systems. This supports the grounded cognition view of semantics, which posits a close link between sensory-motor and conceptual systems of the brain. On the methodological front, these results demonstrate that BOLD responses to lexical variables during naturalistic reading can be extracted by simultaneous use of eye tracking. This opens up new avenues for the study of language and reading in the context of connected text. |
John-Ross Rizzo; Todd E. Hudson; Weiwei Dai; Joel Birkemeier; Rosa M. Pasculli; Ivan Selesnick; Laura J. Balcer; Steven L. Galetta; Janet C. Rucker Rapid number naming in chronic concussion: Eye movements in the King–Devick test Journal Article In: Annals of Clinical and Translational Neurology, vol. 3, no. 10, pp. 801–811, 2016. @article{Rizzo2016, Objective: The King–Devick (KD) test, which is based on rapid number nam- ing speed, is a performance measure that adds vision and eye movement assess- ments to sideline concussion testing. We performed a laboratory-based study to characterize ocular motor behavior during the KD test in a patient cohort with chronic concussion to identify features associated with prolonged KD reading times. Methods: Twenty-five patients with a concussion history (mean age: 31) were compared to control participants with no concussion history (n = 42, mean age: 32). Participants performed a computerized KD test under infrared- based video-oculography. Results: Average intersaccadic intervals for task-speci- fic saccades were significantly longer among concussed patients compared to controls (324.4 ? 85.6 msec vs. 286.1 ? 49.7 msec |
Victoria A. Roach; Graham M. Fraser; James H. Kryklywy; Derek G. V. Mitchell; Timothy D. Wilson The eye of the beholder: Can patterns in eye movement reveal aptitudes for spatial reasoning? Journal Article In: Anatomical Sciences Education, vol. 9, no. 4, pp. 357–366, 2016. @article{Roach2016, Mental rotation ability (MRA) is linked to academic success in the spatially complex Science, Technology, Engineering, Medicine, and Mathematics (STEMM) disciplines, and anatomical sciences. Mental rotation literature suggests that MRA may manifest in the movement of the eyes. Quantification of eye movement data may serve to distinguish MRA across individuals, and serve as a consideration when designing visualizations for instruction. It is hypothesized that high-MRA individuals will demonstrate fewer eye fixations, conduct shorter average fixation durations (AFD), and demonstrate shorter response times, than low-MRA individuals. Additionally, individuals with different levels of MRA will attend to different features of the block-figures presented in the electronic mental rotations test (EMRT). All participants (n = 23) completed the EMRT while metrics of eye movement were collected. The test required participants view pairs of three-dimensional (3D) shapes, and identify if the pair is rotated but identical, or two different structures. Temporal analysis revealed no significant correlations between response time, average fixation durations, or number of fixations and mental rotation ability. Further analysis of within-participant variability yielded a significant correlation for response time variability, but no correlation between AFD variability and variability in the number of fixations. Additional analysis of salience revealed that during problem solving, individuals of differing MRA attended to different features of the block images; suggesting that eye movements directed at salient features may contribute to differences in mental rotations ability, and may ultimately serve to predict success in anatomy. |
Mariel Roberts; Rachel Cymerman; R. Theodore Smith; Lynne Kiorpes; Marisa Carrasco Covert spatial attention is functionally intact in amblyopic human adults Journal Article In: Journal of Vision, vol. 16, no. 15, pp. 1–19, 2016. @article{Roberts2016, Certain abnormalities in behavioral performance and neural signaling have been attributed to a deficit of visual attention in amblyopia, a neurodevelopmental disorder characterized by a diverse array of visual deficits following abnormal binocular childhood experience. Critically, most have inferred attention's role in their task without explicitly manipulating and measuring its effects against a baseline condition. Here, we directly investigate whether human amblyopic adults benefit from covert spatial attention—the selective processing of visual information in the absence of eye movements—to the same degree as neurotypical observers. We manipulated both involuntary (Experiment 1) and voluntary (Experiment 2) attention during an orientation discrimination task for which the effects of covert spatial attention have been well established in neurotypical and special populations. In both experiments, attention significantly improved accuracy and decreased reaction times to a similar extent (a) between the eyes of the amblyopic adults and (b) between the amblyopes and their age- and gender- matched controls. Moreover, deployment of voluntary attention away from the target location significantly impaired task performance (Experiment 2). The magnitudes of the involuntary and voluntary attention benefits did not correlate with amblyopic depth or severity. Both groups of observers showed canonical performance fields (better performance along the horizontal than vertical meridian and at the lower than upper vertical meridian) and similar effects of attention across locations. Despite their characteristic low-level vision impairments, covert spatial attention remains functionally intact in human amblyopic adults. |
Maria M. Robinson; David E. Irwin Shifts of attention bias awareness of voluntary and reflexive eye movements Journal Article In: Experimental Brain Research, vol. 234, no. 6, pp. 1689–1699, 2016. @article{Robinson2016, Current theories regarding factors that influence people's awareness of their actions have underscored the role of peripheral signals (e.g., proprioceptive feedback) and central commands (e.g., the intention to make a response). The role of covert attention has been largely underexplored, even though attention and awareness have been tightly linked. The aim of the current study was to directly examine the impact of shifts of visual attention on people's awareness of their eye movements as they performed the antisaccade task. People tend to be unaware of a high percentage of erroneous eye movements on this task, thus lending it to the study of variables that might modulate people's awareness of their actions. In addition, this task provides the opportunity to compare two classes of actions, voluntary (antisaccade) and involuntary (erroneous prosaccade) eye movements, and thus to assess whether shifts of covert attention can or cannot override sources of information that may be present when people make voluntary but not reflexive responses. We found that shifts of visual attention did indeed influence participants' awareness of their own eye movements, leading them to misperceive reflexive and voluntary movements alike, suggesting that covert attention may override both peripheral and central signals to bias awareness. |
Susanne Röder; Claus-Christian Carbon; Todd K. Shackelford; Katarzyna Pisanski; Bettina Weege; Bernhard Fink Men's visual attention to and perceptions of women's dance movements Journal Article In: Personality and Individual Differences, vol. 101, pp. 1–3, 2016. @article{Roeder2016, Sexual selection may have shaped male visual sensitivity to characteristics that provide information about female mate quality. Indeed, men judge certain facial and bodily configurations of women to be attractive, possibly because those configurations signal health and fertility. Most of this evidence derives from the study of women's facial and body photographs. We tested the hypothesis that attractive female dancers receive greater visual attention from men than do unattractive dancers. Twenty-nine men viewed video pairs of pre-categorized high and low attractive female dancers. Their eye gaze was tracked and they also provided ratings of attractiveness, femininity, and dance movement harmony. High attractive dancers received greater visual attention than did low attractive dancers and men's visual attention correlated positively with their judgments of attractiveness, femininity, and dance movement harmony. We discuss our findings in the context of the 'beauty captures the mind of the beholder' hypothesis and the role of dance movements in human mate selection. |
Tanja C. Roembke; Bob McMurray Observational word learning: Beyond propose-but-verify and associative bean counting Journal Article In: Journal of Memory and Language, vol. 87, pp. 105–127, 2016. @article{Roembke2016, Learning new words is difficult. In any naming situation, there are multiple possible interpretations of a novel word. Recent approaches suggest that learners may solve this problem by tracking co-occurrence statistics between words and referents across multiple naming situations (e.g. Yu & Smith, 2007), overcoming the ambiguity in any one situation. Yet, there remains debate around the underlying mechanisms. We conducted two experiments in which learners acquired eight word-object mappings using cross-situational statistics while eye-movements were tracked. These addressed four unresolved questions regarding the learning mechanism. First, eye-movements during learning showed evidence that listeners maintain multiple hypotheses for a given word and bring them all to bear in the moment of naming. Second, trial-by-trial analyses of accuracy suggested that listeners accumulate continuous statistics about word-object mappings, over and above prior hypotheses they have about a word. Third, consistent, probabilistic context can impede learning, as false associations between words and highly co-occurring referents are formed. Finally, a number of factors not previously considered in prior analysis impact observational word learning: knowledge of the foils, spatial consistency of the target object, and the number of trials between presentations of the same word. This evidence suggests that observational word learning may derive from a combination of gradual statistical or associative learning mechanisms and more rapid real-time processes such as competition, mutual exclusivity and even inference or hypothesis testing. |
Maria C. Romero; Peter Janssen Receptive field properties of neurons in the macaque anterior intraparietal area Journal Article In: Journal of Neurophysiology, vol. 115, no. 3, pp. 1542–1555, 2016. @article{Romero2016, Visual object information is necessary for grasping. In primates, the anterior intraparietal area (AIP) plays an essential role in visually guided grasping. Neurons in AIP encode features of objects, but no study has systematically investigated the receptive field (RF) of AIP neurons. We mapped the RF of posterior AIP (pAIP) neurons in the central visual field, using images of objects and small line fragments that evoked robust responses, together with less effective stimuli. The RF sizes we measured varied between 3°(2)and 90°(2), with the highest response either at the fixation point or at parafoveal positions. A large fraction of pAIP neurons showed nonuniform RFs, with multiple local maxima in both ipsilateral and contralateral hemifields. Moreover, the RF profile could depend strongly on the stimulus used to map the RF. Highly similar results were obtained with the smallest stimulus that evoked reliable responses (line fragments measuring 1-2°). The nonuniformity and dependence of the RF profile on the stimulus in pAIP were comparable to previous observations in the anterior part of the lateral intraparietal area (aLIP), but the average RF of pAIP neurons was located at the fovea whereas the average RF of aLIP neurons was located parafoveally. Thus nonuniformity and stimulus dependence of the RF may represent general RF properties of neurons in the dorsal visual stream involved in object analysis, which contrast markedly with those of neurons in the ventral visual stream. |
Gabriela Rosenblau; Dorit Kliemann; Benjamin Lemme; Henrik Walter; Hauke R. Heekeren; Isabel Dziobek The role of the amygdala in naturalistic mentalising in typical development and in autism spectrum disorder Journal Article In: British Journal of Psychiatry, vol. 208, no. 6, pp. 556–564, 2016. @article{Rosenblau2016, Background: The substantial discrepancy between mentalising in experimental settings v. real-life social interactions hinders the understanding of the neural basis of real-life social cognition and of social impairments in psychiatric disorders. Aims: To determine the neural mechanisms underlying naturalistic mentalising in individuals with and without autism spectrum disorder. Method: We investigated mentalising with a new video-based functional magnetic resonance imaging task in 20 individuals with autism spectrum disorder and 22 matched healthy controls. Results: Naturalistic mentalising implicated regions of the traditional mentalising network (medial prefrontal cortex, temporoparietal junction), and additionally the insula and amygdala. Moreover, amygdala activity predicted implicit mentalising performance on an independent behavioural task. Compared with controls, the autism spectrum disorder group did not show differences in neural activity within classical mentalising regions. They did, however, show reduced amygdala activity and a reduced correlation between amygdala activity and mentalising accuracy on the behavioural task, compared with controls. Conclusions: These findings highlight the crucial role of the amygdala in making accurate implicit mental state inferences in typical development and in the social cognitive impairments of individuals with autism spectrum disorder. |
Zvi N. Roth In: Frontiers in Integrative Neuroscience, vol. 10, pp. 16, 2016. @article{Roth2016, Neural responses in visual cortex are governed by a topographic mapping from retinal locations to cortical responses. Moreover, at the voxel population level early visual cortex (EVC) activity enables accurate decoding of stimuli locations. However, in many cases information enabling one to discriminate between locations (i.e. discriminative information) may be less relevant than information regarding the relative location of two objects (i.e. relative information). For example, when planning to grab a cup, determining whether the cup is located at the same retinal location as the hand is hardly relevant, whereas the location of the cup relative to the hand is crucial for performing the action. We have previously used multivariate pattern analysis techniques to measure discriminative location information, and found the highest levels in early visual cortex, in line with other studies. Here we show, using representational similarity analysis, that availability of discriminative information in fMRI activation patterns does not entail availability of relative information. Specifically, we find that relative location information can be reliably extracted from activity patterns in posterior intraparietal sulcus (pIPS), but not from EVC, where we find the spatial representation to be warped. We further show that this variability in relative information levels between regions can be explained by a computational model based on an array of receptive fields. Moreover, when the model's receptive fields are extended to include inhibitory surround regions, the model can account for the spatial warping in EVC. These results demonstrate how size and shape properties of receptive fields in human visual cortex contribute to the transformation of discriminative spatial representation into relative spatial representation along the visual stream. |
Lars O. M. Rothkegel; Hans A. Trukenbrod; Heiko H. Schütt; Felix A. Wichmann; Ralf Engbert Influence of initial fixation position in scene viewing Journal Article In: Vision Research, vol. 129, pp. 33–49, 2016. @article{Rothkegel2016a, During scene perception our eyes generate complex sequences of fixations. Predictors of fixation locations are bottom-up factors such as luminance contrast, top-down factors like viewing instruction, and systematic biases, e.g., the tendency to place fixations near the center of an image. However, comparatively little is known about the dynamics of scanpaths after experimental manipulation of specific fixation locations. Here we investigate the influence of initial fixation position on subsequent eye-movement behavior on an image. We presented 64 colored photographs to participants who started their scanpaths from one of two experimentally controlled positions in the right or left part of an image. Additionally, we used computational models to predict the images' fixation locations and classified them as balanced images or images with high conspicuity on either the left or right side of a picture. The manipulation of the starting position influenced viewing behavior for several seconds and produced a tendency to overshoot to the image side opposite to the starting position. Possible mechanisms for the generation of this overshoot were investigated using numerical simulations of statistical and dynamical models. Our model comparisons show that inhibitory tagging is a viable mechanism for dynamical planning of scanpaths. |
Yuval Porat; Ehud Zohary Practice improves peri-saccadic shape judgment but does not diminish target mislocalization Journal Article In: Proceedings of the National Academy of Sciences, vol. 113, no. 46, pp. E7327–E7336, 2016. @article{Porat2016, Visual sensitivity is markedly reduced during an eye movement. Peri-saccadic vision is also characterized by a mislocalization of the briefly presented stimulus closer to the saccadic target. These features are commonly viewed as obligatory elements of peri-saccadic vision. However, practice improves performance in many perceptual tasks performed at threshold conditions. We wondered if this could also be the case with peri-saccadic perception. To test this, we used a paradigm in which subjects reported the orientation (or location) of an ellipse briefly presented during a saccade. Practice on peri-saccadic orientation discrimination led to long-lasting gains in that task but did not alter the classical mislocalization of the visual stimulus. Shape discrimination gains were largely generalized to other untrained conditions when the same stimuli were used (discrimination during a saccade in the opposite direction or at a different stimulus location than previously trained). However, performance dropped to baseline level when participants shifted to a novel Vernier discrimination task under identical saccade conditions. Furthermore, practice on the location task did not induce better stimulus localization or discrimination. These results suggest that the limited visual information available during a saccade may be better used with practice, possibly by focusing attention on the specific target features or a better readout of the available information. Saccadic mislocalization, by contrast, is robust and resistant to top-down modulations, suggesting that it involves an automatic process triggered by the upcoming execution of a saccade (e.g., an efference copy signal). |
