Thorndike’s Law of Exercise concerns the role of practice in learning. It states that the strength with which a response will be connected with a situation depends upon the number of times the response has occurred in that situation. In other words, if a response is practiced for a certain number of times. It will tend to be permanently established. Any repeated response gathers some strength. As a result, it becomes easier to repeat it again. Practice will result in strengthening of connections; its discontinuance will result in weakening of connection leading to forgetting.

Law of Exercise operates only in conjunction with Law of Effect. Practice alone will not strengthen connections; it only provides opportunity for reward to occur more frequently to strengthen connections. In a real experiment, incorrect responses occur more frequently and correct responses occur only once per trial. But only correct response, whenever it occurs, brings reward. So its connection with the situation is strengthened in proportion to the number of times it occurs. Thorndike verified this by means of a simple experiment. Students were asked to draw a 3-inch line while blindfolded. Some subjects were given one thousand trials. But their performance did not improve, as they did not get any feedback. So the Law of Exercise does not operate it isolation from the Law of Effect.