Early social isolation of the domestic cat: responses to separation from social and nonsocial rearing stimuli.

The relative contributions of social-rearing stimuli (a mother and/or a littermate) and nonsocial-rearing stimuli (a brooder) to the formation and decline of infant kitten attachments were assessed by counting the frequency of distress cries produced by separation from the following rearing conditions: (1) mother-littermate; (2) mother-only; (3) brooder-littermate; and (4) brooder-only. Four male and 4 female kittens were reared in each condition. Each kitten was separated from its rearing condition once a week, from 2 until 5 weeks of age, and placed in open field for 15 min. The frequency of distress cries in both littermate-reared groups did not significantly differ throughout the experiment. The frequency was consistently high until 5 weeks of age when distress cries were significantly reduced. The frequency of distress cries consistently increased in the mother-only-reared kittens with repeated separations, but consistently decreased in the brooder-only-reared kittens. The results were interpreted as being commensurate with the social conditions at the time of separation.