TETRADIC ENCOUNTERS OF WISTAR RATS (RATTUS-NORVEGICUS) AFTER SOCIAL DEPRIVATION - SPATIAL, SOCIAL, AND NONSOCIAL BEHAVIOR

The influences of social deprivation on behavioural performances were studied in young male albino rats (Wistar). To distinguish between sensory and motor components of deprivation and between short and long durations of isolation four different housing conditions were used: group housing of four individuals (G), short term isolation (8 h; SI), long term isolation (3-4 weeks; LI), and contact housing (C). After three weeks tetradic encounters of 15 min, each were performed in the open field. The time budget of the behaviour during the encounter sessions revealed significant differences between SI/G and LI/C. There were only minor differences between SI and G and between LI and C. In comparison to the former, the latter were nearly twice as active, preferred the proximity to conspecifics, entered more often into the center of the arena, performed more playful and less resting behaviour, and revealed a higher probability of aggressive events mostly embedded in sequences of play. In regard to exploration and social investigation the differences were less expressed. Since the possibility to exchange communicative signals in C individuals did not alter their encounter behaviour compared to LI it was concluded that the motor component of deprivation rather than the sensory one accounts for the raised social motivation. The lower motivational level in non-deprived or shortly deprived animals was interpreted as effect of a negative feed back caused by social activity. © 1990, Brill. All rights reserved.