Classical heart-rate conditioning and differentiation of visual CS with an appetitive UCS in pigeons.

A tachycardic response was classically conditioned in thirsty pigeons using water as an unconditioned stimulus and localized lights as conditioned stimuli. This was successful in 6 out of 9 birds. In one experiment the subjects had their heads immobilized so that the positions of the stimuli within the visual field could be precisely specified. When the stimuli were shifted from the binocular to the monocular field and vice versa there was no initial transfer of a conditioned differentiation between a white and a green light.