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Processes In The Context

of Family Interactions

Laboratory Studies In Animals

It is only within relatively recent years that the major impact of social interactions and, in a sense, social learning, has begun to be felt in an animal psychology traditionally dominated by instinct theory and genetic set. Until recent years, such animal activities as suckling, exploration, maternal behavior, and sexual stereotypes were presumed to be largely unlearned and thus relatively insensitive to environmental influences. Within the past decade, however, increasing attention has been directed to the role of social interaction within families of animals as such interaction shapes and possibly even determines the ultimate forms of more mature behaviors. The most intensive focus has been on a study of the effects of social and sensory deprivation on the growing animal. The selective contributions of social as contrasted with sensory deprivation have not been isolated successfully for study in experiments to the present date. Ideally, the socially deprived environment should nonetheless provide all avenues and occasions for activity and behavior with the exception of living organisms of the same or similar species. Many experimental social isolation environments on analysis also have been discovered to be environments unintentionally deprived of a variety of nonsocial occasions for behavioral interaction and stimulation. This limitation in experimental design does not reduce the impact and significance of studies which already have been completed. Suffice to say that with increasing rigor of design, more successful dissection of the isolated effects of deprivation in social learning experiences as compared with the effects of reduction in sensory input itself will be achieved.

The effect of social interaction and social-learning processes on the maturing sexual behavior of certain fish have been studied recently by Shaw. She has reported that some fish which have quite characteristic and stereotyped adult forms of sexual behavior show striking inadequacies in sexual performance when they developed from hatching in a carefully restricted social environment in which visual as well as tactile contacts with other organisms of the same species are prevented. Such socially deprived males show conspicuous ineptness in a variety of motor activities intimately associated with sexual behavior, but only when they have been reared under circumstances where they have been deprived of physical and visual contact not only with species mates but also with the surrounding environment. By contrast, similar fish reared without visual or physical contact with species mates did show sexual behavior under circumstances where they maintained visual contact with the surrounding environment. In this species, it is interesting to note that visual access to species mates did not appear to be as important to the appearance of sexual behavior as visual access to the general surrounding environment. Also, it was possible to inhibit various sexual behaviors in such isolated animals in a relatively irreversible way, since sexual behavior could not be elicited from such isolates after considerable experiences with females later. The precise conditions of isolation, including qualitative characteristics and duration as well as the period during which isolation occurred, all had substantial significance in determining the effects.

Thompson and Melzack reported on somewhat similar studies in dogs. They state that Scottie puppies, which have been socially isolated from litter mates and other animals from seven to ten months after birth, retained quite immature forms of behavior for fairly long periods thereafter. Thus, for example, these animals maintained a naive type of curiosity and exploratory behavior and for substantially longer periods than in control animals raised in a socially enriched environment. When such animals were confronted with strange or unfamiliar objects, they showed sustained agitation. With objects capable of generating noxious stimuli, like electric shocking devices or sizzling steam pipes, they took much longer to learn to avoid the aversive stimuli than did animals raised in a socially enriched environment. Animals exposed to social isolation made more errors in maze problems, were defective in solving delayed-response tests, and tended to be dominated consistently in their contacts with control animals raised in a normal environment. Similar studies have revealed analogous deficits in kittens isolated for about eight months of the first year of life. Seitz noted that kittens were particularly sensitive to social isolation during the second to sixth week of life. He intimated that this might well be a critical period for the development of many aspects of maturing behavior. He noted, too, that such isolated animals took longer to solve problems, tended to be more disorganized and less goal directed in other ordered types of activity, betrayed more random activity, took longer to recover after intense stimulation, and generally were more vigilant, alert, and aggressive than were nonisolated controls. Rosenblatt has reported conspicuous disturbances in suckling behaviors in kittens isolated early in life.

Mason, working in the laboratories of Harlow at the University of Wisconsin, has reported effects of early isolation on social behavior in the Rhesus monkey. Restricted animals used visual orientation less predominantly, had shorter grooming episodes, showed higher frequencies of play behavior, aggressive activities, and socially facilitated explorations than their controls. Mason's deprived primates also showed lower frequencies and shorter durations of sexual mounting and reduced frequencies of sexual thrusting and coital movements than control animals. Dr. Harlow and his associates, in follow-up studies of animals reared in artificial nurturant and social environments, have studied the animals so isolated from their biologic mothers from birth. They discover striking deviations from normally anticipated behavior in the mature animals resulting from such experiments. Incidentally, the animals in question were raised in contact with wire perches molded to simulate the general mature primate body form and presented uncovered or covered with terry cloth fabric. With respect to so called "instinctual" sexual behavior, the male monkeys raised in contact with substitute mothers showed evident lack of normal, successful male sexual activities at chronological maturity. This laboratory has reported no successful male copulations with females under the circumstances thus far.

Dr. Harlow has described in vivid terms the defects in receptive and other types of sexual activities in young females raised in such isolated conditions. Such animals have been extremely difficult to impregnate. He has reported only a very small number who were successfully impregnated and carried their infants to full term delivery. The maternal activities of the mothers raised in isolation also were strikingly at variance with ordinary primate maternal behaviors. These isolated mothers avoided their infants who, on many occasions, were forced to use a variety of subtle or sneaky maneuvers to reach the mother at all. Such infants who unfortunately fell within the reach of their mothers would be vigorously thrust aside, struck, and not infrequently attacked by the mothers. Attempts at nursing activities were totally frustrated. Such infants frequently had to be rescued from their mothers before they were crushed, bitten, or beaten to death. The mothers would frequently crouch in the far corner of a large activity cage, maintaining a maximum distance between themselves and their own young.

Because all of the animals raised under the conditions that Dr. Harlow has developed are obviously pathologic animals in many areas, the specific determinants of the defects noted cannot be clearly identified. How much these defects reflect the impact of limitations in social learning, how much they are the result of reduction in normal environmental stimulation, contact, play, and exploration, how much they are the result of the artificially imposed biologic circumstances of nurturance is by no means settled. These few experiments do, however, support the inference that many of the so called instinctual or innate behaviors are far more variable and sensitive to environmental circumstances than had previously been suspected.

The effect of social isolation on certain psychologic mechanisms has been explored with some success in families of goats by Hersher and his associates at Cornell. Some years ago, they observed that infant goats reared in social isolation differed substantially in their conditioned responses from normally raised kids. Kids isolated from birth to one year generally were more lethargic and less active during conditioning. They reported, for example, that during prolonged conditioning trials of two hours a day for 24 days without extinction periods, isolated and normal animals responded with approximately equal frequency at the beginning of the 24 day period, but that the responsiveness of isolated animals decreased markedly as conditioning trials continued. On the other hand, normally reared animals continued to be consistently responsive to the conditioning trials throughout the entire period. How much effect the immediate social facilitation of the mother may have had on this conditioning behavior was not clarified in these studies, since the normal animals were conditioned with the mother present, the isolated animals, of course, with the mothers absent. Hersher and his group have also studied the effects of transferring the kids from the biologic to an adoptive mother. They note that the adopted kids and rams tend to be more active, have higher average heart and respiratory rates, become classically conditioned more readily, and are less susceptible to experimentally induced tonic immobility than normal young. Tonic immobility, an interesting form of akinetic inactivity induced by slow stroking, is a form of behavior which the Cornell group uses as a convenient and readily reproducible behavioral measure.

Additional topics

Human Behavior