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Primary Reinforcer & Reinforcement – Psychology

What is a primary reinforcer? How is primary reinforcement used in parenting? How can parents and teachers make good use of it? Let’s explore these questions in detail and find out the psychology in it.

What is Primary Reinforcement

Primary reinforcement is a naturally occurring reaction to a stimulus. The response is innate and doesn’t require intricate learning. Primary reinforcement is a reflex that an organism performs automatically whenever the corresponding stimulus is presented​1​.

For instance, your mouth waters when you detect the delicious smell of your favorite food. It’s a natural reflex, and you don’t need to learn to drool. 

Most primary reinforcements are the result of evolution to ensure a species’ survival. Salivation in anticipation of food intake helps the body optimize digestion​2​.

A boy dreams about food, water, sleep and house. These are all primary reinforcer

Primary Reinforcer

A Primary Reinforcer is a stimulus that is biologically important to an organism, such as food, water, sleep, shelter, safety, pleasure, and sex. It leads to an involuntary response, such as recoiling, drooling, and trembling. In conditioning theories, a primary reinforcer is also called unconditioned reinforcer or unconditioned stimulus (UCS).

Although primary reinforcers are intrinsic drives that are naturally occurring, they may impact individuals differently depending on genetics and their experiences.

For example, some people can tolerate a higher temperature than others. When they touch something hot, their withdrawal reflex may not be triggered unless the object is scalding. The ability to withstand higher temperatures may be inborn, or perhaps due to repeated encountering in the past, i.e., an individual may be trained by experience to react differently to a primary reinforcer.


Example 1: Safety

When you touch a scorching iron, your hand recoils automatically to prevent burning. This reflex is a protective mechanism. The scalding touch is the primary reinforcer that reinforces automatic hand withdrawal.

newborn baby falls asleep while drinking a bottle of milk and being held by a caretaker, both are primary reinforcement.

Example 2: Hunger 

When a baby is hungry, she cries. Her caretaker then feeds her to satisfy her hunger. This response is a survival reflex that doesn’t require learning. In this case, hunger is the primary reinforcer that reinforces the crying.

Primary Reinforcer vs Secondary Reinforcer

While a primary reinforcer is innate, a secondary reinforcer is a stimulus that becomes reinforcing after being paired with a primary reinforcer, such as praise, treats, or money.

Effectiveness and Durability

Primary reinforcements are effective because they are biological and play a fundamental role in survival. They are often more effective than secondary reinforcers.

A hungry worker who is promised food for finishing the work is more intrinsically motivated to do so than someone working for free movie tickets.

Because primary reinforcements are essential for survival, they are hard to unlearn.

For example, it takes a strong will power or training not to scream when a heavy stone drops on your feet.


  1. 1.
    Clark RE. The classical origins of Pavlov’s conditioning. Integr psych behav. October 2004:279-294. doi:10.1007/bf02734167
  2. 2.
    Nederkoorn C, Smulders FTY, Jansen A. Cephalic phase responses, craving and food intake in normal subjects. Appetite. August 2000:45-55. doi:10.1006/appe.2000.0328

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