Pavlov's Experiment- Classical Conditioning

Have you ever wondered why some people flinch at the sight of a needle even before it touches their skin? Or did you feel a sudden sense of calm just by hearing a song?

It is not magic. It is a powerful example of how our minds learn to connect one thing with another, even when those things seem unrelated.

Our brains form associations between unrelated things based on the past. It’s the reason we might fear spiders or feel anxious just seeing a notification pop up on our phones. It shapes our behaviors, fears, habits, and even phobias.

Who was Ivan Pavlov?

Ivan Pavlov was a Russian physiologist who lived from 1849 to 1936. He earned his doctorate from the University of St. Petersburg in 1879 and was later awarded the Nobel Prize in Physiology or Medicine in 1904 for his research on the digestive system [1]. Still, his most lasting impact lies in his discovery of how behaviors can be learned through association.

What did he do?

Dog Experiment

Pavlov’s early research focused on the digestive system, and he discovered that the secretion of gastric juice was not a passive process but rather a response to stimuli. His research paved the way for developing various theories and has been instrumental in understanding human behavior. [1]

This concept was discovered by Ivan Pavlov, not while studying psychology but while researching digestion in dogs.

Setup

In this experiment, dogs were fed food at the same time every day to understand how saliva aids in breaking down food.

Initially, the dogs would only salivate when the food was placed in front of them. Eventually, they began to salivate even before their food arrived. Pavlov realized that the dogs were not salivating to the smell or sight of the food in front of them, but rather the noises and sites that were consistently present before the food even arrived [2].

To test his theory further, he paired the bell with the presentation of food. First, he would ring the bell, then give the dogs food, repeating this several times.

What happened?

After enough repetitions, the dogs learned to associate the sound of the bell with the presentation of the food. They would begin to salivate at the sound of the bell even when no food was given.

This meant the dog had learned to associate the sound of the bell with food. Thus, the dogs were responding not just to the food but to other associated stimuli, such as the sound of the food being prepared or the sight of the person who fed them [1].

Stimuli: things or events that evoke a specific functional reaction.

Classical Conditioning

Classical conditioning is a type of learning in which a neutral stimulus becomes associated with a meaningful stimulus and begins to trigger a similar response. It is often referred to as Pavlovian conditioning [3].

It is like your brain links two things together: if this happens, then that will follow. Eventually, just the first thing is enough to trigger the response.

Pre-conditioning Stage

Unconditioned Stimulus (UCS): Something that naturally or automatically causes a reaction without learning. For example, the food initially placed in front of the dogs was an unconditioned stimulus because it made the dogs automatically salivate.
Unconditioned Response (UCR): The natural reaction to the unconditioned stimulus. For example, the salivation was an unconditioned response.

During Conditioning

Neutral Stimulus (NS): Something that does not cause any response initially. For example, ringing the bell before the arrival of food is the neutral stimulus because the dogs did not salivate. Later, it is paired with the unconditioned stimulus.

After Conditioning

Conditioned Stimulus (CS): a substitute stimulus that triggers the same response in an organism as an unconditioned stimulus because it is associated with something else [4]. For example, when the dogs learned to associate the sound of the bell with the presentation of the food, it becomes the conditioned stimulus.
Conditioned Response (CR): the learned response to the conditioned stimulus. For example, salivating at the sound of the bell becomes the conditioned response.

Classical conditioning is prevalent in our daily lives without us even realizing it.

Panic disorders or panic attacks [4]
Feeling hungry when smelling food.
Jumping at the sound of a loud noise.
Feeling anxious when hearing a dentist’s drill after several dental visits [2].
The bell ringing at the end of class. Even outside of school, hearing a similar bell might make you feel like it's time to leave.

Applications of Classical conditioning in our daily lives

Classical conditioning forms the basis of several strategies in education, therapy, marketing, parenting, and even habit-building.

Phobias: In 1920, behaviorist John B. Watson and his graduate student Rosalie Rayner were the first to demonstrate how classical conditioning could explain the development of phobias.
Marketing: Beyond psychology, classical conditioning also plays a key role in marketing and advertising. Brands often use catchy music, vibrant colors, cute babies, attractive models, or humor to create positive emotional associations with their products. These pleasant connections are highly effective in influencing purchasing decisions.
Education: Teachers might use praise, rewards, or encouraging tones when students answer correctly so that students associate learning with positive feelings. If students are praised for participating, they are more likely to feel good about engaging in class.
Therapy: Exposure therapy—a technique grounded in classical conditioning—is used to treat anxiety disorders. Patients are gradually and safely exposed to their fear triggers, often through images, simulations, or controlled environments, to help reduce their anxiety over time.

Criticisms

Despite the wide-ranging influence of the Classical Conditioning experiment, it has also been subject to criticism:

Pavlov’s experiments focused on classical conditioning, which suggests that behavior is determined solely by external stimuli. However, this oversimplifies the complex nature of human behavior, which is influenced by various factors, including genetics, environment, and personal experience. [1]
Critics argue that classical conditioning focuses too much on observable behavior and completely ignores what is happening inside the mind—our thoughts, feelings, and motivations. This made the theory too mechanical, as if humans and animals were just stimulus-response machines.
Many behaviors—like forming relationships, making decisions, or solving problems—can’t be explained by simple stimulus-response learning. Cognitive processes, like memory and reasoning, play a big role in our actions.
Classical conditioning assumes that everyone learns the same way, but in reality, people vary a lot. Past experiences, personality, and culture all influence how someone reacts to a stimulus.
Pavlov’s experiments on dogs, which may not accurately reflect human behavior. While some principles of classical conditioning may apply to humans, it is essential to recognize that there are also significant differences between species. [1]
Pavlov’s work has been subject to misinterpretation over the years. For example, many people believe that Pavlov’s dogs learned to salivate at the sound of a bell because they associated it with food. However, this is only partially accurate. The dogs learned to associate the sound of the bell with the experimenter’s presence, who would then provide the food. [1]

Classical conditioning can be a powerful tool—whether you want to change your behavior or understand others. From pets to people, from ads to classrooms, this simple mechanism of association influences our everyday lives more than we realize. And by recognizing the power of association, we can harness its potential to improve our lives.

Resources:

[1] Pavlov’s Dog: The Psychology Experiment That Changed Everything – Psychologily

[2] Unconditioned Stimulus In Psychology: Definition & Examples

[3] Classical Conditioning: How It Works With Examples

[4] What Is A Conditioned Stimulus In Classical Conditioning