Vincent Porretta; Benjamin V. Tucker; Juhani Järvikivi The influence of gradient foreign accentedness and listener experience on word recognition Journal Article In: Journal of Phonetics, vol. 58, pp. 1–21, 2016. @article{Porretta2016, The present article examines lexical processing of foreign-accented speech, specifically as it relates to gradient foreign accentedness and listener experience. In two experiments, we investigate the effect of accentedness and experience on the strength of lexical activation and the time-course of word recognition utilizing native- and Mandarin-accented English words. Gradient and non-linear patterns emerged for both accentedness and experience. Experiment 1 employed cross-modal identity priming and the analysis of reaction times indicates that tokens with a greater degree of accentedness result in a reduced effectiveness of the identity prime. Listener experience with Chinese-accented English positively influenced activation strength in a gradient fashion. Experiment 2 employed visual world eye-tracking and the analysis of looks to the target word indicates that the time-course of recognition differs across the accentedness continuum, slowing as accentedness increases. Again, listener experience improved the time-course of word recognition. The results are discussed in terms of foreign-accented speech processing and long-term adaptation to non-native variability and suggest the need for a dynamic systems approach. |
Nicholas L. Port; Jane Trimberger; Steve Hitzeman; Bryan Redick; Stephen Beckerman Micro and regular saccades across the lifespan during a visual search of "Where's Waldo" puzzles Journal Article In: Vision Research, vol. 118, pp. 144–157, 2016. @article{Port2016, Despite the fact that different aspects of visual-motor control mature at different rates and aging is associated with declines in both sensory and motor function, little is known about the relationship between microsaccades and either development or aging. Using a sample of 343 individuals ranging in age from 4 to 66 and a task that has been shown to elicit a high frequency of microsaccades (solving Where's Waldo puzzles), we explored microsaccade frequency and kinematics (main sequence curves) as a function of age. Taking advantage of the large size of our dataset (183,893 saccades), we also address (a) the saccade amplitude limit at which video eye trackers are able to accurately measure microsaccades and (b) the degree and consistency of saccade kinematics at varying amplitudes and directions. Using a modification of the Engbert-Mergenthaler saccade detector, we found that even the smallest amplitude movements (0.25-0.5°) demonstrate basic saccade kinematics. With regard to development and aging, both microsaccade and regular saccade frequency exhibited a very small increase across the life span. Visual search ability, as per many other aspects of visual performance, exhibited a U-shaped function over the lifespan. Finally, both large horizontal and moderate vertical directional biases were detected for all saccade sizes. |
Christian H. Poth; Werner X. Schneider Breaking object correspondence across saccades impairs object recognition: The role of color and luminance Journal Article In: Journal of Vision, vol. 16, no. 11, pp. 1–12, 2016. @article{Poth2016, Rapid saccadic eye movements bring the foveal region of the eye's retina onto objects for high-acuity vision. Saccades change the location and resolution of objects' retinal images. To perceive objects as visually stable across saccades, correspondence between the objects before and after the saccade must be established. We have previously shown that breaking object correspondence across the saccade causes a decrement in object recognition (Poth, Herwig, & Schneider, 2015). Color and luminance can establish object correspondence, but it is unknown how these surface features contribute to transsaccadic visual processing. Here, we investigated whether changing the surface features color-and-luminance and color alone across saccades impairs postsaccadic object recognition. Participants made saccades to peripheral objects, which either maintained or changed their surface features across the saccade. After the saccade, participants briefly viewed a letter within the saccade target object (terminated by a pattern mask). Postsaccadic object recognition was assessed as participants' accuracy in reporting the letter. Experiment A used the colors green and red with different luminances as surface features, Experiment B blue and yellow with approximately the same luminances. Changing the surface features across the saccade deteriorated postsaccadic object recognition in both experiments. These findings reveal a link between object recognition and object correspondence relying on the surface features colors and luminance, which is currently not addressed in theories of transsaccadic perception. We interpret the findings within a recent theory ascribing this link to visual attention (Schneider, 2013). |
Georgie Powell; Zoe Meredith; Rebecca McMillin; Tom C. A. Freeman Bayesian models of individual differences: Combining autistic traits and sensory thresholds to predict motion perception Journal Article In: Psychological Science, vol. 27, no. 12, pp. 1562–1572, 2016. @article{Powell2016, According to Bayesian models, perception and cognition depend on the optimal combination of noisy incoming evidence with prior knowledge of the world. Individual differences in perception should therefore be jointly determined by a person's sensitivity to incoming evidence and his or her prior expectations. It has been proposed that individuals with autism have flatter prior distributions than do nonautistic individuals, which suggests that prior variance is linked to the degree of autistic traits in the general population. We tested this idea by studying how perceived speed changes during pursuit eye movement and at low contrast. We found that individual differences in these two motion phenomena were predicted by differences in thresholds and autistic traits when combined in a quantitative Bayesian model. Our findings therefore support the flatter-prior hypothesis and suggest that individual differences in prior expectations are more systematic than previously thought. In order to be revealed, however, individual differences in sensitivity must also be taken into account. |
Georgie Powell; Petroc Sumner; James J. Harrison; Aline Bompas Interaction between contours and eye movements in the perception of afterimages: A test of the signal ambiguity theory Journal Article In: Journal of Vision, vol. 16, no. 7, pp. 1–11, 2016. @article{Powell2016a, An intriguing property of afterimages is that conscious experience can be strong, weak, or absent following identical stimulus adaptation. Previously we suggested that postadaptation retinal signals are inherently ambiguous, and therefore the perception they evoke is strongly influenced by cues that increase or decrease the likelihood that they represent real objects (the signal ambiguity theory). Here we provide a more definitive test of this theory using two cues previously found to influence afterimage perception in opposite ways and plausibly at separate loci of action. However, by manipulating both cues simultaneously, we found that their effects interacted, consistent with the idea that they affect the same process of object interpretation rather than being independent influences. These findings bring contextual influences on afterimages into more general theories of cue combination, and we suggest that afterimage perception should be considered alongside other areas of vision science where cues are found to interact in their influence on perception. |
Rebecca B. Price; Inez M. Greven; Greg J. Siegle; Ernst H. W. Koster; Rudi De Raedt A Novel Attention Training Paradigm Based on Operant Conditioning of Eye Gaze: Preliminary Findings Journal Article In: Emotion, vol. 16, no. 1, pp. 110–116, 2016. @article{Price2016, A sequential injection system which consists of a syringe pump, a selector valve, a multi-port valve, a gas-liquid separator and a solenoid valve for the determination of arsenic by hydride generation atomic absorption spectrometry using tetrahydroborate as reductant was developed. The reduction time of sample with tetrahydoborate has increased by keeping the reactant in gas-liquid separator by using the solenoid valve. Various parameters affecting the performance of the sequential injection system were optimized, including reaction-time, carrier gas flow, sample volume, tetrahydroborate volume and concentration. Established sequential injection hydride generation technique was simple and automated operation. A sample throughput of 112/h was achieved with 400 μL samples with a precision of 2.0% RSD at 4 μg/L As (n = 10) and a detection limit of 0.09 μg/L. Good agreement with the certified values was obtained for the determination of arsenic in standard reference materials. |
Malcolm Proudfoot; Ricarda A. L. Menke; Rakesh Sharma; Claire M. Berna; Stephen L. Hicks; Christopher Kennard; Kevin Talbot; Martin R. Turner Eye-tracking in amyotrophic lateral sclerosis: A longitudinal study of saccadic and cognitive tasks Journal Article In: Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration, vol. 17, no. 1-2, pp. 101–111, 2016. @article{Proudfoot2016, A relative preservation of eye movements is notable in ALS, but saccadic functions have not been studied longitudinally. ALS overlaps with FTD, typically involving executive dysfunction, and eye-tracking offers additional potential for the assessment of extramotor pathology where writing and speaking are both impaired. Eye-tracking measures (including anti- saccade, trail-making and visual search tasks) were assessed at six-monthly intervals for up to two years in a group of ALS (n ? 61) and primary lateral sclerosis (n ? 7) patients, compared to healthy age-matched controls (n ? 39) assessed on a single occasion. Task performance was explored speculatively in relation to resting-state functional MRI (R-FMRI) network connectivity. Results showed that ALS patients were impaired on executive and visual search tasks despite normal basic saccadic function, and impairments in the PLS patients were unexpectedly often more severe. No significant progression was detected longitudinally in either group. No changes in R-FMRI network connectivity were identified in relation to patient performance. In conclusion, eye-tracking offers an objective means to assess extramotor cerebral involvement in ALS. The relative resistance of pure oculomotor function is confirmed, and higher-level executive impairments do not follow the same rate of decline as physical disability. PLS patients may have more cortical dysfunction than has been previously appreciated. |
Maria Solé Puig; Josep Marco Pallarés; Laura Perez Zapata; Laura Puigcerver; Josep Cañete; Hans Supèr Attentional selection accompanied by eye vergence as revealed by event-related brain potentials Journal Article In: PLoS ONE, vol. 11, no. 12, pp. e0167646, 2016. @article{Puig2016, Neural mechanisms of attention allow selective sensory information processing. Top-down deployment of visual-spatial attention is conveyed by cortical feedback connections from frontal regions to lower sensory areas modulating late stimulus responses. A recent study reported the occurrence of small eye vergence during orienting top-down attention. Here we assessed a possible link between vergence and attention by comparing visual event related potentials (vERPs) to a cue stimulus that induced attention to shift towards the target location to the vERPs to a no-cue stimulus that did not trigger orienting attention. The results replicate the findings of eye vergence responses during orienting attention and show that the strength and time of eye vergence coincide with the onset and strength of the vERPs when subjects oriented attention. Our findings therefore support the idea that eye vergence relates to and possibly has a role in attentional selection. |
Anne Pycha; Delphine Dahan Differences in coda voicing trigger changes in gestural timing: A test case from the American English diphthong /aI/ Journal Article In: Journal of Phonetics, vol. 56, pp. 15–37, 2016. @article{Pycha2016, We investigate the hypothesis that duration and spectral differences in vowels before voiceless versus voiced codas originate from a single source, namely the reorganization of articulatory gestures relative to one another in time. As a test case, we examine the American English diphthong /aI/, in which the acoustic manifestations of the nucleus /a/ and offglide /I/ gestures are relatively easy to identify, and we use the ratio of nucleus-to-offglide duration as an index of the temporal distance between these gestures. Experiment 1 demonstrates that, in production, the ratio is smaller before voiceless codas than before voiced codas; this effect is consistent across speakers as well as changes in speech rate and phrasal position. Experiment 2 demonstrates that, in perception, diphthongs with contextually incongruent ratios delay listeners' identification of target words containing voiceless codas, even when the other durational and spectral correlates of voicing remain intact. This, we argue, is evidence that listeners are sensitive to the gestural origins of voicing differences. Both sets of results support the idea that the voicing contrast triggers changes in timing: gestures are close to one another in time before voiceless codas, but separated from one another before voiced codas. |
Chen Qingrong; Gu Wentao; Christoph Scheepers Effects of text segmentation on silent reading of Chinese regulated poems: Evidence from eye movements Journal Article In: Journal of Chinese Linguistics, vol. 44, no. 2, pp. 265–286, 2016. @article{Qingrong2016, Interword spaces have been reported to play an important role in silent reading of alphabetic languages. However, it has not yet been clear whether text spacing/segmentation facilitates the cognitive process in silent reading of Chinese, a logographic language, especially in reading Chinese regulated poems which have predefined rhythmic structures. An eye-tracking experiment was conducted to monitor eye movements of native participants in reading Chinese regulated poems in four segmenting conditions: normal text, character segmentation, rhythmic segmentation, and syntactic segmentation. By comparing a set of measures of eye movements, both global and local analyses showed that syntactic segmentation boosted reading efficiency, while rhythmic segmentation did not. The findings demonstrate that not rhythmic but syntactic structure plays major roles in the cognitive process in reading Chinese regulated poems, suggesting an intrinsic difference in the information structure between spoken and written languages. |
Romain Quentin; Seth E. Frankston; Marine Vernet; Monica N. Toba; Paolo Bartolomeo; Lorena Chanes; Antoni Valero-Cabré In: Cerebral Cortex, vol. 26, no. 6, pp. 2381–2390, 2016. @article{Quentin2016, Behavioral and electrophysiological studies in humans and non-human primates have correlated frontal high-beta activity with the orienting of endogenous attention and shown the ability of the latter function to modulate visual performance. We here combined rhythmic transcranial magnetic stimulation (TMS) and diffusion imaging to study the relation between frontal oscillatory activity and visual performance, and we associated these phenomena to a specific set of white matter pathways that in humans subtend attentional processes. High-beta rhythmic activity on the right frontal eye field (FEF) was induced with TMS and its causal effects on a contrast sensitivity function were recorded to explore its ability to improve visual detection performance across different stimulus contrast levels. Our results show that frequency-specific activity patterns engaged in the right FEF have the ability to induce a leftward shift of the psychometric function. This increase in visual performance across different levels of stimulus contrast is likely mediated by a contrast gain mechanism. Interestingly, microstructural measures of white matter connectivity suggest a strong implication of right fronto-parietal connectivity linking the FEF and the intraparietal sulcus in propagating high-beta rhythmic signals across brain networks and subtending top-down frontal influences on visual performance. |
Eyal M. Reingold; Heather Sheridan; Katie L. Meadmore; Denis Drieghe; Simon P. Liversedge Attention and eye-movement control in reading: The selective reading paradigm Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 42, no. 12, pp. 2003–2020, 2016. @article{Reingold2016, We introduced a novel paradigm for investigating covert attention and eye-movement control in reading. In 2 experiments, participants read sentence words (shown in blue color) while ignoring interleaved distractor strings (shown in orange color). Each single-line text display contained a target word and a critical distractor. Critical distractors were located just prior to the target in the text and were either words or symbol strings (e.g., @#%&). Target word availability for parafoveal processing (i.e., preview validity) was also manipulated. The results indicated much shallower processing of distractors than targets, and this pattern was more pronounced for symbol than word distractors. The influences of word frequency and fixation location on first-pass fixation durations on distractors were dramatically different than the well-documented pattern obtained in normal reading. Robust preview benefits were demon- strated both when the critical distractors were fixated and when the critical distractors were skipped. Finally, with the exception of larger preview benefits that were obtained in the condition in which the target and critical distractor were identical, the magnitude of the preview effect was largely unaffected by the nature of the critical distractor. Implications of the present paradigm and findings to the study of eye-movement control in reading are discussed. |
James D. Retell; Stefanie I. Becker; Roger W. Remington An effective attentional set for a specific colour does not prevent capture by infrequently presented motion distractors Journal Article In: Quarterly Journal of Experimental Psychology, vol. 69, no. 7, pp. 1340–1365, 2016. @article{Retell2016a, An organism's survival depends on the ability to rapidly orient attention to unanticipated events in the world. Yet, the conditions needed to elicit such involuntary capture remain in doubt. Especially puzzling are spatial cueing experiments, which have consistently shown that involuntary shifts of attention to highly salient distractors are not determined by stimulus properties, but instead are contingent on attentional control settings induced by task demands. Do we always need to be set for an event to be captured by it, or is there a class of events that draw attention involuntarily even when unconnected to task goals? Recent results suggest that a task-irrelevant event will capture attention on first presentation, suggesting that salient stimuli that violate contextual expectations might automatically capture attention. Here, we investigated the role of contextual expectation by examining if an irrelevant motion cue that was presented only rarely (∼3-6% of trials) would capture attention when observers had an active set for a specific target color. The motion cue had no effect when presented frequently, but when rare produced a pattern of interference consistent with attentional capture. The critical dependence on the frequency with which the irrelevant motion singleton was presented is consistent with early theories of involuntary orienting to novel stimuli (Sokolov, 1963). We suggest that attention will be captured by salient stimuli that violate expectations, whereas top-down goals appear to modulate capture by stimuli that broadly conform to contextual expectations. |
