Components of recognition memory: dissociable cognitive processes or just differences in representational complexity?

Many current theoretical views within the literature on recognition memory-a representative sample of which is provided by the present special issue-advocate the dissociation of recognition memory into two cognitive processes: familiarity-based recognition, and recollection/recall. Furthermore, these processes are proposed to be mediated by distinct and dissociable anatomical regions, usually the perirhinal cortex and hippocampus, respectively. In this article, we describe a representational-hierarchical view that provides an account of cognition, including mnemonic and perceptual processing, within a brain pathway we term the ventral visual-perirhinal-hippocampal stream. According to this view cognition, perception, memory, and indeed amnesia may be understood by considering the content and organization of stimulus representations in the brain. Taking this view leads us to question the idea of cognitive modules for introspectively derived notions such as familiarity and recollection. We begin by reviewing the representational-hierarchical framework, explain how it has been used to account for object recognition memory in perirhinal cortex, and review the rationale for extending this framework to the hippocampus. We then discuss whether the principles of the representational-hierarchical framework can be used to understand recollection and familiarity in terms of stimulus complexity, and use these principles to reconsider some of the evidence for neuroanatomical, dual-process models of recognition memory.