Crows learn not to respond under response-independent reinforcement

Abstract

Seven fish crows were trained to respond under either fixed- or variable-interval schedules. Subsequently, the response dependency was systematically eliminated and then reinstated. The distribution of reinforcers in time was the same under the response-independent schedules as had prevailed under the response-dependent schedules. Responding was successfully maintained for all birds when the response dependency was in effect, but it eventually ceased under the response-independent procedure. Responding resumed when the response dependency was reinstated. Terminal patterns of responding under each of the interval schedules were similar to those displayed by pigeons. However, compared to pigeons, fish crows showed substantially less responding under response-independent procedures. An explanation of this result is offered that stresses differences between crows and pigeons in their natural feeding patterns in relation to the type of response (pecking) required to obtain food in the experiment.