The demonstration in the domestic guinea pig of a process resembling classical imprinting

Abstract

The present study, consisting of 6 inter-related experiments with ginea pigs, investigated the hypothesis that an imprinting-like process (on which normal mammalian social behaviours may depend) exists in mammals. In general it showed that the guinea pig, if isolated from normal social contact, can be imprinted on an artificial object (a moving octagonal wood block), and that the resulting imprinted behaviour has definite social characteristics. The findings of the 6 experiments were as follows: Experiment 1 showed that infant subjects are attracted to and will respond socially to an artificial moving object, if not allowed normal social interaction; that is, guinea pigs isolated at birth respond socially to an imprinting object but control subjects do not. Experiment 2 showed that subjects isolated after 5 days of normal living behave similarly to those isolated at birth, when both are exposed to the imprinting object a few days (1 to 4) following the beginning of isolation. Experiment 3 showed that subjects reared by their mother in total darkness for five days are equally strongly attracted by the imprinting object, which indicates that the object is inherently attractive and not simply something that visually resembles the mother. Experiment 4 showed that subjects imprinted on days 7 and 9 continue to respond to the imprinting object after 40 days of isolation. Experiment 5 showed that subjects isolated at 5 days but not tested until the sixth week respond to the imprinting object at their first experience with it, indicating either wide generalization from early experience with the mother, or the possibility of an imprinting-like process at this advanced age. Experiment 6 showed that subjects given two 5-minute imprinting sessions in infancy respond significantly more strongly to the imprinting object at 6 weeks than do subjects given only one such imprinting session in infancy, a finding which suggests that the imprinted social attachment is a gradually learned phenomenon rather than a “one-shot” process. Thus the process of attachment of social responses to a model in the guinea pig resembles the imprinting studied in nidifugous birds in many ways. Attachment is probably possible over a much more extended period than in the Mallard, for example.