Presenting Stimuli in an Eye Tracking Task

If you are building your first eye tracking task in Labvanced, the first practical question is how you actually present your stimuli.

The short answer is straightforward: an eye tracking task is built the same way as any other task in Labvanced, using frames containing objects. Eye tracking runs independently of what those objects are. If you are new to Labvanced generally, Stimulus Presentation in Labvanced covers frames, objects, timing, and trials from the ground up; this page picks up from there and focuses specifically on how eye tracking relates to what you build.

Your Stimuli Are Just Objects

Any object type can serve as a stimulus in an eye tracking task, including:

• Images
• Text
• Video
• Shapes (including SVGs and Polygons)

There is no dedicated "eye tracking stimulus" object type. If your study needs a participant to look at a photograph, place an Image Object on the frame. If it needs a short passage of text, use a Text Object. Eye tracking does not require you to change how you already build frames.

For the general mechanics of adding and configuring objects on a frame, see Working with Objects.

How Gaze Data Relates to Your Objects

While a task runs, eye tracking predicts where on the frame the participant is looking and reports that location as an [X, Y] coordinate, independent of which object (if any) occupies that location. The coordinate system used depends on the frame's display mode:

• Zoom/Adaptive (the default): coordinates are reported in frame units, which scale to fit each participant's screen
• Fixed in Millimeters or Fixed in Visual Degrees: coordinates are reported in a physical unit instead of frame units, which is often preferable for eye tracking studies since it produces measurements that are comparable across participants regardless of screen size

Display mode is a task-level setting, covered in full in Setting Up Eye Tracking in a Task.

Because gaze coordinates are reported independently of your stimuli, you decide afterward which parts of the frame are meaningful. If you want to know whether a participant looked at a specific object, rather than just anywhere on the frame, you define that object as a region of interest. See Using Shapes as Areas of Interest (AOI) for how this works with Polygon and SVG shapes.

What This Page Does Not Cover

This page is about the basic relationship between stimuli and eye tracking, not about optimizing your stimulus design for tracking accuracy (background contrast, stimulus spacing, and similar considerations). For that, see Design Considerations that Affect Webcam Eye Tracking Accuracy.

Frequently Asked Questions

Further Reading