Different attentional selection modes of object information in the encoding and maintenance stages of visual working memory

Visual working memory (VWM) and selective attention are two essential topics of investigation in the field of cognitive psychology. Previous studies have suggested that object-based attention selection modes may be present during the VWM encoding stage, and feature-based attention selection modes may be present during the maintenance stage. Nonetheless, these conclusions are based on different research paradigms, object feature dimensions, and response indicators, so it is prudent to exercise caution when inferring the existence of distinct attention selection modes during different stages of VWM processing. The aim of the present study is to evaluate this hypothesis and provide empirical support. In Experiment 1a, 30 college students were recruited to complete a change-detection task. Participants were instructed to memorize the features of the objects presented in the memory display by means of a pre-cue or retro-cue presented prior to or following the memory display. Specifically, in pre-cue trials, participants were asked to memorize only the cueing task-relevant feature while ignoring the task-irrelevant feature. In retro-cue trials, participants needed to memorize the entire object so that they could select the task-relevant feature according to the retro-cue. The present study examined the "irrelevant-change distracting effect" by comparing memory performance between the condition of task-irrelevant feature changes and no-changes on the memory probe test display. Experiment 1b had a similar procedure, except that the cue types were block designs. Based on the design of Experiment 1b, Experiments 2 and 3 increased the number of memory items to test whether the memory load would modulate the attention selection modes. Twenty-eight participants were recruited for Experiment 1b, Experiment 2, and Experiment 3. All experiments were 2 (cue types: pre-cue, retro-cue) x 2 (task-irrelevant feature change types: change, no-change) within-subjects designs, participants' response times (RTs) and correct rates were recorded, and the sensitivity and criteria of the participants were calculated by signal detection theory ( SDT). The results of the three experiments showed that the change in task-irrelevant features had an impact on task performance in the pre-cue trials, with longer RTs and lower criteria in the task-irrelevant feature change condition than in the no-change condition. This distracting effect was not modulated by the memory load. This suggests the existence of robust object-based attentional selection during the encoding stage in VWM. In contrast, in the retro-cue trials, the distracting effect was present only in the low memory load condition (Experiment 1a/1b) and disappeared when the memory load increased (Experiment 2/3). This suggests that during the maintenance stage, task-irrelevant features are processed only under low memory load conditions, and insufficient resources lead to their inability to be processed as the demand for attentional resources for task-relevant features increases. In summary, the present study provides further evidence for the hypothesis that different modes of attentional selection exist in the encoding and maintenance stages of VWM, specifically that the attention selection mode during the VWM encoding stage is object-based, while the attention selection mode during the maintenance stage is feature-based and regulated by memory load. This study has important implications for resolving the controversy surrounding the attention selection mode of multifeature objects in VWM.