The Storage Of Object Relations In Visual Working Memory

The world is composed of objects and their relations.Identifying and manipulating objects and their relations is critical to establish mental representation and interact with the surrounding environment.As a core component of human cognitive system,working memory maintains and manipulates object relations dynamically.However,while most of the studies on visual working memory has focused on the storage of the objects,only a few of them focused on object relations,which does not match its importance.This study examined the storage mechanism of relations among moving objects in working memory.To this end,we created the "dynamic relation change detection paradigm".The paradigm uses a dynamic display to present relations among objects,requiring participants to memorize the relations,and to report the memorized relations(through change-detection task)after a certain period of time.Experiment 1 adopted the artificially defined kinematic relations to measure the capacity of visual working memory for the relations of objects.We found that the working memory capacity of the independent object relations is about 2 pairs.Experiment 2 adopted natrual kinematic relations that is familiar to participants,obtainninng similiar results as experiment 1.Based on the results of the capacity measured in the first two experiments,Experiment 3 fixed the number of relations at 3 pairs,and manipulated the complexity of relations and the number of objects,to infer the storage form of object relations in visual working memory.The results showed that as the complexity of the relations increased(while the number of objects decreased and the number of relations kept constant),the accuracy decreased.This result did not support the hypotheses of object-based or relation-based storage;rather,object relations were more likely to store in the form of an overall representation that includes all the objects and their relations.The main conclusions of this study are as follows:the capacity of independent object relations in visual working memory is about 2 pairs;the object relations,together with objects,constitute a hierarchical representation to store in working memory,and the hierarchical complexity determines the working memory resource consumed by holding the relations.