‘Unwilling’ versus ‘unable’

Intentionality plays a fundamental part in human social interactions and we know that interpretation of behaviours of conspecifics depends on the intentions underlying them. Most of the studies on intention attribution were undertaken with primates. However, very little is known on this topic in animals more distantly related to humans such as birds. Three hand-reared African grey parrots (Psittacus erithacus) were tested on their ability to understand human intentional actions. The subjects’ attention was not equally distributed across the conditions and their behavioural pattern also changed depending on the condition: the parrots showed more requesting behaviours (opening of the beak and request calls) when the experimenter was unwilling to give them seeds, and bit the wire mesh more that represented the obstacle when the experimenter was trying to give them food. For the first time we showed that a bird species, like primates, may be sensitive to behavioural cues of a human according to his intentions. Keywords: Grey parrots; intention attribution; theory of mind