Many researchers working on animal cognition, however, believe that some species can indeed remember their past and plan for the future. Proving that this is the case is notoriously difficult. In studies of humans, memories and thoughts about the future are measured by asking the volunteer to verbalise what they are thinking or what motivated a decision. Animals, of course, cannot do the same, which makes it difficult to separate the repetition of a learned behaviour from evidence of true memory or planning. A key question is whether animals can recall experiencing an event at a specific time and place in a manner similar to human episodic memory. This is a major bone of contention in the debate. As Tulving saw it, human episodic memory requires self-awareness – the ability to imagine oneself in the past, as opposed to merely remembering what happened when and where. By this definition, the existence of animal episodic memory is virtually impossible to prove. Comparative psychologists who research animal memory, however, work on the basis of “episodic-like memory”. This requires only that the animal can remember what it did, where, and when.
Several studies have shown this to varying degrees. Animal trainers working with a pair of bottlenose dolphins, for example, have found that they are able to remember what they did in the immediate past. After being trained to perform dozens of different tricks in response to specific hand signals, the dolphins were asked, using another hand signal, to repeat the trick they last performed. Both dolphins could do this easily – one, a female called Elele, had a 100 per cent success rate. Similarly, experiments with pigeons and rats have shown that they are able to peck or nose at a particular symbol to indicate what behaviour they have just carried out.
November 25, 2008
Original web page at New Scientist