Functional differences between two shock-induced aggressive behaviors of mice

Five groups of male mice were given either isolation or grouped housing conditions or fight training as manipulations of social backgrounds prior to 5 days of shock-induced aggression under conditions resembling the rat paradigm for shock aggression. Three groups were given similar fight training but different levels of shock intensity during the shock trials. Shocks moderate in intensity as compared to very low intensity shocks produced more biting attacks and upright postures and maintained aggressiveness. Raising the shock intensity further produced fewer biting attacks, more upright postures, and a decline in aggressiveness. Biting attacks proved to be a more discriminating measure of differences created by different social backgrounds than the upright postures.