The Law of Effect of Edward Thorndike

The Law of Effect of Edward Thorndike

Edward Thorndike (1874 - 1949) was a famous psychologist recognized for his work in learning theory that led to the development of operant conditioning in behaviorism.


  • 1 Classic Conditioning and Operator Conditioning
  • 2 Thorndike's experiment: the problem box
  • 3 The Law of Effect

Classic Conditioning and Operating Conditioning

While classical conditioning depends on the generation of associations between events, operant conditioning implies learning from the consequences of our behavior. Skinner was not the first psychologist to study learning by consequences. In fact, Skinner's operant conditioning theory is based on the ideas of Edward Thorndike.

Thorndike's experiment: the problem box

In the late nineteenth century Thorndike studied learning in animals (usually cats). He devised an experiment in which he used a puzzle box created by him, to empirically test the laws of learning.

In 1889, El Thorndike conducted the first experimental demonstration of instrumental conditioning with animals. This author began his studies with the intention of demonstrating that animals did not use reasoning to solve certain situations (opinion that was not shared by researchers of their time) but, in a simpler way, found the solution thanks to a answer learning. Thorndike began to study the learning process in animals using chicks that he placed in mazes built with books, but more systematic experimental studies were carried out with the so-called problem box designed by himself.

These were wooden boxes inside which usually placed a hungry cat (also used dogs) and the animal had to learn which answer was the most appropriate for the door to open the box and access the plate of Outside food that was in sight. Inside the box, the animal was with different mechanisms such as levers, ropes or shelves that, when properly actuated, allowed the opening of the box. Thorndike recorded the latency, that is, the time it took the cat to make the correct answer and closed the animal back into the box. This researcher observed that the duration of latency gradually decreased over successive trials; thus, if on the first occasion that the animal was in the box it took almost ten minutes to open the door, in trial forty it could solve in less than two minutes.

Thorndike puzzle box

Thorndike interpreted this gradual decrease in latencies as a trial and error learning in which reasoning was not involved., since the time curve used did not fall dramatically once the animal found the correct answer. Thus, in learning by trial and error, the caged animal made a series of typical responses of its kind, among which one of them, by chance, gave rise to the opening of the door; The satisfactory consequences of this response (being able to access food) would gradually strengthen a hypothetical association between the stimulus inside the problem box and the correct answer.

The Law of Effect

That was how Thorndike proposed the theory that the animals learn by trial and error. When something works satisfactorily, the animal establishes a connection or association between the behavior and the positive result. This association forms the basis for subsequent behavior. But when the animal makes a mistake or the result it obtains is negative, this association between the behavior and the result is not formed, so the ineffective behavior is less likely to be repeated.

This associative learning between stimulus and response forms the basis of the law of effect formulated by Thorndike in 1911, which states the following:

If a response executed in the presence of a stimulus is followed by a satisfactory fact, the association between the stimulus and the response is strengthened. If the response is followed by an annoying fact, the association weakens.

Initially he established parallels between the positive results, which are called reinforcement in behaviorism, and the negative results, which are known as punishments. However, he later claimed that the punishment was ineffective in eliminating the connection between the behavior and the outcome. Instead, he suggested that, after punishment, the behavior is probably less predictable.

It is important to note that, according to the law of effect, animals learn an association between the response and the stimuli present, and the satisfactory consequences of the response only serve to strengthen this association, but are not directly involved in its formation.