Implicit and explicit memory in young, old, and demented adults.

Previous study of scopolamine and memory (Grober et al., 1989) showed that young adults given moderate or high doses of scopolamine maintained maximum cued recall in spite of a dose-dependent decrement in free recall when memory was assessed by cued selective reminding (CSR), a procedure which circumvents inattention and induces semantic processing. Intact recall by CSR indicates either that scopolamine impairs memory indirectly through effects on attention and information processing or that it impairs explicit memory but not implicit memory. In the present study which was done to determine if CSR reflects explicit or implicit memory, a free association test was used to estimate implicit memory after CSR was administered; explicit memory was estimated with a final trial of cued recall. Data from young, nondemented, and demented adults indicate that CSR reflects explicit memory supporting the interpretation of the previous study that scopolamine does not produce direct impairment of explicit memory.