The Premack principle built on the work of behavioral psychology that was started by B.F. Skinner. While Skinner focused on the link between a stimulus and an organism’s reaction to that stimulus as it manifested in behavior, Premack’s work showed a link between two or more behaviors.

These were high-probability and low-probability behaviors, with high-probability behaviors being those that were enjoyable or immediately rewarding, and low-probability behaviors being those without immediate reward. When the higher-probability behavior was linked to the lower probability behavior as an incentive, this raised the potential for the lower probability behavior to be performed.

The Premack principle is also sometimes called grandma’s rule because of how caregivers use it to teach children. For example, a child cannot have dessert unless they eat their vegetables.

Applied Behavioral Analysis & the Premack Principle

Autism is a developmental disorder that is currently diagnosed through changes in behavior and learning at a young age. Around 2 years old, children with autism stop acquiring language, may not respond to their name, do not begin playing “pretend” games like with dolls or other toys, have obsessive interests in one or two subjects, stop making eye contact, have unusual reactions to sounds or textures, and may begin self-stimulating behaviors like rocking or spinning.

Applied behavior analysis (ABA) therapy is the leading approach to adjusting behaviors associated with autism spectrum disorder, so children with autism can grow up to be as independent and stable as possible. ABA therapy focuses on positive behavioral change by identifying problem behaviors, developing a treatment plan to encourage learning and adjustment of behaviors, and keeping records to monitor results of treatment and ensure that the person with autism benefits from the approach.

One way to encourage behavioral change through ABA therapy is applying the Premack principle to various behaviors. This is a term stemming from operant conditioning, which is the foundation for many principles in modern behavioral therapy.

Basically, the Premack principle states that engaging in more probable behaviors or activities can reinforce engaging in less probable behaviors or activities. It is a reinforcement principle, meaning it can be used to teach adaptive behaviors by offering fun behaviors as a reward.

Again, its nickname as grandma’s rule or grandma’s law comes from its application with children, whether they are neurotypical or are on the autism spectrum. The child wants a sweet treat but their grandma says they must eat their broccoli first. With dessert offered as a reward, the child is more likely to eat the broccoli.

The History of the Premack Principle

The Premack principle, or Premack’s principle, was published in 1965 after Premack’s behavioral studies on animals. The concept has been replicated in several studies, including many involving human participants. A study published in 1980, for example, found that participation in exercise increased in people with developmental disabilities when they were offered the option to play games, an otherwise high-probability activity, as a reward for participating in the lower-probability activity.

Before Premack’s principle, behavioral models relied almost exclusively on B.F. Skinner’s research, so behaviors in organisms were understood as contingent on a stimulus resulting in a behavior. The Premack principle articulated that there was a connection between one behavior and another rather than just a stimulus and one behavior.

For example, a laboratory rat in an experiment is likely to eat if they are hungry and unlikely to press a lever when they are hungry. Giving the rat the option between food and pressing a lever, the rat will use the stimulus of hunger to make the decision, while they are unlikely to press the lever anyway. However, if the preferred behavior of eating to not be hungry becomes contingent on pressing the lever, the rat will learn to press the lever so they can have the reward of eating.

Parents and caregivers often, intentionally or not, use the Premack principle to teach children certain behaviors. In addition to the grandma’s rule example above, caregivers may often tell their child that they must clean their room before watching a favored television program.

How the Premack Principle May Be Used in Therapy

The Premack principle may be applied through ABA therapy as a way of guiding behavior. It can be an effective method of telling a child with autism “no” to certain behaviors because the answer to the child’s request is ultimately “yes, with contingencies.”

For example, if the child wants to play with a favorite toy, but they have not completed a homework assignment, the parent can say that they must complete their homework before playing. This allows the child to find a solution to getting what they want.

Although this principle can seem a bit like a token economy, there are important distinctions. Psychologists recommend working with your child to understand what daily tasks they enjoy. For example, if your child completes their homework, they do not just receive a reward, but they also get to do something fun that they might do anyway, like feed the cat dinner. While giving a reward for a behavior is important, and a core principle of behavioral change in ABA therapy, using the Premack principle to generalize behavioral change can work well for long-term adaptive behavior retention.

A child with autism may grab an item they want from the therapist rather than asking for it. This is a maladaptive behavior, so the ABA therapist wants to teach the child to ask for items rather than just snatching them.

One approach may be for the ABA therapist to give the child a sticker as a reward, in addition to the item after they ask for it. This could be the first few stages of learning that adaptive behaviors have positive outcomes. However, the therapist can also give the object to the child after they ask, positively reinforcing the request. If the child fails to ask or does not complete the sentence, the therapist does not give the item to the child.

Understanding How to Make the Premack Principle Work for Your Child

One important note with the Premack principle is that it works best when the high-frequency behaviors, used as rewards, are personal to the child. ABA therapists will spend time with their clients to understand what is considered a reward and what is not considered valuable. This goes into the treatment plan along with token economy-based rewards.

Working with a child in this way helps to build rapport between the therapist and the child, or the parent and the child. The child has some control over what occurs and understands what the consequence will be if they fail to complete an action.

The Premack principle is an important component of behavioral therapy to help people understand how behaviors can be linked together in positive or negative ways. It can be an important part of ABA therapy.


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Premack Principle. (2013). Encyclopedia of Autism Spectrum Disorders.

Premack Principle. Encyclopedia of School Psychology.

Premack’s Principle. APA Dictionary of Psychology.

An Evaluation of Three Methods of Saying “No” to Avoid an Escalating Response Class Hierarchy. (2011). Journal of Applied Behavior Analysis.