DISSOCIABLE PROPERTIES OF MEMORY-SYSTEMS - DIFFERENCES IN THE FLEXIBILITY OF DECLARATIVE AND NONDECLARATIVE KNOWLEDGE

Amnesic patients (n = 8), who have severely impaired declarative memor y, learned a probabilistic classification task at the same rate as nor mal subjects (n = 16) but subsequently were impaired on transfer tests that required flexible use of their task knowledge. A second group of controls (It = 20) rated the questions on the transfer tests accordin g to whether the questions simply reinstated the training conditions o r required flexible use of task knowledge. The amnesic patients tended to be impaired on the same items that were rated as requiring indirec t or flexible use of knowledge. Thus, control subjects acquired declar ative knowledge about the task that could be applied flexibly to the t ransfer tests. The nondeclarative memory available to amnesic patients was relatively inflexible and available only in conditions that reins tantiated the conditions of training. These findings show that declara tive memory has different operating characteristics than nondeclarativ e memory.