Ivan Pavlov and His Discovery of Classical Conditioning

Pavlov’s Dogs Study and Pavlovian Conditioning Explained

Ivan Pavlov and His Discovery of Classical Conditioning

By Dr. Saul McLeod, updated 2021

many great scientific advances, Pavlovian conditioning (aka classical conditioning) was discovered accidentally. Ivan Pavlov (1849–1936) was aphysiologist, not a psychologist.

During the 1890s, Russian physiologist, Ivan Pavlov was researching salivation in dogs in response to being fed. He inserted a small test tube into the cheek of each dog to measure saliva when the dogs were fed (with a powder made from meat).

Pavlov predicted the dogs would salivate in response to the food placed in front of them, but he noticed that his dogs would begin to salivate whenever they heard the footsteps of his assistant who was bringing them the food.

When Pavlov discovered that any object or event which the dogs learned to associate with food (such as the lab assistant) would trigger the same response, he realized that he had made an important scientific discovery. Accordingly, he devoted the rest of his career to studying this type of learning.

Pavlovian Conditioning

Pavlov (1902) started from the idea that there are some things that a dog does not need to learn. For example, dogs don’t learn to salivate whenever they see food. This reflex is ‘hard-wired’ into the dog.

In behaviorist terms, food is an unconditioned stimulusand salivation is an unconditioned response.(i.e., a stimulus-response connection that required no learning).

Unconditioned Stimulus (Food) >Unconditioned Response (Salivate)

In his experiment, Pavlov used a metronome as his neutral stimulus. By itself the metronome did not elecit a response from the dogs.

Neutral Stimulus (Metronome) >No Conditioned Response

Next, Pavlov began the conditioning procedure, whereby the clicking metronome was introduced just before he gave food to his dogs. After a number of repeats (trials) of this procedure he presented the metronome on its own.

As you might expect, the sound of the clicking metronome on its own now caused an increase in salivation.

Conditioned Stimulus (Metronome) >Conditioned Response (Salivate)

So the dog had learned an association between the metronome and the food and a new behavior had been learned. Because this response was learned (or conditioned), it is called a conditioned response (and also known as a Pavlovian response). The neutral stimulus has become a conditioned stimulus.

Pavlov found that for associations to be made, the two stimuli had to be presented close together in time (such as a bell). He called this the law of temporal contiguity. If the time between the conditioned stimulus (bell) and unconditioned stimulus (food) is too great, then learning will not occur.

Pavlov and his studies of classical conditioning have become famous since his early work between 1890-1930. Classical conditioning is «classical» in that it is the first systematic study of basic laws of learning / conditioning.


To summarize, classical conditioning (later developed by Watson, 1913) involves learning to associate an unconditioned stimulus that already brings about a particular response (i.e., a reflex) with a new (conditioned) stimulus, so that the new stimulus brings about the same response.

Pavlov developed some rather unfriendly technical terms to describe this process. The unconditioned stimulus (or UCS) is the object or event that originally produces the reflexive / natural response.

The response to this is called the unconditioned response (or UCR). The neutral stimulus (NS) is a new stimulus that does not produce a response.

Once the neutral stimulus has become associated with the unconditioned stimulus, it becomes a conditioned stimulus (CS). The conditioned response (CR) is the response to the conditioned stimulus.

Classical conditioning is learning through association and was first demonstrated by Ivan Pavlov.

Pavlov showed that dogs could be conditioned to salivate at the sound of a bell if that sound was repeatedly presented at the same time that they were given food.

First the dogs were presented with the food, they salivated. The food was the unconditioned stimulus and salivation was an unconditioned (innate) response.Then Pavlov sounded the bell (neutral stimulus) before giving the food.

After a few pairings the dogs salivated when they heard the bell even when no food was given. The bell had become the conditioned stimulus and salivation had become the conditioned response.

The dogs had learnt to associate the bell with the food and the sound of the bell and salivation was triggered by the sound of the bell.

Pavlov showed that classical conditioning leads to learning by association. Watson and Rayner showed that phobias can be learnt through classical conditioning in the “little Albert” experiment.

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How to reference this article:

McLeod, S. A. (2018, October 08). Pavlov's dogs. Simply Psychology. www.simplypsychology.org/pavlov.html

APA Style References

Pavlov, I. P. (1897/1902). The work of the digestive glands. London: Griffin.

Pavlov, I. P. (1928). Lectures on conditioned reflexes. (Translated by W.H. Gantt) London: Allen and Unwin.

Pavlov, I. P. (1927). Conditioned Reflexes: An Investigation of the Physiological Activity of the Cerebral Cortex. Translated and edited by Anrep, GV (Oxford University Press, London, 1927).

Pavlov, I. P. (1955). Selected works. Moscow: Foreign Languages Publishing House.

Watson, J.B. (1913). Psychology as the behaviorist Views It. Psychological Review, 20, 158-177.

