AUTOSHAPING THE PIGEONS GAPE RESPONSE - ACQUISITION AND TOPOGRAPHY ASA FUNCTION OF REINFORCER TYPE AND MAGNITUDE

The pigeon's key-pecking response is experimentally dissociable into t ransport (head movement) and gape (jaw movement) components. During co nditioning of the key-pecking response, both components come under the control of the conditioned stimulus. To study the acquisition of gape conditioned responses and to clarify the contribution of unconditione d stimulus (reinforcer) variables to the form of the response, gape an d key-contact responses were recorded during an autoshaping procedure and reinforcer properties were systematically varied. One group of 8 p igeons was food deprived and subgroups of 2 birds each were exposed to four different pellet sizes as reinforcers, each reinforcer signaled by a keylight conditioned stimulus. A second group was water deprived and received water reinforcers paired with the conditioned stimulus. W ater- or food-deprived control groups received appropriate water or fo od reinforcers that were randomly delivered with respect to the keylig ht stimulus. Acquisition of the conditioned gape response frequently p receded key-contact responses, and gape conditioned responses were gen erally elicited al higher rates than were key contacts. The form of th e conditioned gape was similar to, but not identical with, the form of the unconditioned gape. The gape component is a critical topographica l feature of the conditioned key peck, a sensitive measure of conditio ning during autoshaping, and an important source of the observed simil arities in the form of conditioned and consummatory responses.