Pavlov’s dog: the experiment that revolutionized psychology


eople think that psychology is something very complex, while it is not simple, it is very easy to understand the social behavior of humans and how these are involved by the brain. With the theories that have been developed over the past two centuries, it has become much easier to understand the psychology behind social behaviors. However, one search stands out above all.

This experiment took place in 1890 and was designed by Ivan Pavlov, a famous Russian psychologist of the time who made tremendous progress in this particular field. Pavlov’s experiment involving his dog helped uncover what we today call classical conditioning Where respondent conditioning.

Classical conditioning refers to the ability to control or trigger natural behaviors with a new stimulus. Here is an example that will help you understand better.

Imagine a person taking a shower with hot water. Every time someone flushes the toilet in the building, the shower gets very hot, startling the person. Over time, the person begins to understand the pattern and automatically switches back when they hear a flush even though the water coming out of the shower has not changed in temperature.

The brain likes to create patterns that allow connections to develop, thus promoting a more efficient response time when encountering the same stimulus. In the example above, the brain of the person taking a shower has developed a system in which the brain predicts that something is going to happen based on a conditioned stimulus (sound of a toilet flushing) who was accompanied by a unconditioned stimulus (very hot water).

Pavlov has spent a lot of time studying the digestive system of dogs and why their stomach acid changes in acidity depending on the dog’s diet. During his various experiments observing the biology of dogs, he discovered an interesting nervous reflex that dogs had where they only produced saliva when they saw food or ate it.

Pavlov wanted to examine whether this nerve reflex could be trained to be triggered by other stimuli besides food. Pavlov used his dog for this experiment where he surgically re-rooted reduced saliva on the outside of his dog’s cheek in order to see when saliva was being produced as well as to gauge what type of stimuli would produce more.

A photo of Pavlov and his dog from 1893 (Source: RareHistoricalPhotos)

The salivation reflex, as Pavlov called it, was primarily triggered when the dog’s tongue came into contact with food. After the same experiment was done several times, the dog began to learn a pattern and salivate before seeing or eating the food. This was caused by the brain anticipating that the same action would occur under familiar circumstances.

Pavlov changed the experiment by hiding the food behind a screen before the dog received it and also adding a conditioned stimulus in the form of a sound emitted by a metronome. As this experiment continued day after day, the dog’s brain made the connection that caused the dog to salivate only when he heard the ticking sound of the metronome.

To make this experiment as reliable as possible, Pavlov started using different conditional stimuli as well as different dogs and all showed the same exact results, showing that neural reflexes or social behavior can be trained to be triggered by different stimuli from natural ones with repetition.

Here is a video showing a recreation of the experiment (no actual footage).

For many years before Pavlov’s discovery, contemporary psychologists treated the human brain as a simple box that would process neural reflexes and automatic reaction to stimuli without taking into account that these neural reflexes can be personalized by different lived experiences. by each individual and brain capacity. develop and adapt to new stimuli.

“The brain must be studied through the natural reactions of the body that it controls”

Ivan Pavlov

After the publication of his findings, the world was amazed by this research. In 1904 Pavlov was nominated for the Nobel Prize in Psychology which he actually won. Pavlov always wanted to go and teach psychology at renowned universities outside of Russia, but Lenin never allowed it because the Communists felt he was Russia’s intellectual property.

Pavlov died in 1936 with thousands attending his funeral. Today, Pavlov’s work is considered the foundation of modern psychology.