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!
2014 |
Kimberly S. Chiew; Todd S. Braver Dissociable influences of reward motivation and positive emotion on cognitive control Journal Article In: Cognitive, Affective and Behavioral Neuroscience, vol. 14, no. 2, pp. 509–529, 2014. @article{Chiew2014, It is becoming increasingly appreciated that affective and/or motivational influences contribute strongly to goal-oriented cognition and behavior. An unresolved question is whether emotional manipulations (i.e., direct induction of affectively valenced subjective experience) and motivational manipulations (e.g., delivery of performance-contingent rewards and punishments) have similar or distinct effects on cognitive control. Prior work has suggested that reward motivation can reliably enhance a proactive mode of cognitive control, whereas other evidence is suggestive that positive emotion improves cognitive flexibility, but reduces proactive control. However, a limitation of the prior research is that reward motivation and positive emotion have largely been studied independently. Here, we directly compared the effects of positive emotion and reward motivation on cognitive control with a tightly matched, within-subjects design, using the AX-continuous performance task paradigm, which allows for relative measurement of proactive versus reactive cognitive control. High-resolution pupillometry was employed as a secondary measure of cognitive dynamics during task performance. Robust increases in behavioral and pupillometric indices of proactive control were observed with reward motivation. The effects of positive emotion were much weaker, but if anything, also reflected enhancement of proactive control, a pattern that diverges from some prior findings. These results indicate that reward motivation has robust influences on cognitive control, while also highlighting the complexity and heterogeneity of positive-emotion effects. The findings are discussed in terms of potential neurobiological mechanisms. © 2014 The Author(s). |
Joseph D. Chisholm; Alan Kingstone Knowing and avoiding: The influence of distractor awareness on oculomotor capture Journal Article In: Attention, Perception, and Psychophysics, vol. 76, no. 5, pp. 1258–1264, 2014. @article{Chisholm2014, Kramer, Hahn, Irwin, and Theeuwes (2000) reported that the interfering effect of distractors is reduced when participants are aware of the to-be-ignored information. In contrast, recent evidence indicates that distractor interference increases when individuals are aware of the distractors. In the present investigation, we directly assessed the influence of distractor awareness on oculomotor capture, with the hope of resolving this contradiction in the literature and gaining further insight into the influence of awareness on attention. Participants completed a traditional oculomotor capture task. They were not informed of the presence of the distracting information (unaware condition), were informed of distractors (aware condition), or were informed of distractor information and told to avoid attending to it (avoid condition). Being aware of the distractors yielded a performance benefit, relative to the unaware condition; however, this benefit was eliminated when participants were told to actively avoid distraction. This pattern of results reconciles past contradictions in the literature and suggests an inverted-U function of awareness in distractor performance. Too little or too much emphasis yields a performance decrement, but an intermediate level of emphasis provides a performance benefit. |
Kyoung Whan Choe; Randolph Blake; Sang-Hun Lee Dissociation between neural signatures of stimulus and choice in population activity of human V1 during perceptual decision-making Journal Article In: Journal of Neuroscience, vol. 34, no. 7, pp. 2725–2743, 2014. @article{Choe2014, Primary visual cortex (V1) forms the initial cortical representation of objects and events in our visual environment, and it distributes information about that representation to higher cortical areas within the visual hierarchy. Decades of work have established tight linkages between neural activity occurring in V1 and features comprising the retinal image, but it remains debatable how that activity relates to perceptual decisions. An actively debated question is the extent to which V1 responses determine, on a trial-by-trial basis, perceptual choices made by observers. By inspecting the population activity of V1 from human observers engaged in a difficult visual discrimination task, we tested one essential prediction of the deterministic view: choice-related activity, if it exists in V1, and stimulus-related activity should occur in the same neural ensemble of neurons at the same time. Our findings do not support this prediction: while cortical activity signifying the variability in choice behavior was indeed found in V1, that activity was dissociated from activity representing stimulus differences relevant to the task, being advanced in time and carried by a different neural ensemble. The spatiotemporal dynamics of population responses suggest that short-term priors, perhaps formed in higher cortical areas involved in perceptual inference, act to modulate V1 activity prior to stimulus onset without modifying subsequent activity that actually represents stimulus features within V1. |
Jennie E. S. Choi; Pavan A. Vaswani; Reza Shadmehr Vigor of movements and the cost of time in decision making Journal Article In: Journal of Neuroscience, vol. 34, no. 4, pp. 1212–1223, 2014. @article{Choi2014, If we assume that the purpose of a movement is to acquire a rewarding state, the duration of the movement carries a cost because it delays acquisition of reward. For some people, passage of time carries a greater cost, as evidenced by how long they are willing to wait for a rewarding outcome. These steep discounters are considered impulsive. Is there a relationship between cost of time in decision making and cost of time in control of movements? Our theory predicts that people who are more impulsive should in general move faster than subjects who are less impulsive. To test our idea, we considered elementary voluntary movements: saccades of the eye. We found that in humans, saccadic vigor, assessed using velocity as a function of amplitude, was as much as 50% greater in one subject than another; that is, some people consistently moved their eyes with high vigor. We measured the cost of time in a decision-making task in which the same subjects were given a choice between smaller odds of success immediately and better odds if they waited. We measured how long they were willing to wait to obtain the better odds and how much they increased their wait period after they failed. We found that people that exhibited greater vigor in their movements tended to have a steep temporal discount function, as evidenced by their waiting patterns in the decision-making task. The cost of time may be shared between decision making and motor control. |
Mina Choi; Joel Wang; Wei Chung Cheng; Giovanni Ramponi; Luigi Albani; Aldo Badano Effect of veiling glare on detectability in high-dynamic-range medical images Journal Article In: IEEE/OSA Journal of Display Technology, vol. 10, no. 5, pp. 420–428, 2014. @article{Choi2014a, We describe a methodology for predicting the detectability of subtle targets in dark regions of high-dynamic-range (HDR) images in the presence of veiling glare in the human eye. The method relies on predictions of contrast detection thresholds for the human visual system within a HDR image based on psychophysics measurements and modeling of the HDR display device characteristics. We present experimental results used to construct the model and discuss an image-dependent empirical veiling glare model and the validation of the model predictions with test patterns, natural scenes, and medical images. The model predictions are compared to a previously reported model (HDR-VDP2) for predicting HDR image quality accounting for glare effects. © 2005-2012 IEEE. |
Wonil Choi; Rutvik H. Desai; John M. Henderson The neural substrates of natural reading: A comparison of normal and nonword text using eyetracking and fMRI Journal Article In: Frontiers in Human Neuroscience, vol. 8, pp. 1024, 2014. @article{Choi2014c, Most previous studies investigating the neural correlates of reading have presented text using serial visual presentation (SVP), which may not fully reflect the underlying processes of natural reading. In the present study, eye movements and BOLD data were collected while subjects either read normal paragraphs naturally or moved their eyes through "paragraphs" of pseudo-text (pronounceable pseudowords or consonant letter strings) in two pseudo-reading conditions. Eye movement data established that subjects were reading and scanning the stimuli normally. A conjunction fMRI analysis across natural- and pseudo-reading showed that a common eye-movement network including frontal eye fields (FEF), supplementary eye fields (SEF), and intraparietal sulci was activated, consistent with previous studies using simpler eye movement tasks. In addition, natural reading versus pseudo-reading showed different patterns of brain activation: normal reading produced activation in a well-established language network that included superior temporal gyrus/sulcus, middle temporal gyrus (MTG), angular gyrus (AG), inferior frontal gyrus, and middle frontal gyrus, whereas pseudo-reading produced activation in an attentional network that included anterior/posterior cingulate and parietal cortex. These results are consistent with results found in previous single-saccade eye movement tasks and SVP reading studies, suggesting that component processes of eye-movement control and language processing observed in past fMRI research generalize to natural reading. The results also suggest that combining eyetracking and fMRI is a suitable method for investigating the component processes of natural reading in fMRI research. |
Wonil Choi; Peter C. Gordon Word skipping during sentence reading: effects of lexicality on parafoveal processing Journal Article In: Attention, Perception, and Psychophysics, vol. 76, no. 1, pp. 201–213, 2014. @article{Choi2014b, Two experiments examined how lexical status affects the targeting of saccades during reading by using the boundary technique to vary independently the content of a letter string when seen in parafoveal preview and when directly fixated. Experiment 1 measured the skipping rate for a target word embedded in a sentence under three parafoveal preview conditions: full preview (e.g., brain-brain), pseudohomophone preview (e.g., brane-brain), and orthographic nonword control preview (e.g., brant-brain); in the first condition, the preview string was always an English word, while in the second and third conditions, it was always a nonword. Experiment 2 investigated three conditions where the preview string was always a word: full preview (e.g., beach-beach), homophone preview (e.g., beech-beach), and orthographic control preview (e.g., bench-beach). None of the letter string manipulations used to create the preview conditions in the experiments disrupted sublexical orthographic or phonological patterns. In Experiment 1, higher skipping rates were observed for the full (lexical) preview condition, which consisted of a word, than for the nonword preview conditions (pseudohomophone and orthographic control). In contrast, Experiment 2 showed no difference in skipping rates across the three types of lexical preview conditions (full, homophone, and orthographic control), although preview type did influence reading times. This pattern indicates that skipping not only depends on the presence of disrupted sublexical patterns of orthography or phonology, but also is critically dependent on processes that are sensitive to the lexical status of letter strings in the parafovea. |
Wing Yee Chow; Shevaun Lewis; Colin Phillips Immediate sensitivity to structural constraints in pronoun resolution Journal Article In: Frontiers in Psychology, vol. 5, pp. 630, 2014. @article{Chow2014, Real-time interpretation of pronouns is sometimes sensitive to the presence of grammatically-illicit antecedents and sometimes not. This occasional sensitivity has been taken as evidence that structural constraints do not immediately impact the initial antecedent retrieval for pronoun interpretation. We argue that it is important to separate effects that reflect the initial antecedent retrieval process from those that reflect later processes. We present results from five reading comprehension experiments. Both the current results and previous evidence support the hypothesis that agreement features and structural constraints immediately constrain the antecedent retrieval process for pronoun interpretation. Occasional sensitivity to grammatically-illicit antecedents may be due to repair processes triggered when the initial retrieval fails to return a grammatical antecedent. |
T. Chuk; A. B. Chan; J. H. Hsiao Understanding eye movements in face recognition using hidden Markov models Journal Article In: Journal of Vision, vol. 14, no. 11, pp. 1–14, 2014. @article{Chuk2014, We use a hidden Markov model (HMM) based approach to analyze eye movement data in face recognition. HMMs are statistical models that are specialized in handling time-series data. We conducted a face recognition task with Asian participants, and model each participant's eye movement pattern with an HMM, which summarized the participant's scan paths in face recognition with both regions of interest and the transition probabilities among them. By clustering these HMMs, we showed that participants' eye movements could be categorized into holistic or analytic patterns, demonstrating significant individual differences even within the same culture. Participants with the analytic pattern had longer response times, but did not differ significantly in recognition accuracy from those with the holistic pattern. We also found that correct and wrong recognitions were associated with distinctive eye movement patterns; the difference between the two patterns lies in the transitions rather than locations of the fixations alone. |
Ian Cunnings; Clare Patterson; Claudia Felser Variable binding and coreference in sentence comprehension: Evidence from eye movements Journal Article In: Journal of Memory and Language, vol. 71, no. 1, pp. 39–56, 2014. @article{Cunnings2014a, The hypothesis that pronouns can be resolved via either the syntax or the discourse representation has played an important role in linguistic accounts of pronoun interpretation (e.g. Grodzinsky & Reinhart, 1993). We report the results of an eye-movement monitoring study investigating the relative timing of syntactically-mediated variable binding and discourse-based coreference assignment during pronoun resolution. We examined whether ambiguous pronouns are preferentially resolved via either the variable binding or coreference route, and in particular tested the hypothesis that variable binding should always be computed before coreference assignment. Participants' eye movements were monitored while they read sentences containing a pronoun and two potential antecedents, a c-commanding quantified noun phrase and a non c-commanding proper name. Gender congruence between the pronoun and either of the two potential antecedents was manipulated as an experimental diagnostic for dependency formation. In two experiments, we found that participants' reading times were reliably longer when the linearly closest antecedent mismatched in gender with the pronoun. These findings fail to support the hypothesis that variable binding is computed before coreference assignment, and instead suggest that antecedent recency plays an important role in affecting the extent to which a variable binding antecedent is considered. We discuss these results in relation to models of memory retrieval during sentence comprehension, and interpret the antecedent recency preference as an example of forgetting over time. |
Ian Cunnings; Patrick Sturt Coargumenthood and the processing of reflexives Journal Article In: Journal of Memory and Language, vol. 75, pp. 117–139, 2014. @article{Cunnings2014, We report three eye-movement experiments and an antecedent choice task investigating the interpretation of reflexives in different syntactic contexts. This included contexts in which the reflexive and a local antecedent were coarguments of the same verbal predicate (John heard that the soldier had injured himself), and also so-called picture noun phrases, either with a possessor (John heard about the soldier's picture of himself) or without (John heard that the soldier had a picture of himself). While results from the antecedent choice task indicated that comprehenders would choose a nonlocal antecedent ('John' above) for reflexives in either type of picture noun phrase, the eye-movement experiments suggested that participants preferred to initially interpret the reflexive in each context as referring to the local antecedent ('the soldier'), as indexed by longer reading times when it mismatched in gender with the reflexive. We also observed a difference in the time-course of this effect. While it was observed during first-pass processing at the reflexive for coargument reflexives and those in picture noun phrases with a possessor, it was comparatively delayed for reflexives in possessorless picture noun phrases. These results suggest that locality constraints are more strongly weighted cues to retrieval than gender agreement for both coargument reflexives and those inside picture noun phrases. We interpret the observed time-course differences as indexing the relative ease of accessing the local antecedent in different syntactic contexts. |
Michael G. Cutter; Denis Drieghe; Simon P. Liversedge Preview benefit in English spaced compounds Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 40, no. 6, pp. 1778–1786, 2014. @article{Cutter2014, In an eye tracking experiment during reading we examined whether preview benefit could be observed from 2 words to the right of the currently fixated word if that word was the 2nd constituent of a spaced compound. The boundary paradigm (Rayner, 1975) was used to orthogonally manipulate whether participants saw an identity or nonword preview of the 1st (e.g., teddy) and 2nd constituent (e.g., bear) of a spaced compound located immediately beyond the boundary, respectively, words n + 1 and n + 2. Linear mixed-effects models revealed that participants gained an n + 2 preview benefit, such that they spent less time fixated on word n + 1 when given an identity preview of word n + 2. However, this effect was only observed if there was also an identity preview of word n + 1. Our findings suggest that the 2 constituent words of spaced compounds are processed as part of a larger lexical unit during natural reading. |
Marzena Cypryańska; Izabela Krejtz; Aleksandra Jaskółowska; Alicja Kulawik; Aleksandra Żukowska; Agnieszka Golec De Zavala; Jakub Niewiarowski; John B. Nezlek An experimental study of the influence of limited time horizon on positivity effects among young adults using eye-tracking Journal Article In: Psychological Reports, vol. 115, no. 3, pp. 813–827, 2014. @article{Cypryanska2014, Compared to younger adults, older adults attend more to positive stimuli, a positivity effect. Older adults have limited time horizons, and they focus on maintaining positive affect, whereas younger adults have unlimited time horizons, and they focus on acquiring knowledge and developing skills. Time horizons were manipulated by asking participants (66 young adults, M age = 20.5 yr. |
