Recognition memory in amnesic patients: effect of temporal context and familiarity of material.

In Experiment I recognition memory for pictures, high frequency words and low frequency words was examined in Korsakoff patients and alcoholic controls at retention intervals of 10 minutes, one week and seven weeks. Korsakoffs showed (1) surprisingly good recognition of pictures and low frequency words, scoring well above chance even at the longest retention interval; (2) no evidence of a faster than normal rate of forgetting. In experiment II the familiarity of pictures was varied in such a way that correct recognition involved either (a) explicit decisions as to whether items were seen 10 minutes or 24 hours previously or (b)decisions as to whether items had ever been seen before. Korsakoffs were severely impaired in making the first type of discrimination but had little difficulty with the second type. It is suggested that the primary defect in amnesia may concern contextual memory rather than memory for items as such.