| Objects:In order to examine the effect of cognitive biases on emotion memory in optimistic and pessimistic tendencies, this study used the continuous recognition test to research the neurophysiology of the mood-congruent memory in dispositional optimism with ERPs. The aims of the present study were as follows:(1) To explore whether optimistic and pessimistic tendencies show mood-congruent memory; (2) To investigate emotional regulation of working memory by analyzing ERP old/new effects; (3) Combining the behavioral and ERPs results, to explore the brain lateralization of emotional pictures procession.Methods:68 subjects selected from Changsha University with the Chinese version of the Optimism and Pessimism Scale (OPS-C) took part in this study:15 obvious optimists,20 obvious pessimists,15 persons with ambiguous tendencies, and 18 persons with dual tendencies. We employed continuous recognition test with emotional stimuli selected from the International Affective Picture System (IAPS). The behavior and ERP data were recorded during the task. The average reaction times and accuracy were subjected to ANOVA with repeated measures under different conditions (new/old, emotional valence).30 electrode sites were pooled into nine electrode clusters arranged in a three-by-three grid (anterior/central/posterior* left/midline/right). The average ERPs waves under different conditions were overlapped and averaged separately and then the mean amplitude of ERP components in each cluster were compared among 4 groups.Results:(1) The results of behavior data showed no significant difference among 4 groups. The false alarm of neutral pictures was significantly higher than that of negative pictures (p<0.05), and discrimination index (Pr) was significantly lower than emotional pictures (p<0.05). This experiment did not find old/new effects and difference among groups of reaction times. A main effect of valence was found, and responses were slowest to neutral pictures (p<0.01).(2) The ERP waveforms were quantified by mean amplitude measures in three windows:200-400ms,400-700ms,700-900ms, representing the early frontal old/new effect, the parietal old/new effect and the late frontal old/new effect separately. The mean amplitudes of each time window were subjected to repeated measures ANOVAs with valence (positive, neutral, negative), presentation (new, old), caudality (anterior, central, posterior), laterality (left, midline, right) as within-subject-factors, and optimistic and pessimistic groups (obviously optimistic type, obviously pessimistic type, ambiguously tendency type, and dual tendency type). Four groups all showed significant early frontal central old/new effect, parietal old/new effect and late frontal old/new effect.200-400ms:no interactions of groups and old/new effect were found.400-700ms:the interactions of old/new effect and emotional valence were significant (p<0.01), the old/new effect of negative pictures was significantly larger than positive and neutral ones (p<0.05), mainly as a result of more positive amplitude of old-emotional stimuli (p<0.01). 700-900ms:The five-way interactions were significant (p<0.05), for pleasant pictures, optimists showed the most widespread late frontal old/new effect, which was the least widespread for persons with ambiguous tendencies, and the left part of this old/new effect of optimists was bigger than pessimists (p<0.05). For unpleasant pictures, the middle and right parts of the old/new effect of persons with dual tendencies were significant larger than optimists and pessimists (p<0.05).Conclusions:(1) The behavioral results did not support that there is cognitive biases on emotion memory in optimistic and pessimistic tendencies. Neutral pictures showed lower accuracy and longer reaction times. (2) The ERPs data suggested that emotional regulation of parietal old/new effect showed negative bias, which was due to different retrieval of old stimuli. (3) The mood-congruent memory influenced post-retrieval processes. Optimists showed cognitive biases of positive emotion; while pessimists did not show enhanced processing of negative emotion, but reduced processing of positive emotion. |
