FREQUENCY OF ATTACK IN SHOCK‐ELICITED AGGRESSION AS A FUNCTION OF THE PERFORMANCE OF INDIVIDUAL RATS

Fighting rates between paired rats were investigated as a function of the probability of attack by a single animal. Animals from stable high‐fighting and low‐fighting frequency pairs were intermatched to detect individual high‐fighting and low‐fighting rats. Pairs of high‐fighting animals then received saline or different chlorpromazine dosages during successive sessions. Finally, single high‐fighting members of each pair also received the different drug dosages. The chief findings were that: (a) rats showing high fighting rates when matched against each other revealed low fighting rates when matched against one, but not the other member of a low‐fighting pair; and (b) high‐fighting rats decreased their fighting rates as their own or their opponent's chlorpromazine dosage increased. These results indicated that a low rate of fighting on the part of one rat results in a low fighting rate on the part of its opponent. 1969 Society for the Experimental Analysis of Behavior