Premack's principle (relativity theory of reinforcement)
Premack's principle, also known as the relativity theory of reinforcement, is a behavioral psychology concept that suggests individuals are more likely to engage in less preferred activities if they are offered the opportunity to participate in a more preferred activity as a reward. Commonly referred to as "Grandma's law," this principle is exemplified by scenarios where a child must complete a task—like cleaning up toys—before receiving a reward, such as going to the park. Developed by psychologist David Premack through experiments in the 1950s and 1960s, the principle has significant applications in various settings, including education, parenting, and therapy, particularly for children with autism.
The principle posits that more probable behaviors can reinforce less probable behaviors, enabling effective behavior modification. For instance, a child might be encouraged to complete homework by being promised time for video games afterward. The success of this technique hinges on identifying suitable motivators for individuals, as preferences vary widely. This approach fosters compliance by presenting tasks in a positive light through "first-then" statements, which clarify expectations without punitive language. Visual aids can also enhance understanding for children, making the connection between tasks and rewards more tangible. Overall, Premack’s principle serves as a valuable tool for encouraging desired behaviors across diverse contexts.
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Premack's principle (relativity theory of reinforcement)
Premack’s principle, also known as the relativity theory of reinforcement, is a concept in the behavioral therapy field of psychology. It is based on the idea that the promise of being able to take part in a preferred behavior can be used to encourage compliance with a less preferred behavior. It is sometimes called “Grandma’s law” because grandparents and parents instinctively employ this technique when they tell a child to do something like put away toys before they can go to the park. The principle is sometimes thought of as the “first-then” rule because it requires a less preferred behavior to be completed before a more desirable one. Premack’s principle has applications in the classroom, home, workplace, and many other environments. However, it is most frequently thought of as a behavioral therapy technique used for helping children with autism spectrum disorder (ASD). It is also often used in animal obedience training.
Background
Premack's principle is named for American psychologist David Premack. Premack was interested in behavioral psychology with a particular focus on how to encourage and reinforce desired behaviors. During a series of experiments with rats in the 1950s and 1960s, he discovered that if he determined the things rats liked to do, he could use those things as a motivator to encourage them to do something they did not like to do. He later performed multiple experiments with humans, particularly children, to test his theory and further understand how it works.
This technique has since become a foundational part of Applied Behavioral Analysis (ABA), a method therapists use to encourage desired behaviors in children with ASD and in people with some psychological conditions. While other techniques are also used in the ABA process, Premack's principle has proven to be a very effective method of modifying behavior in both children and adults.
Overview
Premack's principle states that more probable behaviors will reinforce less probable behaviors. In other words, people and animals are more likely to do something they do not like or want to do if something they like to do is offered as a reward. The therapist, parent, teacher, or other person attempting to modify behaviors chooses a reward and then makes attaining it conditional on completing another behavior. That behavior can be one that the individual does not like or is challenging, or one that they do not yet know how to do.
For instance, the technique can be used to encourage a child to do homework by promising something the child likes to do in exchange for completing a certain amount of homework. The child might be told they can play five minutes of video games only after writing five vocabulary sentences. In animal training, this principle is demonstrated when a dog does something it does not like to do, such as drop a ball, in exchange for having the ball thrown again to chase it. People even use Premack's principle on themselves when they do something like saying, “First, I will clean the garage, and then I will go to that movie I want to see.”
The key to success with Premack's principle is choosing the right motivator, or reinforcer. The motivator will be different for different people or animals. Therefore, the person applying the principle needs to spend time with the other person or animal involved to determine what can be used as an effective motivator.
For example, a therapist might be working with two siblings who are both reluctant to take a bath. Through observation and conversation with the children and their families, the therapist determines that one child really enjoys having story time and a lullaby, while the other really enjoys time playing with toy animals. These will become each child’s unique motivators. One child will, therefore, be told to get a bath first, and then they can have story time, while the other will be told that they must have their bath before they can play.
The technique can be applied to encourage compliance with less desirable tasks, such as cleaning up, or with challenging ones, such as learning new spelling words. It can also be used to encourage participation in a new task or activity for which there might otherwise be little interest, such as getting a teenager to spend a Saturday visiting out-of-town relatives instead of hanging out with friends.
Several key factors need to be met to ensure the use of Premack's principle is effective. The motivator needs to be sufficiently enticing to encourage compliance. The means of acquiring it needs to be clear, and the “first-then” rules need to be understandable. If the individual chooses not to complete the action the trainer wishes, the individual does not get the motivator. However, no punishment or shaming statements are applied. Losing out on the motivator is the sole consequence.
Premack's principle works because it gives some level of power to the individual. Through the use of the “first-then” statement, the person using the technique creates a contingency arrangement with the individual. It is different than saying to someone, “If you do not do this, then you cannot do that,” because that statement creates a situation where something is lost and often comes across as punitive. Premack's principle and its “first-then” statements present things in a more positive light. With children, and especially with children with ASD, this makes compliance more likely.
When used with children, the technique can be reinforced with the use of visual aids. Pictures that depict the desired activity and the motivator can be displayed side by side, encouraging the child to remember and associate the two behaviors. In some cases, the connection is made so successfully that the previously less-desired behavior becomes desirable because it is seen as a prelude to the motivator.
Bibliography
“About David Premack.” University of Pennsylvania, www.sas.upenn.edu/~premack/About.html. Accessed 18 Jan. 2025.
“Applied Behavioral Analysis.” Psychology Today, 28 June 2022, www.psychologytoday.com/us/therapy-types/applied-behavior-analysis. Accessed 18 Jan. 2025.
Cuncic, Arlin. “How the Premack Principle Regulates Behavior.” Verywell Mind, 27 June 2023, www.verywellmind.com/premack-principle-7549539. Accessed 18 Jan. 2025.
“David Who?” Beacon for Health, www.beaconforhealth.org/TrainingwithPremack.pdf. Accessed 18 Jan. 2025.
“The Premack Principle.” Raising an Extraordinary Person, 10 Dec. 2019, hes-extraordinary.com/the-premack-principle. Accessed 18 Jan. 2025.
Rudy, Lisa Jo. “ABA Therapy for Autism: Benefits and Examples” Verywell Health, 26 Sept. 2024, www.verywellhealth.com/aba-applied-behavioral-analysis-therapy-autism-259913. Accessed 18 Jan. 2025.
Slater, Seth. “Stand and Deliver: What Motivates Us to Do Our Best.” Psychology Today, 12 July 2012, www.psychologytoday.com/us/blog/the-dolphin-divide/201207/stand-and-deliver-what-motivates-us-do-our-best. Accessed 18 Jan. 2025.
“Studies on Using the Premack Principle to Reinforce Work with Work.” Employment Crossing, 2 Mar. 2013, www.employmentcrossing.com/employers/article/900011425/Studies-on-Using-the-Premack-Principle-to-Reinforce-Work-with-Work. Accessed 18 Jan. 2025.