Working memory capacity affects trade-off between quality and quantity only when stimulus exposure duration is sufficient: Evidence for the two-phase model

Chaoxiong Ye,Qiang Liu,Tengfei Liang,Hong-Jin Sun,Yin Zhang,Qianru Xu

doi:10.1038/s41598-019-44998-3

Abstract

The relation between visual working memory (VWM) capacity and attention has attracted much interest. In this study, we investigated the correlation between the participants’ VWM capacity and their ability to voluntarily trade off the precision and number of items remembered. The two-phase resource allocation model proposed by Ye et al. (2017) suggests that for a given set size, it takes a certain amount of consolidation time for an individual to control attention to adjust the VWM resources to trade off the precision and number. To verify whether trade-off ability varies across VWM capacity, we measured each individual’s VWM capacity and then conducted a colour recall task to examine their trade-off ability. By manipulating the task requirement, participants were instructed to memorise either more colours in a low-precision way or fewer colours in a high-precision way. We conducted two experiments by adjusting stimulus duration to be longer than predicted critical value (Experiment 1) and duration shorter than predicted critical value (Experiment 2). While the results of Experiment 1 showed a positive correlation between the VWM capacity and trade-off ability, the results of Experiment 2 showed a lack of such correlation. These results are consistent with the prediction from the two-phase model.

Highlights

The relation between visual working memory (VWM) capacity and attention has attracted much interest
Experiment 1 showed, with a high ratio of duration/set size, that high VWM capacity participants were able to adjust memory precision flexibly according to task requirements, while low VWM capacity participants failed
The VWM capacity of the individual was positively correlated with the ability of voluntary trade-off when most participants, for a given set size, have enough consolidation time to trade off the VWM precision and number

Summary

Introduction

The relation between visual working memory (VWM) capacity and attention has attracted much interest. Evidence provided by Vogel, et al.[13] clearly illustrated this relationship They identified a contralateral delay activity (CDA), an ERP component strongly modulated by the number of items in VWM during the maintenance phase and reaches an asymptote once VWM capacity is exhausted. They asked participants to memorise simple targets and ignore distractors. The individual’s VWM capacity is highly related to the attention efficiency for target selection ( see Cowan and Morey[17]) This individual difference approach successfully clarified the critical relationship between VWM capacity and attention control in the tasks with distractors[11,13,14,18], it is still unclear how attention control ability is affected by the VWM capacity in other tasks

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Conclusion