Acquisition of a free-operant-appetitive response in pigeons as a function of prior experience with response-independent food

Abstract

Deficits in learning to escape from electric shock following exposure to response-independent preshocks have frequently been reported and have been referred to as learned helplessness. Experiments were conducted in order to determine whether a phenomenon similar to learned helplessness could be induced in appetitive free-operant procedures with pigeons. Subjects received preliminary training under one of the following conditions; protracted exposure to response-dependent grain presentations (key pecking), protracted exposure to response-independent grain deliveries, or short-term hopper training. Subjects were then tested for acquisition of a treadle-pressing response which was the only means of access to grain in the experimental chamber. The acquisition of the treadle-pressing response was retarded following protracted exposure to response-independent grain deliveries and the degree of this retardation was related to the complexity of the response-reinforcer contingency.