Memory Systems

Memory can be defined as ‘the mental faculty that enables one to retain and recall previously experienced sensations, impressions, information, and ideas’ (Farlex, c.2011). Memories give meaning to our lives and are one of the most important ways by which our histories animate our current actions and experiences. Remembering is often suffused with emotion, and is closely involved in both extended affective states such as love and grief, and socially significant practices such as promising and commemorating. Memory is essential for much reasoning and decision-making, both individual and collective (Ornstein & Carstensen, 1991).

The subject of memory has intrigued psychologists for over a century now and memory systems, in particular, is such a broad topic that one could not possibly explore every aspect of it. Instead, this essay is intended to discuss the more salient points including the theories of Baddeley and Atkinson & Shiffrin in illustrating the structure and composition of the various memory systems that humans use.

Past experiences are organised into memories which are easy for us to access. This organisation involves three stages – encoding, storage and retrieval (Baddeley, 1986). Mistakes in forgetting and misremembering reflect a failure in one of these three mental operations. As Tulving and Thomson (1973, p. 359) pointed out, ‘Only that can be retrieved that has been stored, and…how it can be retrieved depends on how it was stored.’

Hermann Ebbinghaus (1885) was the first to develop a paradigm for controlled research on memory. By using long lists of nonsense syllables, Ebbinghaus attempted to eliminate any effect that a subjects’ personal experiences might have on their ability to recall information. In this way, Ebbinghaus discovered that the rate of forgetting follows a predictable curve - most forgetting occurs immediately and tapers off as time goes on (See fig. 1).

The recency effect states that we can recall a word at the beginning of a...