Modification by early experience of the tendency toward gregariousness in rats

Abstract

AbstraetAfter they were weaned, albino rats were housed individually (Group 1), in pairs (Group 2), and in groups of five (Group 3). After 18 weeks of housing under these circumstances, the tendency toward gregariousness, defined as a function of the number of approaches to the other rat of the same species, was tested. Group 3 showed the strongest tendency toward gregariousness, Group 2 a weaker tendency, and Group 1 the weakest. Introduetlon Some research evidence (Denenberg, 1963;McClelland, 1956) has shown that the body weight and emotional behavior of rats are significantly influenced by their early experience. Other research evidence (Denenberg et al., 1964) has shown that the rat's behavior is affected by the postweaning social interaction with other organisms of the same species. One logical extension of these studies is to investigate the effect of postweaning social interaction of rats upon their tendency to approach another animal. The purpose of this study is to test the hypothesis that the tendency toward gregariousness is a function of rat's early experience in which the strength of such a tendency is positively related to the number of other rats housed together with the subjects in the homecage.

Attachment behavior of mammals.

“…their own species. As in the cohabitation studies, evidence for this generalization is available for various mammalian species, including rats (Angermeier, 1960;Ashida, 1964), cats (Kuo, 1960;Schneirla & Rosenblatt, 1961), sheep (Scott, 1945), and monkeys (Harlow, 1962;Mason, 1960;Sackett, Porter, & Holmes, 1965). These results are generally consistent with the interpretation that the conspecific object may constitute a disruptive cue, or at the least, not be required for the performance of the isolated animal's basic response repertoire.…”

Population density and social, territorial, and physiological measures in the gerbil (Meriones unguiculatus).

“…Furthermore, there are discrepancies concerning the effects of grouping vs. isolation on measures of sociability. In some situations, isolated rats seemed less gregarious (Angermeier, 1959;Ashida, 1964), and in others, more so (Casey, 1962;Latane, Cappell, & Joy, 1970;Shelley & Hoyenga, 1966, 1967. In one situation, gregariousness was species dependent, with grouped Peromyscus spending more time than isolated Peromyscus near a conspccific, and the reverse being true for C57 mice (Bronson, 1963).…”

Social deprivation and novelty effects on gregarious behavior in the rat

“…Investigators report individual and group housing have no effect on gregarious behavior (Bayroff, 1936), individual housing increases gregarious behavior (Latane, Cappel, & Joy, 1970;Latane, Schneider, Waring, & Zweigenhaft, 1971;Salazar, 1968;Shelley & Hoyenga, 1966;Sloan & Latane, 1974), and -group housing increases gregarious behavior (Ashida, 1964;Stevenson & SimmeL 1967). Latane et al (I970) have suggested gregariousness has drive-like characteristics and is responsive to deprivation.…”