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Thorndike’s Law of Effect: Definition and Examples

The law of effect is an important psychological principle based on a pretty simple premise—behaviors that are followed by positive consequences are more likely to be repeated. At the same time, behaviors followed by negative consequences are less likely to be repeated. 

It was first proposed by psychologist Edward Thorndike and had a significant impact on the development of behavioral theories. 

Origins of the Law of Effect

Edward Thorndike was an American psychologist who conducted a series of experiments known as the “puzzle box” experiments in the late 19th and early 20th centuries. These experiments were crucial in the development of Thorndike’s theory of learning and the formulation of the law of effect.

The puzzle box was a small, enclosed space with a door that could be opened by a specific response or action from the animal placed inside. In Thorndike’s experiments, this was typically a cat. Thorndike would place a hungry cat in the puzzle box and present it with a simple task to escape, such as pulling a lever or pressing a button. The cat would initially display random behaviors in attempting to escape.

Through repeated trials, Thorndike noticed that the cats eventually learned to associate certain behaviors with the opening of the door. When the cats were placed in the box again, they were much faster at displaying the required behavior. This demonstrates that the cats had learned the correct behaviors based on the outcomes of their previous experiences in the box.

How the Law of Effect Works

Learning starts when a person engages in some type of behavior, whether it’s a conscious action, a learned response, or an instinctive reaction.


The behavior is followed by consequences, which can be either positive or negative. 

  • Behaviors followed by positive outcomes or rewards are more likely to be reinforced. Positive reinforcement strengthens the connection between the behavior and its likelihood of repetition.
  • Behaviors followed by negative outcomes or punishments are less likely to be repeated. Negative consequences weaken the association between the behavior and its recurrence.

Learning and Adaptation

After having a number of experiences that involve being exposed to a certain outcome or consequence, people eventually learn to associate specific behaviors with their outcomes.

That means that if a pleasant or desirable outcome happens, people will repeat the behavior. But if the behavior is followed by something aversive or unpleasant, they will likely avoid repeating those actions.

How the Law of Effect Influenced Psychology

The law of effect played an important role in the development of operant conditioning, a form of learning where behaviors are strengthened or weakened based on the consequences that follow them. B.F. Skinner expanded on Thorndike’s work, developing the theory further.

Operant conditioning involves reinforcement and punishment. Reinforcement increases the likelihood of a behavior occurring again, while punishment decreases that likelihood. 

Positive reinforcement involves adding a positive stimulus, while negative reinforcement involves removing an aversive stimulus. On the other hand, positive punishment adds an aversive stimulus, and negative punishment removes a positive stimulus.

Applications for the Law of Effect

The law of effect has practical applications in various fields, including education, parenting, and therapy. Understanding how consequences influence behavior allows educators and parents to shape and modify behaviors effectively. 

Positive reinforcement, for example, can be a powerful tool in encouraging desired behaviors in children and students.

In therapy, behavioral interventions often utilize the principles of the law of effect to help people change their behaviors. By identifying and altering the consequences associated with certain actions, therapists can assist clients in achieving behavioral change.

Businesses often apply the law of effect to influence employee motivation and productivity. Reward systems, recognition programs, and other positive reinforcements can motivate employees to enhance their performance.

Examples of the Law of Effect

To better understand how the law of effect may apply in different contexts, let’s explore a few examples.


Educators often use the law of effect in the classroom when they incorporate positive reinforcement and negative punishment to help manage classroom behavior. 

Consider a classroom scenario where a diligent student completes their homework on time. The teacher recognizes this effort by praising the student, creating a positive consequence. This positive reinforcement increases the likelihood that the student will promptly submit assignments.

On the other hand, if a student disrupts the class with unruly behavior, the teacher may impose negative punishment by temporarily revoking a privilege, such as recess. This consequence uses the law of effect to discourage disruptive actions.


Parents and caregivers can also apply the law of effect to help children’s behavior through consequences. For example, when a child cleans their room, a parent might employ positive reinforcement by offering extra playtime or a small reward.

This positive consequence strengthens the connection between cleaning up and positive outcomes, encouraging the child to repeat the behavior.

On the flip side, if a child engages in undesirable behavior, such as not following rules, a parent might implement negative punishment. Temporarily taking away a beloved toy serves as a consequence to deter the undesirable behavior. In both cases, the law of effect guides parents using consequences to mold their children’s actions.


In the workplace, the law of effect influences employee behavior through positive reinforcement and negative punishment strategies. 

Imagine an employee achieving a challenging sales target; the employer publicly recognizes this accomplishment, providing positive reinforcement. The acknowledgment serves to strengthen the link between outstanding sales performance and positive outcomes, motivating the employee to stay productive.


Therapists can also use the law of effect to help guide clients toward positive behavioral changes. For example, a therapist might offer praise and acknowledgment when a client sticks with their treatment plan by attending therapy sessions and taking their medication as directed. This positive consequence reinforces the commitment to personal growth, encouraging continued participation in therapy. 

Limitations of the Law of Effect

While influential, the law of effect is not without criticism. One potential weakness is that it tends to oversimplify complex human behavior. Instead of acknowledging the role of cognitive processes, individual differences, and emotions, it reduces behavior to a simple stimulus-response mechanism.

Despite its limitations, the law of effect remains a fundamental concept in psychology, providing valuable insights into how behaviors are acquired and maintained.

Key Points to Remember

  • The law of effect, proposed by Edward Thorndike, states that behaviors followed by positive consequences are more likely to be repeated, while those followed by negative consequences are less likely to recur.
  • Positive consequences, or reinforcement, strengthen the likelihood of a behavior reoccurring, while negative consequences, or punishment, weaken that likelihood.
  • The concept is integral to operant conditioning, a form of learning that involves reinforcement and punishment to shape behavior.
  • Practical applications include education, parenting, therapy, and organizational management, where understanding and manipulating consequences can effectively influence behavior.


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