Pierre M. Daye; Lance M. Optican Saccade detection using a particle filter Journal Article In: Journal of Neuroscience Methods, vol. 235, pp. 157–168, 2014. @article{Daye2014, Background: When healthy subjects track a moving target, "catch-up" saccades are triggered to compensate for the non-perfect tracking gain. The evaluation of the pursuit and/or saccade kinematics requires that saccade and pursuit components be separated from the eye movement trace. A similar situation occurs when analyzes eye movements of patients that could contain eye drifts between saccades. This task is especially difficult, because the range of saccadic amplitudes goes from microsaccades (less than 1°) to large exploratory saccades (40°). New method: In this paper we proposed a new algorithm to detect saccades based on a particle filter. The new method suppresses the baseline velocity component linked to smooth pursuit (or to eye drifts) and thus permits a constant threshold during a trial despite the smooth pursuit behavior. It also accounts for a wide range of saccade amplitudes. Results: The new method is validated with five different paradigms, microsaccades, microsaccades plus saccades with drift, linear target motion, non-linear target motion and free viewing. The sensitivity of the method to signal noise is analyzed. Comparison with existing methods: Traditional saccade detection algorithms using a velocity (or acceleration or jerk) threshold can be inadequate because of the baseline velocity component linked to the smooth pursuit (especially if the target motion is non-linear, i.e. not constant velocity) or to eye drifts between saccades. Conclusions: The new method detects saccades in challenging situations involving eye movements between saccades (smooth pursuit and/or eye drifts) and unfiltered recordings. |
Jennifer E. Corbett; David Melcher Stable statistical representations facilitate visual search Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 40, no. 5, pp. 1915–1925, 2014. @article{Corbett2014a, Observers represent the average properties of object ensembles even when they cannot identify individual elements. To investigate the functional role of ensemble statistics, we examined how modulating statistical stability affects visual search. We varied the mean and/or individual sizes of an array of Gabor patches while observers searched for a tilted target. In "stable" blocks, the mean and/or local sizes of the Gabors were constant over successive displays, whereas in "unstable" baseline blocks they changed from trial to trial. Although there was no relationship between the context and the spatial location of the target, observers found targets faster (as indexed by faster correct responses and fewer saccades) as the global mean size became stable over several displays. Building statistical stability also facilitated scanning the scene, as measured by larger saccadic amplitudes, faster saccadic reaction times, and shorter fixation durations. These findings suggest a central role for peripheral visual information, creating context to free resources for detailed processing of salient targets and maintaining the illusion of visual stability. |
Jennifer E. Corbett; David Melcher Characterizing ensemble statistics: Mean size is represented across multiple frames of reference Journal Article In: Attention, Perception, and Psychophysics, vol. 76, no. 3, pp. 746–758, 2014. @article{Corbett2014, The visual system represents the overall statistical, not individual, properties of sets. Here we tested the spatial nature of ensemble statistics. We used a mean-size adaptation paradigm (Corbett et al. in Visual Cognition, 20, 211-231, 2012) to examine whether average size is encoded in multiple reference frames. We adapted observers to patches of small- and large-sized dots in opposite regions of the display (left/right or top/bottom) and then tested their perceptions of the sizes of single test dots presented in regions that corresponded to retinotopic, spatiotopic, and hemispheric coordinates within the adapting displays. We observed retinotopic, spatiotopic, and hemispheric adaptation aftereffects, such that participants perceived a test dot as being larger when it was presented in the area adapted to the patch of small dots than when it was presented in the area adapted to large dots. This aftereffect also transferred between eyes. Our results demonstrate that mean size is represented across multiple spatial frames of reference, supporting the proposal that ensemble statistics play a fundamental role in maintaining perceptual stability. |
Jason C. Coronel; Kara D. Federmeier Task demands modulate decision and eye movement responses in the chimeric face test: Examining the right hemisphere processing account Journal Article In: Frontiers in Psychology, vol. 5, pp. 229, 2014. @article{Coronel2014, A large and growing body of work, conducted in both brain-intact and brain-damaged populations, has used the free viewing chimeric face test as a measure of hemispheric dominance for the extraction of emotional information from faces. These studies generally show that normal right-handed individuals tend to perceive chimeric faces as more emotional if the emotional expression is presented on the half of the face to the viewer's left (“left hemiface”). However, the mechanisms underlying this lateralized bias remain unclear. Here, we examine the extent to which this bias is driven by right hemisphere processing advantages versus default scanning biases in a unique way – by changing task demands. In particular, we compare the original task with one in which right-hemisphere-biased processing cannot provide a decision advantage. Our behavioral and eye-movement data are inconsistent with the predictions of a default scanning bias account and support the idea that the left hemiface bias found in the chimeric face test is largely due to strategic use of right hemisphere processing mechanisms. |
Francisco M. Costela; Jorge Otero-Millan; Michael B. McCamy; Stephen L. Macknik; Xoana G. Troncoso; Ali Najafian Jazi; Sharon M. Crook; Susana Martinez-Conde Fixational eye movement correction of blink-induced gaze position errors Journal Article In: PLoS ONE, vol. 9, no. 10, pp. e110889, 2014. @article{Costela2014, Our eyes move continuously. Even when we attempt to fix our gaze, we produce "fixational" eye movements including microsaccades, drift and tremor. The potential role of microsaccades versus drifts in the control of eye position has been debated for decades and remains in question today. Here we set out to determine the corrective functions of microsaccades and drifts on gaze-position errors due to blinks in non-human primates (Macaca mulatta) and humans. Our results show that blinks contribute to the instability of gaze during fixation, and that microsaccades, but not drifts, correct fixation errors introduced by blinks. These findings provide new insights about eye position control during fixation, and indicate a more general role of microsaccades in fixation correction than thought previously. |
Antoine Coutrot; N. Guyader How saliency, faces, and sound influence gaze in dynamic social scenes Journal Article In: Journal of Vision, vol. 14, no. 8, pp. 1–17, 2014. @article{Coutrot2014, Conversation scenes are a typical example in which classical models of visual attention dramatically fail to predict eye positions. Indeed, these models rarely consider faces as particular gaze attractors and never take into account the important auditory information that always accompanies dynamic social scenes. We recorded the eye movements of participants viewing dynamic conversations taking place in various contexts. Conversations were seen either with their original soundtracks or with unrelated soundtracks (unrelated speech and abrupt or continuous natural sounds). First, we analyze how auditory conditions influence the eye movement parameters of participants. Then, we model the probability distribution of eye positions across each video frame with a statistical method (Expectation- Maximization), allowing the relative contribution of different visual features such as static low-level visual saliency (based on luminance contrast), dynamic low- level visual saliency (based on motion amplitude), faces, and center bias to be quantified. Through experimental and modeling results, we show that regardless of the auditory condition, participants look more at faces, and especially at talking faces. Hearing the original soundtrack makes participants follow the speech turn-taking more closely. However, we do not find any difference between the different types of unrelated soundtracks. These eye- tracking results are confirmed by our model that shows that faces, and particularly talking faces, are the features that best explain the gazes recorded, especially in the original soundtrack condition. Low-level saliency is not a relevant feature to explain eye positions made on social scenes, even dynamic ones. Finally, we propose groundwork for an audiovisual saliency model. |
Antoine Coutrot; Nathalie Guyader; Gelu Ionescu; Alice Caplier Video viewing: Do auditory salient events capture visual attention? Journal Article In: Annals of Telecommunications, vol. 69, no. 1-2, pp. 89–97, 2014. @article{Coutrot2014a, We assess whether salient auditory events contained in soundtracks modify eye movements when exploring videos. In a previous study, we found that, on average, nonspatial sound contained in video soundtracks impacts on eye movements. This result indicates that sound could play a leading part in visual attention models to predict eye movements. In this research, we go further and test whether the effect of sound on eye movements is stronger just after salient auditory events. To automatically spot salient auditory events, we used two auditory saliency models: the discrete energy separation algorithm and the energy model. Both models provide a saliency time curve, based on the fusion of several elementary audio features. The most salient auditory events were extracted by thresholding these curves. We examined some eye movement parameters just after these events rather than on all the video frames. We showed that the effect of sound on eye movements (variability between eye positions, saccade amplitude, and fixation duration) was not stronger after salient auditory events than on average over entire videos. Thus, we suggest that sound could impact on visual exploration not only after salient events but in a more global way. © 2013 Institut Mines-Télécom and Springer-Verlag France. |
David G. Cowan; Eric J. Vanman; Mark Nielsen Motivated empathy: The mechanics of the empathic gaze Journal Article In: Cognition and Emotion, vol. 28, no. 8, pp. 1522–1530, 2014. @article{Cowan2014, Successful human social interactions frequently rely on appropriate interpersonal empathy and eye contact. Here, we report a previously unseen relationship between trait empathy and eye-gaze patterns to affective facial features in video-based stimuli. Fifty-nine healthy adult participants had their eyes tracked while watching a three-minute long "sad" and "emotionally neutral" video. The video stimuli portrayed the head and shoulders of the same actor recounting a fictional personal event. Analyses revealed that the greater participants' trait emotional empathy, the more they fixated on the eye-region of the actor, regardless of the emotional valence of the video stimuli. Our findings provide the first empirical evidence of a relationship between empathic capacity and eye-gaze pattern to the most affective facial region (eyes). |
M. A. Cox; Kaleb A. Lowe; Randolph Blake; A. Maier Sustained perceptual invisibility of solid shapes following contour adaptation to partial outlines Journal Article In: Consciousness and Cognition, vol. 26, no. 1, pp. 37–50, 2014. @article{Cox2014, Contour adaptation (CA) is a recently described paradigm that renders otherwise salient visual stimuli temporarily perceptually invisible. Here we investigate whether this illusion can be exploited to study visual awareness. We found that CA can induce seconds of sustained invisibility following similarly long periods of uninterrupted adaptation. Furthermore, even fragmented adaptors are capable of producing CA, with the strength of CA increasing monotonically as the adaptors encompass a greater fraction of the stimulus outline. However, different types of adaptor patterns, such as distinctive shapes or illusory contours, produce equivalent levels of CA suggesting that the main determinants of CA are low-level stimulus characteristics, with minimal modulation by higher-order visual processes. Taken together, our results indicate that CA has desirable properties for studying visual awareness, including the production of prolonged periods of perceptual dissociation from stimulation as well as parametric dependencies of that dissociation on a host of stimulus parameters. |
David P. Crabb; Nicholas D. Smith; Haogang Zhu What's on TV? Detecting age-related neurodegenerative eye disease using eye movement scanpaths Journal Article In: Frontiers in Aging Neuroscience, vol. 6, pp. 312, 2014. @article{Crabb2014, PURPOSE: We test the hypothesis that age-related neurodegenerative eye disease can be detected by examining patterns of eye movement recorded whilst a person naturally watches a movie.$backslash$n$backslash$nMETHODS: Thirty-two elderly people with healthy vision (median age: 70, interquartile range [IQR] 64-75 years) and 44 patients with a clinical diagnosis of glaucoma (median age: 69, IQR 63-77 years) had standard vision examinations including automated perimetry. Disease severity was measured using a standard clinical measure (visual field mean deviation; MD). All study participants viewed three unmodified TV and film clips on a computer set up incorporating the Eyelink 1000 eyetracker (SR Research, Ontario, Canada). Eye movement scanpaths were plotted using novel methods that first filtered the data and then generated saccade density maps. Maps were then subjected to a feature extraction analysis using kernel principal component analysis (KPCA). Features from the KPCA were then classified using a standard machine based classifier trained and tested by a 10-fold cross validation which was repeated 100 times to estimate the confidence interval (CI) of classification sensitivity and specificity.$backslash$n$backslash$nRESULTS: Patients had a range of disease severity from early to advanced (median [IQR] right eye and left eye MD was -7 [-13 to -5] dB and -9 [-15 to -4] dB, respectively). Average sensitivity for correctly identifying a glaucoma patient at a fixed specificity of 90% was 79% (95% CI: 58-86%). The area under the Receiver Operating Characteristic curve was 0.84 (95% CI: 0.82-0.87).$backslash$n$backslash$nCONCLUSIONS: Huge data from scanpaths of eye movements recorded whilst people freely watch TV type films can be processed into maps that contain a signature of vision loss. In this proof of principle study we have demonstrated that a group of patients with age-related neurodegenerative eye disease can be reasonably well separated from a group of healthy peers by considering these eye movement signatures alone. |
Sarah C. Creel Impossible to _gnore: Word-form inconsistency slows preschool children's word-learning Journal Article In: Language Learning and Development, vol. 10, no. 1, pp. 68–95, 2014. @article{Creel2014, Many studies have examined language acquisition under morphosyntactic or semantic inconsistency, but few have considered word-form inconsistency. Many young learners encounter word-form inconsistency due to accent variation in their communities. The current study asked how preschoolers recognize accent-variants of newly learned words. Can preschoolers generalize recognition based on partial match to the learned form? When learning in two accents simultaneously, do children ignore inconsistent elements, or encode two word forms (one per accent)? Three- to 5-year-olds learned words in a novel-word learning paradigm but did not generalize to new accent-like pronunciations (Experiment 1) unless familiar-word recognition trials were interspersed (Experiments 3 and 4), which apparently generated a familiar-word-recognition pragmatic context. When exposure included two accent-variants per word, children were less accurate (Experiment 2) and slower to look to referents (Experiments 2, 5) relative to one-accent learning. Implications for language learning and accent processing over development are discussed. (PsycINFO Database Record (c) 2016 APA, all rights reserved) |
Sarah C. Creel Tipping the scales: Auditory cue weighting changes over development Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 40, no. 3, pp. 1146–1160, 2014. @article{Creel2014a, How does auditory processing change over development? This study assessed preschoolers' and adults' sensitivity to pitch contour, pitch height, and timbre in an association-memory paradigm, with both explicit (overt recognition) and implicit measures (visual fixations to melody-linked objects). In the first 2 experiments, child and adult participants associated each of 2 melodies with a cartoon picture, and recognition was tested. Experiment 1 pitted pitch contour cues against pitch height cues, and Experiment 2 pitted contour cues against timbre cues. Although adults were sensitive to multiple cues, children responded predominantly based on pitch height and timbre, with little sensitivity to pitch contour. In Experiment 3, however, children detected changes to all 3 cues well above chance levels. Results overall suggest that contour differences, although readily perceptible, are less memorable to children than to adults. Gradual perceptual learning over development may increase the memorability of pitch contour. |
Sarah C. Creel Preschoolers' flexible use of talker information during word learning Journal Article In: Journal of Memory and Language, vol. 73, no. 1, pp. 81–98, 2014. @article{Creel2014b, Previous research suggests that preschool-aged children use novel information about talkers' preferences (e.g. favorite colors) to guide on-line language processing. But can children encode information about talkers while simultaneously learning new words, and if so, how is talker information encoded? In five experiments, children learned pairs of early-overlapping words (geeb, geege); a particular talker spoke each word. Across experiments, children learned labels for novel referents, showing an advantage for original-voice repetitions of words which appeared to stem mainly from semantic person-referent mappings (who liked what referent). Specifically, children looked to voice-matched referents when a talker asked for their own favorite ("I want to see the geege") or when the liker was unspecified ("Point to the geege"), but they looked to voice mismatched referents when a talker asked on behalf of the other talker ("Conor wants to see the geege"). Initial looks to voice-matched referents were flexibly corrected when later information became available (Anna saying "Find the geege for Conor"). Voice-matching looks vanished when talkers labeled the other talker's favorite referent during learning, possibly because children had learned two conflicting person-referent mappings: Anna likes-geeb vs. Anna talks-about-geege. Results imply that children's language input may be conditioned on talker context quite early in language learning. ©2014 Elsevier Inc. |
Sébastien M. Crouzet; Morten Overgaard; Niko A. Busch The fastest saccadic responses escape visual masking Journal Article In: PLoS ONE, vol. 9, no. 2, pp. e87418, 2014. @article{Crouzet2014, Object-substitution masking (OSM) occurs when a briefly presented target in a search array is surrounded by small dots that remain visible after the target disappears. The reduction of target visibility occurring after OSM has been suggested to result from a specific interference with reentrant visual processing while the initial feedforward processing is thought to be left intact. We tested a prediction derived from this hypothesis: the fastest responses, being triggered before the beginning of reentrant processing, should escape the OSM interference. In a saccadic choice reaction time task, which gives access to very early stages of visual processing, target visibility was reduced either by OSM, conventional backward masking, or low stimulus contrast. A general reduction of performance was observed in all three conditions. However, the fastest saccades did not show any sign of interference under either OSM or backward masking, as they did under the low-contrast condition. This finding supports the hypothesis that masking interferes mostly with reentrant processing at later stages, while leaving early feedforward processing largely intact. |
