Contact and Social Attachment in Domestic Chicks

Abstract

Reasons are given for the possible importance of contact stimulation in imprinting or in the development of social attachments in chicks. This possibility was examined in 2 experiments. In the first experiment chicks were reared for 8 days in isolation cages with coloured balls hanging inside and/or outside the cages. The outside balls were connected with, and moved with, the inside ones. All the chicks made social responses to, and spent time alongside, the balls during rearing and a majority chose their familiar colour ball in a two-choice discrimination test. Chicks with only a ball outside the cage showed significantly less responding during rearing than did chicks with a ball inside the cage. There was also a tendency for fewer of them to respond in the discrimination test. In a second experiment chicks were reared singly with either a ball or a ball covered with a wire-mesh jacket. Responding was equally strong in the 2 groups both during rearing and in 10-trial discrimination tests. Chicks reared with both these objects in their cages directed all their responses to the unprotected ball. If reared with the unprotected ball fixed, they directed all their responses to the protected ball. If both objects were fixed to the cage wall there was less responding but it was directed to the 2 objects equally. The results show that contact with the object is not important for social attachment or imprinting in the chick. They also confirm that movement of the imprinting object strongly affects the degree of responding and the preferences in responding but is probably not essential for attachment to occur.