Edward Thorndike: Biography, Experiments, Law Of Effect

Edward L. Thorndike  (1874-1949) was an American psychologist whose work focused on the study of animal learning and behavior. He was one of the most important researchers in this discipline in the 20th century, being also one of the creators of educational psychology and the theory known as connectionism.

Thorndike spent much of his career as a professor at Columbia University, where he did most of his research. In addition, he also dedicated himself to trying to solve industrial problems, creating tools such as exams and tests to test workers.

Due to his contributions, Thorndike was appointed president of the American Psychological Association (APA) in 1912. In addition, he was also a member of the board of the Psychological Corporation, one of the most important organizations in this discipline. His contributions are still highly relevant even today.

In fact, a study in the Review of General Psychology ranked Edward Thorndike as the ninth most cited psychologist of the 20th century. His work had a great impact on reinforcement theories and behavioral psychology, creating the basis for several empirical laws in the field of behaviorism thanks to his law of effect.


Birth and early years

Edward L. Thorndike was born on August 31, 1874 in Williamsburg (Massachusetts) in the United States, and died on August 9, 1949 in Montrose (New York). He began studying at Wesleyan University, from which he graduated in 1895; and from this moment he began to specialize in animal behavior.

Between 1895 and 1897 he studied at Harvard University with William James (one of the founding fathers of American psychology) and at Columbia University with James McKeen Cattell (one of the main exponents of the theory of individual differences). At the latter university he obtained his doctorate.

After finishing his studies, he got a job at Columbia University itself as a professor and researcher, staying there for practically his entire career. Already in his doctoral thesis he proposed his two best known laws of behavior, the law of effect and the law of exercise. This work was published in 1911 under the name  Animal Intelligence .

Career after graduation

Thorndike’s research career began when he proposed that adaptive changes in animal behavior are similar to the way we humans learn. In his thesis, he proposed two laws that he understood to be fundamental to understanding learning in any species.

The law of effect was the first of those he proposed, and the one that has maintained a higher level of importance even today. This law postulates that those behaviors that have been followed by more satisfactory results have a greater probability of being repeated in the future in response to the same stimuli.

The law of exercise, on the contrary, says that a behavior becomes firmer and more frequent the more times it is repeated in response to the same stimulus. However, in 1932 Thorndike himself determined that this second law was not completely valid in all cases.

Later, Thorndike also modified his explanation of the law of effect. In this second version, he said that rewards for appropriate behaviors always strengthen the association between stimulus and action; but that punishments have a much lesser effect in reducing the probability of carrying out a behavior.

Edward Thorndike’s early work is considered the first laboratory study in the field of animal learning. His emphasis on quantitative measurements and empirical data analysis was highly influential in modern psychology, laying the foundation for the behaviorist current that would predominate in subsequent decades.

Other important works

While still a graduate student at Columbia University, Thorndike created a partnership with Robert Woodworth. Together, the two researchers studied the process of learning transfer. In a paper published in 1901, they stated that learning in one area does not mean that it will be easier to do it in another.

Thorndike used the discoveries made in this research to propose a new, more practice-based theory of learning. Later, as a professor of educational psychology at Columbia, he conducted more studies that contributed to the creation of a more efficient and science-based educational system.

Among his most important contributions in this field were the use of psychological discoveries in the teaching of subjects such as arithmetic, reading and languages; and the discovery that adults can also continue to learn with similar efficacy to children.

On the other hand, his attempts to apply the discoveries of psychology to the field of education formed the basis of a totally new trend in this discipline. Today, the psychology of education is one of the most important parts of this science, and can be applied to fields such as teaching or academic guidance.


Thorndike was a pioneer not only in the field of behaviorism and the study of learning, but also in the use of animals to conduct clinical experiments. To a large extent, these animal experiments were what enabled him to create his famous theories of learning.

Problem boxes

At first, Thorndike wanted to know if animals were capable of learning to perform a specific task using mechanisms such as imitation or observation, in the same way that humans do. To see if they had this ability, he created devices known as “problem boxes.”

The problem boxes had a door that could only be opened by a lever or a button inside the door. Thorndike used them to measure the time it took for an animal to push the button or operate the lever naturally. Later, the animal was with a reward, generally food.

Unlike other researchers, Thorndike mainly used cats to carry out his experiments. The first time I put one of these animals in a problem box, they just moved around inside it without knowing how to escape. Eventually, the animal touched the lever or pressed the button by chance.

Using these boxes, Thorndike tried to find out which factors influenced animal learning the most. To do this, he changed certain variables in his experiments. For example, it allowed some cats to observe how others managed to escape from the box before putting them in it, or it brought their paws directly to the button or lever.

