OPERANT CONTROL OF PREENING IN PIGEONS.

Preening in four pigeons was observed and recorded during operant level determinations, continuous and variable interval reinforcement, and extinction. The rate at which preening responses occur seems to be controlled by reinforcement in the same way as other operant behavior. Preening during VI reinforcement and extinction appeared to be similar to preening in many natural situations. With respect to the part of the body preened, considerable stereotypy of responding was shown by all birds, particularly during VI training; there was, however, a conspicuous absence of consistency in the development of stereotypy both within and between individual birds, perhaps due to the nature of the response.