Abstract

There is an asymmetry when switching toward the easy and dominant task than toward the complex and nondominant task in two different strength task-switching.A similar asymmetry phenomenon is observed in human’s daily life：when people switch between joyful task and unpleasant task，people will make different efforts for the joyful task and unpleasant task，and the degree of happy or boring task will also influence the efforts.In addition to positive information and neutral information，the human is in particular sensitive to valence intensity changes in emotionally negative stimuli，while is relatively insensitive to valence intensity changes in positive stimuli，which indicating the different dominant position of different valence polarity.The current book examined whether “asymmetric effect” phenomenon existed and its’ generation mechanism due to the unequal sensitive to different valence emotion informations.This book used improved attention shifting paradigm.Firstly，whether “asymmetric effect” phenomenon existed in the shifting of different valence information was studied.Secondly，investigated the conditions which “asymmetric effect” phenomenon existed.Thirdly，investigated the neural basis of the “asymmetric effect” phenomenon；finally，investigated the inhibition mechanism of the “asymmetric effect” phenomenon.The experimental subjects were normal college students which were excluded the anxiety and depression.The results were as follows.

（1）The “asymmetric effect” existed in switching association with positive information and negative information.

（2）The reaction time of switching association with high and low negative information was significantly higher than repeat task response time，but no significantly difference between high negative information and low negative task in switch task；there was no significant difference for reaction time between high and low positive information of switching and repeat task.These results showed that there was no “asymmetric effect” of emotional information shifting in the same valence polarity.

（3）The same intensity：the reaction time of switching task association with high negative and positive information was significantly higher than repeat task response time，and significant difference between high negative and positive information in switching task，indacating “asymmetric effect”；the different intensity：the reaction time of switching association with negative information was significantly higher than repeat task response time，but no different reaction time of switching association with positive information in switch task，indacating “asymmetric effect”.In a word，these results showed that there was “asymmetric effect” of emotional information shifting in the different valence polarity.

（4）The different intensity：the participant could identify the shifting and repetitive tasks in the early attention processing （N170），and exhibited significantly higher mean amplitude association with high intensity than low intensity of switching task in the late information processing （P3），indicating “asymmetric effect”；the same intensity：the participant exhibited significantly higher mean amplitude association with high positive intensity of switching task than repetitive tasks in the early attention processing （N170），and exhibited significantly higher mean amplitude of shifting task than repeting task association with high negative information task in the late information processing （P3），which indicating “asymmetric effect”.

（5）The “asymmetric effect” in emotion-relevant switching is generated based on the more residual inhibition of the previous negative information than the positive information.

Key Words：emotion-relevant switching，asymmetric effect，valence intensity