Abstract: 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

Key words: positive emotions, task switching, switch cos