Webinar: Implementing the Invisible Boundary Crossing Paradigm in Experiment Builder
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Implementing the Invisible Boundary Crossing Paradigm in Experiment Builder
Delivered - Friday, May 1 2020, 11am EST

One of the advantages of using an eye-tracking device that can provide access to eye position data in real-time (like an EyeLink system) is that you can conduct experiments involving gaze-contingent paradigms that would not otherwise be possible without such a device. The invisible boundary crossing paradigm is one example of such a gaze-contingent paradigm. This paradigm, which is often used in reading research, typically presents one component of the stimulus for each trial (like a word in a sentence) in an altered manner upon initial presentation to the participant. When the participant's gaze crosses an invisible boundary (often just to the left of the altered word in a left-to-right reading paradigm), the altered component will change to a different state (like to its unaltered form in a reading experiment). For example, a participant may be presented with a sentence like this initially:

Quote:The banker that the lawyer praised lcimbed the mountain just after sunrise.

Then, when the participant's gaze crosses an invisible boundary just to the left of the word "lcimbed", the text will change to the following:

Quote:The banker that the lawyer praised climbed the mountain just after sunrise.

Analyzing gaze patterns for trials where the text changes vs. trials where the text does not change, for example, can provide insight into the parafoveal processing that may occur during reading behavior.

This webinar  will cover how to implement the Invisible Boundary Crossing Paradigm in Experiment Builder. The discussion will cover:
  • Invisible Boundary Crossing Paradigm Overview
  • Hardware Considerations for the Invisible Boundary Crossing Paradigm
  • How to Implement the Invisible Boundary Crossing Paradigm in Experiment Builder
    • Pre-Boundary Text Display Screen
    • Generate the Boundary Crossing
    • Detect When Gaze Crosses Boundary
Having basic knowledge of Experiment Builder functionality will help in understanding the concepts discussed in this webinar, but it is not required. For an introduction to the basic functionality of Experiment Builder see the Experiment Builder Video Tutorials.

You can get to a video of the Implementing the Invisible Boundary Crossing Paradigm in Experiment Builder Webinar from the following links: The PowerPoint and Experiment Builder script that is discussed in the webinar can be downloaded from the links below. You can use the File -> Unpack command in Experiment Builder to unzip the EBZ file.

If you have any questions, don't hesitate to get in touch at support@sr-research.com!

Note: EBZ file updated on Aug-2-2021 to remove gaze-contingent red dot that had been used in testing the project.


PowerPoint / Experiment Builder Script

.ppt   InvisibleBoundaryCrossingParadigmEB.ppt (Size: 613.5 KB / Downloads: 100)

.ebz   InvisibleBoundaryCrossingParadigm.ebz (Size: 91.34 KB / Downloads: 106)