Food as a Discriminative Stimulus

Abstract

Three pigeons were trained on a “go-no go” discrimination task in which positive trials were preceded by 1.5-sec. access to food and negative trials were preceded by 0-sec. access to food. By the end of training pretrial access to food was exerting strong discriminative control over responding: each subject responded more than eight times more frequently during positive than negative trials. During a subsequent generalization test in which trials were preceded by various amounts of food, an orderly decremental gradient was obtained between 0- and 1.5-sec. access to food. A comparison with the gradients from three other subjects not given discrimination training showed that the training sharpened the generalization gradient between the training stimuli.