Top 5 Most Unusual Scientific Experiments in History That Will Give You the Chills

We present an overview of the five most eccentric and astonishing scientific experiments in history. From the shocking creation of a two-headed dog to the analysis of the formation of emotional reflexes. In the selection by the zoomboola.com editorial team, you will find stories about the daring attempts by scientists to push the boundaries of knowledge, sometimes balancing on the edge of ethics and common sense.

The "Universe 25" Experiment (1968-1973)

The "Universe 25" study, conducted by American ethologist John Calhoun between 1968 and 1973, examined the impact of high population density on mouse behavior. The scientist created a kind of "utopia" for the rodents—a spacious enclosure with unlimited food, water, and comfortable living conditions.
John Calhoun and the mouse 'paradise'
John Calhoun and the mouse 'paradise'
Initially, four pairs of mice were introduced into this "paradise." The population quickly grew, reaching a peak of 2,200 individuals.

However, significant behavioral anomalies soon emerged: males became either excessively aggressive or apathetic; females started neglecting maternal duties; groups of antisocial individuals formed; unusual forms of sexual behavior appeared; and cases of cannibalism increased.
Scientists observe mice during the study
Scientists observe mice during the study

The "Little Albert" Experiment (1920)

John Watson and Rosalie Rayner conducted this controversial experiment to study conditioned emotional reactions.

The subject of the experiment was a 9-month-old boy named Albert. Initially, he was not afraid of white rats. The researchers began showing him the rodent accompanied by a loud and frightening sound.

As a result, the child developed a strong fear not only of rats but also of other furry objects and animals. The experiment faced severe criticism due to its lack of ethics and the potential harm to the child's psyche.
A frame from the video recording of the
A frame from the video recording of the "Little Albert" experiment

The Experiment with the Two-Headed Dog (1950s)

The Soviet researcher Vladimir Demikhov conducted a series of experiments involving the transplantation of a dog's head. He attached the head and front paws of a puppy to the neck of an adult dog, thus creating a two-headed creature.

Both heads could function independently - they drank, ate, and reacted to the environment. The dog that lived the longest survived for 29 days.

Demikhov's experiments, though ethically shocking, made a significant contribution to the development of transplantology.
Vladimir Demikhov and his dogs
Vladimir Demikhov and his dogs

Training Pigeons to Distinguish Between Picasso and Monet (1990s)

In 1995, Japanese researcher Shigeru Watanabe taught pigeons to distinguish between Picasso and Monet paintings. The birds received grains if they pecked at a Picasso image. Gradually, they learned to associate his paintings with a reward.

Surprisingly, the pigeons could even distinguish works by these artists they had not seen before, demonstrating the ability to generalize and recognize styles.

They managed the task even with black-and-white or blurred images. This discovery raised questions about the nature of art and how different species perceive visual information.
Shigeru Watanabe
Shigeru Watanabe

The Third Wave Experiment (1967)

In 1967, history teacher Ron Jones conducted an experiment called "The Third Wave," demonstrating to high school students the mechanisms of public consciousness manipulation.

He organized a movement with a strict hierarchy, a special uniform, and a unique salute.
Ron Jones these days
Ron Jones these days
In just a few days, "The Third Wave" turned into something reminiscent of a fascist organization. Students began to denounce each other and persecute those with different opinions. Aware of the danger, Jones had to stop the experiment.