James D. Retell; Stefanie I. Becker; Roger W. Remington Previously seen and expected stimuli elicit surprise in the context of visual search Journal Article In: Attention, Perception, and Psychophysics, vol. 78, no. 3, pp. 774–788, 2016. @article{Retell2016, In the context of visual search, surprise is the phenomenon by which a previously unseen and unexpect- ed stimulus exogenously attracts spatial attention. Capture by such a stimulus occurs, by definition, independent of task goals and is thought to be dependent on the extent to which the stimulus deviates from expectations. However, the relative contributions of prior-exposure and explicit knowledge of an unexpected event to the surprise response have not yet been systematically investigated. Here ob- servers searched for a specific color while ignoring irrele- vant cues of different colors presented prior to the target display. After a brief familiarization period, we presented an irrelevant motion cue to elicit surprise. Across condi- tions we varied prior exposure to the motion stimulus – seen versus unseen – and top-down expectations of occur- rence – expected versus unexpected – to assess the extent to which each of these factors contributes to surprise. We found no attenuation of the surprise response when ob- servers were pre-exposed to the motion cue and or had explicit knowledge of its occurrence. Our results show that it is neither sufficient nor necessary that a stimulus be new and unannounced to elicit surprise and suggest that the expectations that determine the surprise response are highly context specific. |
Benedikt Reuter; Björn Elsner; David Möllers; Norbert Kathmann In: Psychophysiology, vol. 53, no. 11, pp. 1712–1720, 2016. @article{Reuter2016, Clinical and theoretical models suggest deficient volitional initiation of action in schizophrenia patients. Recent research provided an experimental model of testing this assumption using saccade tasks. However, inconsistent findings necessitate a specification of conditions on which the deficit may occur. The present study sought to detect mechanisms that may contribute to poor performance. Sixteen schizophrenia patients and 16 healthy control participants performed visually guided and two types of volitional saccade tasks. All tasks varied as to whether the initial fixation stimulus disappeared (fixation stimulus offset) or continued during saccade initiation, and whether a direction cue allowed motor preparation of the specific saccade. Saccade latencies of the two groups were differentially affected by task type, fixation stimulus offset, and cueing, suggesting abnormal volitional saccade generation, fixation release, and motor preparation in schizophrenia. However, substantial performance deficits may only occur if all affected processes are required in a task. |
Gerulf Rieger; Ritch C. Savin-Williams; Meredith L. Chivers; J. Michael Bailey Sexual arousal and masculinity-femininity of women Journal Article In: Journal of Personality and Social Psychology, vol. 111, no. 2, pp. 265–283, 2016. @article{Rieger2016, Studies with volunteers in sexual arousal experiments suggest that women are, on average, physiologically sexually aroused to both male and female sexual stimuli. Lesbians are the exception because they tend to be more aroused to their preferred sex than the other sex, a pattern typically seen in men. A separate research line suggests that lesbians are, on average, more masculine than straight women in their nonsexual behaviors and characteristics. Hence, a common influence could affect the expression of male-typical sexual and nonsexual traits in some women. By integrating these research programs, we tested the hypothesis that male-typical sexual arousal of lesbians relates to their nonsexual masculinity. Moreover, the most masculine-behaving lesbians, in particular, could show the most male-typical sexual responses. Across combined data, Study 1 examined these patterns in women's genital arousal and self-reports of masculine and feminine behaviors. Study 2 examined these patterns with another measure of sexual arousal, pupil dilation to sexual stimuli, and with observer-rated masculinity-femininity in addition to self-reported masculinity-femininity. Although both studies confirmed that lesbians were more male-typical in their sexual arousal and nonsexual characteristics, on average, there were no indications that these 2 patterns were in any way connected. Thus, women's sexual responses and nonsexual traits might be masculinized by independent factors. |
Ioannis Rigas; Evgeniy Abdulin; Oleg V. Komogortsev Towards a multi-source fusion approach for eye movement-driven recognition Journal Article In: Information Fusion, vol. 32, pp. 13–25, 2016. @article{Rigas2016, This paper presents a research for the use of multi-source information fusion in the field of eye movement biometrics. In the current state-of-the-art, there are different techniques developed to extract the physical and the behavioral biometric characteristics of the eye movements. In this work, we explore the effects from the multi-source fusion of the heterogeneous information extracted by different biometric algorithms under the presence of diverse visual stimuli. We propose a two-stage fusion approach with the employment of stimulus-specific and algorithm-specific weights for fusing the information from different matchers based on their identification efficacy. The experimental evaluation performed on a large database of 320 subjects reveals a considerable improvement in biometric recognition accuracy, with minimal equal error rate (EER) of 5.8%, and best case Rank-1 identification rate (Rank-1 IR) of 88.6%. It should be also emphasized that although the concept of multi-stimulus fusion is currently evaluated specifically for the eye movement biometrics, it can be adopted by other biometric modalities too, in cases when an exogenous stimulus affects the extraction of the biometric features. |
Ioannis Rigas; Oleg V. Komogortsev; Reza Shadmehr Biometric recognition via eye movements : Saccadic vigor and acceleration cues Journal Article In: ACM Transactions on Applied Perception, vol. 13, no. 2, pp. 1–21, 2016. @article{Rigas2016a, Previous research shows that human eye movements can serve as a valuable source of information about the structural elements of the oculomotor system and they also can open a window to the neural functions and cognitive mechanisms related to visual attention and perception. The research field of eye movement-driven biometrics explores the extraction of individual-specific characteristics from eye movements and their employment for recognition purposes. In this work, we present a study for the incorporation of dynamic saccadic features into a model of eye movement-driven biometrics. We show that when these features are added to our previous biometric framework and tested on a large database of 322 subjects, the biometric accuracy presents a relative improvement in the range of 31.6–33.5% for the verification scenario, and in range of 22.3–53.1% for the identification scenario. More importantly, this improvement is demonstrated for different types of visual stimulus (random dot, text, video), indicating the enhanced robustness offered by the incorporation of saccadic vigor and acceleration cues. |
L. Rincon-Gonzalez; Luc P. J. Selen; K. Halfwerk; Mathieu Koppen; B. D. Corneil; W. Pieter Medendorp Decisions in motion: Vestibular contributions to saccadic target selection Journal Article In: Journal of Neurophysiology, vol. 116, no. 3, pp. 977–985, 2016. @article{RinconGonzalez2016, The natural world continuously presents us with many opportunities for action, and thus a process of target selection must precede action execution. While there has been considerable progress in understanding target selection in stationary environments, little is known about target selection when we are in motion. Here we investigated the effect of self-motion signals on saccadic target selection in a dynamic environment. Human subjects were sinusoidally translated (f = 0.6 Hz, 30-cm peak-to-peak displacement) along an interaural axis with a vestibular sled. During the motion two visual targets were presented asynchronously but equidistantly on either side of fixation. Subjects had to look at one of these targets as quickly as possible. With an adaptive approach, the time delay between these targets was adjusted until the subject selected both targets equally often. We determined this balanced time delay for different phases of the motion in order to distinguish the effects of body acceleration and velocity on saccadic target selection. Results show that acceleration (or position, as these are indistinguishable during sinusoidal motion), but not velocity, affects target selection for saccades. Subjects preferred to look at targets in the direction of the acceleration-the leftward target was preferred when the sled accelerated to the left, and vice versa. Saccadic reaction times mimicked this selection bias by being reliably shorter to targets in the direction of acceleration. Our results provide evidence that saccade target selection mechanisms are modulated by self-motion signals, which could be derived directly from the otolith system. |
Ryan V. Ringer; Zachary Throneburg; Aaron P. Johnson; Arthur F. Kramer; Lester C. Loschky Impairing the useful field of view in natural scenes: Tunnel vision versus general interference Journal Article In: Journal of Vision, vol. 16, no. 2, pp. 1–25, 2016. @article{Ringer2016, A fundamental issue in visual attention is the relationship between the useful field of view (UFOV), the region of visual space where information is encoded within a single fixation, and eccentricity. A common assumption is that impairing attentional resources reduces the size of the UFOV (i.e., tunnel vision). However, most research has not accounted for eccentricity-dependent changes in spatial resolution, potentially conflating fixed visual properties with flexible changes in visual attention. Williams (1988, 1989) argued that foveal loads are necessary to reduce the size of the UFOV, producing tunnel vision. Without a foveal load, it is argued that the attentional decrement is constant across the visual field (i.e., general interference). However, other research asserts that auditory working memory (WM) loads produce tunnel vision. To date, foveal versus auditory WM loads have not been compared to determine if they differentially change the size of the UFOV. In two experiments, we tested the effects of a foveal (rotated L vs. T discrimination) task and an auditory WM (N-back) task on an extrafoveal (Gabor) discrimination task. Gabor patches were scaled for size and processing time to produce equal performance across the visual field under single-task conditions, thus removing the confound of eccentricity-dependent differences in visual sensitivity. The results showed that although both foveal and auditory loads reduced Gabor orientation sensitivity, only the foveal load interacted with retinal eccentricity to produce tunnel vision, clearly demonstrating task-specific changes to the form of the UFOV. This has theoretical implications for understanding the UFOV. |
Max Schneider; Pamela Hathway; Laura Leuchs; Philipp G. Sämann; Michael Czisch; Victor I. Spoormaker Spontaneous pupil dilations during the resting state are associated with activation of the salience network Journal Article In: NeuroImage, vol. 139, pp. 189–201, 2016. @article{Schneider2016, Resting state functional magnetic resonance imaging (rs-fMRI) is increasingly applied for the development of functional biomarkers in brain disorders. Recent studies have revealed spontaneous vigilance drifts during the resting state, involving changes in brain activity and connectivity that challenge the validity of uncontrolled rs-fMRI findings. In a combined rs-fMRI/eye tracking study, the pupil size of 32 healthy subjects after 2 h of sleep restriction was recorded as an indirect index for activity of the locus coeruleus, the brainstem's noradrenergic arousal center. The spontaneous occurrence of pupil dilations, but not pupil size per se, was associated with increased activity of the salience network, thalamus and frontoparietal regions. In turn, spontaneous constrictions of the pupil were associated with increased activity in visual and sensorimotor regions. These results were largely replicated in a sample of 36 healthy subjects who did not undergo sleep restriction, although in this sample the correlation between thalamus and pupil dilation fell below whole-brain significance. Our data show that spontaneous pupil fluctuations during rest are indeed associated with brain circuitry involved in tonic alertness and vigilance. Pupillometry is an effective method to control for changes in tonic alertness during rs-fMRI. |
Elizabeth R. Schotter; Annie Jia Semantic and plausibility preview benefit effects in English: Evidence from eye movements Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 42, no. 12, pp. 1839–1866, 2016. @article{Schotter2016a, Theories of preview benefit in reading hinge on integration across saccades and the idea that preview benefit is greater the more similar the preview and target are. Schotter (2013) reported preview benefit from a synonymous preview, but it is unclear whether this effect occurs because of similarity between the preview and target (i.e., integration), or because of contextual fit of the preview—synonyms satisfy both accounts. Studies in Chinese have found evidence for preview benefit for words that are unrelated to the target, but are contextually plausible (Yang, Li, Wang, Slattery, & Rayner, 2014; Yang, Wang, Tong, & Rayner, 2012), which is incompatible with an integration account but supports a contextual fit account. Here, we used plausible and implausible unrelated previews in addition to plausible synonym, antonym, and identical previews to further investigate these accounts for readers of English. Early reading measures were shorter for all plausible preview conditions compared to the implausible preview condition. In later reading measures, a benefit for the plausible unrelated preview condition was not observed. In a second experiment, we asked questions that probed whether the reader encoded the preview or target. Readers were more likely to report the preview when they had skipped the word and not regressed to it, and when the preview was plausible. Thus, under certain circumstances, the preview word is processed to a high level of representation (i.e., semantic plausibility) regardless of its relationship to the target, but its influence on reading is relatively short-lived, being replaced by the target word, when fixated. |
Elizabeth R. Schotter; Mallorie Leinenger Reversed preview benefit effects: Forced fixations emphasize the importance of parafoveal vision for efficient reading Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 42, no. 12, pp. 2039–2067, 2016. @article{Schotter2016, Current theories of eye movement control in reading posit that processing of an upcoming parafoveal preview word is used to facilitate processing of that word once it is fixated (i.e., as a foveal target word). This preview benefit is demonstrated by shorter fixation durations in the case of valid (i.e., identical or linguistically similar) compared with invalid (i.e., dissimilar) preview conditions. However, we suggest that processing of the preview can directly influence fixation behavior on the target, independent of similarity between them. In Experiment 1, unrelated high and low frequency words were used as orthogonally crossed previews and targets and we observed a reversed preview benefit for low frequency targets—shorter fixation durations with an invalid, higher frequency preview compared with a valid, low frequency preview. In Experiment 2, the target words were replaced with orthographically legal and illegal nonwords and we found a similar effect of preview frequency on fixation durations on the targets, as well as a bimodal distribution in the illegal nonword target conditions with a denser early peak for high than low frequency previews. In Experiment 3, nonwords were used as previews for high and low frequency targets, replicating standard findings that “denied” preview increases fixation durations and the influence of target properties. These effects can be explained by forced fixations, cases in which fixations on the target were shortened as a consequence of the timing of word recognition of the preview relative to the time course of saccade programming to that word from the prior one. That is, the preview word was (at least partially) recognized so that it should have been skipped, but the word could not be skipped because the saccade to that word was in a nonlabile stage. In these cases, the system preinitiates the subsequent saccade off the upcoming word to the following word and the intervening fixation is short. |
Jillian M. Schuh; Inge Marie Eigsti; Daniel Mirman Discourse comprehension in autism spectrum disorder: Effects of working memory load and common ground Journal Article In: Autism Research, vol. 9, no. 12, pp. 1340–1352, 2016. @article{Schuh2016, Pragmatic language impairments are nearly universal in autism spectrum disorders (ASD). Discourse requires that we monitor information that is shared or mutually known, called "common ground." While many studies have examined the role of Theory of Mind (ToM) in such impairments, few have examined working memory (WM). Common ground impairments in ASD could reflect limitations in both WM and ToM. This study explored common ground use in youth ages 8-17 years with high-functioning ASD (n = 13) and typical development (n = 22); groups did not differ on age, gender, IQ, or standardized language. We tracked participants' eye movements while they performed a discourse task in which some information was known only to the participant (e.g., was privileged; a manipulation of ToM). In addition, the amount of privileged information varied (a manipulation of WM). All participants were slower to fixate the target when considering privileged information, and this effect was greatest during high WM load trials. Further, the ASD group was more likely to fixate competing (non-target) shapes. Predictors of fixation patterns included ASD symptomatology, language ability, ToM, and WM. Groups did not differ in ToM. Individuals with better WM fixated the target more rapidly, suggesting an association between WM capacity and efficient discourse. In addition to ToM knowledge, WM capacity constrains common ground representation and impacts pragmatic skills in ASD. Social impairments in ASD are thus associated with WM capacity, such that deficits in domain-general, nonsocial processes such as WM exert an influence during complex social interactions. |
