Recency judgements in Wernicke-Korsakoff and post-encephalitic amnesia: influences of proactive interference and retention interval.

This study further examines the performance of diencephalic and temporal lobe amnesics on the recency judgement task (Parkin, Leng and Hunkin, 1990). The two patient groups were represented by patients with Wernicke-Korsakoff syndrome (WKS) and post-Herpes simplex encephalitis (HSE). Experiment 1 demonstrated that poorer recency judgements by WKS patients were not due to a general proactive interference effect, but from an inability to remember which items had been designated targets on a given trial. Experiment 2 demonstrated that the superior performance of the HSE group was not attributable to a putative faster forgetting rate. In addition, the study found no relationship between recency judgements and degree of frontal lobe impairment. It is concluded that diencephalic damage has a particular effect on the ability to make recency judgements and that this represents a fundamental difference between diencephalic and temporal lobe amnesia. Theoretical interpretations of this difference are discussed.