Acute and chronic effects of cocaine on extinction-induced aggression.

Researchers gave pigeons cocaine before extinction sessions. The birds had learned to peck a key for food. Then the food stopped. The team watched how the drug changed both pecking and the angry outbursts that usually follow lost reinforcement.

They tested several doses. Low amounts were meant to curb aggression. Higher amounts were meant to see when the drug also hurt the birds’ normal reinforced pecking.

Small cocaine doses cut the birds’ extinction-induced aggression. The same doses left reinforced pecking alone. Larger doses began to wreck the reinforced behavior too.

After many days the birds grew partly tolerant to the performance loss, but the anti-aggression effect stayed strong. The drug silenced anger longer than it silenced work.

Dardano (1970) first showed that extinction itself sparks aggression in pigeons. Pliskoff et al. (1978) now adds that cocaine can pick off that aggression without touching the food response.

Goldman et al. (1979) saw cocaine disrupt pigeons’ learning at low doses. The new data look opposite: low cocaine helped, not hurt. The gap is real—learning tasks are more fragile than emotional outbursts.

Yoon et al. (2009) later found pigeons grow tolerant to cocaine’s rate cuts under conjunctive schedules. Pliskoff et al. (1978) saw the same tolerance, but only for reinforced pecking, not for the anti-aggression benefit.

The study shows that behavioral effects of stimulants are laser-specific. A dose that calms emotional side-effects can leave core skills untouched. When you plan interventions, think about which response class you really need to change. Target the problem behavior, not the whole repertoire.