Directed forgetting in explicit and implicit memory: The role of encoding and retrieval mechanisms

Despite the fact that directed-forgetting effects have been attributed to e ither retrieval inhibition or selective encoding, there has been no compell ing evidence to suggest that either mechanism regulates performance in both implicit and explicit memory. Therefore, in two experiments we sought (a) to determine whether directed forgetting influences tests of implicit (lexi cal decision) and explicit (recognition) memory and (b) to examine the rela tive contributions of the encoding and retrieval mechanisms thought to medi ate directed forgetting by having participants perform an external interfer ence task (i.e., sequential finger tapping) at either encoding or retrieval . In Experiment 1, directed-forgetting effects were demonstrated by better performance on remember-cued than on forget-cued words for both lexical dec ision and recognition. In Experiment 2, external interference disrupted dir ected forgetting in lexical decision when it occurred at retrieval and in r ecognition at encoding. These results demonstrate that although directed fo rgetting occurs on both implicit and explicit tests, it may be independentl y regulated by differential retrieval on the former and selective encoding on the latter. The discussion focuses on the differential excitation of rem ember- and forget-cued word representations, as inhibitory processing seeme d not to account for directed-forgetting effects in either implicit or expl icit memory.