What does Thorndike’s law of effect predict about rewarded animal behaviors?

Thorndike’s law of effect predicts that the probability of an animal repeating a specific learned response depends on the consequences of that behavior. Specifically, it posits that stimulus-response connections are strengthened when a response is followed by a satisfying result.1

In practice, this means that if an animal performs an action—such as pressing a lever—and receives a reward, such as food, the likelihood of the animal performing that same behavior again in the future increases. Through repeated trials, the animal becomes more efficient at executing the rewarded response, as it has learned the connection between its action and the positive outcome. Conversely, if a response is followed by an unpleasant consequence, such as an electrical shock, the probability of the behavior recurring decreases.12

This principle served as a foundational concept for behaviourism and the later development of operant conditioning by B.F. Skinner.12