Lei Cui; Denis Drieghe; Xuejun Bai; Guoli Yan; Simon P. Liversedge Parafoveal preview benefit in unspaced and spaced Chinese reading Journal Article In: Quarterly Journal of Experimental Psychology, vol. 67, no. 11, pp. 2172–2188, 2014. @article{Cui2014, In an eye movement experiment during reading, we compared parafoveal preview benefit during the reading of Chinese sentences either in the familiar, unspaced format or with spaces inserted between the words. Single-character words or the first of a two-character word were either presented normally or were replaced by a pseudocharacter in the preview. Results indicate that word spacing increased the parafoveal preview benefit but only for the one-character target words. We hypothesized that the incorrect preview of the first character of the two-character word prevented parafoveal processing of the ensuing character(s), effectively nullifying any benefits from the spacing. Our results suggest that word boundary demarcation allows for more precise focusing of attention. |
Björn Browatzki; Heinrich H. Bülthoff; Lewis L. Chuang A comparison of geometric- and regression-based mobile gaze-tracking Journal Article In: Frontiers in Human Neuroscience, vol. 8, pp. 200, 2014. @article{Browatzki2014, Video-based gaze-tracking systems are typically restricted in terms of their effective tracking space. This constraint limits the use of eyetrackers in studying mobile human behavior. Here, we compare two possible approaches for estimating the gaze of participants who are free to walk in a large space whilst looking at different regions of a large display. Geometrically, we linearly combined eye-in-head rotations and head-in-world coordinates to derive a gaze vector and its intersection with a planar display, by relying on the use of a head-mounted eyetracker and body-motion tracker. Alternatively, we employed Gaussian process regression to estimate the gaze intersection directly from the input data itself. Our evaluation of both methods indicates that a regression approach can deliver comparable results to a geometric approach. The regression approach is favored, given that it has the potential for further optimization, provides confidence bounds for its gaze estimates and offers greater flexibility in its implementation. Open-source software for the methods reported here is also provided for user implementation. |
Florian Brugger; Michael Schüpbach; Michel Koenig; René M. Müri; Stephan Bohlhalter; Alain Kaelin-Lang; Christian P. Kamm; Georg Kägi The clinical spectrum of ataxia with oculomotor apraxia type 2 Journal Article In: Movement Disorders Clinical Practice, vol. 1, no. 2, pp. 106–109, 2014. @article{Brugger2014, Ataxia with oculomotor apraxia type 2 (AOA2) is an inherited disorder caused by mutations within both alleles of the senataxin gene. First symptoms are usually recognized before the age of 30. Unlike several other autosomal recessive cerebellar ataxia syndromes, levels of alpha-fetoprotein are nearly always elevated in AOA2 and thus narrowing down the differential diagnosis list. We present 3 video cases illustrating and expanding the clinical spectrum of AOA2, with 1 case bearing a novel mutation with cervical dystonia as the first symptom, the absence of neuropathy, and a disease onset beyond the age of 40. Furthermore, all patients were assessed by oculographic analysis, which revealed distinct patterns of oculomotor abnormalities. The clinical spectrum of AOA2 might be even broader than previously described in larger series. Oculography might be a useful tool to detect subclinical oculomotor apraxia in this disorder. |
Robert P. Burriss; Urszula M. Marcinkowska; Minna T. Lyons Gaze properties of women judging the attractiveness of masculine and feminine male faces Journal Article In: Evolutionary Psychology, vol. 12, no. 1, pp. 19–35, 2014. @article{Burriss2014, Most studies of female facial masculinity preference have relied upon self-reported preference, with participants selecting or rating the attractiveness of faces that differ in masculinity. However, researchers have not established a consensus as to whether women's general preference is for male faces that are masculine or feminine, and several studies have indicated that women prefer neither. We investigated women's preferences for male facial masculinity using standard two-alternative forced choice (2AFC) preference trials, paired with eye tracking measures, to determine whether conscious and non-conscious measures of preference yield similar results. We found that women expressed a preference for, gazed longer at, and fixated more frequently on feminized male faces. We also found effects of relationship status, relationship context (whether faced are judged for attractiveness as a long- or short-term partner), and hormonal contraceptive use. These results support previous findings that women express a preference for feminized over masculinized male faces, demonstrate that non-conscious measures of preference for this trait echo consciously expressed preferences, and suggest that certain aspects of the preference decision-making process may be better captured by eye tracking than by 2AFC preference trials. |
D. Brandon Burtis; Kenneth M. Heilman; Jue Mo; Chao Wang; Gregory F. Lewis; Maria I. Davilla; Mingzhou Ding; Stephen W. Porges; John B. Williamson The effects of constrained left versus right monocular viewing on the autonomic nervous system Journal Article In: Biological Psychology, vol. 100, no. 1, pp. 79–85, 2014. @article{Burtis2014, Asymmetrical activation of right and left hemispheres differentially influences the autonomic nervous system. Additionally, each hemisphere primarily receives retinocollicular projections from the contralateral eye. To learn if asymmetrical hemispheric activation induced by monocular viewing would influence relative pupillary size and respiratory hippus variability (RHV), a measure of parasympathetic activity, healthy participants had their left, right or neither eye patched. Pupillary sizes were then recorded with infrared pupillography. Pupillary dilation was significantly greater with left than right eye viewing. RHV, however, was not different between eye viewing conditions. These differences in pupil dilatation may have been caused by relatively greater activation of the right hemispheric-mediated sympathetic activity induced by left monocular viewing or relatively greater deactivation of the left hemispheric-mediated parasympathetic activity induced by right eye patching. The absence of an asymmetry in RHV, however, suggests that hemispheric asymmetry of sympathetic activation was primarily responsible for this ocular asymmetry of pupil dilation. |
Robyn Burton; Nicholas D. Smith; David P. Crabb Eye movements and reading in glaucoma: observations on patients with advanced visual field loss Journal Article In: Graefe's Archive for Clinical and Experimental Ophthalmology, vol. 252, no. 10, pp. 1621–1630, 2014. @article{Burton2014, PURPOSE: To investigate the relationship between reading speed and eye movements in patients with advanced glaucomatous visual field (VF) defects and age-similar visually healthy people.$backslash$n$backslash$nMETHODS: Eighteen patients with advanced bilateral VF defects (mean age: 71, standard deviation [SD]: 7 years) and 39 controls (mean age: 67, SD: 8 years) had reading speed measured using short passages of text on a computer set-up incorporating eye tracking. Scanpaths were plotted and analysed from these experiments to derive measures of 'perceptual span' (total number of letters read per number of saccades) and 'text saturation' (the distance between the first and last fixation on lines of text). Another eye movement measure, termed 'saccadic frequency' (total number of saccades made to read a single word), was derived from a separate lexical decision task, where words were presented in isolation.$backslash$n$backslash$nRESULTS: Significant linear association was demonstrated between perceptual span and reading speed in patients (R (2) = 0.42) and controls (R (2) = 0.56). Linear association between saccadic frequency during the LDT and reading speed was also found in patients (R (2) = 0.42), but not in controls (R (2) = 0.02). Patients also exhibited greater average text saturation than controls (P = 0.004).$backslash$n$backslash$nCONCLUSION: Some, but not all, patients with advanced VF defects read slower than controls using short text passages. Differences in eye movement behaviour may partly account for this variability in patients. These patients were shown to saturate lines of text more during reading, which may explain previously-reported difficulties with sustained reading. |
Thomas Busigny; Goedele Van Belle; Boutheina Jemel; Anthony Hosein; Sven Joubert; Bruno Rossion Face-specific impairment in holistic perception following focal lesion of the right anterior temporal lobe Journal Article In: Neuropsychologia, vol. 56, no. 1, pp. 312–333, 2014. @article{Busigny2014, Recent studies have provided solid evidence for pure cases of prosopagnosia following brain damage. The patients reported so far have posterior lesions encompassing either or both the right inferior occipital cortex and fusiform gyrus, and exhibit a critical impairment in generating a sufficiently detailed holistic percept to individualize faces. Here, we extended these observations to include the prosopagnosic patient LR (Bukach, Bub, Gauthier, & Tarr, 2006), whose damage is restricted to the anterior region of the right temporal lobe. First, we report that LR is able to discriminate parametrically defined individual exemplars of nonface object categories as accurately and quickly as typical observers, which suggests that the visual similarity account of prosopagnosia does not explain his impairments. Then, we show that LR does not present with the typical face inversion effect, whole-part advantage, or composite face effect and, therefore, has impaired holistic perception of individual faces. Moreover, the patient is more impaired at matching faces when the facial part he fixates is masked than when it is selectively revealed by means of gaze contingency. Altogether these observations support the view that the nature of the critical face impairment does not differ qualitatively across patients with acquired prosopagnosia, regardless of the localization of brain damage: all these patients appear to be impaired to some extent at what constitutes the heart of our visual expertise with faces, namely holistic perception at a sufficiently fine-grained level of resolution to discriminate exemplars of the face class efficiently. This conclusion raises issues regarding the existing criteria for diagnosis/classification of patients as cases of apperceptive or associative prosopagnosia. |
Charles F. Cadieu; Ha Hong; Daniel L. K. Yamins; Nicolas Pinto; Diego Ardila; Ethan A. Solomon; Najib J. Majaj; James J. DiCarlo Deep neural networks rival the representation of primate IT cortex for core visual object recognition Journal Article In: PLoS Computational Biology, vol. 10, no. 12, pp. e1003963, 2014. @article{Cadieu2014, The primate visual system achieves remarkable visual object recognition performance even in brief presentations, and under changes to object exemplar, geometric transformations, and background variation (a.k.a. core visual object recognition). This remarkable performance is mediated by the representation formed in inferior temporal (IT) cortex. In parallel, recent advances in machine learning have led to ever higher performing models of object recognition using artificial deep neural networks (DNNs). It remains unclear, however, whether the representational performance of DNNs rivals that of the brain. To accurately produce such a comparison, a major difficulty has been a unifying metric that accounts for experimental limitations, such as the amount of noise, the number of neural recording sites, and the number of trials, and computational limitations, such as the complexity of the decoding classifier and the number of classifier training examples. In this work, we perform a direct comparison that corrects for these experimental limitations and computational considerations. As part of our methodology, we propose an extension of ‘‘kernel analysis'' that measures the generalization accuracy as a function of representational complexity. Our evaluations show that, unlike previous bio-inspired models, the latest DNNs rival the representational performance of IT cortex on this visual object recognition task. Furthermore, we show that models that perform well on measures of representational performance also perform well on measures of representational similarity to IT, and on measures of predicting individual IT multi-unit responses. Whether these DNNs rely on computational mechanisms similar to the primate visual system is yet to be determined, but, unlike all previous bio- inspired models, that possibility cannot be ruled out merely on representational performance grounds. |
Xinying Cai; Camillo Padoa-Schioppa Contributions of orbitofrontal and lateral prefrontal cortices to economic choice and the good-to-action transformation Journal Article In: Neuron, vol. 81, no. 5, pp. 1140–1151, 2014. @article{Cai2014, Previous work indicates that economic decisions can be made independently of the visuomotor contingencies of the choice task (space of goods). However, the neuronal mechanisms through which the choice outcome (the chosen good) is transformed into a suitable action plan remain poorly understood. Here we show that neurons in lateral prefrontal cortex reflect the early stages of this good-to-action transformation. Monkeys chose between different juices. The experimental design dissociated in space and time the presentation of the offers and the saccade targets associated with them. We recorded from the orbital, ventrolateral, and dorsolateral prefrontal cortices (OFC, LPFCv, and LPFCd, respectively). Prior to target presentation, neurons in both LPFCv and LPFCd encoded the choice outcome in goods space. After target presentation, they gradually came to encode the location of the targets and the upcoming action plan. Consistent with the anatomical connectivity, all spatial and action-related signals emerged in LPFCv before LPFCd. |
Aurélie Calabrèse; Jean-Baptiste Bernard; Géraldine Faure; Louis Hoffart; Eric Castet Eye movements and reading speed in macular disease: The shrinking perceptual span hypothesis requires and is supported by a mediation analysis Journal Article In: Investigative Ophthalmology & Visual Science, vol. 55, no. 6, pp. 3638–3645, 2014. @article{Calabrese2014, Purpose. Reading speed of patients with Central Field Loss (CFL) correlates with the size of saccades (measured in letters per forward saccade - L/FS). We assessed whether this effect is mediated by the total number of fixations, by the average fixation duration, or by a mixture of both. Methods. We measured eye movements (with a video eyetracker) of 35 AMD and 4 Stargardt patients (better eye decimal acuity from 0.08 to 0.3) while they monocularly read single-line French sentences continuously displayed on a screen. All patients had a dense scotoma covering the fovea, as assessed with MP1 microperimetry, and therefore used eccentric viewing. Results were analyzed with regression-based mediation analysis, a modeling framework that informs on the underlying factors by which an independent variable affects a dependent variable. Results. Reading speed and average fixation duration are negatively correlated, a result that was not observed in prior studies with CFL patients. This effect of fixation duration on reading speed is still significant when partialling out the effect of the total number of fixations (slope:-0.75, p<0.001). Despite this large effect of fixation duration, mediation analysis shows that the effect of L/FS on reading speed is fully mediated by the total number of fixations (effect size: 0.96; CI[0.82, 1.12]) and not by fixation duration (effect size: 0.02; CI[-0.11,0.14]). Conclusions. Results are consistent with the shrinking perceptual span hypothesis: reading speed decreases with the average number of letters traversed on each forward saccade, an effect fully mediated by the total number of fixations. |
R. Calen Walshe; Antje Nuthmann Asymmetrical control of fixation durations in scene viewing Journal Article In: Vision Research, vol. 100, pp. 38–46, 2014. @article{CalenWalshe2014, In two experiments we investigated the control of fixation durations in naturalistic scene viewing. Empirical evidence from the scene onset delay paradigm and numerical simulations of such data with the CRISP model [Psychological Review 117 (2010) 382-405] have suggested that processing related difficulties may lead to prolonged fixation durations. Here, we ask whether processing related facilitation may lead to comparable decreases to fixation durations. Research in visual search and reading have reported only uni-directional shifts. To address the question of unidirectional (slow down) as opposed to bidirectional (slow down and speed up) adjustment of fixation durations in the context of scene viewing, we used a saccade-contingent display change method to either reduce or increase the luminance of the scene during prespecified critical fixations. Degrading the stimulus by shifting luminance down resulted in an immediate increase to fixation durations. However, clarifying the stimulus by shifting luminance upwards did not result in a comparable decrease to fixation durations. These results suggest that the control of fixation durations in scene viewing is asymmetric, as has been reported for visual search and reading. |
Estela Camara; Lluis Fuentemilla Accessing forgotten memory traces from long-term memory via visual movements Journal Article In: Frontiers in Human Neuroscience, vol. 8, pp. 930, 2014. @article{Camara2014, Because memory retrieval often requires overt responses, it is difficult to determine to what extend forgetting occurs as a problem in explicit accessing of long-term memory traces. In this study, we used eye-tracking measures in combination with a behavioral task that favored high forgetting rates to investigate the existence of memory traces from long-term memory in spite of failure in accessing them consciously. In two experiments, participants were encouraged to encode a large set of sound-picture-location associations. In a later test, sounds were presented and participants were instructed to visually scan, before a verbal memory report, for the correct location of the associated pictures in an empty screen. We found the reactivation of associated memories by sound cues at test biased oculomotor behavior towards locations congruent with memory representations, even when participants failed to consciously provide a memory report of it. These findings reveal the emergence of a memory-guided behavior that can be used to map internal representations of forgotten memories from long-term memory. |
Nathan Caruana; Jon Brock No association between autistic traits and contextual influences on eye-movements during reading Journal Article In: PeerJ, vol. 2, pp. 1–16, 2014. @article{Caruana2014, Individuals with autism spectrum disorders are claimed to show a local cognitive bias, termed " weak central coherence " , which manifests in a reduced influence of con-textual information on linguistic processing. Here, we investigated whether this bias might also be demonstrated by individuals who exhibit sub-clinical levels of autistic traits, as has been found for other aspects of autistic cognition. The eye-movements of 71 university students were monitored as they completed a reading comprehension task. Consistent with previous studies, participants made shorter fixations on words that were highly predicted on the basis of preceding sentence context. However, contrary to the weak central coherence account, this effect was not reduced amongst individuals with high levels of autistic traits, as measured by the Autism Spectrum Quotient (AQ). Further exploratory analyses revealed that participants with high AQ scores fixated longer on words that resolved the meaning of an earlier homograph. However, this was only the case for sentences where the two potential meanings of the homograph result in different pronunciations. The results provide tentative evidence for differences in reading style that are associated with autistic traits, but fail to support the notion of weak central coherence extending into the non-autistic population. |