Sarah Schuster; Stefan Hawelka; Florian Hutzler; Martin Kronbichler; Fabio Richlan Words in context: The effects of length, frequency, and predictability on brain responses during natural reading Journal Article In: Cerebral Cortex, vol. 26, no. 10, pp. 3889–3904, 2016. @article{Schuster2016, Word length, frequency, and predictability count among the most influential variables during reading. Their effects are well-documented in eye movement studies, but pertinent evidence from neuroimaging primarily stem from single-word presentations. We investigated the effects of these variables during reading of whole sentences with simultaneous eye-tracking and functional magnetic resonance imaging (fixation-related fMRI). Increasing word length was associated with increasing activation in occipital areas linked to visual analysis. Additionally, length elicited a U-shaped modulation (i.e., least activation for medium-length words) within a brain stem region presumably linked to eye movement control. These effects, however, were diminished when accounting for multiple fixation cases. Increasing frequency was associated with decreasing activation within left inferior frontal, superior parietal, and occipito-temporal regions. The function of the latter region-hosting the putative visual word form area-was originally considered as limited to sublexical processing. An exploratory analysis revealed that increasing predictability was associated with decreasing activation within middle temporal and inferior frontal regions previously implicated in memory access and unification. The findings are discussed with regard to their correspondence with findings from single-word presentations and with regard to neurocognitive models of visual word recognition, semantic processing, and eye movement control during reading. |
Martijn J. Schut; Jasper H. Fabius; Stefan Van Stigchel; Stefan Van der Stigchel Investigating the parameters of transsaccadic memory: inhibition of return impedes information acquisition near a saccade target Journal Article In: Visual Cognition, vol. 24, no. 2, pp. 141–154, 2016. @article{Schut2016, A limited amount of visual information is retained between saccades, which is subsequently stored into a memory system, such as transsaccadic memory. Since the capacity of transsaccadic memory is limited, selection of information is crucial. Selection of relevant information is modulated by attentional processes such as the presaccadic shift of attention. This involuntary shift of attention occurs prior to execution of the saccade and leads to information acquisition at an intended saccade target. The aim of the present study was to investigate the influence that another attentional effect, inhibition of return (IOR), has on the information that gets stored into transsaccadic memory. IOR is the phenomenon where participants are slower to respond to a cue at a previously attended location. To this end, we used a transsaccadic memory paradigm in which stimuli, oriented on a horizontal axis relative to saccade direction, are only visible to the participant before executing a saccade. Previous research showed that items in close proximity to a saccade target are likely to be reported more accurately. In our current study, participants were cued to fixate one of the stimulus locations and subsequently refixated the centre fixation point before executing the transsaccadic memory task. Results indicate that information at a location near a saccade landing point is less likely to be acquired into transsaccadic memory when this location was previously associated with IOR. Furthermore, we found evidence which implicates a reduction of the overall amount of elements retained in transsaccadic memory when a location near a saccade target is associated with IOR. These results suggest that the presaccadic shift of attention may be modulated by IOR and thereby reduces information acquisition by transsaccadic memory. |
Alexander C. Schütz; Pascal Mamassian; Alexander C. Schu; Pascal Mamassian; Alexander C. Schütz; Pascal Mamassian Early, local motion signals generate directional preferences in depth ordering of transparent motion Journal Article In: Journal of Vision, vol. 16, no. 10, pp. 1–20, 2016. @article{Schuetz2016, Superposition of two dot clouds moving in different directions results in the perception of two transparent layers. Despite the ambiguous depth order of the layers, there are consistent preferences to perceive the layer, which is moving either rightward or downward in front of the other layer. Here we investigated the origin of these depth order biases. For this purpose, we measured the interaction with stereoscopic disparity and the influence of global and local motion properties. Motion direction and stereoscopic disparity were equally effective in determining depth order at a disparity of one arcmin. Global motion properties, such as the aperture location in the visual field or the aperture's motion direction did not affect directional biases. Local motion properties however were effective. When the moving elements were oriented lines rather than dots, the directional biases were shifted towards the direction orthogonal to the lines rather than the actual motion direction of the lines. Therefore, depth order was determined before the aperture problem was fully resolved. Varying the duration of the stimuli, we found that the time constant of the aperture problem was much lower for depth order than for perceived motion direction. Altogether, our results indicate that depth order is determined in one shot on the basis of an early motion signal, while perceived motion direction is continuously updated. Thus, depth ordering in transparent motion appears to be a surprisingly fast process, that relies on early, local motion signals and that precedes high-level motion analysis. |
Florian Schwarz False but slow: Evaluating statements with Non-referring definites Journal Article In: Journal of Semantics, vol. 33, pp. 177–214, 2016. @article{Schwarz2016, One central debate in the analysis of definite descriptions concerns the truth-value of sentences where there is no entity that meets the description in the definite. Classical Russellian accounts predict them to be plain false, whereas presuppositional accounts predict them to be infelicitous. Recent discussions have homed in on the factors that affect actual judgment behaviour in relation to the underlying status posited by different accounts. This article presents experimental evidence for a presuppositional view based on response times for judging statements with non-referring definites to be ‘false', which were longer relative to control statements where existence was asserted. I discuss the theoretical implications ofthese results, as well as of other findings from the literature, arguing that they support a presuppositional view of definites that sees the existence presupposition as conventionally encoded. The article also makes a methodological contribution, as systematic evidence on speakers' judgments in these cases turns out to be hard to come by. Finally, the results inform the more general issue of the online processes involved in the interpretation of presupposed, as opposed to asserted, content. |
Philipp Schwedhelm; B. Suresh Krishna; Stefan Treue An extended normalization model of attention accounts for feature-based attentional enhancement of both response and coherence gain Journal Article In: PLoS Computational Biology, vol. 12, no. 12, pp. e1005225, 2016. @article{Schwedhelm2016, Paying attention to a sensory feature improves its perception and impairs that of others. Recent work has shown that a Normalization Model of Attention (NMoA) can account for a wide range of physiological findings and the influence of different attentional manipulations on visual performance. A key prediction of the NMoA is that attention to a visual feature like an orientation or a motion direction will increase the response of neurons preferring the attended feature (response gain) rather than increase the sensory input strength of the attended stimulus (input gain). This effect of feature-based attention on neuronal responses should translate to similar patterns of improvement in behavioral performance, with psychometric functions showing response gain rather than input gain when attention is directed to the task-relevant feature. In contrast, we report here that when human subjects are cued to attend to one of two motion directions in a transparent motion display, attentional effects manifest as a combination of input and response gain. Further, the impact on input gain is greater when attention is directed towards a narrow range of motion directions than when it is directed towards a broad range. These results are captured by an extended NMoA, which either includes a stimulus-independent attentional contribution to normalization or utilizes direction-tuned normalization. The proposed extensions are consistent with the feature-similarity gain model of attention and the attentional modulation in extrastriate area MT, where neuronal responses are enhanced and suppressed by attention to preferred and non-preferred motion directions respectively. |
Caspar M. Schwiedrzik; Benjamin Bernstein; Lucia Melloni Motion along the mental number line reveals shared representations for numerosity and space Journal Article In: eLife, vol. 5, pp. 1–18, 2016. @article{Schwiedrzik2016, Perception of number and space are tightly intertwined. It has been proposed that this is due to ‘cortical recycling', where numerosity processing takes over circuits originally processing space. Do such ‘recycled' circuits retain their original functionality? Here, we investigate interactions between numerosity and motion direction, two functions that both localize to parietal cortex. We describe a new phenomenon in which visual motion direction adapts nonsymbolic numerosity perception, giving rise to a repulsive aftereffect: motion to the left adapts small numbers, leading to overestimation of numerosity, while motion to the right adapts large numbers, resulting in underestimation. The reference frame of this effect is spatiotopic. Together with the tuning properties of the effect this suggests that motion direction-numerosity cross-adaptation may occur in a homolog of area LIP. ‘Cortical recycling' thus expands but does not obliterate the functions originally performed by the recycled circuit, allowing for shared computations across domains. |
Graham G. Scott; Christopher J. Hand Motivation determines Facebook viewing strategy: An eye movement analysis Journal Article In: Computers in Human Behavior, vol. 56, pp. 267–280, 2016. @article{Scott2016, Individuals' Social Networking Site (SNS) profiles are central to online impression formation. Distinct profile elements (e.g., Profile Picture) experimentally manipulated in isolation can alter perception of profile owners, but it is not known which elements are focused on and attributed most importance when profiles are viewed naturally. The current study recorded the eye movement behaviour of 70 participants who viewed experimenter-generated Facebook timelines of male and female targets carefully controlled for content. Participants were instructed to process the targets either as potential friends or as potential employees. Target timelines were delineated into Regions of Interest (RoIs) prior to data collection. We found pronounced effects of target gender, viewer motivation and interactions between these factors on processing. Global processing patterns differed based on whether a 'social' or a 'professional' viewing motivation was used. Both patterns were distinct to the 'F'-shaped patterns observed in previous research. When viewing potential employees viewers focused on the text content of timelines and when viewing potential friends image content was more important. Viewing patterns provide insight into the characteristics and abilities of targets most valued by viewers with distinct motivations. These results can inform future research, and allow new perspectives on previous findings. |
Mustafa Seckin; M. Marsel Mesulam; Alfred W. Rademaker; Joel L. Voss; Sandra Weintraub; Emily J. Rogalski; Robert S. Hurley Eye movements as probes of lexico-semantic processing in a patient with primary progressive aphasia Journal Article In: Neurocase, vol. 22, no. 1, pp. 65–75, 2016. @article{Seckin2016, Eye movement trajectories during a verbally cued object search task were used as probes of lexico-semantic associations in an anomic patient with primary progressive aphasia. Visual search was normal on trials where the target object could be named but became lengthy and inefficient on trials where the object failed to be named. The abnormality was most profound if the noun denoting the object could not be recognized. Even trials where the name of the target object was recognized but not retrieved triggered abnormal eye movements, demonstrating that retrieval failures can have underlying associative components despite intact comprehension of the corresponding noun. |
Mustafa Seckin; M. Marsel Mesulam; Joel L. Voss; Wei Huang; Emily J. Rogalski; Robert S. Hurley Am I looking at a cat or a dog? Gaze in the semantic variant of primary progressive aphasia is subject to excessive taxonomic capture Journal Article In: Journal of Neurolinguistics, vol. 37, pp. 68–81, 2016. @article{Seckin2016a, Object naming impairments or anomias are the most frequent symptom in aphasia, and can be caused by a variety of underlying neurocognitive mechanisms. Anomia in neurodegenerative or primary progressive aphasias (PPA) often appears to be based on taxonomic blurring of word meaning: words such as "dog" and "cat" are still recognized generically as referring to animals, but are no longer conceptually differentiated from each other, leading to coordinate errors in word-object matching. This blurring is the hallmark symptom of the "semantic variant" of PPA, who invariably show focal atrophy in the left anterior temporal lobe. In this study we used eye tracking to characterize information processing online (in real time) as non-aphasic controls, semantic and non-semantic PPA participants completed a word-to-object matching task. All participants (including controls) showed taxonomic capture of gaze, spending more time viewing foils that were from the same category as the target compared to unrelated foils, but capture was more extreme in the semantic PPA group. The semantic group showed heightened capture even on trials where they ultimately pointed to the correct target, demonstrating the superiority of eye movements over traditional testing methods in detecting subtle processing impairments. Heightened capture was primarily driven by a tendency to direct gaze back and forth, repeatedly, between a set of related foils on each trial, a behavior almost never shown by controls or non-semantic participants. This suggests semantic PPA participants were accumulating and weighing evidence for a probabilistic rather than definitive mapping between the noun and several candidate objects. Neurodegeneration in PPA thus appears to distort lexical concepts prior to extinguishing them altogether, causing uncertainty in recognition and word-object matching. |
Katrine Sand; Thomas Habekost; Anders Petersen; Randi Starrfelt The Word Superiority Effect in central and peripheral vision Journal Article In: Visual Cognition, vol. 24, no. 4, pp. 293–303, 2016. @article{Sand2016, The Word Superiority Effect (WSE) is a well-known phenomenon in reading research, where words are reported more accurately than single letters or non-words. We report two experiments that investigate the WSE in the central and peripheral visual field, as well as laterality differences in the perception of words and letters, using methods based on the Theory of Visual Attention. The results show a WSE in the central visual field, reflected in mean scores, perception thresholds, and processing speed, whereas the effect is eliminated or reversed in the periphery. This may be caused by crowding, which prevents lexical analysis of a word in the periphery. We conclude that perception of words and letters differs according to location in the visual field. Linking our results to previous studies of crowding effects in patients with reading impairments, we hypothesize that similar mechanisms may limit normal word peripheral processing. |
Joseph L. Sanguinetti; Mary A. Peterson A behavioral task sets an upper bound on the time required to access object memories before object segregation Journal Article In: Journal of Vision, vol. 16, no. 15, pp. 1–16, 2016. @article{Sanguinetti2016, Traditional theories of vision assume that object segregation occurs before access to object memories. Yet, behavioral evidence shows that familiar configuration is a prior for segregation, and electrophysiological experiments demonstrate these memories are accessed rapidly. A behavioral index of the speed of access is lacking, however. Here we asked how quickly behavior is influenced by object memories that are accessed in the course of object segregation. We investigated whether access to object memories on the groundside of a border can slow behavior during a rapid categorization task. Participants viewed two silhouettes that depicted a real-world and a novel object. Their task was to saccade toward the real-world object as quickly as possible. Half of the nontarget novel objects were ambiguous in that a portion of a real-world object was suggested, but not consciously perceived, on the groundside of their borders. The rest of the nontargets were unambiguous.We tested whether saccadic reaction times were perturbed by the real-world objects suggested on the groundside of ambiguous novel silhouettes. In Experiments 1 and 2, saccadic reaction times were slowed when nontargets were ambiguous rather than unambiguous. Experiment 2 set an upper limit of 190 ms on the time required for object memories in grounds to influence behavior. Experiment 3 ruled out factors that could have produced longer latencies other than access to object memories. These results provide the first behavioral index of how quickly memories of objects suggested in grounds can influence behavior, placing the upper limit at 190 ms. |
Sameer Saproo; Victor Shih; David C. Jangraw; Paul Sajda Neural mechanisms underlying catastrophic failure in human-machine interaction during aerial navigation Journal Article In: Journal of Neural Engineering, vol. 13, pp. 1–12, 2016. @article{Saproo2016, Objective. We investigated the neural correlates of workload buildup in a fine visuomotor task called the boundary avoidance task (BAT). The BAT has been known to induce naturally occurring failures of human–machine coupling in high performance aircraft that can potentially lead to a crash—these failures are termed pilot induced oscillations (PIOs). Approach. We recorded EEG and pupillometry data from human subjects engaged in a flight BAT simulated within a virtual 3D environment. Main results. We find that workload buildup in a BAT can be successfully decoded from oscillatory features in the electroencephalogram (EEG). Information in delta, theta, alpha, beta, and gamma spectral bands of the EEG all contribute to successful decoding, however gamma band activity with a lateralized somatosensory topography has the highest contribution, while theta band activity with a fronto-central topography has the most robust contribution in terms of real-world usability. We show that the output of the spectral decoder can be used to predict PIO susceptibility. We also find that workload buildup in the task induces pupil dilation, the magnitude of which is significantly correlated with the magnitude of the decoded EEG signals. These results suggest that PIOs may result from the dysregulation of cortical networks such as the locus coeruleus (LC)—anterior cingulate cortex (ACC) circuit. Significance. Our findings may generalize to similar control failures in other cases of tight manmachine coupling where gains and latencies in the control system must be inferred and compensated for by the human operators. A closed-loop intervention using neurophysiological decoding of workload buildup that targets the LC-ACC circuit may positively impact operator performance in such situations. |
