The Index Of Contralateral Delayed Activity （CDA） In The Multiple Object Tracking （MOT） Task

Visual Working Memory（VWM）plays an important role in people’s lives and learning.It is one of the most important cognitive processing systems.The amplitude of the Contralateral Delay Activity（CDA）,an important component of visual working memory,is found to increase with the number of memory items.However,it is still controversial which cognitive function CDA reflects in the working memory storage process.The representational storage account holds that CDA reflects the number of stored representations,while the attentional activation account holds that CDA reflects the number of current attention focuses.Evidence supporting the attentional activation account comes from the fact that CDA components are also observed in Multiple Object Tracking（MOT）tasks.These tasks are thought to require only attentional participation.We believe that there may also have working memory requirements in the classical MOT task,so the CDA components observed in this task cannot effectively deny the representation account.In this study,we will try to exclude possible working memory components in MOT tasks in the unmasked condition and reserve working memory components in the masked condition,then observe the sensitivity of CDA components in both conditions.From this experimental design,we aim to make further contributions to solving theoretical disputes in the indication of CDA.The purpose of Experiment 1 was to test whether working memory was involved in the classical masked MOT task.In this experiment,subjects were asked to complete the MOT task in both unmasked and masked conditions.At the same time,subjects should additionally complete a color change detection task that involves working memory components.The results showed that the additional color working memory task did not affect the accuracy of tracking items in the unmasked condition.On the contrary,the additional color working memory task in the masked condition significantly affected the tracking item accuracy.The experimental results effectively proved that the classical masked MOT task involved working memory processing.Based on masking control in Experiment 1,experiment 2 further recorded the amplitude of the CDA components.And then we can observe the sensitivity of CDA when tracking item numbers with and without masking.The results show that CDA loses sensitivity to the number of items under unmasked condition.But in the case of the masked condition,CDA is still sensitive to changes in the number of items.The experimental results show that CDA reflects the number of representation memory rather than the number of attentional focuses in the multiple targets tracking task.Based on the results of experiment 1 and experiment 2,the main conclusions of this study are as follows: Firstly,working memory is involved in classical multiple objective tracking task;Secondly,CDA may contain EEG components related to sustained attention processing,and EEG components related to the number of memory representations,but only the ones related to memory representations will change with the number of items.This result strongly supports the representation storage account of CDA.