Marta Castellano; Michael Plöchl; Raul Vicente; Gordon Pipa Neuronal oscillations form parietal/frontal networks during contour integration Journal Article In: Frontiers in Integrative Neuroscience, vol. 8, pp. 64, 2014. @article{Castellano2014, The ability to integrate visual features into a global coherent percept that can be further categorized and manipulated are fundamental abilities of the neural system. While the processing of visual information involves activation of early visual cortices, the recruitment of parietal and frontal cortices has been shown to be crucial for perceptual processes. Yet is it not clear how both cortical and long-range oscillatory activity leads to the integration of visual features into a coherent percept. Here, we will investigate perceptual grouping through the analysis of a contour categorization task, where the local elements that form contour must be linked into a coherent structure, which is then further processed and manipulated to perform the categorization task. The contour formation in our visual stimulus is a dynamic process where, for the first time, visual perception of contours is disentangled from the onset of visual stimulation or from motor preparation, cognitive processes that until now have been behaviorally attached to perceptual processes. Our main finding is that, while local and long-range synchronization at several frequencies seem to be an ongoing phenomena, categorization of a contour could only be predicted through local oscillatory activity within parietal/frontal sources, which in turn, would synchronize at gamma (>30 Hz) frequency. Simultaneously, fronto-parietal beta (13-30 Hz) phase locking forms a network spanning across neural sources that are not category specific. Both long range networks, i.e., the gamma network that is category specific, and the beta network that is not category specific, are functionally distinct but spatially overlapping. Altogether, we show that a critical mechanism underlying contour categorization involves oscillatory activity within parietal/frontal cortices, as well as its synchronization across distal cortical sites. |
Francesca Ciardo; Barbara F. M. Marino; Rossana Actis-Grosso; Angela Rossetti; Paola Ricciardelli Face age modulates gaze following in young adults Journal Article In: Scientific Reports, vol. 4, pp. 4746, 2014. @article{Ciardo2014, Gaze-following behaviour is considered crucial for social interactions which are influenced by social similarity. We investigated whether the degree of similarity, as indicated by the perceived age of another person, can modulate gaze following. Participants of three different age-groups (18-25; 35-45; over 65) performed an eye movement (a saccade) towards an instructed target while ignoring the gaze-shift of distracters of different age-ranges (6-10; 18-25; 35-45; over 70). The results show that gaze following was modulated by the distracter face age only for young adults. Particularly, the over 70 year-old distracters exerted the least interference effect. The distracters of a similar age-range as the young adults (18-25; 35-45) had the most effect, indicating a blurred own-age bias (OAB) only for the young age group. These findings suggest that face age can modulate gaze following, but this modulation could be due to factors other than just OAB (e.g., familiarity). |
Moreno I. Coco; Frank Keller Classification of visual and linguistic tasks using eye-movement features Journal Article In: Journal of Vision, vol. 14, no. 3, pp. 1–18, 2014. @article{Coco2014, The role of the task has received special attention in visual-cognition research because it can provide causal explanations of goal-directed eye-movement responses. The dependency between visual attention and task suggests that eye movements can be used to classify the task being performed. A recent study by Greene, Liu, and Wolfe (2012), however, fails to achieve accurate classification of visual tasks based on eye-movement features. In the present study, we hypothesize that tasks can be successfully classified when they differ with respect to the involvement of other cognitive domains, such as language processing. We extract the eye-movement features used by Greene et al. as well as additional features from the data of three different tasks: visual search, object naming, and scene description. First, we demonstrated that eye-movement responses make it possible to characterize the goals of these tasks. Then, we trained three different types of classifiers and predicted the task participants performed with an accuracy well above chance (a maximum of 88% for visual search). An analysis of the relative importance of features for classification accuracy reveals that just one feature, i.e., initiation time, is sufficient for above-chance performance (a maximum of 79% accuracy in object naming). Crucially, this feature is independent of task duration, which differs systematically across the three tasks we investigated. Overall, the best task classification performance was obtained with a set of seven features that included both spatial information (e.g., entropy of attention allocation) and temporal components (e.g., total fixation on objects) of the eye-movement record. This result confirms the task-dependent allocation of visual attention and extends previous work by showing that task classification is possible when tasks differ in the cognitive processes involved (purely visual tasks such as search vs. communicative tasks such as scene description). |
Moreno I. Coco; George L. Malcolm; Frank Keller The interplay of bottom-up and top-down mechanisms in visual guidance during object naming Journal Article In: Quarterly Journal of Experimental Psychology, vol. 67, no. 6, pp. 1096–1120, 2014. @article{Coco2014a, An ongoing issue in visual cognition concerns the roles played by low- and high-level information in guiding visual attention, with current research remaining inconclusive about the interaction between the two. In this study, we bring fresh evidence into this long-standing debate by investigating visual saliency and contextual congruency during object naming (Experiment 1), a task in which visual processing interacts with language processing. We then compare the results of this experiment to data of a memorization task using the same stimuli (Experiment 2). In Experiment 1, we find that both saliency and congruency influence visual and naming responses and interact with linguistic factors. In particular, incongruent objects are fixated later and less often than congruent ones. However, saliency is a significant predictor of object naming, with salient objects being named earlier in a trial. Furthermore, the saliency and congruency of a named object interact with the lexical frequency of the associated word and mediate the time-course of fixations at naming. In Experiment 2, we find a similar overall pattern in the eye-movement responses, but only the congruency of the target is a significant predictor, with incongruent targets fixated less often than congruent targets. Crucially, this finding contrasts with claims in the literature that incongruent objects are more informative than congruent objects by deviating from scene context and hence need a longer processing. Overall, this study suggests that different sources of information are interactively used to guide visual attention on the targets to be named and raises new questions for existing theories of visual attention. |
Michael Coesmans; Christian H. Röder; Albertine E. Smit; Sebastiaan K. E. Koekkoek; Chris I. De Zeeuw; Maarten A. Frens; Josef N. Geest Cerebellar motor learning deficits in medicated and medication-free men with recent-onset schizophrenia Journal Article In: Journal of Psychiatry and Neuroscience, vol. 39, no. 1, pp. 3–11, 2014. @article{Coesmans2014, BACKGROUND: The notion that cerebellar deficits may underlie clinical symptoms in people with schizophrenia is tested by evaluating 2 forms of cerebellar learning in patients with recent-onset schizophrenia. A potential medication effect is evaluated by including patients with or without antipsychotics. METHODS: We assessed saccadic eye movement adaptation and eyeblink conditioning in men with recent-onset schizophrenia who were taking antipsychotic medication or who were antipsychotic-free and in age-matched controls. RESULTS: We included 39 men with schizophrenia (10 who were taking clozapine, 16 who were taking haloperidol and 13 who were antipsychotic-free) and 29 controls in our study. All participants showed significant saccadic adaptation. Adaptation strength did not differ between healthy controls and men with schizophrenia. The speed of saccade adaptation, however, was significantly lower in men with schizophrenia. They showed a significantly lower increase in the number of conditioned eyeblink responses. Over all experiments, no consistent effects of medication were observed. These outcomes did not correlate with age, years of education, psychopathology or dose of antipsychotics. LIMITATIONS: As patients were not randomized for treatment, an influence of confounding variables associated with medication status cannot be excluded. Individual patients also varied along the schizophrenia spectrum despite the relative homogeneity with respect to onset of illness and short usage of medication. Finally, the relatively small number of participants may have concealed effects as a result of insufficient statistical power. CONCLUSION: We found several cerebellar learning deficits in men with schizophrenia that we cannot attribute to the use of antipsychotics. Although this finding, combined with the fact that deficits are already present in patients with recent-onset schizophrenia, could suggest that cerebellar impairments are a trait deficit in people with schizophrenia. This should be confirmed in longitudinal studies. |
Andrew L. Cohen; Adrian Staub Online processing of novel noun-noun compounds: Eye movement evidence Journal Article In: Quarterly Journal of Experimental Psychology, vol. 67, no. 1, pp. 147–165, 2014. @article{Cohen2014, Three eye-tracking experiments investigated online processing of novel noun-noun compounds. The experiments compared processing of compounds that are difficult to interpret in isolation (e.g., dictionary treatment) and more easily interpretable adjective-noun and noun-noun sequences (e.g., rough treatment and torture treatment). In all three experiments, first-pass reading time was longer on the head noun (treatment) when it occurred in a difficult compound. Further, a preceding sentence that provided a potential interpretation of the critical compound reduced processing difficulty, but this modulation by context occurred in later eye movement measures, or downstream of the compound itself. These results are interpreted in relation to the eye movement literature on the processing of implausibility, which demonstrates a similar pattern in which the disruption in early eye movement measures is not alleviated by context, but context does have a later effect. The results also suggest that the interpretation of noun-noun compounds in context does initially depend on the availability of an out-of-context interpretation. |
Derya Çokal; Patrick Sturt; Fernanda Ferreira Deixis: This and that in written narrative discourse Journal Article In: Discourse Processes, vol. 51, no. 3, pp. 201–229, 2014. @article{Cokal2014, The existing literature presents conflicting models of how this and that access different segments of a written discourse, frequently relying on implicit analogies with spoken discourse. On the basis of this literature, we hypothesized that in written discourse, this more readily accesses the adjacent/right frontier of a preceding chunk of text, whereas that more readily accesses the distant/left. We tested this hypothesis in two eye-tracking experiments, one sentence completion experiment, and one corpus study. Our results showed that both this and that access the adjacent frontier more easily than the distant. Contrary to existing theories, this accessed the distant frontier more frequently and easily than that. We propose a processing model integrating segmented discourse representation theory's concept of the left/distant leaf with Grosz and Sidner's attentional and intentional model and Garrod and Sandford's focus framework model, suggesting an important role for working memory and emphasizing the different production modes of readers and writers. |
Thérèse Collins Trade-off between spatiotopy and saccadic plasticity Journal Article In: Journal of Vision, vol. 4, no. 12, pp. 1–14, 2014. @article{Collins2014, Saccadic eye movements bring objects of interest onto the high-resolution fovea. They also change the retinal location of objects, but our impression of the visual world is stable: We represent our visual world in spatiotopic coordinates. Visual stability could be the result of a null hypothesis that things do not move during a saccade, or of realigning retinal images based on an internal copy of the eye movement (remapping). The current studies disentangled these hypotheses. Subjects saccaded to peripheral targets that were displaced by different amounts during execution, and detected or discriminated displacement direction. Evidence for a null hypothesis was provided by the relatively poor perceptual performance, and evidence for remapping by the independence of performance from saccade endpoint. There was a trade-off between spatiotopic performance and saccadic plasticity: Good performance (perception of displacements) led to small compensative modifications in saccade amplitude on the next trial while poor performance led to larger modifications. Results also showed that variations in saccade amplitude also depended on the size of the retinal error and of the saccade itself. These results suggest that when faced with a discrepancy between the saccade endpoint and visual target, the visual system attributes the discrepancy to object displacement or to saccade error, in which case the subsequent saccade is corrected. This result reconciles the two hypotheses by suggesting that accurate remapping serves oculomotor accuracy but not visual stability. Internal copies of eye movements may thus be used separately to establish spatiotopic representations and to maintain oculomotor accuracy. |
Michael Colombo; James S. Magnuson Eye movements reveal planning in humans: A comparison with Scarf and Colombo's (2009) monkeys Journal Article In: Journal of Experimental Psychology: Animal Learning and Cognition, vol. 40, no. 2, pp. 178–184, 2014. @article{Colombo2014, On sequential response tasks, a long pause preceding the first response is thought to reflect participants taking time to plan a sequence of responses. By tracking the eye movements of two monkeys (Macaca fascicularis), Scarf and Colombo (2009, Eye Movements During List Execution Reveal No Planning in Monkeys [Macaca fascicularis], Journal of Experimental Psychology: Animal Behavior Processes, Vol. 35, pp. 587–592) demonstrated that, at least with respect to monkeys, the long pause preceding the first response is not necessarily the product of planning. In the present experiment, we tracked the eye movements of adult humans using the paradigm employed by Scarf and Colombo and found that, in contrast to monkeys, the pause preceding the first item is indicative of planning in humans. These findings highlight the fact that similar response time profiles, displayed by human and nonhuman animals, do not necessarily reflect similar underlying cognitive operations. |
Dejan Draschkow; Jeremy M. Wolfe; Melissa L. -H. Võ Seek and you shall remember: Scene semantics interact with visual search to build better memories Journal Article In: Journal of Vision, vol. 14, no. 8, pp. 1–18, 2014. @article{Draschkow2014, Memorizing critical objects and their locations is an essential part of everyday life. In the present study, incidental encoding of objects in naturalistic scenes during search was compared to explicit memorization of those scenes. To investigate if prior knowledge of scene structure influences these two types of encoding differently, we used meaningless arrays of objects as well as objects in real-world, semantically meaningful images. Surprisingly, when participants were asked to recall scenes, their memory performance was markedly better for searched objects than for objects they had explicitly tried to memorize, even though participants in the search condition were not explicitly asked to memorize objects. This finding held true even when objects were observed for an equal amount of time in both conditions. Critically, the recall benefit for searched over memorized objects in scenes was eliminated when objects were presented on uniform, non-scene backgrounds rather than in a full scene context. Thus, scene semantics not only help us search for objects in naturalistic scenes, but appear to produce a representation that supports our memory for those objects beyond intentional memorization. |
Jan Drewes; Weina Zhu; Yingzhou Hu; Xintian Hu Smaller is better: Drift in gaze measurements due to pupil dynamics Journal Article In: PLoS ONE, vol. 9, no. 10, pp. e111197, 2014. @article{Drewes2014, Camera-based eye trackers are the mainstay of eye movement research and countless practical applications of eye tracking. Recently, a significant impact of changes in pupil size on gaze position as measured by camera-based eye trackers has been reported. In an attempt to improve the understanding of the magnitude and population-wise distribution of the pupil-size dependent shift in reported gaze position, we present the first collection of binocular pupil drift measurements recorded from 39 subjects. The pupil-size dependent shift varied greatly between subjects (from 0.3 to 5.2 deg of deviation, mean 2.6 deg), but also between the eyes of individual subjects (0.1 to 3.0 deg difference, mean difference 1.0 deg). We observed a wide range of drift direction, mostly downward and nasal. We demonstrate two methods to partially compensate the pupil-based shift using separate calibrations in pupil-constricted and pupil-dilated conditions, and evaluate an improved method of compensation based on individual look-up-tables, achieving up to 74% of compensation. |
Serge O. Dumoulin; R. F. Hess; Keith A. May; Ben M. Harvey Contour extracting networks in early extrastriate cortex Journal Article In: Journal of Vision, vol. 14, no. 5, pp. 1–14, 2014. @article{Dumoulin2014, Neurons in the visual cortex process a local region of visual space, but in order to adequately analyze natural images, neurons need to interact. The notion of an ‘‘association field'' proposes that neurons interact to extract extended contours. Here, we identify the site and properties of contour integration mechanisms. We used functional magnetic resonance imaging (fMRI) and population receptive field (pRF) analyses. We devised pRF mapping stimuli consisting of contours. We isolated the contribution of contour integration mechanisms to the pRF by manipulating the contour content. This stimulus manipulation led to systematic changes in pRF size. Whereas a bank of Gabor filters quantitatively explains pRF size changes in V1, only V2/V3 pRF sizes match the predictions of the association field. pRF size changes in later visual field maps, hV4, LO-1, and LO-2 do not follow either prediction and are probably driven by distinct classical receptive field properties or other extraclassical integration mechanisms. These pRF changes do not follow conventional fMRI signal strength measures. Therefore, analyses of pRF changes provide a novel computational neuroimaging approach to investigating neural interactions. We interpreted these results as evidence for neural interactions along co- oriented, cocircular receptive fields in the early extrastriate visual cortex (V2/V3), consistent with the notion of a contour association field. |
