Imprinting in birds and primates.

Abstract

AbstractBirds and Primates might be expected to have some similar behaviour patterns because they have some similarities in the nature and organization of their distance and contact receptors. An analysis of the reactions of newly-hatched chicks and neonatal monkeys to objects reveals many similarities and suggests that the contact provided by objects is an important factor influencing these reactions. Further similarities are evident in the behaviour of neonatal chicks and monkeys which are reared without objects either alone or in small groups, and in the behaviour of these infants when they are subsequently presented with objects or placed in small groups. The behaviour of neonates towards large objects is analysed into approach responses mediated by distance receptor systems and contacting responses mediated by contact receptor systems. It is suggested that contact reinforcement is required for the establishment of enduring social attachments and for distance perceptions to become secondary reinforcers for social behaviour. Available data on the role of contact reinforcement in imprinting are reviewed. The fear behaviour of chicks and infant monkeys is compared. There are similarities in their fear responses to strange obj ects both when tested alone and when tested in the presence of imprinting objects to which they have developed social attachments. In both chicks and monkeys fear of the unfamiliar object or situation is alleviated by the presence of the imprinting object. The social and sexual behaviour of chickens and monkeys that have been reared in isolation is briefly described and the similarities of their abnormal and inadequate responses are indicated. Normal social and sexual behaviour is prevented by fear, aggression, and lack of acquired stimulus-response adjustments to an active social partner. A similar analysis of social attachment in the human infant is presented and it is suggested that contact stimulation is necessary for such attachment but not for the establishment of distance perceptions of a familiar environment. The smiling response is treated as an ambivalent fear/relief response involving recognition of familiar distance stimulation. Social smiling differentiates from this ambivalent response through reinforcement by the social partner. The paper is based on available published experimental studies of neonatal birds and Primates and is intended to provoke new analysis and further studies rather than to provide a definitive analysis of the behaviour of neonates.