The History and Studies of Ivan Pavlov and Burrhus Frederic Skinner and Their Impact on Classical and Operant Conditioning

Publishing Author : Jay Gray

Date Published : 11/09/18


The Behaviourist Approach and Basic Assumptions


Ivan Pavlov and Burrhus Frederic Skinner (Pavlov and Skinner) are two of the leading forefathers to classical and operant conditioning.  Although arguments are prevalent in whether or not they were the first to the post as it were, there is no doubt that these two names are the leading names in the history of psychology and psychological study as we know it today.

Behaviourism is the reference to a psychological approach which uses both scientific and objective methods of investigation.  This approach has only one concern, and that is the clear observable stimulus-response behaviours.  Behaviourism states that all behaviours are learned through the direct interaction with the environment.

The behaviourist movement began back in 1913 when Mr John Watson wrote an article titled ‘Psychology as The Behaviourist Views It’ which immediately set out a number of underlying and initial assumptions that questioned methodology and behavioural analysis.

The emphasis on the role of environmental factors in behaviourism is extremely strong.  It states that all behaviour is impacted by an external environmental factor which almost conclusively excludes any innate or inherited factors that should also be considered.   Collectively, the way that all sentient beings learn is called ‘learning theory’ and this can be broken down into classical and operant conditioning.

John Watson’s goal with ‘Psychology as The Behaviourist Views It’ was to treat psychology as a science, rather than as a string of unproven thought processes he thought that theories needed to be supported by empirical data that was actually obtained through a controlled observation and measurement of behaviour.  In 1913 he stated that:
‘Psychology as a behaviourist views it is a purely objective experimental branch of natural science.  Its theoretical goal is… prediction and control’ (p.158).  In short, he believed that the entire field of psychology should be measurable, much like the other natural sciences.

Where most other fields of psychology concern themselves with internal procedures such as thoughts and emotion, behaviourism only concerns itself with the measurable aspects of behaviour and psychology.  Behaviourists do tend to accept the existence of cognition and emotion, but they prefer not to study because internal behaviour cannot be objectively or scientifically measured.  During these studies, behaviourists also interestingly discovered that there was very little to no difference in the studies of humans and any other animal.  Because of this, rats and pigeons were most commonly used in these studies, so the external environment could be easily controlled.

Before delving into the work of Pavlov and Skinner we need to understand the two types of behaviourism.  Methodological Behaviourism and Radical Behaviourism.
Watson wrote in his article:
‘Psychology as the behaviourist views it is a purely objective experimental branch of natural science. Its theoretical goal is the prediction and control of behaviour. Introspection forms no essential part of its methods, nor is the scientific value of its data dependent upon the readiness with which they lend themselves to interpretation in terms of consciousness.

The behaviourist, in his efforts to get a unitary scheme of animal response, recognizes no dividing line between man and brute. The behaviour of man, with all of its refinement and complexity, forms only a part of the behaviourist’s total scheme.’

Radical Behaviourism was founded by Skinner himself and actually agreed with the assumptions based in methodological behaviourism that the goal of psychology should be the ability to predict and control behaviour in a controlled and scientific manner. Skinner, much like Watson also recognised the role of the internal mental events (like thoughts and emotions) and whilst they agreed that you could not measure this and use it to explain behaviour, Skinner did propose that they should be explained in the overviewing analysis of behaviour.

One of the most important distinctions between methodological and radical behaviourism concerns the extent to which the external environmental factors would influence behaviour. Watson’s methodological behaviourism speaks of the mind being tabula rasa at birth whereas radical behaviourism accepts the view that organisms are born with both innate behaviours and intuitive instincts and thus recognises the role of genes, genetic makeup and biological components in their behaviour.


The History of Ivan Pavlov

Ivan Petrovich Pavlov was a Russian physiologist known most well for his work in classical conditioning, specifically the study he did that was famously known as Pavlov’s Dog.   From his early childhood days, he demonstrated an intriguing curiosity which he would later refer to as ‘the instinct for research’.  Pavlov abandoned his religious career that he initially had planned for himself and abandoned the entire thing for a career in science.  He enrolled in the physics and mathematics department in 1870 at the University of St Petersburg in order to pursue his studies in natural science.

