Conditioned Stimulus Definition And Its Role In Psychology

By Danni Peck

Updated April 30, 2020

Reviewer Whitney White, MS. CMHC, NCC., LPC

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Through conditioning, people and other organisms alter their behavioral processes where a response becomes more frequent or predictable as a result of reinforcement. This form of learning usually involves one of two parameters:

  • A given stimulus or signal becomes more effective in creating a response.
  • A response occurs with more regularity in a well-specified, stable environment.

One of the key components of conditioning is a conditioned stimulus.

Conditioned Stimulus Definition

A conditioned stimulus is a learned substitute stimulus triggering the same response as an unconditioned stimulus. In other words, a conditioned stimulus is a neutral stimulus that, over time and training, evokes a response by repeatedly being linked with another naturally occurring stimulus.

Conditioned Stimulus Vs Unconditioned Stimulus

To understand the difference between a conditioned and unconditioned stimulus, we must first understand the meaning of stimulus. A stimulus is any external or internal event, situation, or agent that elicits a response from an animal or human. It is the cause of a human or animal's behavioral response.

The main difference between a conditioned stimulus and an unconditioned one is the former is a product of learned behavior. Unconditioned stimulus refers to any stimulus that naturally and automatically triggers a specific response in humans or organisms.

Pavlov and Conditioned Stimulus

One of the most widely known examples of a conditioned stimulus are the experiments conducted by Russian physiologist Ivan P. Pavlov. His research in classical conditioning was notable for demonstrating how to create associations between the occurrence of one event and the anticipation of another.


Pavlov's Dog Experiments

Pavlov unintentionally discovered classical conditioning while doing research on animals' gastric systems. He found dogs produced saliva while hearing or smelling food in anticipation of feeding. This normal, unconditioned stimulus is an expected occurrence since saliva plays a key role in the digestion of food. He also noticed dogs could be conditioned to associate neutral, unrelated events with feeding time unconsciously.

In his experiment, Pavlov placed dogs in harnesses in an isolated environment. A food bowl was nearby as well as a device measuring the rates of saliva secretions. He found dogs began salivating when a researcher opened the door to feed them. The door opening was a neutral event, but the dogs began to associate the opening door with feeding. Thus, a conditioned stimulus was created when the door opened, and dogs began to salivate.

Pavlov continued to test his theory using different conditioned stimuli including bells, metronomes, and even electrical shocks.

For example, in the same controlled environment, Pavlov rang a bell just before an air puff blew food powder into the dog's mouth. Within time, just hearing the bell (conditioned stimulus) caused the dogs to salivate.

How Conditioned Stimulus Works

Some time is required for a neutral stimulus to become a conditioned stimulus. This period is called the acquisition phase. During this time, humans or animals learn to connect the neutral stimulus with the unconditioned response. These repeated connections transform the neutral stimulus to a conditioned stimulus.

Conditioned Stimuli Can Fade or Become "Extinct."

If the conditioned stimulus no longer follows the unconditioned stimulus, the conditioned response will fade in a process known as extinction. Once Pavlov's dogs associated a specific tone with food, he began making the sound but not providing food. Over time, when hearing the tone, the dogs produced less saliva in a process known as "experimental extinction" or unlearning the association.

Once experimental extinction occurs, Pavlov's research suggests it is not completely wiped from the mind. By reintroducing the original conditioning of tones then food, the dogs would again reinstate their conditioned responses. This is known as spontaneous recovery.

Conditioned Stimulus Psychology Definition and Generalization

Another interesting finding of Pavlov's experiments was the dogs' ability to generalize the conditioned stimuli to other similar stimuli. For example, when a tone was used as a conditioned stimulus, Pavlov would differ the tones and still get the same conditioned response. This response was often better when the tones were closer to the original stimulus.

Also, it is possible for a conditioned stimulus to condition another stimulus. This is known as second-order (or higher-order conditioning). For example, if a dog hears a can opener just before he is fed, this would be the original conditioned stimulus. If the owner has to take the can opener out of a cabinet before using it, the dog will eventually associate the owner going to a cabinet with being fed. Second-order conditioning is usually the highest level of conditioning that can be achieved. Trying to use more than two levels of conditioning usually proves difficult or ineffective.

