Pavlov, the discoverer of the conditioned reflex

On September 14, 1849 was Ivan Petrovich Pavlov was born on a farm, the first of 11 children. In 1870 he went to the University of St. Petersburg, where he first studied law and natural sciences, from 1875 he studied medicine there. In 1890 Pavlov became a professor of pharmacology and later a professor of physiology in St. Petersburg. In 1904 he received the Nobel Prize for his work in explaining the digestive processes. Pavlov was still working every day in his laboratory in Leningrad when he was 86 years old. He died on February 27, 1936.

Pavlov’s famous experiment

His investigations into the digestive behavior of dogs became famous. During his research, Pavlov noticed that whenever he showed his dogs food, they   reacted with increased salivation . This is an automatic reaction that is innate in dogs. Such behavior, which occurs unconditionally, is called an  unconditional reflex .

Pavlovian dogs

Pavlov then rearranged his experiment so that a bell rang just before the food was administered. Since food was only available after a ringtone, the dog learned to react to the ringtone over time.

After a while he started drooling at the sound of the bell – before he could even see or  smell the food  . During this time, the dog had learned that a reward inevitably follows the ring tone. The perception of the sound alone was now sufficient to trigger salivation in the test dog.

The result of the experiment

The ringing of the bell was initially a neutral stimulus and had nothing to do with the food itself. Now that Pavlov had performed this experiment, the learned reflex reliably led to increased secretion of saliva. From this time on, the formerly neutral stimulus triggered a new reflex reaction. A neutral stimulus had become a conditioned stimulus. This reaction, described by Pavlov, is called  the  conditioned  reflex . This is a learned, not natural, reflex.