Pavlov won the Nobel Prize for Physiology or Medicine years later in 1904, becoming the first ever Nobel laureate.  He was ranked much later in 2002 as the 24th most cited psychologist of the 20th century.  Since his demise, Pavlov’s studies and principles in classical conditioning have been used in multiple behaviour therapies, training methods and experimental clinical settings around the world.  His findings are used in everything from educational classrooms to the therapy to reduce phobias.

Once he had completed his doctorate, Pavlov moved to Germany where he studied in Leipzig with Carl Ludwig and Eimear Kelly.  He remained at the Heidenhain laboratories from 1884 to 1886.  Heidenhain was studying digestion in dogs, using a section of stomach but Pavlov perfected the technique further by working out how to deal with the external nerve supply issue.  This eventually would become known as the Pavlov Pouch.

In 1886 he returned to Russia to look for a new position in the sciences.  After a few rejections he was eventually offered the chair of pharmacology at Tomsk University in Siberia and at the University of Warsaw in Poland.  He declined both of these prestigious posts even after his earlier rejections. In 1890 he was appointed as the professor of Pharmacology at the Military Medical Academy and he stayed there for five years, at which time he invited to the Imperial Institute of Experimental Medicine in St Petersburg to organise and oversee the entire Department of Psychology.

He remained there for a forty-five-year period and under his direction, the institute became one of the most important centres for psychological research on the entire planet.  Pavlov continued to direct the department whilst also taking up the chair of Physiology at the Medical Military Academy.  He would go on to head the physiology department there for over three decades.

Pavlov was nominated for the Nobel Prize over four successive years, but he was unsuccessful until 1904 because his previous nominations were not specific to any discovery but only based on a variety of laboratory findings.

It was at the Institute of Experimental Medicine that Pavlov would carry out his classical experiments on the digestive glands.  It was with these studies that he would later win his first Nobel Prize mentioned above.  He investigated the gastric function of dogs and later, even children by externalizing the salivary gland, so he could collect, measure and analyse the saliva and what response it had to food under varying conditions.  He noticed that dogs tended to salivate before food was actually delivered into their mouths and set out to investigate this further which was the beginning of the birth of Pavlov’s Dog and classical conditioning as we know it today.

Pavlov’s lab had a full-scale kennel for the experimental animals because he was interested in observing their long-term physiological processes, which meant keeping them alive and healthy in order to conduct the experiments and retrieve accurate diet from them.  Chronic studies had not been done before this and all other studies were known as acute meaning the animals went through vicious vivisection ultimately resulting in their demise.

The first sign of anybody being concerned about welfare in such experiments came from S Morgulis in the journal ‘Science’ where he criticised Pavlov’s work, raising multiple concerns about the environment that the animals were being kept and tested in.

Conscious until his final moments, it is reported that Pavlov asked one of his students to sit beside his bed and record his dying circumstances in order to create unique evidence of subjective experiences of this final phase of his life.  Pavlov died of double pneumonia at the age of 86 years and was given a grandiose funeral.  Both his study and laboratory were preserved as a museum in his honour

Pavlov was made famous by the ‘conditioned reflex’ (the study that would later become known as Pavlov’s Dog.  He was assisted in this joint venture by Ivan Flippovitch Tolochinov in 1901 and they came to learn about the concept of conditioned reflex when examining the salivation rates among dogs.  Pavlov learned that when a buzzer (commonly referred to as a bell in modern writings) was sounded in subsequent time with the food being presented to the dog in consecutive sequences the dog would initially salivate when the food was presented.  The dog would later come to associate the sound with the presentation of the food and salivate upon the presentation of the external stimulus. Tolochinov called this phenomenon ‘reflex at a distance’ and he communicated the results at the congress of Natural Sciences in Helsinki in 1903.  Later the same year, Pavlov more fully explained the findings at The Experimental Psychology and Psychopathology of Animals.

