Most complex cognitive skills require access to representations formed as the products of recent perceptual and cognitive operations. A small subset of these representations can be maintained in the current focus of attention, and are readily available to be employed for ongoing cognitive processes. In contrast, representations that fall outside the contents of focal attention need to be brought back from memory to be restored to active processing. A series of studies investigate how recently processed information is retrieved from memory. Two complementary methodologies were used to examine the behavioral and neural mechanisms that underlie short-term or working memory retrieval operations: The speed-accuracy trade-off (SAT) procedure was used to independently measure the probability of retrieval success (availability of the memory representation) and retrieval dynamics (the speed with which the memory representation can be accessed), and to further characterize the differential contributions of automatic and controlled processes to these retrieval operations. Functional magnetic resonance imaging (fMRI) was used to provide converging evidence to the behavioral findings and to identify the neural bases of the cognitive processes identified from the behavioral analyses.
Collectively, the studies indicate that the nature of the retrieval operation is determined by the type of information that needs to be accessed and the amount of interference present in the retrieval context. Results further indicate that the left inferior prefrontal cortex, the left posterior parietal cortex, and the medial temporal lobes jointly support working memory retrieval.