Matt J. Dunn; Tom H. Margrain; J. Margaret Woodhouse; Fergal A. Ennis; Christopher M. Harris; Jonathan T. Erichsen Grating visual acuity in infantile nystagmus in the absence of image motion Journal Article In: Investigative Ophthalmology & Visual Science, vol. 55, no. 4, pp. 2682–2686, 2014. @article{Dunn2014, PURPOSE: Infantile nystagmus (IN) consists of largely horizontal oscillations of the eyes that usually begin shortly after birth. The condition is almost always associated with lower-than-normal visual acuity (VA). This is assumed to be at least partially due to motion blur induced by the eye movements. Here, we investigated the effect of image motion on VA. METHODS: Grating stimuli were presented, illuminated by either multiple tachistoscopic flashes (0.76 ms) to circumvent retinal image motion, or under constant illumination, to subjects with horizontal idiopathic IN and controls. A staircase procedure was used to estimate VA (by judging direction of tilt) under each condition. Orientation-specific effects were investigated by testing gratings oriented about both the horizontal and vertical axes. RESULTS: Nystagmats had poorer VA than controls under both constant and tachistoscopic illumination. Neither group showed a significant difference in VA between illumination conditions. Nystagmats performed worse for vertically oriented gratings, even under tachistoscopic conditions (P < 0.01), but there was no significant effect of orientation in controls. CONCLUSIONS: The fact that VA was not significantly affected by either illumination condition strongly suggests that the eye movements themselves do not significantly degrade VA in adults with IN. Treatments and therapies that seek to modify and/or reduce eye movements may therefore be fundamentally limited in any improvement that can be achieved with respect to VA. |
Lien Dupont; Marc Antrop; Veerle Van Eetvelde Eye-tracking analysis in landscape perception research: Influence of photograph properties and landscape characteristics Journal Article In: Landscape Research, vol. 39, no. 4, pp. 417–432, 2014. @article{Dupont2014, The European Landscape Convention emphasises the need for public participation in landscape planning and management. This demands understanding of how people perceive and observe landscapes. This can objectively be measured using eye tracking, a system recording eye movements and fixations while observing images. In this study, 23 participants were asked to observe 90 landscape photographs, representing 18 landscape character types in Flanders (Belgium) differing in degree of openness and heterogeneity. For each landscape, five types of photographs were shown, varying in view angle. This experiment design allowed testing the effect of the landscape characteristics and photograph types on the observation pattern, measured by Eye-tracking Metrics (ETM). The results show that panoramic and detail photographs are observed differently than the other types. The degree of openness and heterogeneity also seems to exert a significant influence on the observation of the landscape. |
Muriel Dysli; Nicolas Vogel; Mathias Abegg Reading performance is not affected by a prism induced increase of horizontal and vertical vergence demand Journal Article In: Frontiers in Human Neuroscience, vol. 8, pp. 431, 2014. @article{Dysli2014, PURPOSE: Dyslexia is the most common developmental reading disorder that affects language skills. Latent strabismus (heterophoria) has been suspected to be causally involved. Even though phoria correction in dyslexic children is commonly applied, the evidence in support of a benefit is poor. In order to provide experimental evidence on this issue, we simulated phoria in healthy readers by modifying the vergence tone required to maintain binocular alignment. METHODS: Vergence tone was altered with prisms that were placed in front of one eye in 16 healthy subjects to induce exophoria, esophoria, or vertical phoria. Subjects were to read one paragraph for each condition, from which reading speed was determined. Text comprehension was tested with a forced multiple choice test. Eye movements were recorded during reading and subsequently analyzed for saccadic amplitudes, saccades per 10 letters, percentage of regressive (backward) saccades, average fixation duration, first fixation duration on a word, and gaze duration. RESULTS: Acute change of horizontal and vertical vergence tone does neither significantly affect reading performance nor reading associated eye movements. CONCLUSION: Prisms in healthy subjects fail to induce a significant change of reading performance. This finding is not compatible with a role of phoria in dyslexia. Our results contrast the proposal for correcting small angle heterophorias in dyslexic children. |
R. Becket Ebitz; John M. Pearson; Michael L. Platt Pupil size and social vigilance in rhesus macaques Journal Article In: Frontiers in Neuroscience, vol. 8, pp. 100, 2014. @article{Ebitz2014, Complex natural environments favor the dynamic alignment of neural processing between goal-relevant stimuli and conflicting but biologically salient stimuli like social competitors or predators. The biological mechanisms that regulate dynamic changes in vigilance have not been fully elucidated. Arousal systems that ready the body to respond adaptively to threat may contribute to dynamic regulation of vigilance. Under conditions of constant luminance, pupil diameter provides a peripheral index of arousal state. Although pupil size varies with the processing of goal-relevant stimuli, it remains unclear whether pupil size also predicts attention to biologically salient objects and events like social competitors, whose presence interferes with current goals. Here we show that pupil size in rhesus macaques both reflects the biological salience of task-irrelevant social distractors and predicts vigilance for these stimuli. We measured pupil size in monkeys performing a visual orienting task in which distractors-monkey faces and phase-scrambled versions of the same images-could appear in a congruent, incongruent, or neutral position relative to a rewarded target. Baseline pupil size under constant illumination predicted distractor interference, consistent with the hypothesis that pupil-linked arousal mechanisms regulate task engagement and distractibility. Notably, pupil size also predicted enhanced vigilance for social distractors, suggesting that pupil-linked arousal may adjust the balance of processing resources between goal-relevant and biologically important stimuli. The magnitude of pupil constriction in response to distractors closely tracked distractor interference, saccade planning and the social relevance of distractors, endorsing the idea that the pupillary light response is modulated by attention. These findings indicate that pupil size indexes dynamic changes in attention evoked by both the social environment and arousal. |
Jonas Everaert; Wouter Duyck; Ernst H. W. Koster Attention, interpretation, and memory biases in subclinical depression: A proof-of-principle test of the combined cognitive biases hypothesis Journal Article In: Emotion, vol. 14, no. 2, pp. 331–340, 2014. @article{Everaert2014, Emotional biases in attention, interpretation, and memory are viewed as important cognitive processes underlying symptoms of depression. To date, there is a limited understanding of the interplay among these processing biases. This study tested the dependence of memory on depression-related biases in attention and interpretation. Subclinically depressed and non- depressed participants completed a computerized version of the scrambled sentences test (measuring interpretation bias) while their eye movements were recorded (measuring attention bias). This task was followed by an incidental free recall test of previously constructed interpretations (measuring memory bias). Path analysis revealed a good fit for the model in which selective orienting of attention was associated with interpretation bias, which in turn was associated with a congruent bias in memory. Also, a good fit was observed for a path model in which biases in the maintenance of attention and interpretation were associated with memory bias. Both path models attained a superior fit compared to path models without the theorized functional relations among processing biases. These findings enhance understanding of how mechanisms of attention and interpretation regulate what is remembered. As such, they offer support for the combined cognitive biases hypothesis or the notion that emotionally biased cognitive processes are not isolated mechanisms but instead influence each other. Implications for theoretical models and emotion regulation across the spectrum of depressive symptoms are discussed. |
Ashley Farris-Trimble; Bob McMurray; Nicole Cigrand; J. Bruce Tomblin The process of spoken word recognition in the face of signal degradation Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 40, no. 1, pp. 308–327, 2014. @article{FarrisTrimble2014, Though much is known about how words are recognized, little research has focused on how a degraded signal affects the fine-grained temporal aspects of real-time word recognition. The perception of degraded speech was examined in two populations with the goal of describing the time course of word recognition and lexical competition. Thirty-three postlingually deafened cochlear implant (CI) users and 57 normal hearing (NH) adults (16 in a CI-simulation condition) participated in a visual world paradigm eye-tracking task in which their fixations to a set of phonologically related items were monitored as they heard one item being named. Each degraded-speech group was compared with a set of age-matched NH participants listening to unfiltered speech. CI users and the simulation group showed a delay in activation relative to the NH listeners, and there is weak evidence that the CI users showed differences in the degree of peak and late competitor activation. In general, though, the degraded-speech groups behaved statistically similarly with respect to activation levels. |
Alexandra Fayel; Sylvie Chokron; Céline Cavézian; Dorine Vergilino-Perez; Christelle Lemoine; Karine Doré-Mazars Characteristics of contralesional and ipsilesional saccades in hemianopic patients Journal Article In: Experimental Brain Research, vol. 232, no. 3, pp. 903–917, 2014. @article{Fayel2014, In order to further our understanding of action-blindsight, four hemianopic patients suffering from visual field loss contralateral to a unilateral occipital lesion were compared to six healthy controls during a double task of verbally reported target detection and saccadic responses toward the target. Three oculomotor tasks were used: a fixation task (i.e., without saccade) and two saccade tasks (eliciting reflexive and voluntary saccades, using step and overlap 600 ms paradigms, respectively), in separate sessions. The visual target was briefly presented at two different eccentricities (5° and 8°), in the right or left visual hemifield. Blank trials were interleaved with target trials, and signal detection theory was applied. Despite their hemifield defect, hemianopic patients retained the ability to direct a saccade toward their contralesional hemifield, whereas verbal detection reports were at chance level. However, saccade parameters (latency and amplitude) were altered by the defect. Saccades to the contralesional hemifield exhibited longer latencies and shorter amplitudes compared to those of the healthy group, whereas only the latencies of reflexive saccades to the ipsilesional hemifield were altered. Furthermore, healthy participants showed the expected latency difference between reflexive and voluntary saccades, with the latter longer than the former. This difference was not found in three out of four patients in either hemifield. Our results show action-blindsight for saccades, but also show that unilateral occipital lesions have effects on saccade generation in both visual hemifields. |
Tomer Fekete; Felix D. C. C. Beacher; Jiook Cha; Denis Rubin; Lilianne R. Mujica-Parodi Small-world network properties in prefrontal cortex correlate with predictors of psychopathology risk in young children: A NIRS study Journal Article In: NeuroImage, vol. 85, pp. 345–353, 2014. @article{Fekete2014, Near infrared spectroscopy (NIRS) is an emerging imaging technique that is relatively inexpensive, portable, and particularly well suited for collecting data in ecological settings. Therefore, it holds promise as a potential neurodiagnostic for young children. We set out to explore whether NIRS could be utilized in assessing the risk of developmental psychopathology in young children. A growing body of work indicates that temperament at young age is associated with vulnerability to psychopathology later on in life. In particular, it has been shown that low effortful control (EC), which includes the focusing and shifting of attention, inhibitory control, perceptual sensitivity, and a low threshold for pleasure, is linked to conditions such as anxiety, depression and attention deficit hyperactivity disorder (ADHD). Physiologically, EC has been linked to a control network spanning among other sites the prefrontal cortex. Several psychopathologies, such as depression and ADHD, have been shown to result in compromised small-world network properties. Therefore we set out to explore the relationship between EC and the small-world properties of PFC using NIRS. NIRS data were collected from 44 toddlers, ages 3-5, while watching naturalistic stimuli (movie clips). Derived complex network measures were then correlated to EC as derived from the Children's Behavior Questionnaire (CBQ). We found that reduced levels of EC were associated with compromised small-world properties of the prefrontal network. Our results suggest that the longitudinal NIRS studies of complex network properties in young children hold promise in furthering our understanding of developmental psychopathology. |
Joost Felius; Cynthia L. Beauchamp; David R. Stager Visual acuity deficits in children with nystagmus and down syndrome Journal Article In: American Journal of Ophthalmology, vol. 157, no. 2, pp. 458–463, 2014. @article{Felius2014, Purpose: To investigate the association between visual acuity deficits and fixation instability in children with Down syndrome and nystagmus. Design Prospective cross-sectional study. Methods: setting: Institutional. study population: Sixteen children (aged 10 months-14 years) with Down syndrome and nystagmus, and a control group of 93 age-similar children with unassociated infantile nystagmus. observation procedures: Binocular Teller acuity card testing and eye-movement recordings. Fixation stability was quantified using the nystagmus optimal fixation function (NOFF). An exponential model based on results from the control group with unassociated infantile nystagmus was used to relate fixation stability to age-corrected visual acuity deficits. main outcome measures: Binocular grating visual acuity and NOFF. Results: Visual acuity was 0.2-0.9 logMAR (20/30-20/174 Snellen equivalent) and corresponded to a 0.4 logMAR (4 lines) mean age-corrected visual acuity deficit. Fixation stability ranged from poor to mildly affected. Although visual acuity deficit was on average 0.17 logMAR larger (P =.005) than predicted by the model, most children had visual acuity deficit within the 95% predictive interval. Conclusions: There was a small mean difference between the measured visual acuity deficit and the prediction of the nystagmus model. Although other factors also contribute to visual acuity loss in Down syndrome, nystagmus alone could account for most of the visual acuity deficit in these children. |
Jenni Deveau; Gary Lovcik; Aaron R. Seitz Broad-based visual benefits from training with an integrated perceptual-learning video game Journal Article In: Vision Research, vol. 99, pp. 134–140, 2014. @article{Deveau2014, Perception is the window through which we understand all information about our environment, and therefore deficits in perception due to disease, injury, stroke or aging can have significant negative impacts on individuals' lives. Research in the field of perceptual learning has demonstrated that vision can be improved in both normally seeing and visually impaired individuals, however, a limitation of most perceptual learning approaches is their emphasis on isolating particular mechanisms. In the current study, we adopted an integrative approach where the goal is not to achieve highly specific learning but instead to achieve general improvements to vision. We combined multiple perceptual learning approaches that have individually contributed to increasing the speed, magnitude and generality of learning into a perceptual-learning based video-game. Our results demonstrate broad-based benefits of vision in a healthy adult population. Transfer from the game includes; improvements in acuity (measured with self-paced standard eye-charts), improvement along the full contrast sensitivity function, and improvements in peripheral acuity and contrast thresholds. The use of this type of this custom video game framework built up from psychophysical approaches takes advantage of the benefits found from video game training while maintaining a tight link to psychophysical designs that enable understanding of mechanisms of perceptual learning and has great potential both as a scientific tool and as therapy to help improve vision. |
Leandro Luigi Di Stasi; Raúl Cabestrero; Michael B. Mccamy; Francisco Ríos; Andrés Catena; Pilar Quirós; Jose A. Lopez; Carolina Saez; Stephen L. Macknik; Susana Martinez-Conde Intersaccadic drift velocity is sensitive to short-term hypobaric hypoxia Journal Article In: European Journal of Neuroscience, vol. 39, no. 8, pp. 1384–1390, 2014. @article{DiStasi2014, Hypoxia, defined as decreased availability of oxygen in the body's tissues, can lead to dyspnea, rapid pulse, syncope, visual dysfunction, mental disturbances such as delirium or euphoria, and even death. It is considered to be one of the most serious hazards during flight. Thus, early and objective detection of the physiological effects of hypoxia is critical to prevent catastrophes in civil and military aviation. The few studies that have addressed the effects of hypoxia on objective oculomotor metrics have had inconsistent results, however. Thus, the question of whether hypoxia modulates eye movement behavior remains open. Here we examined the effects of short-term hypobaric hypoxia on the velocity of saccadic eye movements and intersaccadic drift of Spanish Air Force pilots and flight engineers, compared with a control group that did not experience hypoxia. Saccadic velocity decreased with time-on-duty in both groups, in correlation with subjective fatigue. Intersaccadic drift velocity increased in the hypoxia group only, suggesting that acute hypoxia diminishes eye stability, independently of fatigue. Our results suggest that intersaccadic drift velocity could serve as a biomarker of acute hypoxia. These findings may also contribute to our understanding of the relationship between hypoxia episodes and central nervous system impairments. |
Leandro Luigi Di Stasi; Michael B. McCamy; Stephen L. Macknik; James A. Mankin; Nicole Hooft; Andrés Catena; Susana Martinez-Conde Saccadic eye movement metrics reflect surgical residents′ fatigue Journal Article In: Annals of Surgery, vol. 259, no. 4, pp. 824–829, 2014. @article{DiStasi2014a, OBJECTIVE: Little is known about the effects of surgical residentsÊ fatigue on patient safety. We monitored surgical residentsÊ fatigue levels during their call day using (1) eye movement metrics, (2) objective measures of laparoscopic surgical performance, and (3) subjective reports based on standardized questionnaires. BACKGROUND: Prior attempts to investigate the effects of fatigue on surgical performance have suffered from methodological limitations, including inconsistent definitions and lack of objective measures of fatigue, and nonstandardized measures of surgical performance. Recent research has shown that fatigue can affect the characteristics of saccadic (fast ballistic) eye movements in nonsurgical scenarios. Here we asked whether fatigue induced by time-on-duty (∼24 hours) might affect saccadic metrics in surgical residents. Because saccadic velocity is not under voluntary control, a fatigue index based on saccadic velocity has the potential to provide an accurate and unbiased measure of the residentÊs fatigue level. METHODS: We measured the eye movements of members of the general surgery resident team at St. JosephÊs Hospital and Medical Center (Phoenix, AZ) (6 males and 6 females), using a head-mounted video eye tracker (similar configuration to a surgical headlight), during the performance of 3 tasks: 2 simulated laparoscopic surgery tasks (peg transfer and precision cutting) and a guided saccade task, before and after their call day. Residents rated their perceived fatigue level every 3 hours throughout their 24-hour shift, using a standardized scale. RESULTS:: Time-on-duty decreased saccadic velocity and increased subjective fatigue but did not affect laparoscopic performance. These results support the hypothesis that saccadic indices reflect graded changes in fatigue. They also indicate that fatigue due to prolonged time-on-duty does not result necessarily in medical error, highlighting the complicated relationship among continuity of care, patient safety, and fatigued providers. CONCLUSIONS: Our data show, for the first time, that saccadic velocity is a reliable indicator of the subjective fatigue of health care professionals during prolonged time-on-duty. These findings have potential impacts for the development of neuroergonomic tools to detect fatigue among health professionals and in the specifications of future guidelines regarding residentsÊ duty hours. |
