Retrospective cognition by food-caching western scrub-jays

Episodic-like memory, the retrospective component of cognitive time travel in animals, needs to fulfil three criteria to meet the behavioral properties of episodic memory as defined for humans. Here, we review results obtained with the cache-recovery paradigm with western scrub-jays and conclude that they fulfil these three criteria. The jays remember the what-when-where components of a caching episode (content), these components are integrated (structure), and can be updated and generalized over situations (flexibility). The interpretation of the temporal aspect of the jays' episodic memory remains contentious however. For the memory to be episodic-like, the when component needs to result from time being encoded explicitly in memory as opposed to being a by-product of a decaying memory trace. We present new data in favor of explicit encoding of temporal information in the memory of scrub-jays. Finally, we discuss episodic-like memory in scrub-jays in relation to results obtained with other species.