In order to further address the possibility that the relationship between P3 amplitude and EXT may reflect the fact that the task was more difficult for those higher in EXT or that they were less engaged in it, we also examined reaction time (RT) and a measure of discrimination accuracy. We performed correlations 1) between EXT and mean RT and 2) between EXT and d-prime. There were small, non-significant positive correlations between EXT and RT for both easy (r = .065) and hard (r = .058) target conditions (both p values ≥ .150). There was a small, non-significant negative correlation between EXT and d-prime (r = −.012, p = .716).
