The Peck of the Pigeon: Free for All

This chapter presents a summary of some research on the behaviour of the pigeon, a classical subject of both the behaviourist and the ethological traditions. We interpreted the stimulus-reinforcement compatibilities-incompatibilities in terms of a constraint of learning of phylogenetic origin. In the normal environment of pigeons, sounds are unlikely predictors of food whereas tones are likely predictors of pain. Pigeons only learned the discrimination when the tones followed directly upon the pecks, much as natural auditory feedback does, but not otherwise. Pigeons were taught to discriminate several pairs of visual patterns with a successive free operant method. The concept-like same-different principle used by pigeons gives us the possibility of investigating the invariance of pattern recognition. Pigeons also mastered the concept-like discrimination of symmetric versus non-symmetric stimuli when they could use only one eye. This indicates that the recognition of bilaterally symmetrical patterns has little to do with the gross symmetrical organisation of the visual system.