Long-term effects of prior experience in attenuating amnesia.

In Experiment I, prior experience with passive-avoidance training followed by latent extinction was given 1, 3, 5, or 15 days before criterion (re) training and an amnesic treatment. It produced nearly complete protection from retrograde amnesia at the three shorter intervals; at the longest interval, amnesia was present but less severe than in a control group without the familiarization. In Experiment II, prior experience was given 1, 5, or 15 days before a noncontingent shock and an amnesic treatment. Evidence of a reactivation of memory was obtained only at the longest interval. Thus, familiarization and reactivation seem to represent different processes. The results are interpreted as consistent with explanations stressing the disruption of retrieval in retrograde amnesia.