A method of quantitating aggressive behaviour revealing possible dissociation of motor activity and aggression

A method is described for quantitating isolation-induced aggression in wild male mice by measuring coarse motor activity. It is based on the operational definition that aggression is the form of motor activity in which two (or more) animals are involved in behaviour patterns, such as physical attack and/or defence including pursuit and flight. Both coarse and fine motor activity were measured by means of an electromagnetic activity meter. Four hundred ninety-two fights occurring among mice treated with various hormones, neurotransmitter antagonists, hashish, and cyproterone acetate were recorded; a positive significant correlation (P less than 0.001) between indices of fighting behaviour as well as fighting time and coarse motor activity were found. The simultaneous measurement of motor activity and aggression revealed dissociated effects of some drugs on non-aggressive fine motor activity and aggression.