The effects of novelty, isolation, light and ethanol on the social behavior of mice.

The social behavior of pairs of male NIH Swiss mice was assessed under a variety of experimental conditions. Increasing periods of isolation increased both the total time spent in social interaction and also increased the incidence of aggressive behavior. Familiarity with the testing arena tended to increase social behavior, but the magnitude of this effect was considerably less than that previously observed in rats. High light levels reduced social interaction. Ethanol (0.8-2.4 g/kg) caused a dose-related decrease in the total time spent in social interaction, a biphasic effect on aggressive behavior and a dose-related increase in locomotor activity. While the social interaction test in this form may not be a suitable model of anxiety in NIH Swiss mice, it should provide a useful method of assessing drug effects and investigating genetic influences on social and aggressive behavior.