Rehearsal-Independent Episodic Memory: Long-Term Forgetting

Abstract

Research on age differences in episodic memory began to move in an exciting new direction following the distinction made by Hasher and Zacks (1979, 1984) between effortful- and automatic-encoding processes. We discovered in Chapter 6 (pp. 354–355) that automatic-encoding processes are presumably unaffected by an individual’s limited-cognitive resources. The usual position is that they function independently of working memory’s limited capacity (see Figure 6.27). According to Hasher and Zacks, “Automatic processes function at optimal levels, continuously and independently of intention…and these processes require only that the event be attended to…. The information encoded in this way is no different than it is when intention is activated” (1984, p. 1373). From this perspective, automatic forms of episodic memory should be rehearsal independent in the sense that rehearsal activity initiated by the intent to memorize should have little effect on subsequent memorability (Kausler & Lichty, 1988). By contrast, cognitively effortful forms of memory, as represented by traditional free-recall tasks, are rehearsal dependent. That is, memory performance is dependent on the quality and/or quantity of the rehearsal the to-be-remembered events receive. When translated to laboratory conditions, rehearsal independency means that memory performances should be no better under incidental- memory conditions than under intentional-memory conditions. The null effect for intentionality is, in fact, a primary criterion for determining whether or not memory for specific kinds of events is truly automatic. Hasher and Zacks (1979) reasoned that automaticity of encoding occurs for information that is essential for maintaining continuity with the everyday world. Presumably, automaticity is ensured either by being innately programmed in the human organism or by being the end product of years of frequent practice during childhood (Hasher & Zacks, 1979).