Flexible working memory representation of the relationship between an object and its location as revealed by interactions with attention

Working memory (WM) selectively maintains a limited amount of currently relevant information in an active state to influence future perceptual processing, thought, and behavior. The representation of the information held in WM is unknown, particularly the degree of separation between the representation of an object's identity and its location. The present experiments examined the flexibility of object and location WM representations by measuring reaction times on a visual discrimination task during the delay period of a WM recognition task for object identities, locations, or both. The results demonstrate that during WM delay periods, attention is biased toward information that matches the current contents of WM. Attention is not biased toward information that was present in the encoded memory sample but not relevant for the memory recognition test. This specificity of the interaction between WM and attention applies to both the identity and the location of the remembered stimulus and to the relationship between an object and its location. The results suggest that when this relationship is necessary for task performance, WM represents an object and its identity in an integrated manner. However, if this relationship is not task relevant, the object and location information are represented in WM separately.