Effects of emotion and sex difference on item-method directed forgetting.

It is crucial to remember or forget others' faces in daily life. People can intentionally forget things they wish to forget, a phenomenon called directed forgetting (DF). This study examined the effects of stimuli's emotions and sex differences in participants and stimuli on DF. We used happy and angry faces as the items in a typical item-method paradigm and conducted three behavioral experiments. In Experiment 1, we recruited 60 participants to examine how emotions of stimuli and sex differences in participants and stimuli affected DF. In Experiment 2, we recruited 60 female participants and manipulated the durations of items presented during the study phase to examine whether the selective rehearsal theory was held. In Experiment 3, we recruited 50 female participants and attached recognition cues to the items presented during the test phase to examine whether the inhibitory control theory was held. We treated the sex of participants in Experiment 1, the durations of items presented during the study phase in Experiment 2 as the between-subject factors, and emotion and sex of stimuli as the with-subject factors. We conducted the mixed-design ANOVA for corrected hit rate, sensitivity, and bias based on the signal detection theory. As a result, we found that DF occurred easily for male participants, whereas not for female participants because of females' superior memorial performances and stronger sensitivities. Furthermore, we found that female participants owned the best and worst recognition rates for angry female faces and happy male faces, respectively. Our results supported the selective rehearsal theory, suggesting manipulations during the study phase had the potential to help females forget what they wished to forget. We presumed that psychologists and therapists should pay attention to the roles of sex difference in twofold, self and others, when studying people's memory and forgetting. Furthermore, the sensitivity of self and the emotion of others should be considered as well.