Adele Diederich; Annette Schomburg; Marieke K. Vugt Fronto-central theta oscillations are related to oscillations in saccadic response times (SRT): An EEG and behavioral data analysis Journal Article In: PLoS ONE, vol. 9, no. 11, pp. e112974, 2014. @article{Diederich2014, The phase reset hypothesis states that the phase of an ongoing neural oscillation, reflecting periodic fluctuations in neural activity between states of high and low excitability, can be shifted by the occurrence of a sensory stimulus so that the phase value become highly constant across trials (Schroeder et al., 2008). From EEG/MEG studies it has been hypothesized that coupled oscillatory activity in primary sensory cortices regulates multi sensory processing (Senkowski et al. 2008). We follow up on a study in which evidence of phase reset was found using a purely behavioral paradigm by including also EEG measures. In this paradigm, presentation of an auditory accessory stimulus was followed by a visual target with a stimulus-onset asynchrony (SOA) across a range from 0 to 404 ms in steps of 4 ms. This fine-grained stimulus presentation allowed us to do a spectral analysis on the mean SRT as a function of the SOA, which revealed distinct peak spectral components within a frequency range of 6 to 11 Hz with a modus of 7 Hz. The EEG analysis showed that the auditory stimulus caused a phase reset in 7-Hz brain oscillations in a widespread set of channels. Moreover, there was a significant difference in the average phase at which the visual target stimulus appeared between slow and fast SRT trials. This effect was evident in three different analyses, and occurred primarily in frontal and central electrodes. |
Kevin C. Dieter; Bo Hu; David C. Knill; Randolph Blake; Duje Tadin Kinesthesis can make an invisible hand visible Journal Article In: Psychological Science, vol. 25, no. 1, pp. 66–75, 2014. @article{Dieter2014, Self-generated body movements have reliable visual consequences. This predictive association between vision and action likely underlies modulatory effects of action on visual processing. However, it is unknown whether actions can have generative effects on visual perception. We asked whether, in total darkness, self-generated body movements are sufficient to evoke normally concomitant visual perceptions. Using a deceptive experimental design, we discovered that waving one's own hand in front of one's covered eyes can cause visual sensations of motion. Conjecturing that these visual sensations arise from multisensory connectivity, we showed that grapheme-color synesthetes experience substantially stronger kinesthesis-induced visual sensations than nonsynesthetes do. Finally, we found that the perceived vividness of kinesthesis-induced visual sensations predicted participants' ability to smoothly track self-generated hand movements with their eyes in darkness, which indicates that these sensations function like typical retinally driven visual sensations. Evidently, even in the complete absence of external visual input, the brain predicts visual consequences of actions. |
Barnaby J. Dixson; Gina M. Grimshaw; Diane K. Ormsby; Alan F. Dixson Eye-tracking women's preferences for men's somatotypes Journal Article In: Evolution and Human Behavior, vol. 35, no. 2, pp. 73–79, 2014. @article{Dixson2014, Judging physical attractiveness involves sight, touch, sound and smells. Where visual judgments are concerned, attentional processes may have evolved to prioritize sex-typical traits that reflect cues signaling direct or indirect (i.e. genetic) benefits. Behavioral techniques that measure response times or eye movements provide a powerful test of this assumption by directly assessing how attractiveness influences the deployment of attention. We used eye-tracking to characterize women's visual attention to men's back-posed bodies, which varied in overall fat and muscle distribution, while they judged the potential of each model for a short- or long-term relationship. We hypothesized that when judging male bodily attractiveness women would focus more on the upper body musculature of all somatotypes, as it is a signal of metabolic health, immunocompetence and underlying endocrine function. Results showed that mesomorphs (muscular men) received the highest attractiveness ratings, followed by ectomorphs (lean men) and endomorphs (heavily-set men). For eye movements, attention was evenly distributed to the upper and lower back of both ectomorphs and mesomorphs. In contrast, for endomorphs the lower back, including the waist, captured more attention over the viewing period. These patterns in visual attention were evident in the first second of viewing, suggesting that body composition is identified early in viewing and guides attention to body regions that provide salient biological information during judgments of men's bodily attractiveness. |
Hans Peter Frey; Anita M. Schmid; Jeremy W. Murphy; Sophie Molholm; Edmund C. Lalor; John J. Foxe Modulation of early cortical processing during divided attention to non-contiguous locations Journal Article In: European Journal of Neuroscience, vol. 39, no. 9, pp. 1499–1507, 2014. @article{Frey2014, We often face the challenge of simultaneously attending to multiple non-contiguous regions of space. There is ongoing debate as to how spatial attention is divided under these situations. Whereas, for several years, the predominant view was that humans could divide the attentional spotlight, several recent studies argue in favor of a unitary spotlight that rhythmically samples relevant locations. Here, this issue was addressed by the use of high-density electrophysiology in concert with the multifocal m-sequence technique to examine visual evoked responses to multiple simultaneous streams of stimulation. Concurrently, we assayed the topographic distribution of alpha-band oscillatory mechanisms, a measure of attentional suppression. Participants performed a difficult detection task that required simultaneous attention to two stimuli in contiguous (undivided) or non-contiguous parts of space. In the undivided condition, the classic pattern of attentional modulation was observed, with increased amplitude of the early visual evoked response and increased alpha amplitude ipsilateral to the attended hemifield. For the divided condition, early visual responses to attended stimuli were also enhanced, and the observed multifocal topographic distribution of alpha suppression was in line with the divided attention hypothesis. These results support the existence of divided attentional spotlights, providing evidence that the corresponding modulation occurs during initial sensory processing time-frames in hierarchically early visual regions, and that suppressive mechanisms of visual attention selectively target distracter locations during divided spatial attention. |
Moshe Fried; Eteri Tsitsiashvili; Yoram S. Bonneh; Anna Sterkin; Tamara Wygnanski-Jaffe; Tamir Epstein; Uri Polat ADHD subjects fail to suppress eye blinks and microsaccades while anticipating visual stimuli but recover with medication Journal Article In: Vision Research, vol. 101, pp. 62–72, 2014. @article{Fried2014, Oculomotor behavior and parameters are known to be affected by the allocation of attention and could potentially be used to investigate attention disorders. We explored the oculomotor markers of Attention-deficit/hyperactivity disorder (ADHD) that are involuntary and quantitative and that could be used to reveal the core-affected mechanisms, as well as be used for differential diagnosis. We recorded eye movements in a group of 22 ADHD-diagnosed patients with and without medication (methylphenidate) and in 22 control observers while performing the test of variables of attention (t.o.v.a.). We found that the average microsaccade and blink rates were higher in the ADHD group, especially in the time interval around stimulus onset. These rates increased monotonically over session time for both groups, but with significantly faster increments in the unmedicated ADHD group. With medication, the level and time course of the microsaccade rate were fully normalized to the control level, regardless of the time interval within trials. In contrast, the pupil diameter decreased over time within sessions and significantly increased above the control level with medication. We interpreted the suppression of microsaccades and eye blinks around the stimulus onset as reflecting a temporal anticipation mechanism for the transient allocation of attention, and their overall rates as inversely reflecting the level of arousal. We suggest that ADHD subjects fail to maintain sufficient levels of arousal during a simple and prolonged task, which limits their ability to dynamically allocate attention while anticipating visual stimuli. This impairment normalizes with medication and its oculomotor quantification could potentially be used for differential diagnosis. |
Daniel Frings; John Parkin; Anne M. Ridley The effects of cycle lanes, vehicle to kerb distance and vehicle type on cyclists' attention allocation during junction negotiation Journal Article In: Accident Analysis and Prevention, vol. 72, pp. 411–421, 2014. @article{Frings2014, Increased frequency of cycle journeys has led to an escalation in collisions between cyclists and vehicles, particularly at shared junctions. Risks associated with passing decisions have been shown to influence cyclists' behavioural intentions. The current study extended this research by linking not only risk perception but also attention allocation (via tracking the eye movements of twenty cyclists viewing junction approaches presented on video) to behavioural intentions. These constructs were measured in a variety of contexts: junctions featuring cycle lanes, large vs. small vehicles and differing kerb to vehicle distances). Overall, cyclists devoted the majority of their attention to the nearside (side closest to kerb) of vehicles, and perceived near and offside (side furthest from kerb) passing as most risky. Waiting behind was the most frequent behavioural intention, followed by nearside and then offside passing. While cycle lane presence did not affect behaviour, it did lead to nearside passing being perceived as less risky, and to less attention being devoted to the offside. Large vehicles led to increased risk perceived with passing, and more attention directed towards the rear of vehicles, with reduced offside passing and increased intentions to remain behind the vehicle. Whether the vehicle was large or small, nearside passing was preferred around 30% of the time. Wide kerb distances increased nearside passing intentions and lower associated perceptions of risk. Additionally, relationships between attention and both risk evaluations and behaviours were observed. These results are discussed in relation to the cyclists' situational awareness and biases that various contextual factors can introduce. From these, recommendations for road safety and training are suggested. |
Daniel Frings; Nicola Rycroft; Mark S. Allen; Richard Fenn Watching for gains and losses: The effects of motivational challenge and threat on attention allocation during a visual search task Journal Article In: Motivation and Emotion, vol. 38, no. 4, pp. 513–522, 2014. @article{Frings2014a, This experiment tests predictions based on research and evidence around the biopsychosocial model (BPSM) that people in a challenge state have faster, more gain orientated search patterns than those in a threat state. Participants (n = 44) completed a motivated performance task involving the location of a target appearing in one of two search arrays: one associated with gaining points and the other associated with avoiding the loss of points. Midway through the task, participants received a false feedback prime about their performance invoking either challenge or threat. We found that participants receiving a challenge prime (high performance feedback) spent longer searching the gain array and made fewer fixations on the loss array. Those receiving a threat prime (low performance feedback) made fewer fixations on the gain array. These findings are in line with the BPSM and provide evidence that allocation of attention (measured using eye movement data) is related to challenge and threat. |
Steven Frisson; Nathalie N. Bélanger; Keith Rayner Phonological and orthographic overlap effects in fast and masked priming Journal Article In: Quarterly Journal of Experimental Psychology, vol. 67, no. 9, pp. 1742–1767, 2014. @article{Frisson2014, We investigated how orthographic and phonological information is activated during reading, using a fast priming task, and during single word recognition, using masked priming. Specifically, different types of overlap between prime and target were contrasted: high orthographic and high phonological overlap (track-crack), high orthographic and low phonological overlap (bear-gear), or low orthographic and high phonological overlap (fruit-chute). In addition, we examined whether (orthographic) beginning overlap (swoop-swoon) yielded the same priming pattern as end (rhyme) overlap (track-crack). Prime durations were 32 and 50ms in the fast priming version, and 50ms in the masked priming version, and mode of presentation (prime and target in lower case) was identical. The fast priming experiment showed facilitatory priming effects when both orthography and phonology overlapped, with no apparent differences between beginning and end overlap pairs. Facilitation was also found when prime and target only overlapped orthographically. In contrast, the masked priming experiment showed inhibition for both types of end overlap pairs (with and without phonological overlap), and no difference for begin overlap items. When prime and target only shared principally phonological information, facilitation was only found with a long prime duration in the fast priming experiment, while no differences were found in the masked priming version. These contrasting results suggest that fast priming and masked priming do not necessarily tap into the same type of processing. |
Steven Frisson; Hannah Koole; Louisa Hughes; Andrew Olson; Linda Wheeldon Competition between orthographically and phonologically similar words during sentence reading: Evidence from eye movements Journal Article In: Journal of Memory and Language, vol. 73, no. 1, pp. 148–173, 2014. @article{Frisson2014a, Two eye movement experiments tested the effect of orthographic and/or phonological overlap between prime and target words embedded in a sentence. In Experiment 1, four types of overlap were tested: phonological and orthographic overlap (O+P+) occurring word initially .strain-strait) or word finally .wings-kings), orthographic overlap alone (O+P-, bear-gear) and phonological overlap alone (O-P+, smile-aisle). Only O+P+ overlap resulted in inhibition, with the rhyming condition showing an immediate inhibition effect on the target word and the non-rhyming condition on the spillover region. No priming effects were found on any eye movement measure for the O+P- or the O-P+ conditions. Experiment 2 demonstrated that the size of this inhibition effect is affected by both the distance between the prime and target words and by syntactic structure. Inhibition was again observed when primes and targets appeared close together (approximately 3 words). In contrast, no inhibition was observed when the separation was nine words on average, with the prime and target either appearing in the same sentence or separated by a sentence break. However, when the target was delayed but still in the same sentence, the size of the inhibitory effect was affected by the participants' level of reading comprehension. Skilled comprehenders were more negatively impacted by related primes than less skilled comprehenders. This suggests that good readers keep lexical representations active across larger chunks of text, and that they discard this activation at the end of the sentence. This pattern of results is difficult to accommodate in existing competition or episodic memory models of priming. |
Galit Fuhrmann Alpert; Ran Manor; Assaf B. Spanier; Leon Y. Deouell; Amir B. Geva Spatiotemporal representations of rapid visual target detection: A single-trial EEG classification algorithm Journal Article In: IEEE Transactions on Biomedical Engineering, vol. 61, no. 8, pp. 2290–2303, 2014. @article{FuhrmannAlpert2014a, Brain computer interface applications, developed for both healthy and clinical populations, critically depend on decoding brain activity in single trials. The goal of the present study was to detect distinctive spatiotemporal brain patterns within a set of event related responses. We introduce a novel classification algorithm, the spatially weighted FLD-PCA (SWFP), which is based on a two-step linear classification of event-related responses, using fisher linear discriminant (FLD) classifier and principal component analysis (PCA) for dimensionality reduction. As a benchmark algorithm, we consider the hierarchical discriminant component Analysis (HDCA), introduced by Parra, et al. 2007. We also consider a modified version of the HDCA, namely the hierarchical discriminant principal component analysis algorithm (HDPCA). We compare single-trial classification accuracies of all the three algorithms, each applied to detect target images within a rapid serial visual presentation (RSVP, 10 Hz) of images from five different object categories, based on single-trial brain responses. We find a systematic superiority of our classification algorithm in the tested paradigm. Additionally, HDPCA significantly increases classification accuracies compared to the HDCA. Finally, we show that presenting several repetitions of the same image exemplars improve accuracy, and thus may be important in cases where high accuracy is crucial. |
Galit Fuhrmann Alpert; Ran Manor; Assaf B. Spanier; Leon Y. Deouell; Amir B. Geva Spatio-temporal representations of rapid visual target detection: A single trial EEG classification Journal Article In: IEEE Transactions on Biomedical Engineering, vol. 61, no. 8, pp. 2290–2303, 2014. @article{FuhrmannAlpert2014, Brain computer interface applications, developed for both healthy and clinical populations, critically depend on decod- ing brain activity in single trials. The goal of the present study was to detect distinctive spatiotemporal brain patterns within a set of event related responses. We introduce a novel classification algo- rithm, the spatially weighted FLD-PCA (SWFP), which is based on a two-step linear classification of event-related responses, using fisher linear discriminant (FLD) classifier and principal compo- nent analysis (PCA) for dimensionality reduction. As a benchmark algorithm, we consider the hierarchical discriminant component Analysis (HDCA), introduced by Parra, et al. 2007. We also con- sider a modified version of the HDCA, namely the hierarchical discriminant principal component analysis algorithm (HDPCA). We compare single-trial classification accuracies of all the three algorithms, each applied to detect target images within a rapid serial visual presentation (RSVP, 10 Hz) of images from five dif- ferent object categories, based on single-trial brain responses. We find a systematic superiority of our classification algorithm in the tested paradigm.Additionally, HDPCA significantly increases clas- sification accuracies compared to the HDCA. Finally, we show that presenting several repetitions of the same image exemplars im- prove accuracy, and thus may be important in cases where high accuracy is crucial. |