Arup Sarma; Nicolas Y. Masse; Xiao-Jing Wang; David J. Freedman Task-specific versus generalized mnemonic representations in parietal and prefrontal cortices Journal Article In: Nature Neuroscience, vol. 19, no. 1, pp. 143–149, 2016. @article{Sarma2016, Our ability to learn a wide range of behavioral tasks is essential for responding appropriately to sensory stimuli according to behavioral demands, but the underlying neural mechanism has been rarely examined by neurophysiological recordings in the same subjects across learning. To understand how learning new behavioral tasks affects neuronal representations, we recorded from posterior parietal cortex (PPC) before and after training on a visual motion categorization task. We found that categorization training influenced cognitive encoding in PPC, with a marked enhancement of memory-related delay-period encoding during the categorization task that was absent during a motion discrimination task before categorization training. In contrast, the prefrontal cortex (PFC) exhibited strong delay-period encoding during both discrimination and categorization tasks. This reveals a dissociation between PFC's and PPC's roles in working memory, with general engagement of PFC across multiple tasks, in contrast with more task-specific mnemonic encoding in PPC. |
Kyle C. Scherr; Stephen J. Agauas; Jane Ashby The text matters: Eye movements reflect the cognitive processing of interrogation rights Journal Article In: Applied Cognitive Psychology, vol. 30, no. 2, pp. 234–241, 2016. @article{Scherr2016, Suspects' decisions to waive or invoke interrogation rights have considerable impact on whether subsequent interrogations ensue, self-incriminating information is offered, and in the case of innocent suspects, wrongful convictions occur. Although interrogation warnings differ in their text characteristics, empirically examining the influence of these text differences on suspects' ability to process and comprehend their rights has largely been neglected, which is especially problematic for vulnerable populations. Using a novel approach, we monitored the eye movements of 60 juveniles as they silently read different versions of Miranda warnings in order to investigate the relationship among text characteristics, processing difficulty, and comprehension problems. Results indicated that text characteristics were associated with processing difficulties and these processing difficulties were strongly correlated with comprehension of the warnings. Along with advancing basic and applied research programs, this approach can inform policy decisions and benefit vulnerable populations whose comprehension of interrogation rights is encumbered by legalese. |
Anne Schienle; Andreas Gremsl; Sonja Übel; Christof Körner Testing the effects of a disgust placebo with eye tracking Journal Article In: International Journal of Psychophysiology, vol. 101, pp. 69–75, 2016. @article{Schienle2016a, Previous neuroimaging research showed that a disgust placebo (inert pill presented with the verbal suggestion of disgust relief) reduced visual cortex activation during the viewing of disgust-inducing images. In order to investigate whether this effect of automatic emotion regulation was associated with changed visual scanning patterns of the pictures, we conducted two eye tracking experiments. In the first study, 23 women underwent a retest design during which they passively viewed images depicting disgusting, fear-eliciting, neutral items and fractals both with, and without a placebo. The placebo provoked a substantial decrease in experienced disgust. Although none of the recorded eye movement parameters (number of fixations, fixation duration, saccade amplitude, blinking rate) showed placebo-related changes, placebo effects were suggested by an analysis of spatial fixation patterns. In the second study, which focused on attentional (dis)engagement, 46 women looked at two pictures which were presented side-by-side on the screen. These picture pairs (disgust-neutral, neutral-neutral) were once viewed with and once without a placebo. The placebo again provoked a marked decrease of experienced disgust and enhanced the number of fixations for disgusting images. This change might reflect a greater willingness of the participants to view these stimuli while on the placebo. |
Anne Schienle; Sonja Übel; Andreas Gremsl; Florian Schöngassner; Christof Körner Disgust proneness and the perception of disgust-evoking pictures: An eye-tracking experiment Journal Article In: Journal of Psychophysiology, vol. 30, no. 3, pp. 124–129, 2016. @article{Schienle2016, Disgust has been conceptualized as an emotion which promotes disease-avoidance behavior. The present eye-tracking experiment investigated whether disgust-evoking stimuli provoke specific eye movements and pupillary responses. Forty-three women viewed images depicting disgusting, fear-eliciting, neutral items and fractals while their eye movements (fixation duration and frequency, blinking rate, saccade amplitude) and pupil size were recorded. Disgust and fear ratings for the pictures as well as trait disgust and trait anxiety were assessed. The disgust pictures evoked the target emotion specifically and prompted characteristic scanning patterns. The participants made more and shorter fixations when looking at the repulsive pictures compared to all other categories. Moreover, state and trait disgust of the participants correlated negatively with their pupil size during disgust elicitation. Our data point to a disgust-specific visual exploration behavior, which possibly supports the fast identification of health-threatening aspects of a stimulus. |
Ricarda Schmidt; Patrick Lüthold; Rebekka Kittel; Anne Tetzlaff; Anja Hilbert Visual attentional bias for food in adolescents with binge-eating disorder Journal Article In: Journal of Psychiatric Research, vol. 80, pp. 22–29, 2016. @article{Schmidt2016, Evidence suggests that adults with binge-eating disorder (BED) are prone of having their attention interfered by food cues, and that food-related attentional biases are associated with calorie intake and eating disorder psychopathology. For adolescents with BED experimental evidence on attentional processing of food cues is lacking. Using eye-tracking and a visual search task, the present study examined visual orienting and disengagement processes of food in youth with BED. Eye-movement data and reaction times were recorded in 25 adolescents (12-20 years) with BED and 25 controls (CG) individually matched for sex, age, body mass index, and socio-economic status. During a free exploration paradigm, the BED group showed a greater gaze duration bias for food images than the CG. Groups did not differ in gaze direction biases. In a visual search task, the BED group showed a greater detection bias for food targets than the CG. Group differences were more pronounced for personally attractive than unattractive food images. Regarding clinical associations, only in the BED group the gaze duration bias for food was associated with increased hunger and lower body mass index, and the detection bias for food targets was associated with greater reward sensitivity. The study provided first evidence of an attentional bias to food in adolescents with BED. However, more research is needed for further specifying disengagement and orienting processes in adolescent BED, including overt and covert attention, and their prospective associations with binge-eating behaviors and associated psychopathology. |
Mary Vining Radomski; Mattie Anheluk; M. Penny Bartzen; Joette Zola In: American Journal of Occupational Therapy, vol. 70, no. 3, pp. 1–9, 2016. @article{Radomski2016, OBJECTIVE: To determine the effectiveness of interventions addressing cognitive impairments to improve occupational performance for people with traumatic brain injury. METHOD: A total of 37 studies met inclusion criteria: 9 Level I systematic reviews, 14 Level I studies, 5 Level II studies, and 9 Level III studies. RESULTS: Strong evidence supports use of direct attention training, dual-task training, and strategy training to optimize executive functioning, encoding, and use of memory compensations, including assistive technology. However, in most studies, occupational performance was a secondary outcome, if it was evaluated at all. CONCLUSION: Although evidence supports many intervention approaches used by occupational therapy practitioners to address cognitive impairments of adults with traumatic brain injury, more studies are needed in which occupational performance is the primary outcome of cognitive intervention. |
Ana Radonjić; David H. Brainard The nature of instructional effects in color constancy Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 42, no. 6, pp. 847–865, 2016. @article{Radonjic2016, The instructions subjects receive can have a large effect on experimentally measured color constancy, but the nature of these effects and how their existence should inform our understanding of color perception remains unclear. We used a factorial design to measure how instructional effects on constancy vary with experimental task and stimulus set. In each of 2 experiments, we employed both a classic adjustment- based asymmetric matching task and a novel color selection task. Four groups of naive subjects were instructed to make adjustments/selections based on (a) color (neutral instructions); (b) the light reaching the eye (physical spectrum instructions); (c) the actual surface reflectance of an object (objective reflectance instructions); or (d) the apparent surface reflectance of an object (apparent reflectance instructions). Across the 2 experiments we varied the naturalness of the stimuli. We find clear interac- tions between instructions, task, and stimuli. With simplified stimuli (Experiment 1), instructional effects were large and the data revealed 2 instruction-dependent patterns. In 1 (neutral and physical spectrum instructions) constancy was low, intersubject variability was also low, and adjustment-based and selection-based constancy were in agreement. In the other (reflectance instructions) constancy was high, intersubject variability was large, adjustment-based constancy deviated from selection-based constancy and for some subjects selection-based constancy increased across sessions. Similar patterns held for naturalistic stimuli (Experiment 2), although instructional effects were smaller. We interpret these 2 patterns as signatures of distinct task strategies—1 is perceptual, with judgments based primarily on the perceptual representation of color; the other involves explicit instruction-driven reasoning. |
Jenni Radun; Mikko Nuutinen; Tuomas Leisti; Jukka Häkkinen Individual differences in image-quality estimations: Estimation rules and viewing strategies Journal Article In: ACM Transactions on Applied Perception, vol. 13, no. 3, pp. 1–22, 2016. @article{Radun2016, Subjective image-quality estimation with high-quality images is often a preference-estimation task. Preferences are subjective, and individual differences exist. Individual differences are also seen in the eye movements of people. A task's subjectivity can result from people using different rules as a basis for their estimation. Using two studies, we investigated whether different preference-estimation rules are related to individual differences in viewing behaviour by examining the process of preference es-timation of high-quality images. The estimation rules were measured from free subjective reports on important quality-related attributes (Study 1) and from estimations of the attributes' importance in preference estimation (Study 2). The free reports showed that the observers used both feature-based image-quality attributes (e.g., sharpness, illumination) and abstract attributes, which include an interpretation of the image features (e.g., atmosphere and naturalness). In addition, the observers were classified into three viewing-strategy groups differing in fixation durations in both studies. These groups also used different estimation rules. In both studies, the group with medium-length fixations differed in their estimation rules from the other groups. In Study 1, the observers in this group used more abstract attributes than those in the other groups; in Study 2, they con-sidered atmosphere to be a more important image feature. The study shows that individual differences in a quality-estimation task are related to both estimation rules and viewing strategies, and that the difference is related to the level of abstraction of the estimations. |
Pavan Ramkumar; Bruce C. Hansen; Sebastian Pannasch; Lester C. Loschky Visual information representation and rapid-scene categorization are simultaneous across cortex: An MEG study Journal Article In: NeuroImage, vol. 134, pp. 295–304, 2016. @article{Ramkumar2016, Perceiving the visual world around us requires the brain to represent the features of stimuli and to categorize the stimulus based on these features. Incorrect categorization can result either from errors in visual representation or from errors in processes that lead to categorical choice. To understand the temporal relationship between the neural signatures of such systematic errors, we recorded whole-scalp magnetoencephalography (MEG) data from human subjects performing a rapid-scene categorization task. We built scene category decoders based on (1) spatiotemporally resolved neural activity, (2) spatial envelope (SpEn) image features, and (3) behavioral responses. Using confusion matrices, we tracked how well the pattern of errors from neural decoders could be explained by SpEn decoders and behavioral errors, over time and across cortical areas. Across the visual cortex and the medial temporal lobe, we found that both SpEn and behavioral errors explained unique variance in the errors of neural decoders. Critically, these effects were nearly simultaneous, and most prominent between 100 and 250 ms after stimulus onset. Thus, during rapid-scene categorization, neural processes that ultimately result in behavioral categorization are simultaneous and co-localized with neural processes underlying visual information representation. |
Meike Ramon; Sébastien Miellet; Anna M. Dzieciol; Boris Nikolai Konrad; Martin Dresler; Roberto Caldara Super-memorizers are not super-recognizers Journal Article In: PLoS ONE, vol. 11, no. 3, pp. e0150972, 2016. @article{Ramon2016, Humans have a natural expertise in recognizing faces. However, the nature of the interaction between this critical visual biological skill and memory is yet unclear. Here, we had the unique opportunity to test two individuals who have had exceptional success in the World Memory Championships, including several world records in face-name association memory. We designed a range of face processing tasks to determine whether superior/expert face memory skills are associated with distinctive perceptual strategies for processing faces. Superior memorizers excelled at tasks involving associative face-name learning. Nevertheless, they were as impaired as controls in tasks probing the efficiency of the face system: face inversion and the other-race effect. Super memorizers did not show increased hippocampal volumes, and exhibited optimal generic eye movement strategies when they performed complex multi-item face-name associations. Our data show that the visual computations of the face system are not malleable and are robust to acquired expertise involving extensive training of associative memory. |
Matthew T. Rätsep; Andrew F. Hickman; Brandon Maser; Jessica Pudwell; Graeme N. Smith; Donald Brien; Patrick W. Stroman; Michael A. Adams; James N. Reynolds; B. Anne Croy; Angelina Paolozza Impact of preeclampsia on cognitive function in the offspring Journal Article In: Behavioural Brain Research, vol. 302, pp. 175–181, 2016. @article{Raetsep2016, Preeclampsia (PE) is a significant clinical disorder occurring in 3-5% of all human pregnancies. Offspring of PE pregnancies (PE-F1s) are reported to exhibit greater cognitive impairment than offspring from uncomplicated pregnancies. Previous studies of PE-F1 cognitive ability used tests with bias that do not assess specific cognitive domains. To improve cognitive impairment classification in PE-F1s we used standardized clinical psychometric testing and eye tracking studies of saccadic eye movements. PE-F1s ( n= 10) and sex/age matched control participants ( n= 41 for psychometrics; n= 59 for eye-tracking) were recruited from the PE-NET study or extracted from the NeuroDevNet study databases. Participants completed a selected array of psychometric tests which assessed executive function, working memory, attention, inhibition, visuospatial processing, reading, and math skills. Eye-tracking studies included the prosaccade, antisaccade, and memory-guided tasks. Psychometric testing revealed an impairment in working memory among PE-F1s. Eye-tracking studies revealed numerous impairments among PE-F1s including additional saccades required to reach the target, poor endpoint accuracy, and slower reaction time. However, PE-F1s made faster saccades than controls, and fewer sequence errors in the memory-guided task. Our study provides a comprehensive assessment of cognitive function among PE-F1s. The development of PE may be seen as an early predictor of reduced cognitive function in children, specifically in working memory and oculomotor control. Future studies should extended to a larger study populations, and may be valuable for early studies of children born to pregnancies complicated by other disorders, such as gestational diabetes or intrauterine growth restriction. |
Anne K. Rau; Kristina Moll; Korbinian Moeller; Stefan Huber; Margaret J. Snowling; Karin Landerl Same same, but different: Word and sentence reading in German and English Journal Article In: Scientific Studies of Reading, vol. 20, no. 3, pp. 203–219, 2016. @article{Rau2016, The current study compared eye fixation patterns during word and sentence processing in a consistent and an inconsistent alphabetic orthography. German and English children as well as adults matched on word reading ability read matched sentences while their eye fixation behavior was recorded. Results indicated that German children read in a more small-unit plodder-like style with more diligent first-pass reading and less rereading. In contrast, English children read in a more large-unit explorer-like style with a greater tendency to skip words, and more regressions. It is important that these cross-linguistic processing differences largely persisted in the adult readers. Orthographic consistency thus influences both local word recognition and global sentence processing in developing and skilled readers. |
