AN EFFECT OF IMPRINTING ON THE PERCEPTUAL DEVELOPMENT OF DOMESTIC CHICKS.

Abstract

SEVERAL species of bird have been found to direct their first sexual responses towards objects already familiar to them. The preferences of the birds were at least partially affected by experience occurring before sexual behaviour had matured or was artificially induced1–4. Lorenz1 argued that this long-term effect of ‘imprinting’, as the learning process has been called, is one of the criteria which distinguishes it from ‘associative learning’. At the time this view seemed justifiable since it was generally supposed that associative learning involves the attachment of a specific response to a specific stimulus. However, more recently it has been shown that an animal can use familiar cues more readily than those of which it has had no previous experience, regardless of the response which must be given5,6. This suggests that the long-term effect of imprinting on sexual behaviour is only one aspect of a more general consequence of the learning process and should not be regarded as a special feature of imprinting. The experiment described here provided preliminary evidence that birds can more easily distinguish an imprinted stimulus than unfamiliar stimuli in a situation which does not involve filial or sexual responses. The experiment made use of the finding that isolated domestic chicks (Gallus domesticus) can learn the characteristics of the pens in which they are reared7.