PARALLEL BRAIN SYSTEMS FOR LEARNING WITH AND WITHOUT AWARENESS

A fundamental issue about memory and its different forms is whether le arning can occur without the development of conscious knowledge of wha t is learned. Amnesic patients and control subjects performed a serial reaction time task, exhibiting equivalent learning of an imbedded rep eating sequence as measured by gradually improving reaction times. In contrast, four tests of declarative (explicit) knowledge indicated tha t the amnesic patients were unaware of their knowledge. Moreover, afte r taking the tests of declarative memory, all subjects continued to de monstrate tacit knowledge of the repeating sequence. This dissociation between declarative and nondeclarative knowledge indicates that the p arallel brain systems supporting learning and memory differ in their c apacity for affording awareness of what is learned.