Ralph S. Redden; Matthew D. Hilchey; Raymond M. Klein Peripheral stimuli generate different forms of inhibition of return when participants make prosaccades versus antisaccades to them Journal Article In: Attention, Perception, and Psychophysics, vol. 78, no. 8, pp. 2283–2291, 2016. @article{Redden2016, Inhibition of return (IOR) is usually viewed as an inhibitory aftermath ofvisual orienting typically seen in the form ofslower responses to targets presented in a previously oriented to location. As shown by Taylor and Klein (2000. Journal of Experimental Psychology: Human Perception and Performance, 26, 1639–1656), the nature ofthe inhibitory effects resulting from an uninformative cue seemto be contingent on the activation state ofthe oculomotor system. Herewe contrast target discrimination performance following either a prosaccade or antisaccade in the spatial cueing paradigm. Our findings suggest that the level of activation of the reflexive oculomotor system determines the dynamics of the inhibitory effect, wherein an effect nearer to the input end of processing is observed when the reflexive oculomotor system is actively suppressed, and an effect nearer to the output end ofprocessing is observedwhen the reflexive oculomotor system is actively engaged. These effects interact differently with the Simon effect—providing converging evidence that they are dissociable inhibitory phenomena. |
Paul Roux; Pauline Smith; Christine Passerieux; Franck Ramus Preserved implicit mentalizing in schizophrenia despite poor explicit performance: Evidence from eye tracking Journal Article In: Scientific Reports, vol. 6, pp. 34728, 2016. @article{Roux2016, Schizophrenia has been characterized by an impaired mentalizing. It has been suggested that distinguishing implicit from explicit processes is crucial in social cognition, and only the latter might be affected in schizophrenia. Two other questions remain open: (1) Is schizophrenia characterized by an hypo- or hyper attribution of intentions? (2) Is it characterized by a deficit in the attribution of intention or of contingency? To test these three questions, spontaneous mentalizing was tested in 29 individuals with schizophrenia and 29 control subjects using the Frith-Happé animations, while eye movements were recorded. Explicit mentalizing was measured from participants' verbal descriptions and was contrasted with implicit mentalizing measured through eye tracking. As a group, patients made less accurate and less intentional descriptions of the goal-directed and theory of mind animations. No group differences were found in the attribution of contingency. Eye tracking results revealed that patients and controls showed a similar modulation of eye movements in response to the mental states displayed in the Frith-Happé animations. To conclude, in this paradigm, participants with schizophrenia showed a dissociation between explicit and implicit mentalizing, with a decrease in the explicit attribution of intentions, whereas their eye movements suggested a preserved implicit perception of intentions. |
Annie Roy-Charland; Melanie Perron; Krystle-Lee Turgeon; Nichola Hoffman; Justin A. Chamberland The link between text difficulty, reading speed and exploration of printed text during shared book reading Journal Article In: Reading and Writing, vol. 29, no. 4, pp. 731–743, 2016. @article{RoyCharland2016, In the current study the reading speed of the narration and the difficulty of the text was manipulated and links were explored with children's attention to the printed text in shared book reading. Thirty-nine children (24 grade 1 and 15 grade 2) were presented easy and difficult books at slow (syllable by syllable) or fast (adult reading speed) pace while their eye movements were monitored. Results revealed an interaction between speed and difficulty. For the easy and difficult books, children spent more time and made more fixations on the printed text when it was presented at slow speed than at fast speed. However, at fast speed, children spend more time and made more fixations on the text of the easy rather than the difficult books, but at slow speed no difference was observed. In addition, at slow speed positive correlations were observed between attention to print and letter knowledge and word reading skills. Results provide important information for the practice of shared book reading suggesting that to increase attention to print, speed should be reduced. Future research should investigate the role of reading speed on reading related outcomes such as discourse comprehension and children's interest in reading activities. |
Cristina Rubino; Sherryse L. Corrow; Jeffrey C. Corrow; Brad Duchaine; Jason J. S. Barton Word and text processing in developmental prosopagnosia Journal Article In: Cognitive Neuropsychology, vol. 33, no. 5-6, pp. 315–328, 2016. @article{Rubino2016a, The many-to-many hypothesis proposes that visual object processing is supported by distributed circuits that overlap for different object categories. For faces and words the hypothesis posits that both posterior fusiform regions contribute to both face and visual word perception and predicts that unilateral lesions impairing one will affect the other. However, studies testing this hypothesis have produced mixed results. We evaluated visual word processing in subjects with developmental prosopagnosia, a condition linked to right posterior fusiform abnormalities. Ten developmental prosopagnosic subjects performed a word-length effect task and a task evaluating the recognition of word content across variations in text style, and the recognition of style across variations in word content. All subjects had normal word-length effects. One had prolonged sorting time for word recognition in handwritten stimuli. These results suggest that the deficit in developmental prosopagnosia is unlikely to affect visual word processing, contrary to predictions of the many-to-many hypothesis. |
Cristina Rubino; Shanna C. Yeung; Jason J. S. Barton The impact of central sparing on the word-length effect in hemianopia Journal Article In: Cognitive Neuropsychology, vol. 33, no. 7-8, pp. 353–361, 2016. @article{Rubino2016, Studies suggest that a word-length effect of up to 160 ms/letter distinguishes hemianopic dyslexia from pure alexia. However, partial preservation of central vision is common in right hemianopia, but its effects on single-word reading are unknown. Eighteen healthy subjects read single words with a gaze-contingent right hemianopia simulation that varied the degree of central sparing. Mean reading onset time declined with small degrees of central sparing, but the word-length effect did not decrease until sparing exceeded 3.15 degrees . We next evaluated the effects of font size. Effects of central sparing were constant when expressed in number of letters, with a decline in word-length effect beginning as sparing approached 4 letters. We conclude that the effects of central sparing on mean reading onset time and the word-length effect are distinct. We provide diagnostic word-length criteria for discriminating between pure alexia and hemianopic dyslexia with various degrees of central sparing. |
Paula Rubio-Fernández; Chris Cummins; Ye Tian Are single and extended metaphors processed differently? A test of two Relevance-Theoretic accounts Journal Article In: Journal of Pragmatics, vol. 94, pp. 15–28, 2016. @article{RubioFernandez2016, Carston (2010) proposes that metaphors can be processed via two different routes. In line with the standard Relevance-Theoretic account of loose use, single metaphors are interpreted by a local pragmatic process of meaning adjustment, resulting in the construction of an ad hoc concept. In extended metaphorical passages, by contrast, the reader switches to a second processing mode because the various semantic associates in the passage are mutually reinforcing, which makes the literal meaning highly activated relative to possible meaning adjustments. In the second processing mode the literal meaning of the whole passage is metarepresented and entertained as an 'imaginary world' and the intended figurative implications are derived later in processing. The results of three experiments comparing the interpretation of the same target expressions across literal, single-metaphorical and extended-metaphorical contexts, using self-paced reading (Experiment 1), eye-tracking during natural reading (Experiment 2) and cued recall (Experiment 3), offered initial support to Carston's distinction between the processing of single and extended metaphors. We end with a comparison between extended metaphors and allegories, and make a call for further theoretical and experimental work to increase our understanding of the similarities and differences between the interpretation and processing of different figurative uses, single and extended. |
Douglas A. Ruff; Joshua J. Alberts; Marlene R. Cohen Relating normalization to neuronal populations across cortical areas Journal Article In: Journal of Neurophysiology, vol. 116, no. 3, pp. 1375–1386, 2016. @article{Ruff2016b, Normalization, which divisively scales neuronal responses to multiple stimuli, is thought to underlie many sensory, motor, and cognitive processes. In every study where it has been investigated, neurons measured in the same brain area under identical conditions exhibit a range of normalization, ranging from suppression by nonpreferred stimuli (strong normalization) to additive responses to combinations of stimuli (no normalization; for examples, Lee and Maunsell, 2009; Busse et al., 2009). Normalization has been hypothesized to arise from interactions between neuronal populations, either in the same or different brain areas (Heeger, 1992; Carandini et al., 1997; Carandini and Heeger, 2012; Busse et al., 2009; Chance et al., 2002; Rubin et al., 2013; Rust et al., 2006; Sit et al., 2009), but current models of normalization are not mechanistic and focus on trial-averaged responses. To gain insight into the mechanisms underlying normalization, we examined interactions between neurons that exhibit different degrees of normalization. We recorded from multiple neurons in three cortical areas while rhesus monkeys viewed superimposed drifting gratings. We found that neurons showing strong normalization shared less trial-to-trial variability with other neurons in the same cortical area and more variability with neurons in other cortical areas than did units with weak normalization. Furthermore, the cortical organization of normalization was not random: neurons recorded on nearby electrodes tended to exhibit similar amounts of normalization. Together, our results suggest that normalization reflects a neuron's role in its local network and that modulatory factors like normalization share the topographic organization typical of sensory tuning properties. |
Douglas A. Ruff; Marlene R. Cohen Stimulus dependence of correlated variability across cortical areas Journal Article In: Journal of Neuroscience, vol. 36, no. 28, pp. 7546–7556, 2016. @article{Ruff2016, The way that correlated trial-to-trial variability between pairs ofneurons in the same brain area (termed spike count or noise correlation, rSC) depends on stimulus or task conditions can constrain models ofcortical circuits and ofthe computations performed by networks of neurons (Cohen and Kohn, 2011). In visual cortex, rSC tends not to depend on stimulus properties (Kohn and Smith, 2005; Huang and Lisberger, 2009) but does depend on cognitive factors like visual attention (Cohen and Maunsell, 2009; Mitchell et al., 2009). However, neurons across visual areas respond to any visual stimulus or contribute to any perceptual decision, and the way that information from multiple areas is combined to guide perception is unknown. To gain insight into these issues, we recorded simultaneously from neurons in two areas ofvisual cortex (primary visual cortex, V1, and the middle temporal area, MT) while rhesus monkeys viewed different visual stimuli in different attention conditions.Wefound that correlations betweenneurons in different areasdependonstimulusandattention conditions in very different ways than do correlations within an area. Correlations across, but not within, areas depend on stimulus direction and the presence ofa second stimulus, and attention has opposite effects on correlations within and across areas. This observed pattern ofcross-area correlations is predicted bya normalization model whereMTunits sumV1 inputs that are passed through a divisive nonlinearity. Together, our results provide insight into how neurons in different areas interact and constrain models of the neural computations performed across cortical areas. |
Douglas A. Ruff; Marlene R. Cohen Attention increases spike count correlations between visual cortical areas Journal Article In: Journal of Neuroscience, vol. 36, no. 28, pp. 7523–7534, 2016. @article{Ruff2016a, Visual attention, which improves perception of attended locations or objects, has long been known to affect many aspects of the responses of neuronal populations in visual cortex. There are two nonmutually exclusive hypotheses concerning the neuronal mechanisms that underlie these perceptual improvements. The first hypothesis, that attention improves the information encoded by a population of neurons in a particular cortical area, has considerable physiological support. The second hypothesis is that attention improves perception by selectively communicating relevant visual information. This idea has been tested primarily by measuring interactions between neurons on very short timescales, which are mathematically nearly independent of neuronal interactions on longer timescales. We tested the hypothesis that attention changes the way visual information is communicated between cortical areas on longer timescales by recording simultaneously from neurons in primary visual cortex (V1) and the middle temporal area (MT) in rhesus monkeys. We used two independent and complementary approaches. Our correlative experiment showed that attention increases the trial-to-trial response variability that is shared between the two areas. In our causal experiment, we electrically microstimulated V1 and found that attention increased the effect of stimulation on MT responses. Together, our results suggest that attention affects both the way visual stimuli are encoded within a cortical area and the extent to which visual information is communicated between areas on behaviorally relevant timescales. |
Nicolas Ruffieux; Meike Ramon; Junpeng Lao; Françoise Colombo; Lisa Stacchi; François-Xavier Borruat; Ettore Accolla; Jean-Marie Annoni; Roberto Caldara Residual perception of biological motion in cortical blindness Journal Article In: Neuropsychologia, vol. 93, pp. 301–311, 2016. @article{Ruffieux2016, From birth, the human visual system shows a remarkable sensitivity for perceiving biological motion. This visual ability relies on a distributed network of brain regions and can be preserved even after damage of high-level ventral visual areas. However, it remains unknown whether this critical biological skill can withstand the loss of vision following bilateral striate damage. To address this question, we tested the categorization of human and animal biological motion in BC, a rare case of cortical blindness after anoxia-induced bilateral striate damage. The severity of his impairment, encompassing various aspects of vision (i.e., color, shape, face, and object recognition) and causing blind-like behavior, contrasts with a residual ability to process motion. We presented BC with static or dynamic point-light displays (PLDs) of human or animal walkers. These stimuli were presented either individually, or in pairs in two alternative forced choice (2AFC) tasks. When confronted with individual PLDs, the patient was unable to categorize the stimuli, irrespective of whether they were static or dynamic. In the 2AFC task, BC exhibited appropriate eye movements towards diagnostic information, but performed at chance level with static PLDs, in stark contrast to his ability to efficiently categorize dynamic biological agents. This striking ability to categorize biological motion provided top-down information is important for at least two reasons. Firstly, it emphasizes the importance of assessing patients' (visual) abilities across a range of task constraints, which can reveal potential residual abilities that may in turn represent a key feature for patient rehabilitation. Finally, our findings reinforce the view that the neural network processing biological motion can efficiently operate despite severely impaired low-level vision, positing our natural predisposition for processing dynamicity in biological agents as a robust feature of human vision. |
Rachel A. Ryskin; Ranxiao Frances Wang; Sarah Brown-Schmidt Listeners use speaker identity to access representations of spatial perspective during online language comprehension Journal Article In: Cognition, vol. 147, pp. 75–84, 2016. @article{Ryskin2016, Little is known about how listeners represent another person's spatial perspective during language processing (e.g., two people looking at a map from different angles). Can listeners use contextual cues such as speaker identity to access a representation of the interlocutor's spatial perspective? In two eye-tracking experiments, participants received auditory instructions to move objects around a screen from two randomly alternating spatial perspectives (45° vs. 315° or 135° vs. 225° rotations from the participant's viewpoint). Instructions were spoken either by one voice, where the speaker's perspective switched at random, or by two voices, where each speaker maintained one perspective. Analysis of participant eye-gaze showed that interpretation of the instructions improved when each viewpoint was associated with a different voice. These findings demonstrate that listeners can learn mappings between individual talkers and viewpoints, and use these mappings to guide online language processing. |
Donghyun Ryu; David L. Mann; Bruce Abernethy; Jamie M. Poolton Gaze-contingent training enhances perceptual skill acquisition Journal Article In: Journal of Vision, vol. 16, no. 2, pp. 1–21, 2016. @article{Ryu2016, The purpose of this study was to determine whether decision-making skill in perceptual-cognitive tasks could be enhanced using a training technique that impaired selective areas of the visual field. Recreational basketball players performed perceptual training over 3 days while viewing with a gaze-contingent manipulation that displayed either (a) a moving window (clear central and blurred peripheral vision), (b) a moving mask (blurred central and clear peripheral vision), or (c) full (unrestricted) vision. During the training, participants watched video clips of basketball play and at the conclusion of each clip made a decision about to which teammate the player in possession of the ball should pass. A further control group watched unrelated videos with full vision. The effects of training were assessed using separate tests of decision-making skill conducted in a pretest, posttest, and 2-week retention test. The accuracy of decision making was greater in the posttest than in the pretest for all three intervention groups when compared with the control group. Remarkably, training with blurred peripheral vision resulted in a further improvement in performance from posttest to retention test that was not apparent for the other groups. The type of training had no measurable impact on the visual search strategies of the participants, and so the training improvements appear to be grounded in changes in information pickup. The findings show that learning with impaired peripheral vision offers a promising form of training to support improvements in perceptual skill. |