Conditioned Stimulus Isn't Just for the Dogs

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Our furry friends aren't the only ones who learn from conditioning. Conditioned stimuli are present in our everyday lives-sometimes more than we realize. By understanding the conditioned stimulus definition, we are better able to understand how they are shaping our thought patterns and lives.

John B. Watson used Pavlov's findings in the early twentieth century to reproduce classical conditioning in a very young child. This unethical experiment took an emotionally stable nine-month-old child and subjected him to classical conditioning to create a phobia of white fuzzy animals. During the "Little Albert Experiment," Watson introduced the child to some furry animals including a rabbit, dog, and white rat.

When "Albert" (not his real name) was around the rat, Watson made loud, unpleasant noises that distressed Albert. Very soon the conditioned stimulus of the loud noise caused Albert to fear the rat. Also, without further conditioning, Albert's fear generalized to other furry animals and even Watson in a white furry mask. This experiment had its shortfalls and crossed ethical boundaries not established at the time, but it was a powerful reminder how conditioning could shape one's thoughts and behaviors.

Classical conditioning using a controlled stimulus isn't just for the laboratory. Here are a few examples of everyday conditioned stimuli and how they affect our lives:

Every evening you like to enjoy your favorite television show with a cup of tea. As time goes on, every time the show starts (conditioned stimulus) you get a craving for a cup of tea.

When a father comes home from work, he always pulls the car into the garage. His children hear the garage door opening from inside the house. Soon the children associate the sound of the garage door (conditioned stimulus) with their father.

A mother of a young child always tries to do some yoga when her child is taking an afternoon nap. As part of the nap routine, the mother reads a couple of books to her child. As she is reading the books (conditioned stimulus), she starts thinking about her yoga routine.


Sometimes, a single, often dramatic event, could lead to creating a conditioned stimulus. For example:

One day at a family picnic you have a plate of potato salad that was sitting out a little too long. That night you become violently ill. The potato salad was initially a neutral stimulus, but the illness turns it into a conditioned stimulus. Now every time you see or smell potato salad, you think of the time you got sick from eating it. This could also be considered a psychological food aversion.

As you were backing out of a parking space (neutral stimulus), your car was hit by another car. After that experience, when you back out of a parking spot you feel a tinge of hypervigilance and anxiety. The trauma of the car accident turned backing out of a parking space into a conditioned stimulus.

How Classical Conditioning Can Be Used in Therapy and Counselling

Our brains are optimized to perceive and respond to the world with automatic associations and pattern matching. This allows us to respond in ways we learn are effective and normal. Our inherited and learned thought patterns allow us to respond to stimuli quickly and unconsciously.

Unfortunately, the brain's pursuit of efficiency can create depressive, addictive, or traumatic thought patterns impacting our mental health and well-being. Through therapy, these thought patterns can be broken or replaced with healthier ones.

Three Ways Conditioning Can Help With Therapy:

  • Changing our self-talk: Words are all about association. They stream through our consciousness endlessly throughout the day. Our self-defeating thoughts and negative self-talk have the power to make us feel worse. Therapists can help restructure thought patterns and self-talk to create a more positive environment inside our heads.
  • Changing how we think about places: Due to past experiences, places can have strong associations. A painful visit to the dentist as a child could unconsciously make us break out in a cold sweat each time we even think about a dental appointment. Therapists can help calm the anxiety by having us imagine the dentist as a positive experience necessary for our health. Also, they could slowly desensitize these feelings through conditioning.
  • Changing physical patterns: Our body responds to emotions physically. Think of the last time you were angry. Did you ball your fists? Clench your teeth? Therapists help people deal with strong emotions by using conditioning. For example, once a person realizes they are angry, a therapist may encourage them to take a deep breath or do ten jumping jacks. Soon the conditioned response to anger will be more effective at diffusing it.

If you considered psychotherapy but found traditional settings too expensive or inconvenient, online therapists can help. offers affordable online therapy by licensed and accredited therapists. In the convenience of your home, a therapist can help with conditioning or many other proven strategies for improving mental health. Take the first brave step of getting control of your life with the dedicated therapists at

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