Looking at choice blindness: Evidence from gaze patterns and pupil dilation

In a choice blindness task, participants often do not notice when their choices and outcomes are mismatched, and they tend to endorse the outcome that they initially rejected. Previous studies on choice blindness have mainly relied on participants’ subjective reports to assess their detection of the mismatch. In this study, we measured participants’ response times, pupil responses and eye-movements during the false feedback phase of a computerized choice blindness task. We found significant differences in all measures between trials where participants detected and corrected the mismatch and trials where they accepted the mismatch or where no mismatch occurred. Trials where participants accepted the mismatched outcome as their own showed similar eye-movement patterns to control trials, but longer response times and increased pupil responses, possibly indicating effortful rationalization. Together the patterns of results allow us to reject notions that participants are aware of, but fail to report, the manipulations during accepted manipulated trials.