It is widely known that human beings are born with only two natural fears. One is the fear of falling and the second is the fear of loud noises. Where, then, do all of our other fears come from?

In 1920, John B. Watson and Rosalie Rayner performed a conditioning experiment on an infant by the name of Albert B. He was given a white rat and his reaction was noted to be playful. He had no fear of the white rat and was even comfortable picking the rodent up while playing with it.

The next time the rat was given to Albert, he did exactly the same thing. This time, the psychologists made a loud noise using a metal pipe and a hammer. The noise was so sudden and loud that it made little Albert cry. They did the same thing mutliple times. Finally, when they gave Albert the rat without the noise, the child would cry at the mere sight of the animal.

Next, they introduced a white rabbit and as soon as Albert saw the animal, he began to cry. They gave him a Santa Claus mask which also made him cry. Little Albert was conditioned to cry at the sight of the white rat, but in the process, he made the connection to anything that was white and furry would lead to a loud noise.

This experiment gives us much insight into the parameters of the human mind. However, this experiment would be considered unethical by today's standards.