Gradual molding of responses to a final desired pattern. We can reward responses that come closer and closer to the final desired pattern until it occurs. Successive approximations are reinforced. Successive approximations . Biological constraints .
Some responses are easier to learn than others.
Instinctive drift . Laws of learning operate within a framework of biological limits and possibilities. Operant extinction . If a learned response is not reinforced, it gradually drops out of behavior. It takes time, though.