Peter Konstantinovich Denisov was born on December 9, 1899 in Samara in the family of a psalm reader. He graduated from theological seminary, then served in the Red Army. In 1920 he joined the Communist Party.

After graduating from the Kazan Veterinary Institute and completing four years of the Medical Institute, from 1927 to 1930, the scientist was a graduate student at the State Institute of Experimental Veterinary Medicine in Moscow. Later he became the head of the physiological laboratory.

Denisov really wanted to work in Pavlov’s laboratory and came to Leningrad in 1929. He was afraid that Ivan Petrovich would not take him because of his negative relation to communists party members. But Pavlov’s love for work and perseverance in work were important, so he took Denisov as a graduate student. The scientist was engaged in the study of trace conditioned reflexes and investigated the formation of conditioned reflexes in dogs in an illuminated and darkened chamber.

Thanks to membership of CPSU party, Pyotr Konstantinovich twice visited France on scientific trips to the laboratories of Louis Lapik and Sergei Abramovich Voronov. In Lapik’s laboratory, he investigated the chronaxia of the brain during thermal stimuli. At Voronov’s, he got acquainted with the conditions of keeping great apes and their behavior. From there, in 1933, Denisov brought two chimpanzees, Rosa and Raphael, as a gift to Pavlov and began a systematic study of the behavior of anthropoids at the Biostation in Koltushi. Together with Mikhail Petrovich Shtoditny, the scientist began to study the cognitive capabilities of chimpanzees. They conducted experiments on the construction of a pyramid where the goal was to get a high suspended banana. In addition they conducted an experiment with extinguishing a fire in the laboratory and on the water of Lake Koltush. Interestingly chimpanzees do not swim and are afraid of water.

In 1935 Denisov became a candidate of biological sciences. At the XV International Congress of Physiologists the scientist spoke about studies of the behavior of monkeys by the method of conditioned reflexes and demonstrated the scientific film "Analytical and synthetic function of the chimpanzee cerebral hemispheres." In the same year, together with the director Vladimir Nikolaevich Nikolai he created the popular science film "Raphael and the Rose" which was awarded an award at a festival in Paris.

In 1936, during the repressions, Pyotr Konstantinovich was expelled from the ranks of the party. At this time, he was preparing for the defense of his doctoral dissertation on the analytic and synthetic functions of the cerebral hemispheres of the chimpanzee’s brain which he defended on May 5, 1937. Denisov could not continue his research — on June 14, 1937 almost immediately after defending his thesis, he was arrested, on December 1 of the same year he was sentenced to capital punishment and shot on the same day. 20 years after his death, Denisov was rehabilitated posthumously.

In the anthropoid book, comparative physiological studies of the cognitive activity of macaques and preschool children are still being carried out. This makes it possible to study the reserve capacities of the brain of monkeys and come closer to understanding the norm, characteristics and deviations in the mental behavior of the child.