Classifying Human Long-term Memory: Evidence from Converging Dissociations

This paper reviews the support for multiple human long-term memory systems that is provided by experimental findings of dissociations reported in the literature. Four putative systems are examined: episodic, semantic, perceptual representation (PRS) and procedural memory. The four systems are contrasted for four different forms of dissociations (functional, developmental, pharmacological and brain damage). At least one example of 23 of the 24 different types of dissociations is described. It is argued that this evidence from converging dissociations provides support for the existence of multiple long-term memory systems. The studies reviewed provide some hints about the critical neural substrates of different systems. This neuroanatomical information was compared and found to be consistent with the results of available functional neuroimaging studies.