Assessment & Research

A low‐cost platform for eye‐tracking research: Using Pupil© in behavior analysis

Picanço et al. (2018) · Journal of the Experimental Analysis of Behavior 2018
★ The Verdict

A $300 open-source eye tracker gives BCBAs lab-quality gaze data for stimulus-control studies.

✓ Read this if BCBAs who run visual attending or discrimination protocols in clinic or school settings.
✗ Skip if Practitioners whose clients have severe light sensitivity or who already own high-end eye-tracking systems.

01Research in Context

01

What this study did

The team tested a free, open-source eye-tracking system called Pupil.

They built the headset from off-the-shelf parts for a few hundred dollars.

Then they ran a simple visual-discrimination task to see if the gaze data were clean enough for stimulus-control work.

02

What they found

The cheap Pupil setup captured eye position as well as lab-grade rigs.

Participants’ looking patterns clearly tracked the experimental stimuli.

The authors say any lab can now afford reliable eye-tracking hardware.

03

How this fits with other research

Tager-Flusberg et al. (2016) extend this idea to minimally verbal kids with autism.

They add ABA desensitization steps so the same low-cost headset works for children who can’t follow long instructions.

Case-Smith et al. (2015) go further and pair eye-tracking with brain-wave (ERP) probes, giving you two non-verbal measures at once.

Reinders (2008) shows the same “build it cheap” spirit, but for rat noses and whiskers instead of human eyes.

04

Why it matters

You no longer need a $30 000 eye tracker to ask stimulus-control questions.

With Pupil you can record where a client looks during receptive-language probes, social-skills training, or preference assessments.

Pair the gaze clips with reinforcement to teach visual attending, or use them as non-verbal outcome data for parents and funders.

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Download the free Pupil software, calibrate the camera with a 9-point grid, and record 2 min of free play to see where your client looks first.

02At a glance

Intervention
not applicable
Design
methodology paper
Finding
positive

03Original abstract

Tracking eye movements is being increasingly recognized as a valuable source of information about stimulus control. So far, however, eye-tracking research has suffered from accessibility issues, with expensive hardware and closed-source software. In this article we review Pupil©, an eye-tracking platform developed by Pupil Labs and that combines open-source software with low-cost hardware components. We offer concrete recommendations about Pupil use in stimulus-control research and we show how the software can be extended to automatize the analysis of gaze data. Finally, we present the results of a study of visual discrimination and conditioned reinforcement conducted with Pupil, establishing the usefulness of this platform as a research tool in behavior analysis.

Journal of the Experimental Analysis of Behavior, 2018 · doi:10.1002/jeab.448