ATTACK PRODUCED BY INTERMITTENT REINFORCEMENT OF A CONCURRENT OPERANT RESPONSE¹

Abstract

Squirrel monkeys pressed a lever to produce food on several fixed-ratio schedules; they could also bite a rubber hose. Biting attack occurred during the postreinforcement pause and in early portions of the ratio response run. Also, biting attacks increased after transitions to higher values of the fixed-ratio requirement and in extinction. The results show that extinction-induced aggression effects occur in primates.Aggressive behavior is elicited by several different types of noxious stimulation (negative reinforcers). Ulrich and Azrin (1962) demonstrated that electric shock, as well as intense heat, would elicit attack by a rat against another rat. Azrin, Hake, and Hutchinson (1965) demonstrated that a physical blow could also elicit attack in monkeys.More recently, Azrin, Hutchinson, and Hake (1966) have shown that removing food from a food-deprived pigeon will produce attack against another pigeon. Subjects attacked when a transition was made from a high frequency of reinforcement to extinction.The present experiments sought to determine the effects of intermittent reinforcement of an independent operant response upon attack behavior. An additional objective was to discover whether extinction-induced aggression effects occurred in primates.Squirrel monkeys were trained to press a lever for food pellets delivered on various fixed-ratio schedules. Biting attack on a rubber hose could be recorded simultaneously during each of the different schedules. Occasionally, subjects were exposed to extinction.

Attack behavior in a multiple fixed-ratio schedule of reinforcement

“…Rather, both birds would first orient themselves in frontofthe blue response key and then advance to the target bird. DISCUSSION The experiment supports the general observations of Hutehinson, Azrin, & Hunt (1968) and Gentry (1968) that fIXed-ratio food schedules generate concurrent aggressive behavior. The present data also support the finding of Hutehinson et al (1968) that attack behavior increased with increases in the fIXed-ratio response requirement.…”

“…Recent experiments with pigeons (Azrin, Hutchinson, & Hake, 1966), rats (Thompson & Bloom, 1966), and monkeys (Hutchinson, Azrin, & Hunt, 1968) establish as an attack-inducing condition the transition from high reinforcement frequency to extinction. Furthermore, monkeys will bite a nearby rubber tube (Hutchinson et al, 1968), and pigeons will attack another live but restrained pigeon (Gentry, 1968) during early portions of an intermittent food schedule. The purpose of the present study was to (1) Each was maintained at 80% of its free-feeding body weight throughout the experiment.…”

Fixed-interval-induced aggression

“…Hutchinson et al (1968) reported a similar shift in the distribution of aggressive biting to the postreinforcement pause and early stages of the ratio run during fixed-ratio responding in squirrel monkeys. The low incidence of attack responses during the final segment (40-60 sec) of the fixed interval appears to preclude the maintenance of aggressive behavior by superstitious reinforcement.…”

Escape From Serial Stimuli Leading to Food

“…Again, behavior that has been categorized as "aggressive" occurs most frequently during the pause (Gentry, 1968;Hutchinson, Azrin, & Hunt, 1968). Again, during the pause pigeons peck a key that terminates the stimulus normally accompanying the schedule, even when that action reduces the frequency of reinforcement (Appel, 1963;Azrin, 1961;Thompson, 1964Thompson, , 1965.…”