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Pavlovian Conditioning: Ivan Pavlov’s Dogs Experiment

Ivan Pavlov and His Discovery of Classical Conditioning

Ivan Petrovich Pavlov (1849-1936) lived during a golden age of scientific discovery.

Born into the Russian Empire, and known within his family for being intellectually curious and unusually energetic from a young age, Pavlov won the Nobel Prize in Physiology or Medicine in 1904 for his work on the physiology of digestion, making him the first Russian Nobel laureate. Despite this, Pavlov’s most well-known contribution to science was through his dogs experiments, which became the basis for Pavlovian conditioning (also known as classical conditioning).

In this article I’m going to look into Pavlov’s dogs experiment, followed by a detailed look at the what, where, and why of Pavlovian conditioning, before moving on to a section on further reading for anyone interested in learning more about where this field has moved to since.

What is Pavlov’s Dogs Experiment?

Ivan Pavlov’s dogs experiment is an experiment that took place in the 1890s in which the Russian physiologist surgically implanted small tubes into the cheeks of dogs to measure the buildup of saliva that took place under a variety of conditions.

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Pavlov’s dogs experiment came about as part of an accidental discovery. Pavlov had at the time been conducting research experiments into the dogs’ gastric systems.

As part of this research, Pavlov and his assistants would enter the room where the dogs were housed with a variety of edible and non-edible items, with the intention of measuring the amount of saliva that each dog produced when each item was placed in front of them.

Pavlov prediction that the dogs would salivate when presented with edible items was soon proved correct. This represents an unconditioned response in the animals, in which the sight and smell of the food causes them to salivate. Pavlov couldn’t have predicted what happened next.

A Pavlovian Response

While conducting his gastric experiment, Pavlov began to notice something peculiar. He noticed that the dogs would begin salivating not when food was placed in front of them, but when they heard the footsteps of one of Pavlov’s assistants coming down the hall to bring food to them.

Pavlov soon realized that he could teach his dogs to associate almost any sound, item, or event with the reward of food. To put this another way, it became clear that salivation was a learned response.

The most famous item used in Pavlov’s dogs experiment was that of a bell—Pavlov or one of his assistants would ring a bell before feeding his dogs.

Soon enough, the single act of ringing the bell would be enough for the dogs to associate this seemingly neutral act with the promise of food.

Pavlovian conditioning was born, and Pavlov’s dogs experiment became his life’s work.

An Unconditioned Stimulus Causes an Unconditioned Response

Prior to Pavlov’s experiment and the discovery of Pavlovian conditioning, it was well-known in the scientific world that an unconditioned stimulus causes an unconditioned response.

An example of this in terms of Pavlov’s dogs experiment would be the food being placed directly in front of the dogs, causing them to salivate.

The unconditioned stimulus in this example is the food, and the unconditioned response is the salivation.

Pavlov’s dogs’ response (to salivate) was unconditioned because they didn’t need to be trained to respond to the food in this way—it simply happened naturally.

A Neutral Stimulus Causes No Response

In the same way that an unconditioned stimulus causes an unconditioned response, Pavlov confirmed the commonly agreed-upon theory that a neutral stimulus causes no response.

An example of this in terms of Pavlov’s dogs experiment would be the act of Pavlov or one of his assistants ringing a bell before feeding the dogs, before they had taken the time to condition the bell as a stimulus to the food.

If they were to ring the bell while it was still a neutral stimulus, no response, conditioned or unconditioned, would have occurred.

(Depending on how loud the bell was, the dogs may have been startled the first few times it rang, but this is superfluous to the experiment.)

A Conditioned Stimulus Causes a Conditioned Response

Finally, Pavlov discovered through the course of his experiment that a conditioned stimulus causes a conditioned response.

An example of this in terms of Pavlov’s dogs experiment would be the act of Pavlov or one of his assistants ringing a bell before feeding the dogs, after they have already conditioned the sound of the bell to the promise of food. In this case, the sound of the bell has graduated from being a neutral stimulus to a conditioned stimulus, therefore the dogs’ response (to salivate) became a conditioned response.

Further Reading

In this article I have introduced Pavlov’s dogs experiment and Pavlovian conditioning. The field of classical conditioning and behavioral psychology is vast, and if you found this article interesting I recommend you take a look at some of the following:

Ivan Pavlov’s dogs experiment and the birth of Pavlovian conditioning was an instrumental scientific discovery at its time that deserves the acclaim and spirited conversation that it entails to this day.

If you’re interested in hearing more from me, be sure to subscribe to my free email newsletter, and if you enjoyed this article, please share it on social media, link to it from your website, or bookmark it so you can come back to it often. ∎

Benjamin Spall is the co-author of My Morning Routine (Portfolio/Penguin). He has written for outlets including the New York Times, New York Observer, Quartz, Entrepreneur, Business Insider, CNBC, and more.

