PAVLOV (1927)
SALIVATION REFLEX IN DOGS

This research is actually a series of lectures by the Nobel Prize-winning Russian scientist Ivan Pavlov. Pavlov was interested in the workings of the human brain, but conducted tests on animal brains, notably dogs. However, he was aware of the cross-over between biology and psychology and his lectures developed the status of Psychology as a scientific discipline, shedding new light on how the brain works by observing behaviour.

Perhaps without meaning to, he promoted the behaviourist school of Psychology, which regards all behaviour as conditioned responses.

This research is significant for students in other ways:

• It shows how scientific research proceeds, because Pavlov brought physiology (the study of the body) together with psychology (the study of the mind). He also showed how the Learning Approach and the Biological Approach cross over.
• It illustrates the usefulness of the observational method, especially controlled observations in artificial conditions
• However, it raises important methodological issues about drawing conclusions from animal research and the low ecological validity of artificial situations

PAVLOV'S 23 LECTURES

Students don't need to know everything Pavlov discussed in his lectures; the study on dogs is what matters. However, Pavlov spends time justifying and evaluating his research and it is worth noting some of the points he raises.

The Biological Link

Pavlov is interested in the human brain but did his research on dogs. He justifies this by appealing to the Theory of Evolution. If, as Charles Darwin proposes, humans and animals have common ancestors, then humans are really a particular type of animal. If this is true, then you would expect the rules of animal behaviour to apply to humans too.

Pavlov is particularly interested in animal behaviour called "reflexes". Reflexes are involuntary behaviours that are passed on down the species because they have "survival value". For example, dogs have a salivary reflex: they slobber because this helps them separate good food from bad.

However, reflexes alone don't explain how animals survive and evolve. In the wild, animals have to find food and avoid predators. Reflexes alone won't help them do this, which is why Pavlov is interested in learning. Learning, for Pavlov, is how animals apply their reflexes to new problems and situations.

The Scientific Method

Pavlov believes an important part of being a scientist is studying things objectively. To do this, he explains how he observed and took meticulous notes on every detail of the dogs' behaviour.

In his lectures, Pavlov reports on 25 years worth of study by over 100 researchers: a huge research project. So another aspect of being scientific is setting up standardised procedures that other researchers can copy, so that they carry out their research the same way.

Pavlov is aware of the risk of carrying out artificial research that is completely different from real life situations. However, he argues that you have to sacrifice some ecological validity in order to study complicated reflexes in an objective, reliable and scientifically credible way.

Research on Dogs

Pavlov's original research was on the salivary reflex in dogs. He chose dogs because they are "higher animals" who have reasonably complex brains and behaviours, but at the same time they can be housed and managed easily.

He chose the salivary reflex because it is an easy reflex to measure: you can gather drops of saliva to see how strong the reflex is. Pavlov even used surgery to attach test tubes to dogs' mouths so that the saliva could be collected and measured accurately.

However, his research was disrupted by the tendency of the dogs to start salivating before the food was presented to them. After being fed by lab assistants, the dogs started to salivate at the mere sight of a lab assistant, or the sound of their footsteps. This was the "learning" Pavlov was interested in, but to study it, he had to keep the dogs in a sealed environment where he could carefully control the stimuli they were exposed to.

Don't become a mere recorder of facts, but try to penetrate the mystery of their origin - Ivan Pavlov

PAVLOV'S STUDY
APRC

Aim

To find out if a reflexive behaviour can be produced in new situations through learning. In particular, to see if associating a reflex with a neutral stimulus (a sound) causes learning to take place, producing a conditioned reflex in new situations.

IV

This is a Repeated Measures design, since it studies the same dogs before and after their conditioning

One condition of the IV is the dogs' natural reflexive behaviour: salivating when food is in their mouths. Other condition of the IV is the dogs' behaviour after they have been conditioned to associate food with a different stimulus.

DV

Pavlov's careful set-up enabled him to count how many drops of saliva the dogs produced.

Sample

35 dogs of a variety of breeds, raised in kennels in the lab

Procedure

Pavlov placed each dog in a sealed room that didn't allow the dog to see, smell or hear anything outside. This was to prevent other stimuli (extraneous variables) from making the dog salivate.

