积极情绪对任务转换的影响

通过两个行为实验考察了积极情绪图片所诱发的情绪状态对任务转换的影响及其机制。研究任务是数字分类任务，分为保持和转换两个阶段。首先要求被试对靶刺激形成一定的习惯化反应，然后改变任务要求。实验1以53名大学生为被试，分别在积极情绪、消极情绪和中性条件下完成任务，发现在与中性条件相比时，积极情绪促进任务转换，消极情绪延缓任务转换。实验2以37名大学生为被试，增加了一种转换条件，考察积极情绪促进任务转换的心理原因，结果表明积极情绪因偏好新异刺激而促进任务转换

The Effects of Positive Emotions on Task Switching

The generation of appropriate behavioral responses requires the ability to understand the global rules governing stimulus classification, to select the most fitting response from among competing possibilities, and to inhibit task-inappropriate prepotent responses. Cognitive flexibility refers to the ability to shift to a different thought or action according to the changes in a situation. Task switching is the most important component of cognitive flexibility. In task switching paradigms, subjects are assigned two or more tasks and are asked to perform each when certain conditions are met. In some trials, the subjects repeatedly perform each task, whereas in others, they switch from one task to another. Response times (RTs) on repeated-task trials are typically shorter than those in “switch” trials. Switch cost is empirically defined as the reaction time difference between switch trials and repeat trials. According to the broaden-and-build theory of positive emotions, these kinds of emotions do not typically arise in life-threatening circumstances, and perhaps by consequence, they broaden a person’s momentary thought-action repertoire and especially enhance cognitive flexibility. The present study was conducted to investigate the effects of emotional responses on task switching. Two experiments were conducted. In Experiment 1, the participants performed a digit-categorization task in the following three moods: positive emotion, negative emotion, and neutral mood. The task involved two conditions: maintaining condition and switching condition. In the maintaining condition, participants were required to respond to a target digit appearing in a pre-specified color, while ignoring a distracter digit appearing in a different color. In the switching condition, the participants had to respond to the stimuli in a new color, while the distracters appeared in the color of the previous target. Experiment 2 further explored the facilitating effect of positive emotions upon task switching by the addition of another switching condition. The results of Experiment 1 indicated that emotional conditions influenced the performance of task switching. Compared with the neutral condition, positive emotions always reduced the switching cost, while negative emotions increased it. In Experiment 2, the results indicated that positive emotions biased attention toward novel stimuli, thus facilitating the switch to a new stimulus category. These results demonstrated that compared with neutral or negative emotions, positive emotions promoted cognitive flexibility and reduced perseveration. These results are consistent with those of other studies on the effects of positive emotions on cognitive control. This study supports and extends Fredrickson’s broaden-and-build theory of positive emotions. In addition, the results of the present study also provide a possible explanation for positive emotions reducing the switching cost