ABSTRACT
Apart from administrations of morphine, repeated beyond the point of addiction, no motivating event used in animal experiments has as long-term an effect on future behaviour as the delivery of painful electric shocks. If responses have previously been rewarded, and are punished mildly, there is no reason why they should be suppressed completely. In a typical experiment, rats were allowed to run back and forth along a plank or alley, at one end of which there was a goal box in which they were both fed and shocked. In the learning of particular responses to escape from and avoid electric shocks, the importance of natural patterns of behaviour is even more obvious than in other forms of animal learning. Pigeons will peck at almost anything in surroundings where food has been recently presented, but can be trained to peck keys to escape or avoid shocks only with the utmost difficulty.
