The combined effects of frustrative nonreward and shock on aggression between rats

Abstract

Twenty-eight rats were individually placed in an operant chamber where they received food-reinforced barpress training for 15 min each day for 7 days. An additional 28 rats were similarly placed into the chamber, but were given no training. On the next 2 days, two food-reinforced or two nonreinforced Ss were placed in the chamber together. Previously reinforced Ss were given extinction training for 4 min. Then one-half of the pairs in each condition received shock and the other half did not. The group given extinction training plus shock displayed significantly more aggression than the group given only shock, and both shocked groups exhibited more aggression than both nonshocked groups. Thus, the effects of shock and frustrative nonreward combined to enhance aggressive responding.