Recognition of visual pattern components in squirrel monkeys.

In 4 mixed-age captive groups of squirrel monkeys the predator alarm behavior control by means of visual stimuli was studied, and the extent to which socially inexperienced infant squirrel monkeys are capable of species-specific alarm behavior. By means of color film projection it was shown that both the socially experienced and inexperienced subjects recognized two-dimensional representations of real objects or situations. Behavioral reactions to visual stimulus patterns of terrestrial predators and graded controls revealed that recognition involves complex perceptional processes and is dependent on social experience. Using a series of systematically varied spot patterns, it was found that the monkeys generalize within a wide but well-defined range of stimuli. There was a clear-cut gender difference in alarm responses, with the males exerting a leading role both in onset and ceasing of terrestrial predator alarm. Both the socially experienced and inexperienced subjects responded with the species-specific avian alarm and flight reaction to fast moving patterns. Only the speed, not the shape, was relevant.