The Gender Difference In Processing Emotion-irrelevant Novel Events

Novel event occurs unpredictably; often interspersed in the context of routine events. The ability to detect and cope with novel events is fundamental for adapting to a rapidly changing environment and ensuring survival of the organism. The novel events enable human being’s orienting responses, which facilitates the mobilization of coping strategies and helps the organism to survive in an emergency. In life and laboratory settings, novel events are typically infrequent but emotionally relevant, and thus linked with affective responses such as fear or surprise.Despite knowledge of gender differences in emotional processing, but nothing is known about the impact of gender on neural processing of emotion-irrelevant, novel stimuli.In three experiments, the present study used adapted three-stimulus oddball tasks and event related potential to investigate neurophysiological mechanisms of possible gender effect in processing novel events.In Experiment 1, both novel and non-novel control stimuli in this experiment were task-irrelevant, and subjects were instructed to detect the target and press the space key. The behavioral assessment of subjective novelty showed higher novelty scores in females in comparison with males, in which standard and novel stimuli are task-irrelevant distracters. In addition, ERP results demonstrated remarkable novelty effect which was larger in females than in males on the mean amplitudes of the 200-300ms and 300-430ms intervals.Experiment 2-A excluded the contribution of stimulus probability, and subjects were asked to distinguish the target and the non-target stimuli by pressing different key. Experiment 2 continued to display significant novelty effect in the response time (RT) and in the average ERP amplitudes of 130-600ms interval. More importantly, experiment 2 displayed significantly more pronounced novelty effect in females, indexed by larger novelty-related LPC (late positive component) amplitudes in females than in males in the 500-600ms interval.Besides, the program of Experiment 2-B is likely to Experiment 2-A, but subject just need notice the target stimulus and press the space key. The ERP results showed the considerable novelty effect in the early time, and significantly more prominent novelty effect in females than in male in the 500-700ms interval.Therefore, behavioral and ERP results of Experiment 1,2-A and 2-B consistently revealed that females are equipped with enhanced sensitivity to emotion-irrelevant, novel stimuli, which is an independent phenomenon irrelevant to the known gender difference in rare stimulus processing. This probably results from differential adaptive demands for females and males during evolution.