Picture-object recognition in pigeons

Photo-, computo-, and videographic pictures have been popular stimuli in ex perimental studies on the cognitive capacities of pigeons. Most authors hav e simply considered them as complex stimuli but some authors have talked ab out them as being natural stimuli. More popular accounts of these studies h ave mostly assumed that the pigeons were recognising the equivalencies betw een the pictures presented and the objects or scenes that were represented on them. We argue that this assumption may often not be warranted because p icture technology is adjusted to fool human vision but not pigeon vision. M ammalian and avian visual systems have a long divergent evolutionary histor y. Anatomical, physiological, and behavioural investigations indicate that colour, depth, flicker, movement and other aspects of vision are probably s ufficiently different from humans in pigeons and other birds, enough for pi ctures to appear to them quite different from reality. We review a number o f studies in pigeons and chickens that were concerned with the cross-recogn ition of real objects or scenes and pictures thereof. The conclusion is tha t these animals are capable of some gross transfer of recognition between p ictures and reality and vice-versa but that when the behavioural tasks requ ire more complex or refined discriminations this transfer generally brakes down.