Over time, Pavlov’s work became well known in the West, particularly through the writings of John Watson and Skinner.  The idea of conditioning as an automated form of learning became a key concept in the development of comparative psychology and the general approach to psychology on the whole.  Pavlov’s work with classical conditioning was one of the biggest influences as to how humans perceive themselves and their learning processes.

It is commonly believed that Pavlov always signalled the sending of food by ringing a bell but this was not true.  In his writings he recorded the use of a huge variety of stimuli, including electrical shocks, whistles, metronomes, tuning forks and even a range of visual stimuli in addition to the sound of the bell.

In conclusion, the experiments by Pavlov were harsh and likely fairly inhumane to most in our modern day, but they did indeed trigger a new form of thinking that helped millions to come in the hundred plus years that have passed since.


The History of Burrhus Frederic Skinner

Burrhus Frederic Skinner was an American psychologist, behaviourist and social philosopher.  He was the Edgar Pierce Professor of Psychology at the prestigious Harvard University from 1958 until he retired later in 1974.

Skinner had the controversial view that free will was an illusion and human action purely depended on the consequences of previous actions.  If the consequences of an action are bad, there is a high chance that the action will not be repeated, whereas if the consequences are good, the probability of the action being repeated becomes much stronger.  Skinner, famously called this the principle of reinforcement.  The principle of reinforcement, much like Pavlov’s studies are key to modern dog training and our movement in more advanced behaviours.

To strengthen behaviour, Skinner used operant conditioning and he considered the rate of response to be the most effective measurable variable of response strength.  The study operant conditioning.  In order to study this effect, he invented something called the operant conditioning chamber, which is more commonly known as the Skinner Box, and to measure rate of response he invented the cumulative order.  Using these tools, he and C.B Ferster produced his influential, experimental work which later appeared in their book ‘Schedules of Reinforcement’.

Skinner developed behavioural analysis, the philosophy of that science he called radical behaviourism and founded a school of experimental research psychology.  Skinner was also a prolific author who published 21 books and 180 articles.  Modern academia considers skinner a pioneer in behaviourism along with Watson and Pavlov.  He was listed as the most influential psychologist of the 20th century.

The philosophy of behavioural science assumes that behaviour is a consequence of environmental histories of reinforcement.  In contrast to this, the approach of cognitive science behaviourism does not accept private events such as thinking, perceptions and unobservable emotions.  These were the key differences between Skinner and Pavlov in their teachings and studies.  Skinner did accept the thoughts, emotions and other ‘private events’ as responses subject to the same rules as overt behaviour.  In his words:
The position can be stated as follows: what is felt or introspectively observed is not some nonphysical world of consciousness, mind, or mental life but the observer’s own body. This does not mean, as I shall show later, that introspection is a kind of psychological research, nor does it mean (and this is the heart of the argument) that what are felt or introspectively observed are the causes of the behaviour. An organism behaves as it does because of its current structure, but most of this is out of reach of introspection. At the moment we must content ourselves, as the methodological behaviourist insists, with a person’s genetic and environment histories. What are introspectively observed are certain collateral products of those histories.

In this way we repair the major damage wrought by mentalism. When what a person does [is] attributed to what is going on inside him, investigation is brought to an end. Why explain the explanation? For twenty-five hundred years people have been preoccupied with feelings and mental life, but only recently has any interest been shown in a more precise analysis of the role of the environment. Ignorance of that role led in the first place to mental fictions, and it has been perpetuated by the explanatory practices to which they gave rise.

Skinner differentiated behaviours into two groups.  Respondent behaviours were dependant on Classical conditioning (often known as Pavlovian Conditioning) where a neutral stimulus is paired with an eliciting stimulus, whereas Operant behaviours, in contrast are emitted through operant conditioning (otherwise known as Instrumental Conditioning) in which the occurrence of a response yields a reinforced.  Pavlov had previously studied respondent behaviours and Thorndike had previously studied operants so Skinner was not the first to the table, but he was one of the first to bring the studies under a single roof.  Skinner’s argument that behaviour is strengthened or weakened by its consequences raises several vital questions.  Among the most important are:
1 – Operant responses are strengthened by reinforcement, but where do they come from in the first place?
2 – Once it is in the organism’s repertoire, how is a response directed or controlled?
3 – How can very complex and seemingly novel behaviours be explained.

