LATERALIZATION IN CHICKS AND HENS - NEW EVIDENCE FOR CONTROL OF RESPONSE BY THE RIGHT EYE SYSTEM

Domestic chicks show marked lateralization of visually evoked behaviou r: left eye use is associated with, and has advantage for, the detecti on of novelty; right eye use is associated with the use of selected cu es to determine what response should be given. Experiments undertaken to see how far such lateralization might be a transient feature of dev elopment showed similar patterns in both adults and chicks: (i) use of the right, but not the left, frontal held allowed the inhibition of p ecks at a familiar social partner; (ii) in distant viewing, there was spontaneous preference for more use of the left eye when the social pa rtner was familiar rather than unfamiliar. The chick data, in particul ar, support the hypothesis that the visual system fed by the right eye is especially competent in the control of response. This is shown by the ability of birds that are using the right eye to inhibit approach to an entirely novel potential social partner, and inhibit pecks at a familiar partner. The resemblances between chick and hen are sufficien t to show that the basic adult pattern is already present in the young chick: the various developmental changes in features of lateralizatio n, such as days of bias to control by one or other hemisphere, thus do not cause the appearance of the adult pattern. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.