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 either retrieval inhibition or selective encoding, there has been no compelling 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 (lexical decision) and explicit (recognition) memory and (b) to examine the relative contributions of the encoding and retrieval mechanisms thought to mediate directed forgetting by having participants perform an external interference 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 decision and recognition. In Experiment 2, external interference disrupted directed forgetting in lexical decision when it occurred at retrieval and in recognition at encoding. These results demonstrate that although directed forgetting occurs on both implicit and explicit tests, it may be independently regulated by differential retrieval on the former and selective encoding on the latter. The discussion focuses on the differential excitation of remember- and forget-cued word representations, as inhibitory processing seemed not to account for directed-forgetting effects in either implicit or explicit memory.