Attentional Mechanism Inderlying Retaining Relational Binding In Working Memory

Binding problem is a core issue in working memory(WM),which has both theoretical and practical significance.Nowadays,binding research in WM mainly focuses on the attention mechanism of retaining binding in WM.More specifically,these studies predominately focused on conjunctive binding,and have reached a consensus in that object-based attention plays a key role in retaining conjunctive bindings in WM.However,there are few studies exploring the attentional mechanisms of retaining relational binding,whose processing neural mechanism is distinct from conjunctive binding in WM.Particularly,the extant four studies investigating the role of domain-general attention and their conclusions were in discrepancy,and no study has systematically investigated the role of object-based attention in holding relational binding in WM,particularly for the binding constituted by complex objects.To fully uncover the processing mechanism of binding in WM,and resolve the discrepancy in previous studies,the current study aimed to explore the attentional mechanisms of retaining relational binding in WM,focusing on domain-general attention and obj ect-based attention.The current study consisted of three experiments,wherein a dual-task paradigm was adopted.This paradigm required subjects to perform a secondary task consuming a specific type of attention while conducting a WM task.The logic was that if one specific type of attention plays a key role in the WM maintenance of binding,secondary task will lead to a larger impairment to the binding than that to the constituent elements(i.e.selective binding impairment).Experiments 1 and 2 investigated the role of domain-general attention in holding relational bindings in WM,and a backward counting task was inserted to consume domain-general attention.Since the key factors leading to the previous discrepancy were related to different task settings(mixed design vs.block design)and memory stimuli(complex objects vs.simple objects),Experiments 1 and 2 addressed the two issues,respectively.Experiment 1 examined the effect of task setting,by using a mixed design(Experiment la)and a block design(.Experiment lb)separately.with complex obj ects(faces and scenes)as the memory stimuli.Experiment 2 explored the effect of memory stimuli by using complex objects(Experiment 2a)and simple objects(Experiment 2b)separately.Finally,Experiment 3investigated the role of object-based attention in holding relational bindings in WM,by using complex objects as the memory stimuli.Critically,a Duncan task as a secondary task was inserted to the WM maintenance phase to consume obj ect-based attention in the experiment.Experiments 1 and 2 consistently found that the backward counting task did not lead to a selective impairment for holding relational bindings.Whereas Experiment 3 demonstrated that the Duncan task led to a selective binding impairment.Taken together,the current study suggests that object-based attention,instead of domain-general attention plays a pivotal role in retaining relational bindings in WM.