The dog was strapped into a harness to stop it moving about and its mouth was linked to a tube that drained saliva away into a measuring bottle.

In the Control Condition, Pavlov presented the dog with food (meat powder) through a hatch. The dog salivated.

As an experimental Control, Pavlov presented the dog with the Neutral Stimulus sound. The dog did not salivate at this, showing that it was indeed a Neutral Stimulus.

For a Neutral Stimulus, Pavlov used a tuning fork, an electric buzzer or a metronome (a machine producing regular ticking). No, he didn't use a bell. Lots of websites and books will tell you he used a bell, but he didn't. It's another of those Psychological Urban Myths.

Click here for more myth-busting on Pavlov

To condition the dog, Pavlov paired the sound with the presentation of food. He usually did this 20 times, but it depended on how attentive the dog was.

After it was conditioned, Pavlov presented the dog with the sound but no meat.

Results

Pavlov found that the conditioned dog started to salivate 9 seconds after hearing the sound and, by 45 seconds, had produced 11 drops of saliva.

Conclusions

Pavlov had discovered Classical Conditioning. The Neutral Stimulus, after being repeatedly paired with an Unconditioned Stimulus (the meat), turned into a Conditioned Stimulus, producing the Conditioned Response (salivation) all by itself.

Pavlov explains how the brain learns to see the new sound as a "signal" and links the reflex to it. This is how animals in the wild learn to hunt or escape being hunted: they learn to apply their reflexes to new situations based on experiences they've had before

You'll have spotted that Eddie Izzard is under the (wrong!) impression that Pavlov conditioned his dogs to eat. Silly Eddie! The whole point is that you don't need to do that: eating is reflexive, natural behaviour. Conditioning is about learning to do things that don't come naturally.

WHAT ABOUT THE DOGGIES?

Perhaps you find the description of the way Pavlov's dogs were treated distressing. It is true that research like this would be considered unethical today:

• Animal research should aim at providing a clear benefit, not just satisfying scientific curiousity
• Animals must be kept in humane conditions, with room to move and other animals to interact with
  

However, these rules weren't in place in 1927 (or earlier, when the research started). Pavlov regarded his lab as a factory and the dogs were simply machines to him; he saw nothing wrong with operating on them to understand better the workings of their brains.

On a positive note, Pavlov's research did add immensely to our understanding of conditioning, the brain and animal physiology.

Pavlov had one of his dogs stuffed! It can be seen in the Pavlov Museum in Russia. Click the picture below to find out more:

AND CHILDREN TOO?

Pavlov's experiments on dogs are disturbing, but Pavlov also supervised the conditioning of children.

Junior researcher Nikolai Krasnogorsky replicated Pavlov's methods on orphaned children. The neutral stimulus (NS) was a pressure squeeze on the child's wrist and the unconditioned stimulus (UCS) was a cookie fed to the child by a machine. Salivation was measured, just like the dogs, and the records suggest the children were operated on to fit drip-tubes to their throats to measure saliva accurately.

Creepy dramatisation of Pavlovian research on children

EVALUATING PAVLOV AO3
GRAVE

Generalisability

The main problem here is generalising from dogs to humans.

On the one hand, the Theory of Evolution supports the idea that humans will learn through association (Pavlov calls it "signalisation") in the same way as other animals. There is some evidence for this in the success of programmes to treat alcoholics with aversion therapy.

On the other hand, humans have different brains from dogs and much more complicated thoughts and motives. They're not strongly motivated by finding food all the time, for example. But perhaps humans have other motives that drive them just as strongly and they can be conditioned by those.

Reliability

This is a good example of a reliable study because it has standardised procedures and it was carefully documented. In fact, Pavlov did repeat the study many times over 25 years, with different dogs and different Neutral Stimuli (but never with a bell!). He even got different researchers to observe the dog and measure the saliva. This gives the research inter-rater reliability and test-retest reliability.

Application

The applications of this study are diverse. For psychologist, the application is in further research into Classical Conditioning in humans. For example, John Watson conditioned Little Albert to show fear and this research was directly inspired by Pavlov.