Skinner’s answer to the first question was very similar to Darwin’s answer to the question of the origin of a new bodily structure, namely, variation and selection.  Similarly the behaviour of an individual varies from moment to moment; a variation that is followed by reinforcement is strengthened and thus becomes prominent in the individual’s behavioural repertoire.  Skinner used the term ‘shaping’ for the gradual modification of behaviour by the reinforcement and this has become a prominent term in contemporary dog training.

The second question arises because, in the beginning, the behaviour is emitted without any reference to a particular stimulus.  Skinner answered this by saying that a stimulus comes to control an operant if it is present when the response is reinforced and absent when it is not.  For example, if pressing a button only brings food when a light is on next to it then a dog or child will learn to only press the lever when they see that the light is on.  The discriminative stimulus sets the occasion for the reinforcement of the operant. This very famous, three stage contingencies (stimulus-response-reinforcer) is one of Skinner’s most important concepts and one of the strongest separations between his studies, and others of similar times.

In response to the third question, Skinner had to devote a lot of time and effort into dealing with the problem.  Most behaviours in humans can not be easily pin pointed in terms of individual responses reinforced one by one, and Skinner knew this.  Some complex behaviour can be seen as a sequence of relatively simple or straight forward responses and here the idea of ‘chaining’ was born (another prominent term in modern dog training).  Chaining is based on the fact that a discriminative stimulus  not only sets the occasion for the behaviour following, but it can also reinforce a behaviour that precedes it.  That is, a discriminative stimulus is also a conditioned reinforcer.  For example, the light that sets the occasion for button pressing may also be used to reinforce ‘turning around’ in the presence of an initial noise.  This results in the sequence ‘noise-turn around- light-press lever-food.’ Even longer chains than this can be built by adding more stimuli and responses to the behaviour chain.

However, Skinner recognised that a great deal of behaviour, especially in humans, cannot be accounted for by gradual shaping, or the construction of response sequences.  Complex behaviour almost always appears suddenly and in its final form, as when the person first finds their way to the stairs by following instructions given by the receptionist.  To account for this kind of behaviour, Skinner introduced the concept of ‘rule-governed-behaviour’.  First, simple behaviours come under the control of verbal stimuli.  A child learns to ‘swim’, ‘open the door’ and so on.  After a large number of responses under such verbal control, a sequence of much smaller stimuli can evoke an almost unlimited variety of complex responses.


A Brief Conclusion

The work of Pavlov and Skinner is almost endless, but the important factor of this essay is that both of them had a profound impact on Canine Science as we understand it today.  Although morally, many of their experiments were abhorrent, it is important to see what good they have produced in years gone by.



  • The Behaviour of Organisms: An Experimental Analysis, 1938
  • Walden Two,ISBN 0-87220-779-X (revised 1976 edition).
  • Science and Human Behaviour,
  • Schedules of Reinforcement, with  B. Firster,
  • Verbal Behaviour, 1957.
  • The Analysis of Behaviour: A Program for Self Instruction, with James G. Holland, 1961.
  • The Technology of Teaching, 1968. New York: Appleton-Century-Crofts Library of Congress Card Number 68-12340 E 81290
  • Contingencies of Reinforcement: A Theoretical Analysis, 1969. .
  • Beyond Freedom and Dignity, 1971.
  • About Behaviourism, 1974.
  • Particulars of My Life: Part One of an Autobiography, 1976.
  • Reflections on Behaviourism and Society, 1978.
  • The Shaping of a Behaviourist: Part Two of an Autobiography, 1979.
  • Notebooks, edited by Robert Epstein, 1980.
  • Skinner for the Classroom, edited by R. Epstein, 1982.
  • Enjoy Old Age: A Program of Self-Management, with M. E. Vaughan, 1983
  • A Matter of Consequences: Part Three of an Autobiography, 1983.
  • Upon Further Reflection, 1987.



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