The enhanced processing of visual novel events in females: ERP correlates from two modified three-stimulus oddball...

The ability to detect and cope with unpredictable novel events is fundamental for adapting to a rapidly changing environment and ensuring the survival of the organism. Despite knowledge of gender differences in emotional processing, little is currently known about the impact of gender on neural processing of emotion-irrelevant, novel stimuli. Using two modified three-stimulus oddball tasks and event-related potentials (ERPs), the present study investigated the impact of sex on brain processing of novel events and the associated neurophysiological correlates. With novel and non-novel control stimuli used as task-irrelevant distracters, Experiment 1 showed higher novelty rating scores and larger size of novelty effects in brain potentials at 200-300 ms and 300-430 ms time intervals in females compared to males. After excluding the contribution of stimulus probability, Experiment 2 continued to display significant novelty effects in the response times and the amplitudes of the 130-500 ms time windows. Most importantly, females displayed a sustained novelty effect in the late positive component (LPC) amplitudes of the 500-600 ms interval, which was not observed in males. Therefore, Experiment 1 and 2 demonstrated that females are equipped with enhanced brain processing of emotion-irrelevant, novel stimuli. This phenomenon is independent of the established gender difference in infrequent stimulus processing. We suggest that our findings reflect the differential adaptive demands on females and males during evolution.