ABSTRACT
By "common processes" of vertebrate learning, is meant processes to be found at least in a wide range of living vertebrates. In classical conditioning, stimuli are paired. In fact, some evidence that the classical conditioning of flexion evoked by electrical stimulation of the motor cortex may represent nothing more than a postural adjustment to the disequillibrating effect of the forced movement. Flexion of a limb may be conditioned to a stimulus paired with shock only because flexion minimizes the pain of shock. A stimulus paired with shock from the floor of a compartment in which a rat is contained may come to elicit a variety of responses, lever pressing has a relatively low probability of occurrence. Various phenomena have been described which it seems reasonable now to think of as general phenomena of vertebrate learning because they are found in members of rather diverse vertebrate groups.