Results of your experiments

One of the first discoveries made by investigations with problem boxes was that most animals are not capable of learning by observation, something that humans can do. Nor did the fact of placing a cat’s paw over the button made it more likely that it would find its way out on subsequent occasions.

In contrast, cats only learned to solve the problem after having accidentally touched the button or lever several times and received a reward. Thus, Thorndike postulated the idea that animals learn primarily through trial and error. In addition, he also discovered that each species has a different learning rate.

In this sense, Thorndike’s main contribution was that he disproved the theory that animals learn through  insights , in the same way that humans do. From these investigations, he was able to later create his own theory of learning.

Law of effect

One of Edward Thorndike’s main contributions to the field of psychology was his postulate of the Law of Effect. This law became one of the foundations of the branch that would later become known as behaviorism, becoming the predominant theory in psychology for several decades.

The simple explanation of the Law of Effect is as follows: when an action results in a pleasant result, this action has a greater probability of reoccurring in a similar context. On the contrary, behaviors that produce negative consequences will occur to a lesser extent in the future.

This theory forms the basis of operant conditioning , which in turn completely changed the paradigm of psychology as a discipline. Up to this point, the study of the human mind focused on introspection and subjective experience. From Thorndike’s studies, psychology began to move towards objectivity and empiricism.

On the other hand, Thorndike also placed great emphasis on the importance of the situation and the internal state of the organism in the appearance of a given response. For example, if the cats had not been hungry, the reward would not have had an effect and therefore the behavior of pressing the lever would not have been reinforced.

On the other hand, if the animals had not been found in a problem box, the response of pressing the button or the lever simply could not have appeared. For this reason, for this psychologist, both learning and the Law of effect are totally determined by the context in which they occur.

Examples of the Law of effect in real life

The Law of Effect, as part of the mechanisms of operant conditioning, have great importance in our daily lives. This law is neutral, in the sense that its consequences can be both positive and negative. Below we will see an example of each type to make it clearer how it works.

One of the simplest examples in which you can see the Law of Effect in action is drug abuse. When a person takes drugs for the first time, they get pleasant effects that make it more likely that they will ingest the same substance again in the future. The more times you use it, the greater your chance of addiction.

In the opposite way, physical exercise also exploits the Law of Effect. When a person trains, at first they have a hard time; But if you can persevere, little by little you will feel more and more positive effects, such as the release of endorphins , greater physical well-being and greater self-confidence .

In this way, people who are able to overcome the first stage of suffering when training are very likely to end up developing the habit of exercising regularly.

Contributions to science and psychology

As we have seen previously, Thorndike was one of the most important psychologists of the 20th century, laying the foundations of many modern theories that continue to be used even today.

In general, it is considered that the work of this researcher was one of the main causes of the abandonment of the subjective model that psychology was following up to that moment, and began to carry out experiments that placed the emphasis on objectivity, empiricism and data analysis.

The main school of thought Thorndike influenced was behaviorism. However, he was not the only one: his ideas were used in fields as diverse as philosophy, education, administration, and many other branches of psychology.

Fields of psychology in which the discoveries of Edward Thorndike are applied

The work of this researcher with animals had a great influence on ethology and animal psychology. Until then, it was believed that less developed species were capable of generating new knowledge through  insight , something that was disproved by his experiments.

On the other hand, Thorndike was the first person to try to apply the discoveries of psychology to the field of learning. This laid the foundation for creating a completely new branch of this discipline, which today is used to design educational systems and to alleviate the difficulties that arise in this area.

Many of the studies of this psychologist were later used by researchers of other currents, such as those who developed the Gestalt theories, ethologists, behaviorists and even cognitive psychologists. Because of this, Thorndike is considered one of the fathers of modern psychology.


  1. “Edward L. Thorndike” in: Britannica. Retrieved on: March 14, 2019 from Britannica: britannica.com.
  2. “Edward Thorndike’s Contribution to the Field of Psychology” in: VeryWell Mind. Retrieved on: March 14, 2019 from VeryWell Mind: verywellmind.com.
  3. “Edward Thorndike (1874-1949)” in: Good Therapy. Retrieved on: March 14, 2019 from Good Therapy: goodtherapy.org.
  4. “Edward Thorndike: The Law of Effect” in: Simply Psychology. Retrieved on: March 14, 2019 from Simply Psychology: simplypsychology.org.
  5. “Edward Thorndike” in: Wikipedia. Retrieved on: March 14, 2019 from Wikipedia: en.wikipedia.org.

Add a Comment

Your email address will not be published. Required fields are marked *