EEG and Eye Tracking: My Summer in the Compton Lab

This summer I worked in Rebecca Compton’s Cognitive Neuroscience lab, studying the effects mind wandering, ERNs (error related negativity), and error related alpha suppression. A majority of the summer was spent testing out and preparing the lab’s new Eye-tracking system, Tobii, and working with Curry 7–new EEG software. After learning the two new programs, the other RAs and myself began running participants for Becky’s grant proposal.

In Study 1a, we examined the differences in pupil diameter after correct and incorrect responses. Using Eprime and Tobii Eye-tracking software, we designed a Stroop task–a word color task where participants must press a key indicating the color of the word, not the meaning of the word–to analyze correct and incorrect responses. The task consisted of 6 blocks of 72 trials each. Participants responded with a ~93% overall rate of accuracy. In this study, we found a significant main effect of period, F(2,18) = 27.5, p < .001, indicating that pupil diameter was greatest following the response button press. We also found an interaction effect of trial type by period, F(2,18) = 7.5, p <.005, indicating that pupil diameter was significantly greater for errors compared to correct trials during the post-response period. This study replicated prior findings of error related pupil dilation.

In Study 1b, we combined Eye-tracking and EEG methods to simultaneously examine pupil diameter and EEG oscillations following correct and incorrect responses. Similarly to Study 1a, we found that pupil diameter was significantly greater for error vs. correct trials during the post-response period. There was a main effect of period, F(2,18) = 5.5, p <.02, and an interaction effect of trial by period, F(2,18) = 6.6, p < .008. Further, we found that there was more alpha related suppression following error trials compared to correct trails, F(1,9) = 11.6, p < ,01. These findings replicated Carp & Compton (2009)’s prior findings that there is great alpha suppression following error than correct trials.

Following Study 1a and 1b, this year we will be running participants for part 1c. We hope to replicate these findings with a larger sample size and to examine between and within-subjects correlations between error-related pupillary and EEG effects.

Thanks to Becky, Liz, Steph, and all of the Psych department and KINSC this summer for your support on our work!