Molood S. Safavi; Samar Husain; Shravan Vasishth In: Frontiers in Psychology, vol. 7, pp. 403, 2016. @article{Safavi2016, Delaying the appearance of a verb in a noun-verb dependency tends to increase processing difficulty at the verb; one explanation for this locality effect is decay and/or interference of the noun in working memory. Surprisal, an expectation-based account, predicts that delaying the appearance of a verb either renders it no more predictable or more predictable, leading respectively to a prediction of no effect of distance or a facilitation. Recently, Husain et al (2014) suggested that when the exact identity of the upcoming verb is predictable (strong predictability), increasing argument-verb distance leads to facilitation effects, which is consistent with surprisal; but when the exact identity of the upcoming verb is not predictable (weak predictability), locality effects are seen. We investigated Husain et al.'s proposal using Persian complex predicates (CPs), which consist of a non-verbal element—a noun in the current study—and a verb. In CPs, once the noun has been read, the exact identity of the verb is highly predictable (strong predictability); this was confirmed using a sentence completion study. In two self-paced reading (SPR) and two eye-tracking (ET) experiments, we delayed the appearance of the verb by interposing a relative clause (Expt. 1 and 3) or a long PP (Expt. 2 and 4). We also included a simple Noun-Verb predicate configuration with the same distance manipulation; here, the exact identity of the verb was not predictable (weak predictability). Thus, the design crossed Predictability Strength and Distance. We found that, consistent with surprisal, the verb in the strong predictability conditions was read faster than in the weak predictability conditions. Furthermore, greater verb-argument distance led to slower reading times; strong predictability did not neutralize or attenuate the locality effects. As regards the effect of distance on dependency resolution difficulty, these four experiments present evidence in favor of working memory accounts of argument-verb dependency resolution, and against the surprisal-based expectation account of Levy (2008). However, another expectation-based measure, entropy, which was computed using the offline sentence completion data, predicts reading times in Experiment 1. We suggest that forgetting due to memory overload leads to greater entropy at the verb. |
Gerardo Salvato; Eva Z. Patai; Tayla Mccloud; Anna C. Nobre In: Cortex, vol. 82, pp. 206–216, 2016. @article{Salvato2016, Apolipoprotein (APOE) ɛ4 genotype has been identified as a risk factor for late-onset Alzheimer disease (AD). The memory system is mostly involved in AD, and memory deficits represent its key feature. A growing body of studies has focused on the earlier identification of cognitive dysfunctions in younger and older APOE ɛ4 carriers, but investigation on middle-aged individuals remains rare. Here we sought to investigate if the APOE ɛ4 genotype modulates declarative memory and its influences on perception in the middle of the life span. We tested 60 middle-aged individuals recruited according to their APOE allele variants (ɛ3/ɛ3, ɛ3/ɛ4, ɛ4/ɛ4) on a long-term memory-based orienting of attention task. Results showed that the APOE ɛ4 genotype impaired neither explicit memory nor memory-based orienting of spatial attention. Interestingly, however, we found that the possession of the ɛ4 allele broke the relationship between declarative long-term memory and memory-guided orienting of visuo-spatial attention, suggesting an earlier modulation exerted by pure genetic characteristics on cognition. These findings are discussed in light of possible accelerated brain ageing in middle-aged ɛ4-carriers, and earlier structural changes in the brain occurring at this stage of the lifespan. |
Gerardo Salvato; Eva Z. Patai; Anna C. Nobre Preserved memory-based orienting of attention with impaired explicit memory in healthy ageing Journal Article In: Cortex, vol. 74, pp. 67–78, 2016. @article{Salvato2016a, It is increasingly recognised that spatial contextual long-term memory (LTM) prepares neural activity for guiding visuo-spatial attention in a proactive manner. In the current study, we investigated whether the decline in explicit memory observed in healthy ageing would compromise this mechanism. We compared the behavioural performance of younger and older participants on learning new contextual memories, on orienting visual attention based on these learnt contextual associations, and on explicit recall of contextual memories. We found a striking dissociation between older versus younger participants in the relationship between the ability to retrieve contextual memories versus the ability to use these to guide attention to enhance performance on a target-detection task. Older participants showed significant deficits in the explicit retrieval task, but their behavioural benefits from memory-based orienting of attention were equivalent to those in young participants. Furthermore, memory-based orienting correlated significantly with explicit contextual LTM in younger adults but not in older adults. These results suggest that explicit memory deficits in ageing might not compromise initial perception and encoding of events. Importantly, the results also shed light on the mechanisms of memory-guided attention, suggesting that explicit contextual memories are not necessary. |
Carola Salvi; Emanuela Bricolo; John Kounios; Edward Bowden; Mark Beeman Insight solutions are correct more often than analytic solutions Journal Article In: Thinking and Reasoning, vol. 22, no. 4, pp. 443–460, 2016. @article{Salvi2016, How accurate are insights compared to analytical solutions? In four experiments, we investigated how participants' solving strategies influenced their solution accuracies across different types of problems, including one that was linguistic, one that was visual and two that were mixed visual-linguistic. In each experiment, participants' self-judged insight solutions were, on average, more accurate than their analytic ones. We hypothesised that insight solutions have superior accuracy because they emerge into consciousness in an all-or-nothing fashion when the unconscious solving process is complete, whereas analytic solutions can be guesses based on conscious, prematurely terminated, processing. This hypothesis is supported by the finding that participants' analytic solutions included relatively more incorrect responses (i.e., errors of commission) than timeouts (i.e., errors of omission) compared to their insight responses. |
Angelina Paolozza; Douglas P. Munoz; Donald Brien; James N. Reynolds Immediate neural plasticity involving reaction time in a saccadic eye movement task is intact in children with fetal alcohol spectrum disorder Journal Article In: Alcoholism: Clinical and Experimental Research, vol. 40, no. 11, pp. 2351–2358, 2016. @article{Paolozza2016, Background: Saccades are rapid eye movements that bring an image of interest onto the retina. Previous research has found that in healthy individuals performing eye movement tasks, the location of a previous visual target can influence performance of the saccade on the next trial. This rapid behavioral adaptation represents a form of immediate neural plasticity within the saccadic circuitry. Our studies have shown that children with fetal alcohol spectrum disorder (FASD) are impaired on multiple saccade measures. We therefore investigated these previous trial effects in typically developing children and children with FASD to measure sensory neural plasticity and how these effects vary with age and pathology. Methods: Both typically developing control children (n = 102; mean age = 10.54 +/- 3.25; 48 males) and children with FASD (n = 66; mean age = 11.85 +/- 3.42; 35 males) were recruited from 5 sites across Canada. Each child performed a visually guided saccade task. Reaction time and saccade amplitude were analyzed and then assessed based on the previous trial. Results: There was a robust previous trial effect for both reaction time and amplitude, with both the control and FASD groups displaying faster reaction times and smaller saccades during alternation trials (visual target presented on the opposite side to the previous trial). Children with FASD exhibited smaller overall mean amplitude and smaller amplitude selectively on alternation trials compared with controls. The effect of the previous trial on reaction time and amplitude did not differ across childhood and adolescent development. Conclusions: Children with FASD did not display any significant reaction time differences, despite exhibiting numerous deficits in motor and higher level cognitive control over saccades in other studies. These results suggest that this form of immediate neural plasticity in response to sensory information before saccade initiation remains intact in children with FASD. In contrast, the previous trial effect on amplitude suggests that the motor component of saccades may be affected, signifying differential vulnerability to prenatal alcohol exposure. |
Anna Antonia Pape; Markus Siegel Motor cortex activity predicts response alternation during sensorimotor decisions Journal Article In: Nature Communications, vol. 7, pp. 13098, 2016. @article{Pape2016, Our actions are constantly guided by decisions based on sensory information. The motor cortex is traditionally viewed as the final output stage in this process, merely executing motor responses based on these decisions. However, it is not clear if, beyond this role, the motor cortex itself impacts response selection. Here, we report activity fluctuations over motor cortex measured using MEG, which are unrelated to choice content and predict responses to a visuomotor task seconds before decisions are made. These fluctuations are strongly influenced by the previous trial's response and predict a tendency to switch between response alternatives for consecutive decisions. This alternation behaviour depends on the size of neural signals still present from the previous response. Our results uncover a response-alternation bias in sensorimotor decision making. Furthermore, they suggest that motor cortex is more than an output stage and instead shapes response selection during sensorimotor decision making. |
Hyojin Park; Christoph Kayser; Gregor Thut; Joachim Gross Lip movements entrain the observers' low-frequency brain oscillations to facilitate speech intelligibility Journal Article In: eLife, vol. 5, pp. 1–17, 2016. @article{Park2016, During continuous speech, lip movements provide visual temporal signals that facilitate speech processing. Here, using MEG we directly investigated how these visual signals interact with rhythmic brain activity in participants listening to and seeing the speaker. First, we investigated coherence between oscillatory brain activity and speaker's lip movements and demonstrated significant entrainment in visual cortex. We then used partial coherence to remove contributions of the coherent auditory speech signal from the lip-brain coherence. Comparing this synchronization between different attention conditions revealed that attending visual speech enhances the coherence between activity in visual cortex and the speaker's lips. Further, we identified a significant partial coherence between left motor cortex and lip movements and this partial coherence directly predicted comprehension accuracy. Our results emphasize the importance of visually entrained and attention-modulated rhythmic brain activity for the enhancement of audiovisual speech processing. |
Umesh Patil; Shravan Vasishth; Richard L. Lewis Retrieval interference in syntactic processing: The case of reflexive binding in English Journal Article In: Frontiers in Psychology, vol. 7, pp. 329, 2016. @article{Patil2016, It has been proposed that in online sentence comprehension the dependency between a reflexive pronoun such as himself/herself and its antecedent is resolved using exclusively syntactic constraints. Under this strictly syntactic search account, Principle A of the binding theory-which requires that the antecedent c-command the reflexive within the same clause that the reflexive occurs in-constrains the parser's search for an antecedent. The parser thus ignores candidate antecedents that might match agreement features of the reflexive (e.g., gender) but are ineligible as potential antecedents because they are in structurally illicit positions. An alternative possibility accords no special status to structural constraints: in addition to using Principle A, the parser also uses non-structural cues such as gender to access the antecedent. According to cue-based retrieval theories of memory (e.g., Lewis and Vasishth, 2005), the use of non-structural cues should result in increased retrieval times and occasional errors when candidates partially match the cues, even if the candidates are in structurally illicit positions. In this paper, we first show how the retrieval processes that underlie the reflexive binding are naturally realized in the Lewis and Vasishth (2005) model. We present the predictions of the model under the assumption that both structural and non-structural cues are used during retrieval, and provide a critical analysis of previous empirical studies that failed to find evidence for the use of non-structural cues, suggesting that these failures may be Type II errors. We use this analysis and the results of further modeling to motivate a new empirical design that we use in an eye tracking study. The results of this study confirm the key predictions of the model concerning the use of non-structural cues, and are inconsistent with the strictly syntactic search account. These results present a challenge for theories advocating the infallibility of the human parser in the case of reflexive resolution, and provide support for the inclusion of agreement features such as gender in the set of retrieval cues. |
Katerina Pavlou; Valerie Benson; Julie A. Hadwin Exploring links between neuroticism and psychoticism personality traits, attentional biases to threat and friendship quality in 9-11-year-olds Journal Article In: Journal of Experimental Psychopathology, vol. 7, no. 3, pp. 437–450, 2016. @article{Pavlou2016, The current study used an eye-movement Remote Distractor Paradigm (RDP) to explore attention to threat and considered associations with personality traits (neuroticism and psychoticism) and self-reported friendship quality in children aged 9-11 years. The RDP asked children to look at and identify a target presented on a computer display in the presence or absence of a central, parafoveal or peripheral visual distractor (an angry, happy or neutral face). The results showed that symptoms of neuroticism were associated with hypervigilance for threat (i.e., slower latencies to initiate eye movements to the target in the presence of angry versus happy or neutral faces). In addition, when distractors were presented centrally, this relationship was most evident in children who reported lower levels of attentional control. Psychoticism traits were associated with increased selective attention to all distractors (as measured by directional errors to face stimuli) and to child reported lower friendship quality. Moreover, the negative relationship between psychoticism and friendship characteristics associated with companionship was mediated via attentional capture of threat (i.e., a greater proportion of directional errors to angry distractors). The findings have potential to inform the development of translational research, to reduce symptoms of psychopathology and address attentional biases to threat with an aim to improve peer relationships in late childhood. |
Brennan R. Payne; Mallory C. Stites; Kara D. Federmeier Out of the corner of my eye: Foveal semantic load modulates parafoveal processing in reading Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 42, no. 11, pp. 1839–1857, 2016. @article{Payne2016, In 2 experiments, we examined the impact of foveal semantic expectancy and congruity on parafoveal word processing during reading. Experiment 1 utilized an eye-tracking gaze-contingent display change paradigm, and Experiment 2 measured event-related brain potentials (ERPs) in a modified flanker rapid serial visual presentation (RSVP) paradigm. Eye-tracking and ERP data converged to reveal graded effects of foveal load on parafoveal processing. In Experiment 1, when word n was highly expected, and thus foveal load was low, there was a large parafoveal preview benefit to word n = 1. When word n was unexpected but still plausible, preview benefits to n = 1 were reduced in magnitude, and when word n was semantically incongruent, the preview benefit to n = 1 was unreliable in early pass measures. In Experiment 2, ERPs indicated that when word n was expected, and thus foveal load was low, readers successfully discriminated between valid and orthographically invalid previews during parafoveal perception. However, when word n was unexpected, parafoveal processing of n = 1 was reduced, and it was eliminated when word n was semantically incongruent. Taken together, these findings suggest that sentential context modulates the allocation of attention in the parafovea, such that covert allocation of attention to parafoveal processing is disrupted when foveal words are inconsistent with expectations based on various contextual constraints. |
Wayne E. Mackey; Orrin Devinsky; Werner K. Doyle; John G. Golfinos; Clayton E. Curtis Human parietal cortex lesions impact the precision of spatial working memory Journal Article In: Journal of Neurophysiology, vol. 116, no. 3, pp. 1049–1054, 2016. @article{Mackey2016, The neural mechanisms that support working memory (WM) depend on persistent neural activity. Within topographically organized maps of space in dorsal parietal cortex, spatially selective neural activity persists during WM for location. However, to date the necessity of these topographic subregions of human parietal cortex for WM remain unknown. To test the causal relationship of these areas to WM, we compared the performance of patients with lesions to topographically organized parietal cortex to controls on a memory-guided saccade (MGS) task as well as a visually-guided saccade (VGS) task. The MGS task allowed us to measure WM precision continuously with great sensitivity, while the VGS task allowed us to control for any deficits in general spatial or visuomotor processing. Compared to controls, patients generated memory-guided saccades that were significantly slower and less accurate, while visually-guided saccades were unaffected. These results provide key missing evidence for the causal role of topographic areas in human parietal cortex for WM, as well as the neural mechanisms supporting WM. |