Spall, B. (2020, May 29). Pavlovian Conditioning: Ivan Pavlov’s Dogs Experiment. Retrieved from https://benjaminspall.com/pavlov-dogs/

Источник: https://benjaminspall.com/pavlov-dogs/

Ivan Pavlov (1849-1936)

Ivan Pavlov and His Discovery of Classical Conditioning

Ivan Pavlov was a late 19th and early 20th century Russian physiologist best known for his research into conditioned reflexes. 

Professional Life

Ivan Pavlov was born in 1849 in Ryazan, Russia. He was originally enrolled in seminary, but because of his strong scientific interests, he changed direction and began to pursue science. He attended the University of St. Petersburg and studied physiology and chemistry, graduating in 1875.

Pavlov continued his education at the Military Medical Academy, where he earned his medical degree in 1879 and a Gold Medal for his doctoral dissertation in 1883. In his thesis, he explored theories of “nervism” and reflex patterns.

Pavlov worked as a professor at the Military Medical Academy from 1895–1925; he also became director of the department of physiology at the Institute of Experimental Medicine in 1895.

Pavlov researched the physiology of the digestive system, for which he was awarded the Nobel Prize for Physiology or Medicine in 1904.

Later in life, Pavlov became an outspoken critic of the Soviet government. His fame, however, provided some protection from persecution.

Pavlov married Seraphima Vasilievna Karchevskaya in 1881. They had five children, though the first died early in childhood. Pavlov died of pneumonia in 1936. 

Contribution to Psychology

Pavlov began examining the reflex system while studying the gastric systems of dogs. He studied the digestive system in earnest, and looked to determine the effects of nerves on digestive organs.

He later studied the reflex system in relation to pain and stress. He realized that subjects often responded in the same way to different stimuli, regardless of their temperament.

Carl Jung and William Sargant continued Pavlov’s theories by researching human temperament types.

Pavlov is best known for his classical conditioning study, also known as Pavlovian conditioning, as published in Conditioned Reflexes in 1926. He developed this theory with Ivan Filippovitch Tolochinov, his assistant, in 1901.

They found that when a bell was closely associated with the delivery of food, a dog would begin to salivate when the bell was rung. The bell served as a conditioned stimulus, which elicits a conditioned reflex. Salivating in response to food alone, by contrast, is an unconditioned reflex to an unconditioned stimulus.

The experiments that Pavlov conducted on the salivating dogs have become recognized throughout common culture with the term “Pavlov’s Dogs.”

Pavlov's research into classical conditioning began to lay the foundation for the field of behaviorism and comparative psychology, and conditioning techniques are still used in behavior modification. For example, one highly popular form of dog training, called clicker training, conditions a dog to respond to a clicker as if it is a food reward.

Although he was best known for his work in conditioning, Pavlov also developed the theory of transmarginal inhibition. Transmarginal inhibition provides a gauge of a person or non-human animal's response to overwhelming, and often painful, stimuli.

Pain tolerance varies between species and among individuals, and Pavlov found that all organisms ultimately reached a “shut-down point.

” He believed an organism's shut-down point could provide important information about its nervous system, and argued that there are three stages to TMI: 

  1. Equivalency phase, during which an organism's response is proportional to the stimuli. For example, someone who stubs his or her toe might yelp and quickly recover.
  2. Paradoxical phase, during which insignificant stimuli elicit exaggerated responses, while significant stimuli result in muted responses. For example, a child might scream in pain in response to a paper cut but seem unaware of a broken bone. 
  3. Ultra-paradoxical response, which occurs when negative stimuli elicit a positive reaction. 

He also found that a certain percentage of the population qualified as “highly sensitive persons,” whose reaction to stimuli seemed disproportionate.


  1. Ivan Pavlov — Biographical. (n.d.). NobelPrize.org. Retrieved from http://www.nobelprize.org/nobel_prizes/medicine/laureates/1904/pavlov-bio.html
  2. Ivan Petrovich Pavlov. (2008). Notable Scientists from 1900 to the Present. Retrieved from http://www.gale.cengage.com/InContext/bio.htm

Last Update: 07-07-2015

Источник: https://www.goodtherapy.org/famous-psychologists/ivan-pavlov.html

Key Figures In Psychology: Ivan Pavlov (1849-1936)

Ivan Pavlov and His Discovery of Classical Conditioning

 Ivan Pavlov (1849-1936)

Ivan Petrovich Pavlov (1849-1936) was a Russian physiologist remembered for his theories of learning by conditioning, which were developed as a result of his acclaimed research into digestion.

In particular, Pavlov’s research during the 1890s and early 1900s (often referred to as Pavlov’s dogs) used classical conditioning to demonstrate conditioned reflexes. He used conditioning to train the animals to respond in a particular way (e.g.

to salivate) when he presented them with a stimulus, such as the ringing of a bell.