Benjamin Gagl; Stefan Hawelka; Florian Hutzler A similar correction mechanism in slow and fluent readers after suboptimal landing positions Journal Article In: Frontiers in Human Neuroscience, vol. 8, pp. 355, 2014. @article{Gagl2014, The present eye movements study investigated the optimal viewing position (OVP) and inverted-optimal viewing position (I-OVP) effects in slow readers. The basis of these effects is a phenomenon called corrective re-fixations, which describes a short saccade from a suboptimal landing position (word beginning or end) to the center of the word. The present study found corrective re-fixations in slow readers, which was evident from the I-OVP effects in first fixation durations, the OVP effect in number of fixations and the OVP effect in re-fixation probability. The main result is that slow readers, despite being characterized by a fragmented eye movement pattern during reading, nevertheless share an intact mechanism for performing corrective re-fixations. This correction mechanism is not linked to linguistic processing, but to visual and oculomotor processes, which suggests the integrity of oculomotor and visual processes in slow readers. |
Benjamin Gagl; Stefan Hawelka; Fabio Richlan; Sarah Schuster; Florian Hutzler Parafoveal preprocessing in reading revisited: Evidence from a novel preview manipulation Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 40, no. 2, pp. 588–595, 2014. @article{Gagl2014a, The study investigated parafoveal preprocessing by the means of the classical invisible boundary paradigm and a novel manipulation of the parafoveal previews (i.e., visual degradation). Eye movements were investigated on 5-letter target words with constraining (i.e., highly informative) initial letters or similarly constraining final letters. Visual degradation was administered to all, no, the initial, or the final 2 letters of the parafoveal preview of the target words. Critically, the manipulation of the parafoveal previews did not interfere with foveal processing. Thus, we had a proper baseline to which we could relate our main findings, which were as follows: First, the valid (i.e., nondegraded) preview of the target words' final letters led to shorter fixation times compared to the baseline condition (i.e., the degradation of all letters). Second, this preview benefit for the final letters was comparable to the benefit of previewing the initial letters. Third, the preview of a constraining initial letter sequence, however, yielded a larger preview benefit than the preview of an unconstraining initial letter sequence. The latter finding indicates that preprocessing constraining initial letters is particularly conducive to foveal word recognition. |
Ricki-Leigh Elliot; Linda E. Campbell; Mick Hunter; Gavin Cooper; Jessica L. Melville; Kathryn L. McCabe; Louise Newman; Carmel M. Loughland When I look into my baby's eyes... infant emotion recognition by mothers with Borderline Personality Disorder Journal Article In: Infant Mental Health Journal, vol. 35, pp. 21–32, 2014. @article{Elliot2014, Mothers with borderline personality disorder (BPD) have disturbed relationships with their infants, possibly associated with poor nonverbal cue perception. Individuals with BPD are poor at recognizing emotion in adults and tend to misattribute neutral (i.e., no emotion) as sad. This study extends previous research by examining how mothers with BPD perceive known (own) and unknown (control) infant stimuli depicting happy, sad, and neutral emotions. The sample consisted of 13 women diagnosed with BPD and 13 healthy control mothers. All participants completed clinical and parenting questionnaires and an infant emotion recognition task. Compared to control mothers, mothers with BPD were significantly poorer at infant emotion recognition overall, but especially neutral expressions which were misattributed most often as sad. Performance was not related to disturbed parenting but rather mothers' age and illness duration. Neither the BPD nor control mothers showed enhanced accuracy for emotional displays of their own verses unknown infant-face images. Although the sample size was small, this study provides evidence that mothers with BPD negatively misinterpret neutral images, which may impact sensitive responding to infant emotional cues. These findings have implications for clinical practiceand the development of remediation programs targeting emotion-perception disturbances in mothers with BPD. |
Jessica J. Ellis; Eyal M. Reingold The Einstellung effect in anagram problem solving: Evidence from eye movements Journal Article In: Frontiers in Psychology, vol. 5, pp. 679, 2014. @article{Ellis2014, The Einstellung effect is the counterintuitive finding that prior experience or domain-specific knowledge can under some circumstances interfere with problem solving performance. This effect has been demonstrated in several domains of expertise including medicine and chess. In the present study we explored this effect in the context of a simplified anagram problem solving task. Participants solved anagram problems while their eye movements were monitored. Each problem consisted of six letters: a central three-letter string whose letters were part of the solution word, and three additional individual letters. Participants were informed that one of the individual letters was a distractor letter and were asked to find a five-letter solution word. In order to examine the impact of stimulus familiarity on problem solving performance and eye movements, the central letter string was presented either as a familiar three-letter word, or the letters were rearranged to form a three-letter nonword. Replicating the classic Einstellung effect, overall performance was better for nonword than word trials. However, participants' eye movements revealed a more complex pattern of both interference and facilitation as a function of the familiarity of the central letter string. Specifically, word trials resulted in shorter viewing times on the central letter string and longer viewing times on the individual letters than nonword trials. These findings suggest that while participants were better able to encode and maintain the meaningful word stimuli in working memory, they found it more challenging to integrate the individual letters into the central letter string when it was presented as a word. |
Nick C. Ellis; Kausar Hafeez; Katherine I. Martin; Lillian Chen; Julie E. Boland; Nuria Sagarra An eye-tracking study of learned attention in second language acquisition Journal Article In: Applied Psycholinguistics, vol. 35, no. 3, pp. 547–579, 2014. @article{Ellis2014a, This paper investigates the limited attainment of adult compared to child language acquisition in terms of learned attention to morphological cues. It replicates Ellis and Sagarra in demonstrating short-term learned attention in the acquisition of temporal reference in Latin, and it extends the investigation using eye-tracking indicators to determine the extent to which these biases are overt or covert. English native speakers learned adverbial and morphological cues to temporal reference in a small set of Latin phrases under experimental conditions. Comprehension and production data demonstrated that early experience with adverbial cues enhanced subsequent use of this cue dimension and blocked the acquisition of verbal tense morphology. Effects of early experience of verbal morphology were less pronounced. Eye-tracking measures showed that early experience of particular cue dimensions affected what participants overtly focused upon during subsequent language processing and how this overt study resulted in turn in covert attentional biases in comprehension and in productive knowledge. |
Paul E. Engelhardt Children's and adolescents' processing of temporary syntactic ambiguity: An eye movement study Journal Article In: Child Development Research, vol. 2014, no. 13, pp. 1–13, 2014. @article{Engelhardt2014, This study examined the eye movements of 24 children and adolescents as they read sentences containing temporary syntactic ambiguities. Prior research suggested that children primarily use grammatical information when making initial parsing decisions, and they tend to disregard semantic and contextual information. On each trial, participants read a garden path sentence (e.g., While the storm blew the boat sat in the shed ), and, afterwards, they answered a comprehension question (e.g., Did the storm blow the boat? ). The design was 2 × 2 (verb type × ambiguity) repeated measures. Verb type was optionally transitive or reflexive, and sentences were ambiguous or unambiguous. Results showed no differences in first pass reading times at the disambiguating verb (e.g., sat ). However, regressions did show a significant interaction. The unambiguous-reflexive condition had approximately half the number of regressions, suggesting less processing difficulty in this condition. Developmentally, we found that adolescents had significantly better comprehension, which seemed to be linked to the increased tendency to regress from the disambiguating word. Findings are consistent with the assumption that the processing architecture is more restricted in children compared to adolescents. In addition, results indicated that variance in ambiguity resolution was associated with interference control but not working memory. |
Paul E. Engelhardt; Fernanda Ferreira In: Language, Cognition and Neuroscience, vol. 29, no. 8, pp. 975–985, 2014. @article{Engelhardt2014a, Studies have shown that speakers often include unnecessary modifiers when producing referential expressions, which is contrary to the Maxim of Quantity. In this study, we examined the production of referring expressions (e.g. the red triangle) that contained an over-described (or redundant) pre-nominal adjective modifier. These expressions were compared to similar expressions that were uttered in a context that made the modifier necessary for unique referent identification. Our hypothesis was that speakers articulate over-described modifiers differently from those used to distinguish contrasting objects. Results showed that over-described modifiers were significantly shorter in duration than modifiers used to distinguish two objects. Conclusions focus on how these acoustic differences can be modelled by Natural Language Generation algorithms, such as the Incremental Algorithm, in combination with probabilistic prosodic reduction. |
Yulia Esaulova; Chiara Reali; Lisa Stockhausen Influences of grammatical and stereotypical gender during reading: Eye movements in pronominal and noun phrase anaphor resolution Journal Article In: Language, Cognition and Neuroscience, vol. 29, no. 7, pp. 781–803, 2014. @article{Esaulova2014, Two eye-tracking studies addressed the processing of grammatical and stereotypical gender cues in anaphor resolution in German. The authors investigated pronominal (er ‘he'/sie ‘she') and noun phrase (dieser Mann ‘this man'/diese Frau ‘this woman') anaphors in sentences containing stereotypical role nouns as antecedents (Example: Oft hatte der Elektriker gute Einfalle, regelmassig plante er/dieser Mann neue Projekte' Often had the electrician good ideas, regularly planned he/this man new projects'). Participants were native speakers of German (N=40 and N=24 in Experiments 1 and 2, respectively). Results show that influences of grammatical gender occur in early stages of processing, whereas the influences of stereotypical gender appear only in later measures. Both effects, however, strongly depend on the type of anaphor. Furthermore, the results provide evidence for asymmetries in processing feminine and masculine grammatical gender and are discussed with reference to two-stage models of anaphor resolution. |
Gerardo Fernández; Jochen Laubrock; Pablo Mandolesi; Oscar Colombo; Osvaldo Agamennoni Registering eye movements during reading in Alzheimers disease: Difficulties in predicting upcoming words Journal Article In: Journal of Clinical and Experimental Neuropsychology, vol. 36, no. 3, pp. 302–316, 2014. @article{Fernandez2014, Reading requires the fine integration of attention, ocular movements, word identification, and language comprehension, among other cognitive parameters. Several of the associated cognitive processes such as working memory and semantic memory are known to be impaired by Alzheimer's disease (AD). This study analyzes eye movement behavior of 18 patients with probable AD and 40 age-matched controls during Spanish sentence reading. Controls focused mainly on word properties and considered syntactic and semantic structures. At the same time, controls' knowledge and prediction about sentence meaning and grammatical structure are quite evident when we consider some aspects of visual exploration, such as word skipping, and forward saccades. By contrast, in the AD group, the predictability effect of the upcoming word was absent, visual exploration was less focused, fixations were much longer, and outgoing saccade amplitudes were smaller than those in controls. The altered visual exploration and the absence of a contextual predictability effect might be related to impairments in working memory and long-term memory retrieval functions. These eye movement measures demonstrate considerable sensitivity with respect to evaluating cognitive processes in Alzheimer's disease. They could provide a user-friendly marker of early disease symptoms and of its posterior progression. |
Gerardo Fernández; Facundo Manes; Nora P. Rotstein; Oscar Colombo; Pablo Mandolesi; Luis E. Politi; Osvaldo Agamennoni Lack of contextual-word predictability during reading in patients with mild Alzheimer disease Journal Article In: Neuropsychologia, vol. 62, no. 1, pp. 143–151, 2014. @article{Fernandez2014a, In the present work we analyzed the effect of contextual word predictability on the eye movement behavior of patients with mild Alzheimer disease (AD) compared to age-matched controls, by using the eyetracking technique and lineal mixed models. Twenty AD patients and 40 age-matched controls participated in the study. We first evaluated gaze duration during reading low and highly predictable sentences. AD patients showed an increase in gaze duration, compared to controls, both in sentences of low or high predictability. In controls, highly predictable sentences led to shorter gaze durations; by contrary, AD patients showed similar gaze durations in both types of sentences. Similarly, gaze duration in controls was affected by the cloze predictability of word N and N+1, whereas it was the same in AD patients. In contrast, the effects of word frequency and word length were similar in controls and AD patients. Our results imply that contextual-word predictability, whose processing is proposed to require memory retrieval, facilitated reading behavior in healthy subjects, but this facilitation was lost in early AD patients. This loss might reveal impairments in brain areas such as those corresponding to working memory, memory retrieval, and semantic memory functions that are already present at early stages of AD. In contrast, word frequency and length processing might require less complex mechanisms, which were still retained by AD patients. To the best of our knowledge, this is the first study measuring how patients with early AD process well-defined words embedded in sentences of high and low predictability. Evaluation of the resulting changes in eye movement behavior might provide a useful tool for a more precise early diagnosis of AD. |
Gerardo Fernández; Diego E. Shalom; Reinhold Kliegl; Mariano Sigman Eye movements during reading proverbs and regular sentences: The incoming word predictability effect Journal Article In: Language, Cognition and Neuroscience, vol. 29, no. 3, pp. 260–273, 2014. @article{Fernandez2014b, Reading is an everyday activity requiring the efficient integration of several central cognitive subsystems ranging from attention and oculomotor control to word identification and language comprehension. Effects of frequency, length and cloze predictability of words on reading times reliably indicate local processing difficulty of fixated words; also, a reader's expectation about an upcoming word apparently influences fixation duration even before the eyes reach this word. Moreover, this effect has been reported as noncanonical (i.e., longer fixation durations on word N when word N1 is of high cloze predictability). However, this effect is difficult to observe because in natural sentences the fluctuations in predictability in content words are very small. To overcome this difficulty we investigated eye movements while reading proverbs as well as sentences constructed for high- and low-average cloze predictability. We also determined for each sentence a word at which predictability of words jumps from a low to high value. Fixation durations while reading proverbs and high-predictable sentences exhibited significant effects of the change in predictability along the sentence (when the successive word is more predictable than the fixated word). Results are in agreement with the proposal that cloze predictability of upcoming words exerts an influence on fixation durations via memory retrieval. |
Katja Fiehler; Christian Wolf; Mathias Klinghammer; Gunnar Blohm Integration of egocentric and allocentric information during memory-guided reaching to images of a natural environment Journal Article In: Frontiers in Human Neuroscience, vol. 8, pp. 636, 2014. @article{Fiehler2014, When interacting with our environment we generally make use of egocentric and allocentric object information by coding object positions relative to the observer or relative to the environment, respectively. Bayesian theories suggest that the brain integrates both sources of information optimally for perception and action. However, experimental evidence for egocentric and allocentric integration is sparse and has only been studied using abstract stimuli lacking ecological relevance. Here, we investigated the use of egocentric and allocentric information during memory-guided reaching to images of naturalistic scenes. Participants encoded a breakfast scene containing six objects on a table (local objects) and three objects in the environment (global objects). After a 2 s delay, a visual test scene reappeared for 1 s in which 1 local object was missing (= target) and of the remaining, 1, 3 or 5 local objects or one of the global objects were shifted to the left or to the right. The offset of the test scene prompted participants to reach to the target as precisely as possible. Only local objects served as potential reach targets and thus were task-relevant. When shifting objects we predicted accurate reaching if participants only used egocentric coding of object position and systematic shifts of reach endpoints if allocentric information were used for movement planning. We found that reaching movements were largely affected by allocentric shifts showing an increase in endpoint errors in the direction of object shifts with the number of local objects shifted. No effect occurred when one local or one global object was shifted. Our findings suggest that allocentric cues are indeed used by the brain for memory-guided reaching towards targets in naturalistic visual scenes. Moreover, the integration of egocentric and allocentric object information seems to depend on the extent of changes in the scene. |
Ruth Filik; Hartmut Leuthold; Katie Wallington; Jemma Page Testing theories of irony processing using eye-tracking and ERPs Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 40, no. 3, pp. 811–828, 2014. @article{Filik2014, Not much is known about how people comprehend ironic utterances, and to date, most studies have simply compared processing of ironic versus non-ironic statements. A key aspect of the graded salience hypothesis, distinguishing it from other accounts (such as the standard pragmatic view and direct access view), is that it predicts differences between processing of familiar and unfamiliar ironies. Specifically, if an ironic utterance is familiar, then the ironic interpretation should be available without the need for extra inferential processes, whereas for unfamiliar ironies, the literal interpretation would be computed first, and a mismatch with context would lead to a re-interpretation of the statement as being ironic. We recorded participants' eye movements while they were reading (Experiment 1), and electrical brain activity while they were listening to (Experiment 2), familiar and unfamiliar ironies compared to non-ironic controls. Results show disruption to eye movements and an N400-like effect for unfamiliar ironies only, supporting the predictions of the graded salience hypothesis. In addition, in Experiment 2, a late positivity was found for both familiar and unfamiliar ironic materials, compared to non-ironic controls. We interpret this positivity as reflecting ongoing conflict between the literal and ironic interpretations of the utterance. |
