Episodic memory is our memory for recollecting details of previous events we experiences in the first person. Episodic events are coded automatically, meaning we are not actively trying to remember them for the future.

When we are asked about a past event we personally experienced, we can communicate details about it verbally. In non-verbal subjects such as non-human animals, assessing this capacity becomes challenging – we do so through behavioral approaches, leaving phenomenological aspects aside. As those are essential to the human definition of episodic memory, we make a distinction by referring to this type of memory in animals as episodic-like memory.

When testing for episodic-like memory, to ensure that the event we want the subject to recall later is automatically encoded, the subject must not know that what is happening might be relevant for later. Therefore, a test aiming to assess this capacity in animals must be unexpected – meaning that the animal should not expect to be asked about recalling the event in question.

In the current study, to achieve this effect, I recurred to the violation of expectation paradigm, which consists in presenting a question or test to a subject in a situation where there is a strong expectation to do something specific instead. This paradigm predicts that subjects tend to look longer at the source of the violation when a situation is unexpected, when in comparison with an expected situation.

However, this is an effect that has been reported mostly in mammals, including in humans, but not yet in macaws…