The Task-triplet After Bivalent Stimulation Does Not Bind Together

During task-switching,if we occasionally encounter stimuli that cue more than one task,response slowing is observed on all univalent trials within that block,even when no features overlap with the bivalent stimuli.This observation is known as the bivalency effect.At present,the research on the bivalency effect is still under exploration hypothetical stage.Researchers have begun to explain the bivalency effect from cognitive control recently.Researchers do not have a unified conclusion on the theoretical and neural mechanisms involved in the bivalency effect.This study will be further studied.This study includes two parts.Experiment 1 chose 21 college students,using color,numbers and letters as the univalent stimuli,and colored numbers as bivalent stimuli.By comparing the three tasks in the mixed block and the univalent block,the existence of the bivalency effect is investigated.By analyzing the difference of the three tasks before and after the bivalent stimuli,the different effects of the bivalent stimulus on the three tasks are investigated.The results showed that:(1)The three tasks in the mixed block is significantly slower than that in the univalent block,which proves that there is bivalency effect in all three tasks.(2)The letter tasks after bivalent stimulation were significantly slower than before;there was no significant difference in color and number tasks.Experiment 2 chose 22 college students as the subjects,using color,numbers and letters as univalent stimuli,colored letters as bivalent stimuli.By changing type and presentation sequence of bivalent stimuli,it is investigated whether the bivalency effect still exists,and combined with ERP technology to investigate the neural mechanisms of the bivalency effect of the three tasks.At the same time,by analyzing the different performances of the three tasks before and after the bivalent stimuli,the processing mechanism of the bivalent stimuli in the cognitive control system is inferred.The results showed that:(1)The three univalent stimuli in the mixed block is significantly slower than the corresponding stimulus in the univalent block,proving that there is a bivalency effect in all three tasks.(2)As the practice increase,the bivalency effect gradually diminishes or disappears,and the bivalency effect of digital tasks is more sensitive to practice.(3)The digital tasks after bivalent stimulation was significantly slower than before;there was no significant difference in the color and letter tasks.(4)After the bivalent stimulus is presented,the processing of the color task is mainly reflected in the N1,N270 components and 340-460 ms time window;the processing of the digital task is mainly in the time window of 180-210ms;the processing of the letter task is notsignificantly different.(5)The bivalency effect on the color task reveals three related time windows: 180-240ms(P2),280-340ms(N270),340-460 ms.In addition,the bivalency effect of the letter task is related to the time windows of170-260ms(P2)and270-440 ms.In this study,two experiments were carried out to show that the bivalency effect is universal,there are different processing mechanisms for the bivalency effect of the three tasks.Bivalent stimuli have different effects on the three tasks.The three tasks after bivalent stimuli are not bound together.Individual processing of bivalent stimuli reflects the cognitive control’s monitoring of conflict.