Wayne E. Mackey; Orrin Devinsky; Werner K. Doyle; Michael R. Meager; Clayton E. Curtis Human dorsolateral prefrontal cortex is not necessary for spatial working memory Journal Article In: Journal of Neuroscience, vol. 36, no. 10, pp. 2847–2856, 2016. @article{Mackey2016a, A dominant theory, based on electrophysiological and lesion evidence from nonhuman primate studies, posits that the dorsolateral prefrontal cortex (dlPFC) stores and maintains working memory (WM) representations. Yet, neuroimaging studies have consistently failed to translate these results to humans; these studies normally find that neural activity persists in the human precentral sulcus (PCS) during WM delays. Here, we attempt to resolve this discrepancy. To test the degree to which dlPFC is necessary for WM, we compared the performance of patients with dlPFC lesions and neurologically healthy controls on a memory-guided saccade task that was used in the monkey studies to measure spatial WM. We found that dlPFC damage only impairs the accuracy of memory-guided saccades if the damage impacts the PCS; lesions to dorsolateral dlPFC that spare the PCS have no effect on WM. These results identify the necessary subregion of the frontal cortex for WM and specify how this influential animal model of human cognition must be revised. |
Guido Maiello; William J. Harrison; Peter J. Bex Monocular and binocular contributions to oculomotor plasticity Journal Article In: Scientific Reports, vol. 6, pp. 31861, 2016. @article{Maiello2016, Most eye movements in the real-world redirect the foveae to objects at a new depth and thus require the co-ordination of monocular saccade amplitudes and binocular vergence eye movements. Additionally to maintain the accuracy of these oculomotor control processes across the lifespan, ongoing calibration is required to compensate for errors in foveal landing positions. Such oculomotor plasticity has generally been studied under conditions in which both eyes receive a common error signal, which cannot resolve the long-standing debate regarding whether both eyes are innervated by a common cortical signal or by a separate signal for each eye. Here we examine oculomotor plasticity when error signals are independently manipulated in each eye, which can occur naturally owing to aging changes in each eye's orbit and extra-ocular muscles, or in oculomotor dysfunctions. We find that both rapid saccades and slow vergence eye movements are continuously recalibrated independently of one another and corrections can occur in opposite directions in each eye. Whereas existing models assume a single cortical representation of space employed for the control of both eyes, our findings provide evidence for independent monoculomotor and binoculomotor plasticities and dissociable spatial mapping for each eye. |
Nadine Matton; Pierre-Vincent Paubel; Julien Cegarra; Éric Raufaste Differences in multitask resource reallocation after change in task values Journal Article In: Human Factors, vol. 58, no. 8, pp. 1128–1142, 2016. @article{Matton2016, Objective: The objective was to characterize multitask resource reallocation strategies when managing subtasks with various assigned values. Background: When solving a resource conflict in multitasking, Salvucci and Taatgen predict a globally rational strategy will be followed that favors the most urgent subtask and optimizes global performance. However, Katidioti and Taatgen identified a locally rational strategy that optimizes only a subcomponent of the whole task, leading to detrimental consequences on global performance. Moreover, the question remains open whether expertise would have an impact on the choice of the strategy. Method: We adopted a multitask environment used for pilot selection with a change in emphasis on two out of four subtasks while all subtasks had to be maintained over a minimum performance. A laboratory eye-tracking study contrasted 20 recently selected pilot students considered as experienced with this task and 15 university students considered as novices. Results: When two subtasks were emphasized, novices focused their resources particularly on one high-value subtask and failed to prevent both low-value subtasks falling below minimum performance. On the contrary, experienced people delayed the processing of one low-value subtask but managed to optimize global performance. Conclusion: In a multitasking environment where some subtasks are emphasized, novices follow a locally rational strategy whereas experienced participants follow a globally rational strategy. Application: During complex training, trainees are only able to adjust their resource allocation strategy to subtask emphasis changes once they are familiar with the multitasking environment. |
Maria Matziridi; Eli Brenner; Jeroen B. J. Smeets Moving your head reduces perisaccadic compression Journal Article In: Journal of Vision, vol. 16, no. 13, pp. 1–8, 2016. @article{Matziridi2016, Flashes presented around the time of a saccade appear to be closer to the saccade endpoint than they really are. The resulting compression of perceived positions has been found to increase with the amplitude of the saccade. In most studies on perisaccadic compression the head is static, so the eye-in-head movement is equal to the change in gaze. What if moving the head causes part of the change in gaze? Does decreasing the eye-in-head rotation by moving the head decrease the compression of perceived positions? To find out, we asked participants to shift their gaze between two positions, either without moving their head or with the head contributing to the change in gaze. Around the time of the saccades we flashed bars that participants had to localize. When the head contributed to the change in gaze, the duration of the saccade was shorter and compression was reduced. We interpret this reduction in compression as being caused by a reduction in uncertainty about gaze position at the time of the flash. We conclude that moving one's head can reduce the systematic mislocalization of flashes presented around the time of saccades. |
Daniel R. McCloy; Eric D. Larson; Bonnie K. Lau; Adrian K. C. Lee Temporal alignment of pupillary response with stimulus events via deconvolution Journal Article In: The Journal of the Acoustical Society of America, vol. 139, no. 3, pp. EL57–EL62, 2016. @article{McCloy2016, Analysis of pupil dilation has been used as an index of attentional effort in the auditory domain. Previous work has modeled the pupillary response to attentional effort as a linear time-invariant system with a characteristic impulse response, and used deconvolution to estimate the attentional effort that gives rise to changes in pupil size. Here it is argued that one parameter of the impulse response (the latency of response maximum, t(max)) has been mis-estimated in the literature; a different estimate is presented, and it is shown how deconvolution with this value of t(max) yields more intuitively plausible and informative results. |
Brónagh McCoy; Jan Theeuwes Effects of reward on oculomotor control Journal Article In: Journal of Neurophysiology, vol. 116, no. 5, pp. 2453–2466, 2016. @article{McCoy2016, The present study examines the extent to which distractors that signal the availability of monetary reward on a given trial affect eye movements. We used a novel eye movement task in which observers had to follow a target around the screen while ignoring distractors presented at varying locations. We examined the effects of reward magnitude and distractor location on a host of oculomotor properties, including saccade latency, amplitude, landing position, curvature, and erroneous saccades toward the distractor. We found consistent effects of reward magnitude on classic oculomotor phenomena such as the remote distractor effect, the global effect, and oculomotor capture by the distractor. We also show that a distractor in the visual hemifield opposite to the target had a larger effect on oculomotor control than an equidistant distractor in the same hemifield as the target. Bayesian hierarchical drift diffusion modeling revealed large differences in drift rate depending on the reward value, location, and visual hemifield of the distractor stimulus. Our findings suggest that high reward distractors not only capture the eyes but also affect a multitude of oculomotor properties associated with oculomotor inhibition and control. |
Vincent B. McGinty; Antonio Rangel; William T. Newsome Orbitofrontal cortex value signals depend on fixation location during free viewing Journal Article In: Neuron, vol. 90, no. 6, pp. 1299–1311, 2016. @article{McGinty2016, In the natural world, monkeys and humans judge the economic value of numerous competing stimuli by moving their gaze from one object to another, in a rapid series of eye movements. This suggests that the primate brain processes value serially, and that value-coding neurons may be modulated by changes in gaze. To test this hypothesis, we presented monkeys with value-associated visual cues and took the unusual step of allowing unrestricted free viewing while we recorded neurons in the orbitofrontal cortex (OFC). By leveraging natural gaze patterns, we found that a large proportion of OFC cells encode gaze location and, that in some cells, value coding is amplified when subjects fixate near the cue. These findings provide the first cellular-level mechanism for previously documented behavioral effects of gaze on valuation and suggest a major role for gaze in neural mechanisms of valuation and decision-making under ecologically realistic conditions. |
Mel McKendrick; Stephen H. Butler; Madeleine A. Grealy The effect of self-referential expectation on emotional face processing Journal Article In: PLoS ONE, vol. 11, no. 5, pp. e0155576, 2016. @article{McKendrick2016, The role of self-relevance has been somewhat neglected in static face processing paradigms but may be important in understanding how emotional faces impact on attention, cognition and affect. The aim of the current study was to investigate the effect of self-relevant primes on processing emotional composite faces. Sentence primes created an expectation of the emotion of the face before sad, happy, neutral or composite face photos were viewed. Eye movements were recorded and subsequent responses measured the cognitive and affective impact of the emotion expressed. Results indicated that primes did not guide attention, but impacted on judgments of valence intensity and self-esteem ratings. Negative self-relevant primes led to the most negative self-esteem ratings, although the effect of the prime was qualified by salient facial features. Self-relevant expectations about the emotion of a face and subsequent attention to a face that is congruent with these expectations strengthened the affective impact of viewing the face. |
Catherine M. McMahon; Isabelle Boisvert; Peter Lissa; Louise Granger; Ronny Ibrahim; Chi Yhun Lo; Kelly Miles; Petra L. Graham Monitoring alpha oscillations and pupil dilation across a performance-intensity function Journal Article In: Frontiers in Psychology, vol. 7, pp. 745, 2016. @article{McMahon2016, Listening to degraded speech can be challenging and requires a continuous investment of cognitive resources, which is more challenging for those with hearing loss. However, while alpha power (8-12 Hz) and pupil dilation have been suggested as objective correlates of listening effort, it is not clear whether they assess the same cognitive processes involved, or other sensory and/or neurophysiological mechanisms that are associated with the task. Therefore, the aim of this study is to compare alpha power and pupil dilation during a sentence recognition task in 15 randomized levels of noise (-7dB to +7dB SNR) using highly intelligible (16 channel vocoded) and moderately intelligible (6 channel vocoded) speech. Twenty young normal hearing adults participated in the study; however, due to extraneous noise, data from 16 (10 females, 6 males; aged 19-28 years) was used in the EEG analysis and 10 in the pupil analysis. Behavioral testing of perceived effort and speech performance was assessed at 3 fixed SNRs per participant and was comparable to sentence recognition performance assessed in the physiological test session for both 16- and 6-channel vocoded sentences. Results showed a significant interaction between channel vocoding for both the alpha power and the pupil size changes. While both measures significantly decreased with more positive SNRs for the 16-channel vocoding, this was not observed with the 6-channel vocoding. The results of this study suggest that these measures may encode different processes involved in speech perception, which show similar trends for highly intelligible speech, but diverge for more spectrally degraded speech. The results to date suggest that these objective correlates of listening effort, and the cognitive processes involved in listening effort, are not yet sufficiently well understood to be used within a clinical setting. |
Bob McMurray; Ashley Farris-Trimble; Michael Seedorff; Hannah Rigler The effect of residual acoustic hearing and adaptation to uncertainty on speech perception in cochlear implant users: Evidence from eye-tracking Journal Article In: Ear & Hearing, vol. 37, no. 1, pp. e37–e51, 2016. @article{McMurray2016, OBJECTIVES: While outcomes with cochlear implants (CIs) are generally good, performance can be fragile. The authors examined two factors that are crucial for good CI performance. First, while there is a clear benefit for adding residual acoustic hearing to CI stimulation (typically in low frequencies), it is unclear whether this contributes directly to phonetic categorization. Thus, the authors examined perception of voicing (which uses low-frequency acoustic cues) and fricative place of articulation (s/ʃ, which does not) in CI users with and without residual acoustic hearing. Second, in speech categorization experiments, CI users typically show shallower identification functions. These are typically interpreted as deriving from noisy encoding of the signal. However, psycholinguistic work suggests shallow slopes may also be a useful way to adapt to uncertainty. The authors thus employed an eye-tracking paradigm to examine this in CI users. DESIGN: Participants were 30 CI users (with a variety of configurations) and 22 age-matched normal hearing (NH) controls. Participants heard tokens from six b/p and six s/ʃ continua (eight steps) spanning real words (e.g., beach/peach, sip/ship). Participants selected the picture corresponding to the word they heard from a screen containing four items (a b-, p-, s- and ʃ-initial item). Eye movements to each object were monitored as a measure of how strongly they were considering each interpretation in the moments leading up to their final percept. RESULTS: Mouse-click results (analogous to phoneme identification) for voicing showed a shallower slope for CI users than NH listeners, but no differences between CI users with and without residual acoustic hearing. For fricatives, CI users also showed a shallower slope, but unexpectedly, acoustic + electric listeners showed an even shallower slope. Eye movements showed a gradient response to fine-grained acoustic differences for all listeners. Even considering only trials in which a participant clicked "b" (for example), and accounting for variation in the category boundary, participants made more looks to the competitor ("p") as the voice onset time neared the boundary. CI users showed a similar pattern, but looked to the competitor more than NH listeners, and this was not different at different continuum steps. CONCLUSION: Residual acoustic hearing did not improve voicing categorization suggesting it may not help identify these phonetic cues. The fact that acoustic + electric users showed poorer performance on fricatives was unexpected as they usually show a benefit in standardized perception measures, and as sibilants contain little energy in the low-frequency (acoustic) range. The authors hypothesize that these listeners may overweight acoustic input, and have problems when this is not available (in fricatives). Thus, the benefit (or cost) of acoustic hearing for phonetic categorization may be complex. Eye movements suggest that in both CI and NH listeners, phoneme categorization is not a process of mapping continuous cues to discrete categories. Rather listeners preserve gradiency as a way to deal with uncertainty. CI listeners appear to adapt to their implant (in part) by amplifying competitor activation to preserve their flexibility in the face of potential misperceptions. |
Eugene McSorley; Rachel McCloy; Louis Williams The concurrent programming of saccades Journal Article In: PLoS ONE, vol. 11, no. 12, pp. e0168724, 2016. @article{McSorley2016, Sequences of saccades have been shown to be prepared concurrently however it remains unclear exactly what aspects of those saccades are programmed in parallel. To examine this participants were asked to make one or two target-driven saccades: a reflexive sac- cade; a voluntary saccade; a reflexive then a voluntary saccade; or vice versa. During the first response the position of a second target was manipulated. The new location of the sec- ond saccade target was found to impact on second saccade latencies and second saccade accuracy showing that some aspects of the second saccade program are prepared in paral- lel with the first. However, differences were found in the specific pattern of effects for each sequence type. These differences fit well within a general framework for saccade control in which a common priority map for saccade control is computed and the influence of saccade programs on one another depends not so much on the types of saccade being produced but rather on the rate at which their programs develop. |
Laura Piccardi; Maria De Luca; Raffaella Nori; Liana Palermo; Fabiana Iachini; Cecilia Guariglia Navigational style influences eye movement pattern during exploration and learning of an environmental map Journal Article In: Frontiers in Behavioral Neuroscience, vol. 10, pp. 140, 2016. @article{Piccardi2016, During navigation people may adopt three different spatial styles (i.e., Landmark, Route, and Survey). Landmark style (LS) people are able to recall familiar landmarks but cannot combine them with directional information; Route style (RS) people connect landmarks to each other using egocentric information about direction; Survey style (SS) people use a map-like representation of the environment. SS individuals generally navigate better than LS and RS people. Fifty-one college students (20 LS; 17 RS, and 14 SS) took part in the experiment. The spatial cognitive style (SCS) was assessed by means of the SCS test; participants then had to learn a schematic map of a city, and after 5 min had to recall the path depicted on it. During the learning and delayed recall phases, eye-movements were recorded. Our intent was to investigate whether there is a peculiar way to explore an environmental map related to the individual's spatial style. Results support the presence of differences in the strategy used by the three spatial styles for learning the path and its delayed recall. Specifically, LS individuals produced a greater number of fixations of short duration, while the opposite eye movement pattern characterized SS individuals. Moreover, SS individuals showed a more spread and comprehensive explorative pattern of the map, while LS individuals focused their exploration on the path and related targets. RS individuals showed a pattern of exploration at a level of proficiency between LS and SS individuals. We discuss the clinical and anatomical implications of our data. |