Joel Fishbein; Jesse A. Harris Making sense of Kafka: Structural biases induce early sense commitment for metonyms Journal Article In: Journal of Memory and Language, vol. 76, pp. 94–112, 2014. @article{Fishbein2014, Prior research suggests that the language processor initially activates an underspecified representation of a metonym consistent with all its senses, potentially selecting a specific sense if supported by contextual and lexical information. We explored whether a structural heuristic, the Subject as Agent Principle, which provisionally assigns an agent theta role to canonical subjects, would prompt immediate sense selection. In Experiment 1, we found initial evidence that this principle is active during offline and online processing of metonymic names like Kafka. Reading time results from Experiments 2 and 3 demonstrated that previous context biasing towards the metonymic sense of the name reduced, but did not remove, the agent preference, consistent with Frazier's (1999) proposal that the processor may avoid selecting a specific sense, unless grammatically required. |
Rebecca M. Foerster; Elena Carbone; Werner X. Schneider Long-term memory-based control of attention in multi-step tasks requires working memory: Evidence from domain-specific interference Journal Article In: Frontiers in Psychology, vol. 5, pp. 408, 2014. @article{Foerster2014, Evidence for long-term memory (LTM)-based control of attention has been found during the execution of highly practiced multi-step tasks. However, does LTM directly control for attention or are working memory (WM) processes involved? In the present study, this question was investigated with a dual-task paradigm. Participants executed either a highly practiced visuospatial sensorimotor task (speed stacking) or a verbal task (high-speed poem reciting), while maintaining visuospatial or verbal information in WM. Results revealed unidirectional and domain-specific interference. Neither speed stacking nor high-speed poem reciting was influenced by WM retention. Stacking disrupted the retention of visuospatial locations, but did not modify memory performance of verbal material (letters). Reciting reduced the retention of verbal material substantially whereas it affected the memory performance of visuospatial locations to a smaller degree. We suggest that the selection of task-relevant information from LTM for the execution of overlearned multi-step tasks recruits domain-specific WM. |
Anouk J. Brouwer; Eli Brenner; W. Pieter Medendorp; Jeroen B. J. Smeets Time course of the effect of the Muller-Lyer illusion on saccades and perceptual judgments Journal Article In: Journal of Vision, vol. 14, no. 1, pp. 1–11, 2014. @article{Brouwer2014, The amplitude of saccadic eye movements is affected by size illusions such as the Müller-Lyer illusion, but this effect varies highly between studies. Here we examine the origin of this variability by testing the influence of three temporal factors on the effect of the Müller-Lyer illusion: presentation time, response delay, and saccade latency. Subjects performed reflexive saccades, deferred saccades, and memory-guided saccades along the shaft of the illusion. We evaluated the time course of the saccadic illusion effects. We compared it to the influence of presentation time on the illusion effect in a perceptual judgment task. According to the "two visual systems hypothesis", visual perception and visual memory rely on a perceptual representation coded along the ventral "perception" pathway, which is affected by visual contextual illusions. Visuomotor actions, such as saccades, depend on the dorsal "action" pathway that is largely immune to illusions. In contrast with this hypothesis, our results show that the illusion affected both saccade amplitude and perceptual judgments with a similar time course. Presentation time of the Müller-Lyer illusion, not response delay or saccade latency, was the major factor in determining the size of the illusion effect. Longer presentation times resulted in smaller effects, suggesting that our visual representation is dynamic and becomes more accurate when we look at an object for a longer time before we act on it. |
Natalie Bruin; Devon C. Bryant; Claudia L. R. Gonzalez "Left neglected," but only in far space: Spatial biases in healthy participants revealed in a visually guided grasping task Journal Article In: Frontiers in Neurology, vol. 5, pp. 4, 2014. @article{Bruin2014, Hemispatial neglect is a common outcome of stroke that is characterized by the inability to orient toward, and attend to stimuli in contralesional space. It is established that hemispatial neglect has a perceptual component, however, the presence and severity of motor impairments is controversial. Establishing the nature of space use and spatial biases during visually guided actions amongst healthy individuals is critical to understanding the presence of visuomotor deficits in patients with neglect. Accordingly, three experiments were conducted to investigate the effect of object spatial location on patterns of grasping. Experiment 1 required right-handed participants to reach and grasp for blocks in order to construct 3D models. The blocks were scattered on a tabletop divided into equal size quadrants: left near, left far, right near, and right far. Identical sets of building blocks were available in each quadrant. Space use was dynamic, with participants initially grasping blocks from right near space and tending to "neglect" left far space until the final stages of the task. Experiment 2 repeated the protocol with left-handed participants. Remarkably, left-handed participants displayed a similar pattern of space use to right-handed participants. In Experiment 3 eye movements were examined to investigate whether "neglect" for grasping in left far reachable space had its origins in attentional biases. It was found that patterns of eye movements mirrored patterns of reach-to-grasp movements. We conclude that there are spatial biases during visually guided grasping, specifically, a tendency to neglect left far reachable space, and that this "neglect" is attentional in origin. The results raise the possibility that visuomotor impairments reported among patients with right hemisphere lesions when working in contralesional space may result in part from this inherent tendency to "neglect" left far space irrespective of the presence of unilateral visuospatial neglect. |
Jan Willem Gee; Tomas Knapen; Tobias H. Donner Decision-related pupil dilation reflects upcoming choice and individual bias Journal Article In: Proceedings of the National Academy of Sciences, vol. 111, pp. E618–E625, 2014. @article{Gee2014, A number of studies have shown that pupil size increases transiently during effortful decisions. These decision-related changes in pupil size are mediated by central neuromodulatory systems, which also influence the internal state of brain regions engaged in decision making. It has been proposed that pupil-linked neuromodulatory systems are activated by the termination of decision processes, and, consequently, that these systems primarily affect the postdecisional brain state. Here, we present pupil results that run contrary to this proposal, suggesting an important intradecisional role. We measured pupil size while subjects formed protracted decisions about the presence or absence (“yes” vs. “no”) of a visual contrast signal embedded in dynamic noise. Linear systems analysis revealed that the pupil was significantly driven by a sustained input throughout the course of the decision formation. This sustained component was larger than the transient component during the final choice (indicated by button press). The overall amplitude of pupil dilation during decision formation was bigger before yes than no choices, irrespective of the physical presence of the target signal. Remarkably, the magnitude of this pupil choice effect (yes > no) reflected the individual criterion: it was strongest in conservative subjects choosing yes against their bias. We conclude that the central neuromodulatory systems controlling pupil size are continuously engaged during decision formation in a way that reveals how the upcoming choice relates to the decision maker's attitude. Changes in brain state seem to interact with biased decision making in the face of uncertainty. |
Peter Lissa; Genevieve McArthur; Stefan Hawelka; Romina Palermo; Yatin Mahajan; Florian Hutzler Fixation location on upright and inverted faces modulates the N170 Journal Article In: Neuropsychologia, vol. 57, no. 1, pp. 1–11, 2014. @article{Lissa2014, The current study used event-related potentials (ERP) in combination with a variable viewing position paradigm (VVPP) to direct fixations to specific face parts (eyes or mouths) in upright or inverted whole faces. The N170 elicited by the VVPP was greater to faces than to non-face objects (wristwatches), and was delayed and enhanced in response to face inversion. A larger N170 response was elicited when the participants[U+05F3] fixation was directed to the eyes than when directed to the mouths of both upright and inverted faces, an effect that was also modulated by the spatial location of the face in the visual field. The N170 face inversion effect (upright minus inverted) was greater when fixations were directed to the mouth than when directed to the eyes, suggesting that the point of fixation within a face modulates brain potentials due to contributions from the features themselves, as well as their relative location in the visual field. |
Benoît De Smet; Lorent Lempereur; Zohreh Sharafi; Yann Gaël Guéhéneuc; Giuliano Antoniol; Naji Habra Taupe: Visualizing and analyzing eye-tracking data Journal Article In: Science of Computer Programming, vol. 79, pp. 260–278, 2014. @article{DeSmet2014, Program comprehension is an essential part of any maintenance activity. It allows developers to build mental models of the program before undertaking any change. It has been studied by the research community for many years with the aim to devise models and tools to understand and ease this activity. Recently, researchers have introduced the use of eye-tracking devices to gather and analyze data about the developers' cognitive processes during program comprehension. However, eye-tracking devices are not completely reliable and, thus, recorded data sometimes must be processed, filtered, or corrected. Moreover, the analysis software tools packaged with eye-tracking devices are not open-source and do not always provide extension points to seamlessly integrate new sophisticated analyses. Consequently, we develop the Taupe software system to help researchers visualize, analyze, and edit the data recorded by eye-tracking devices. The two main objectives of Taupe are compatibility and extensibility so that researchers can easily: (1) apply the system on any eye-tracking data and (2) extend the system with their own analyses. To meet our objectives, we base the development of Taupe: (1) on well-known good practices, such as design patterns and a plug-in architecture using reflection, (2) on a thorough documentation, validation, and verification process, and (3) on lessons learned from existing analysis software systems. This paper describes the context of development of Taupe, the architectural and design choices made during its development, and its documentation, validation and verification process. It also illustrates the application of Taupe in three experiments on the use of design patterns by developers during program comprehension. |
Stefania Vito; Antimo Buonocore; Jean François Bonnefon; Sergio Della Sala Eye movements disrupt spatial but not visual mental imagery Journal Article In: Cognitive Processing, vol. 15, no. 4, pp. 543–549, 2014. @article{Vito2014, It has long been known that eye movements are functionally involved in the generation and maintenance of mental images. Indeed, a number of studies demonstrated that voluntary eye movements interfere with mental imagery tasks (e.g., Laeng and Teodorescu in Cogn Sci 26:207-231, 2002). However, mental imagery is conceived as a multifarious cognitive function with at least two components, a spatial component and a visual component. The present study investigated the question of whether eye movements disrupt mental imagery in general or only its spatial component. We present data on healthy young adults, who performed visual and spatial imagery tasks concurrently with a smooth pursuit. In line with previous literature, results revealed that eye movements had a strong disruptive effect on spatial imagery. Moreover, we crucially demonstrated that eye movements had no disruptive effect when participants visualized the depictive aspects of an object. Therefore, we suggest that eye movements serve to a greater extent the spatial than the visual component of mental imagery. |
Jelmer P. De Vries; Ignace T. C. Hooge; Frans A. J. Verstraten Saccades toward the target are planned as sequences rather than as single steps Journal Article In: Psychological Science, vol. 25, no. 1, pp. 215–223, 2014. @article{DeVries2014, To find a target during visual search, observers often need to make multiple eye movements, which results in a scan path. It is an open question whether the saccade destinations in scan paths are planned ahead. In the two experiments reported here, we investigated this question by focusing on the observer's ability to deviate from potentially planned paths. In the first experiment, the stimulus configuration could change during the initial saccade. We found that the observer's ability to deviate from potentially planned paths crucially depended on whether altered configurations could be processed with sufficient rapidity. In a follow-up experiment, we asked whether planned paths can include more than two saccade destinations. Investigating the influence of potentially planned paths on a secondary task demonstrated that planned paths can include at least three saccade destinations. Together, these experiments provide the first evidence of scan-path planning in visual search. |
Louis F. Dell'Osso; Faruk H. Orge; Jonathan B. Jacobs; Zhong I. Wang; Louis F. Dell'Osso; Faruk H. Orge; Jonathan B. Jacobs; Zhong I. Wang Fusion maldevelopment (latent/manifest latent) nystagmus syndrome: Effects of four-muscle tenotomy and reattachment Journal Article In: Journal of Pediatric Ophthalmology & Strabismus, vol. 51, no. 3, pp. 180–188, 2014. @article{DellOsso2014, PURPOSE: To examine the waveform and clinical effects of the four-muscle tenotomy and reattachment procedure in fusion maldevelopment nystagmus syndrome (FMNS) and to compare them to those documented in infantile nystagmus syndrome (INS) and acquired nystagmus. METHODS: Both infrared reflection and high-speed digital video systems were used to record the eye movements in a patient with FMNS (before and after tenotomy and reattachment). Data were analyzed using the eXpanded Nystagmus Acuity Function (NAFX) that is part of the OMtools software. Model simulations and predictions were performed using the authors' behavioral ocular motor system model in MATLAB Simulink (The MathWorks, Inc., Natick, MA). RESULTS: The model predicted, and the patient's data confirmed, that the tenotomy and reattachment procedure produces improvements in FMN waveforms across a broader field of gaze and decreases the Alexander's law variation. The patient's tenotomy and reattachment plots of NAFX after surgery versus gaze angle were higher and had lower slope than before surgery. Clinically, despite moderate improvements in both peak measured acuity and stereoacuity, dramatic improvements in the patient's abilities and lifestyle resulted. CONCLUSIONS: The four-muscle tenotomy and reattachment nystagmus surgery produced beneficial therapeutic effects on FMN waveforms that are similar to those demonstrated in INS and acquired nystagmus. These results support the authors' prior recommendation that tenotomy and reattachment nystagmus should be added to required strabismus procedures in patients who also have FMNS (ie, perform tenotomy and reattachment on all unoperated muscles in the plane of the nystagmus). Furthermore, when strabismus surgery is not required, four-muscle tenotomy and reattachment may be used to improve FMN waveforms and visual function. |
Denton J. DeLoss; Takeo Watanabe; George J. Andersen Optimization of perceptual learning: Effects of task difficulty and external noise in older adults Journal Article In: Vision Research, vol. 99, pp. 37–45, 2014. @article{DeLoss2014, Previous research has shown a wide array of age-related declines in vision. The current study examined the effects of perceptual learning (PL), external noise, and task difficulty in fine orientation discrimination with older individuals (mean age 71.73, range 65-91). Thirty-two older subjects participated in seven 1.5-h sessions conducted on separate days over a three-week period. A two-alternative forced choice procedure was used in discriminating the orientation of Gabor patches. Four training groups were examined in which the standard orientations for training were either easy or difficult and included either external noise (additive Gaussian noise) or no external noise. In addition, the transfer to an untrained orientation and noise levels were examined. An analysis of the four groups prior to training indicated no significant differences between the groups. An analysis of the change in performance post-training indicated that the degree of learning was related to task difficulty and the presence of external noise during training. In addition, measurements of pupil diameter indicated that changes in orientation discrimination were not associated with changes in retinal illuminance. These results suggest that task difficulty and training in noise are factors important for optimizing the effects of training among older individuals. |
Maartje Velde; Antje S. Meyer; Agnieszka E. Konopka Message formulation and structural assembly: Describing "easy" and "hard" events with preferred and dispreferred syntactic structures Journal Article In: Journal of Memory and Language, vol. 71, no. 1, pp. 124–144, 2014. @article{Velde2014, When formulating simple sentences to describe pictured events, speakers look at the referents they are describing in the order of mention. Accounts of incrementality in sentence production rely heavily on analyses of this gaze-speech link. To identify systematic sources of variability in message and sentence formulation, two experiments evaluated differences in formulation for sentences describing "easy" and "hard" events (more codable and less codable events) with preferred and dispreferred structures (actives and passives). Experiment 1 employed a subliminal cuing manipulation and a cumulative priming manipulation to increase production of passive sentences. Experiment 2 examined the influence of event codability on formulation without a cuing manipulation. In both experiments, speakers showed an early preference for looking at the agent of the event when constructing active sentences. This preference was attenuated by event codability, suggesting that speakers were less likely to prioritize encoding of a single character at the outset of formulation in "easy" events than in "harder" events. Accessibility of the agent influenced formulation primarily when an event was "harder" to describe. Formulation of passive sentences in Experiment 1 also began with early fixations to the agent but changed with exposure to passive syntax: speakers were more likely to consider the patient as a suitable sentential starting point after cumulative priming. The results show that the message-to-language mapping in production can vary with the ease of encoding an event structure and of generating a suitable linguistic structure. |