OBSERVING RESPONSES IN PIGEONS

Abstract

Pigeons were trained on an observing‐response procedure in which periods of VR 100 and EXT alternated unpredictably during a white light (mixed stimulus). During VR 100, responses on a food‐producing key (the first key) were intermittently reinforced. Responses on the observing key (the second key) produced a green light (positive stimulus) when VR 100 was in effect, and a red light (negative stimulus) for EXT. The birds did not respond on either key during the negative stimulus, but they responded on the food‐producing key when the positive stimulus appeared. When observing responses produced the positive or negative stimulus on FR, observing responses were maintained until the FR reached a maximum; beyond this, only food‐producing responses occurred. When observing responses did not produce either stimulus, the observing‐response rates fell to zero. With prolonged exposure to an FR 20 schedule of observing, observing‐response rates during EXT were higher than during VR 100. Chlorpromazine hydrochloride decreased the total response output but markedly increased observing‐response rates except when it was administered before sessions of observing response extinction.