Observing behaviour in pigeons : an investigation of the reinforcing value of the negative discriminitive stimulus

To determine if a stimulus associated with nonreinforcement can maintain observing behaviour as predicted by Hendry's information hypothesis, three pigeons were trained in a three-key operant chamber. On the yellow center key, periods during which food reinforcement for key pecking was available on a random-interval schedule, alternated irregularly with periods of nonreinforcement (extinction). Pecking the yellow right key produced, on a random-interval schedule, stimuli associated with the prevailing reinforcement condition on the center key: green (S₊), when the random-interval schedule was in effect; red (S₋), when extinction was in effect. Pecking the yellow left key was reinforced by food on a random-interval schedule. The inclusion of this key was intended to attenuate a possible punishing effect S₋ might have upon observing by arranging that reinforcement occasionally occurred on this key when reinforcement for pecking the center key was unavailable. After training, the consequences of pecking the observing key were manipulated. In one condition, S₊ was eliminated as a consequence and only S₋ could be produced. In another condition, S₋ was eliminated and only S₊ could be produced. When the consequences of observing were only S₊ or both S₊ and S₋, observing was maintained. When only S₋ was a consequence, observing extinguished. There was little difference between the observing rates when only S₊ and when both S₊ and S₋ were consequences. The results do not support Hendry's information theory of observing, but are consistent with reinforcement accounts of observing.Arts, Faculty ofPsychology, Department ofGraduat