The storage mechanism of dynamic relations in visual working memory

The ability to briefly hold and manipulate object relations provides a foundation for interacting with our complex environment. Previous studies on working memory focused more on objects than their relations, which is disproportionate in the context of their theoretical importance. This study examined dynamic relations of objects to better understand the storage mechanism (capacity and representation) using a self-developed modified change detection paradigm, where an object moved dynamically, based on its relation to other objects. Eighty-four university students participated in four experiments (21 each), wherein they observed dynamic relations between objects presented on a display, memorized them, and reported whether the memorized relations were identical to the probatory relations. Results showed that visual working memory had an upper limitation of holding dynamic relations. When relations were independent of each other, the limitation was two; whereas in non-independent cases where different relations shared an object, memory accuracy decreased with increasing relations complexity, rather than with the number of objects or relations. Thus, dynamic relations are probably not stored as object features, nor stored independent of objects. More likely, relations and objects are represented in visual working memory as an integrated perceptual unit.