Wednesday, 11 January 2012

Elements of episodic memory

Keen students of memory will recognise that the title of this post is an homage to the seminal book of the same title by the great memory researcher, Endel Tulving.  To my mind, Tulving’s Elements is one of the finest books that has been written about memory, along with William James’s Principles of Psychology and Dan Schacter’s Searching for Memory. (It’s quite possible that Charles Fernyhough’s forthcoming Pieces of Light may soon join that list).

In Tulving’s book, he describes how episodic memories of experienced events are unlikely to be stored as fixed, separate, discrete “memory traces”, but rather as “bundles” of features.  It makes sense, given the enormous number of events we may have to remember over a lifetime, that our brains would have evolved a more efficient strategy than simply storing each event separately, as a bound trace comprising all its different components.  The redundancy would be huge.  Instead, it appears that we store single representations of features distributed around the brain which are then shared between different event memories via associative networks. Tulving acknowledges that “we have no idea about the number and identity of features that the human mind or its memory system has at its disposal” (p. 161).  However, he speculates that “the features of the mind correspond to discriminable differences in our perceptual environment and to the categories and the concepts that the language we use imposes on the world.” (ibid)