Researchers like Watson and (later) Skinner went on to promote the school of Behaviourism - a branch of Psychology that holds that all human behaviour is conditioned and psychologists should study behaviour objectively, the way Pavlov did, rather than engage in the subjective study of thoughts and feelings.

These ideas about behaviour led to programmes for changing human behaviour. A good example is aversion therapy which has had some success at curing people with addictions. However, it doesn't work all the time on humans. Aversion therapy does not seem successful at modifying all human behaviours and there have been tragic failures when it was misguidedly used to treat homosexual men.

Validity

Pavlov's carefully controlled setting makes his findings objective and scientifically credible. There don't seem to be any other stimuli that could be making the dogs salivate, so Pavlov's conclusions about conditioning seem to be the best explanation.

One criticism, that Pavlov was aware of, was the low ecological validity of these studies. The dogs were kept in very unusual conditions (tied up in a harness in a box, cut off from other dogs and humans, with a drip feed attached to their mouths) and they were presented with odd stimuli. There was nothing normal about their reactions.

Nonetheless, if the dogs' reflexes change and get attached to new signals in these odd circumstances, how much easier might it be to condition a dog under realistic conditions. It took Pavlov 20 pairings to produce a Conditioned Response from his dogs, but in the real world conditioning might be much quicker. And, indeed, we do condition dogs under realistic conditions: it's called 'house training'.

Ethics

If research like this was carried out today, it would be unethical. Research animals should be treated humanely, not sealed up in small rooms, tied in harnesses and subjected to surgery.

However, there were no Ethical Guidelines for Psychologists in the early 20th century.

Moreover, research into Classical Conditioning wasn't the only, or even the main, reason why Pavlov used these dogs. His most significant research was into how digestion worked and it was for this he received the Nobel Prize for Medicine. This is research that has led to medical and dietary benefits for millions of humans (and dogs) which might be said to outweigh the discomfort or distress experienced by the 35 dogs Pavlov used over 25 years.

​Krasnagorsky's research on orphaned children is much harder to defend - especially if the children were operated on as part of the process. Pavlov clearly knew about this and approved it and it casts a dark cloud over his research.

EXEMPLAR ESSAY
An 8-mark essay on the Contemporary Study

Evaluate Pavlov's research into salivation in dogs. (8 marks)

• A 8-mark “evaluate” question awards 4 marks for AO1 (Describe) and 4 marks for AO3 (Evaluate). You need a conclusion for top band (7-8) marks.

Description
Pavlov carried out research on dogs over 25 years and reported it in a series of lectures about Classical Conditioning.
Pavlov had been studying the dogs' salivary reflex but noticed that they started salivating at other things beside food - like the sight of the researchers or the sound of their approaching footsteps. To stop this, Pavlov built a special environmet to test the dogs.
Pavlov tested that food produced saliva but the sound of a tuning fork did not. This showed that the tuning fork was a neutral stimulus for the dogs.
After pairing the sound with food 20 times, the sound became a conditioned stimulus and Pavlov collected 11 drops of saliva after the dog heard it.

Evaluation
Pavlov claimed his research on dogs could be generalised to humans. He thought this because of the Theory of Evolution, which suggests that humans learn the same way animals do because we have the same ancestors.
If this research does generalise to humans, it has many applications, such as aversion therapy, which uses conditioning to cure people of addictions.
However, aversion therapy doesn't always work on humans. Some alcoholics carry on drinking despite conditioning and aversion therapy was disastrous when it was used on homosexuals n the 1960s.
Another problem might be the artificial nature of Pavlov's tests, which involves the dogs being tied up in sealed cages. You cannot expect such unrealistic tests to explain or predict behaviour in the real world.

Conclusion
Pavlov's research has been hugely influential and inspired Behaviourist psychologists like Watson and Skinner. However, even if some human behaviour is learned by association, studies on dogs are never going to tell us everything about how humans learn.

• Notice that for a 8-mark answer you don’t have to include everything Pavlov did. I haven’t mentioned the dogs' cages or the details of the conditioning or Pavlov's views about science. I haven’t described Pavlov's conclusions. But I have tried to make the two halves – Description and Evaluation – evenly balanced.