Effects of visual complexity during rearing on chicks’ reactions to environmental change


The reactions of 6-day-old chicks to the illumination of a torch bulb in the home pen differed according to the conditions of rearing. Birds which were able to see stationary objects in an adjacent pen during rearing reacted in the same way as birds in a grey-walled pen but birds reared with a moving object visible reacted differently. The initial, very brief, orienting reaction was shown by all birds but after this those birds which had been reared with a moving object present for 3 or 6 days in total, and those which had a mirror on the wall, spent more time near the object or mirror than they had while undisturbed. The reaction to the novel change, as measured by the extent and duration of the period of reduced activity and loud calling, was greater among birds reared in a grey pen or with statinary objects present than among those whose rearing conditions had been made more complex by the presence of a moving object or mirror. It is suggested that the 'environmental model' formed within the animal as a result of experience during development is different, if that experience has been more complex, in such a way that an environmental change is followed by a less marked reaction. © 1969.