Nature Reviews Neuroscience 4, 685-691 (August 2003) | doi:10.1038/nrn1180

OpinionCan animals recall the past and plan for the future?

Nicola S. Clayton1, Timothy J. Bussey1 & Anthony Dickinson1  About the authors


According to the 'mental time travel hypothesis' animals, unlike humans, cannot mentally travel backwards in time to recollect specific past events (episodic memory) or forwards to anticipate future needs (future planning). Until recently, there was little evidence in animals for either ability. Experiments on memory in food-caching birds, however, question this assumption by showing that western scrub-jays form integrated, flexible, trial-unique memories of what they hid, where and when. Moreover, these birds can adjust their caching behaviour in anticipation of future needs. We suggest that some animals have elements of both episodic-like memory and future planning.

Author affiliations

  1. Nicola S. Clayton, Timothy J. Bussey and Anthony Dickinson are at the Department of Experimental Psychology, University of Cambridge, Cambridge CB2 3EB, United Kingdom.

Correspondence to: Nicola S. Clayton1 Email:

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