Episodic memory and mental time travel

We argue that from an evolutionary perspective memory systems have to be evaluated not in terms of how accurately they reflect the past, but in terms of their contribution to present and future survival and reproduction. Memory systems differ in the degree of flexibility in offering anticipatory behavior. Episodic memory is the most flexible system in that it enables humans to envisage virtually any particular future event. It may have evolved only as a design feature of this anticipation and planning system. Several chapters in this volume discuss animal models of this ability. Here, we warn that there must also be uniquely human traits for which there can be no such animal models and suggest that human mental time travel may be based on several such traits. Animal comparisons may still be extremely important in their own right, and because identification of what is unique about the human capacity and what is shared with other species; may hold decisive clues about how mental time travel is created in the human brain