Early Life and Education

Pavlov was born on September 14th, 1849 in Ryazan, Russia to Peter Dmitrievich Pavlov (1823-1899) and Varvara Ivanovna (1826-1890).

His mother was a homemaker and his father was a village priest in the Russian Orthodox Church. He attended the local church school, followed by a theological seminary.

Serious injuries resulting from a fall at an early age meant that his formal education did not begin until the age of 11.

Despite a religious upbringing and schooling, Pavlov was impressed by the work of the writer Dmitry Pisarev, as well as by the scientific ideas of Charles Darwin and physiologist Ivan Sechenov.

He abandoned his religious pursuits in favor of a career in physiology. In 1870 he enrolled in the physics and mathematics department at the University of St.

Petersburg, taking classes in natural sciences.

He graduated in 1875 with a Candidate of Natural Sciences degree, and continued his education at the Imperial Medical Academy, where he completed his studies and received his M.D. in 1879.

Whilst studying, Pavlov met his future wife, Seraphima Vasilievna Karchevskaya, who was a friend of the writer Fyodor Dostoyevsky.

The couple married in 1881 and, after a miscarriage blamed on having to keep up with her husband’s fast-paced walking, she gave birth to 4 sons and a daughter.

Pavlov completed his doctoral thesis, entitled “The Centrifugal Nerves of the Heart”, in 1883. The following year, he travelled to Leipzig to study under supervision of German physician Carl Ludwig before returning in 1886.

In 1890, Pavlov accepted a role as professor of pharmacology at the Military Medical Academy, and in 1895 he was appointed chair of the Institute of Experimental Medicine’s Department of Physiology. He retained his position at the institute until 1925.

Pavlov’s Dogs

Pavlov is best remembered for his ‘Pavlov’s dogs’ experiments, which were carried out whilst he was conducting research into salivatory secretion during digestion at the Institute of Experimental Medicine in the 1890s.

In previous experiments, he had noticed that dogs only needed to sense the presence of food — seeing or hearing it — for saliva to be produced. Pavlov understood that saliva plays a role in digestion, and that this anticipatory response was to be expected.

However, he also found that the animals would begin to salivate when they experienced other stimuli, such as the opening of a door by the researcher who would feed them. Pavlov wanted to learn more about how associative learning led the dogs to instinctively anticipate feeding time whenever they experienced a particular audio or visual stimulus.

Pavlov devised an experiment in which measured the salivary rates of dogs as they experienced a variety of stimuli. Restraining subjects in a harness and placing a food bowl in front of them, Pavlov attached a device which would enable him to monitor levels of secretion made by the dogs’ saliva glands.

During the experiment, the dogs were exposed to a range of stimuli, including a bell sound, a ticking metronome and electric shocks. These neutral stimuli initially prompted no distinct response from the dogs. However, when a stimulus coincided with feeding time, subjects began to salivate in response to them.

For example, when a bell sounded as the dogs were about to be fed, they eventually began to salivate whenever they hear the sound. The dogs had learnt to associate the sound with an unconditioned stimulus (receiving food), and the signal became a conditioned stimulus (Pavlov, 1927).

In further experiments, it was found that behavior could also be ‘unlearnt’ if a conditioned stimulus was presented but feeding did not follow on numerous occasions. This process is known as experimental extinction and allows an individual to adapt their behavior to a changing environment.

The discovery Pavlov made through his experiments were significant because his theory of conditioning can be applied to learning not just in dogs, but also in other species, including humans.

For example, a child may associate the sound of a door opening (a neutral stimulus) with greeting his or her parents in an evening.

The repeated association of these two events leads the child to become excited whenever they hear the door opening — a conditioned response.

Later on, Pavlov’s contemporaries further extended his theory of conditioning. B.F. Skinner (1904-1990) argued that operant conditioning could be used to modify behavior when a schedule of reinforcement was used to promote or discourage an action.

He demonstrated this by placing rats and pigeons in an operant conditioning chamber (a ‘Skinner box’). The animals were presented with a lever or other mechanism which, when pressed, resulted in a reinforcement.

Positive reinforcements such as food encouraged his subjects to repeat their behavior, whilst punishments (such as electric shocks) led to them avoiding pressing the lever.

Learn more about Pavlov’s dogs here

Later Life and Recognition

Following annual nominations for a Nobel Prize dating from 1901 without success, Pavlov was eventually awarded the 1904 Nobel Prize for Physiology or Medicine for his research into the physiology of digestion.

He died on February 27th, 1936 in Leningrad, Russia at the age of 86 from double pneumonia. His former home in Ryazan was converted into the Pavlov Memorial Estate Museum, which celebrates his life and academic achievements.

Источник: https://www.psychologistworld.com/psychologists/ivan-pavlov

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