| Positivity effect refers to that elderly individual who tends to process stimuli with positive emotional characteristics more than negative emotional stimuli.In recent years,studies on the positivity effects of working memory(WM)have found that when emotional materials are task-irrelevant stimuli,there are different effects on the positive effects of working memory in the elderly.No positive effect has been found in studies that set emotional material as a task-irrelevant attribute of the target stimulus.These results suggest that the differences in the internal processing mechanism of different emotional distraction tasks may further lead to the differences in emotional bias in WM.However,previous studies did not clearly distinguish the two kinds of emotional distraction tasks,nor have they studied and discussed the differences in the intrinsic processing mechanism of the two kinds of emotional distraction tasks.Objective:This study will distinguish two different kinds of emotional distraction tasks,emotional stimuli as task-irrelevant distractors and task-irrelevant attributes on WM updating in the elderly were investigated,and the effects of WM load and valence were also studied.Event-related potentials(ERPs)were used to further explore the effects of task-irrelevant emotional stimuli on the different stages of WM processing in older adults.Methods:The first study was a behavioral study,emotional face N-back task paradigm was used,with a four-factor mixed experiment design of 2(WM load:1-back/2-back)× 3(emotional valence:neutral/happy/angry)×2(task:face/number)× 2(group:young person/old person).The second study was an ERPs experiment,with a three-factor mixed experiment design of 3(emotional valence:neutral/happy/angry)×2(task:face/number)× 2(group:young adults/older adults).Results:In the first study,interaction effect between cognitive load,task was found,and the main effect of group was significant.There was no difference in task performance between the elderly and the young participants in the number 1-back task.the elderly participants performed worse than the young participants in the gender 1-back task,the gender 2-back task,and the number 2-back task.At the same time,the response accuracy was poorest under distractors with anger expression,which indicated a largest interference effect of the negative emotional face to the current WM task.In the second study,the interaction effect between task and emotional valence was significant.In the gender 2-back task,the response speed under the happy condition was significantly faster than that of the angry condition,suggesting a smaller interference effect of positive irrelevant emotional stimuli.In the number 2-back task,the response speed under the angry condition and the happy condition were significantly slower than that of the neutral condition,suggesting a larger interference effect of emotional irrelevant stimuli.ERP data showed a task and group interaction on P2 and LPP amplitudes,a significant effect of emotional valence on P2 and LPP amplitudes were found in the elderly participants,and there was no significant difference in the P2 and LPP amplitudes of the young participants with different emotional distractors.Conclusion:(1)the two kinds of distractors are different;(2)Both WM load and types of distractor affected the ability to inhibit task-irrelevant emotional stimuli in older adults.(3)ERPs study revealed an effect of emotional distractors to the middle and later stages of WM processing. |
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