Hemispheric asymmetries in the time course of recognition memory.

Hemispheric specialization has been studied extensively within subfields ranging from perception to language comprehension. However, the study of asymmetries for basic memory functions--an area that holds promise for bridging these low- and high-level cognitive domains--has been sporadic at best. We examined each hemisphere's tendency to retain verbal information over time, using a continuous recognition memory task with lateralized study items and central test probes. We found that the ubiquitous advantage of the left hemisphere for the processing and retention of verbal information is attenuated and perhaps even reversed over long retention intervals. This result is consistent with theories that propose differences in the degree to which the hemispheres maintain veridical versus semantically transformed representations of the input they receive.