Elements of episodic-like memory in animals

A number of psychologists have suggested that episodic memory is a uniquely human phenomenon and, until recently, there vas little evidence that anima ls could recall a unique past experience and respond appropriately. Experim ents on food-caching memory in scrub jays question this assumption. On the basis of a single caching episode, scrub jays can remember when and where t hey cached a variety of foods that differ in the rate at which they degrade , in a way that is inexplicable by relative familiarity. They can update th eir memory of the contents of a cache depending on whether or not they have emptied the cache site, and can also remember where another bird has hidde n caches, suggesting that they encode rich representations of the caching e vent. They make temporal generalizations about Mien perishable items should degrade and also remember the relative time since caching NN,hen the same food is cached in distinct sites at different times. These results show tha t jays form integrated memories for the location, content and time of cachi ng. This memory capability fulfils Tulving's behavioural criteria for episo dic memory and is thus termed 'episodic-like'. We suggest that several feat ures of episodic memory may not be unique to humans.