The Little Albert experiment was a famous psychology experiment conducted by behaviorist John B. Watson and graduate student Rosalie Rayner.﻿﻿ Previously, Russian physiologist Ivan Pavlov had conducted experiments demonstrating the conditioning process in dogs. Watson took Pavlov's research a step further by showing that emotional reactions could be classically conditioned in people.

Verywell / Jessica Olah

A Closer Look

The participant in the experiment was a child that Watson and Rayner called "Albert B." but is known popularly today as Little Albert. When Little Albert was 9 months old, Watson and Rayner exposed him to a series of stimuli including a white rat, a rabbit, a monkey, masks, and burning newspapers and observed the boy's reactions.

The boy initially showed no fear of any of the objects he was shown.

The next time Albert was exposed to the rat, Watson made a loud noise by hitting a metal pipe with a hammer. Naturally, the child began to cry after hearing the loud noise. After repeatedly pairing the white rat with the loud noise, Albert began to expect a frightening noise whenever he saw the white rate. Soon, Albert began to cry simply after seeing the rat.

Watson and Rayner wrote: "The instant the rat was shown, the baby began to cry. Almost instantly he turned sharply to the left, fell over on [his] left side, raised himself on all fours and began to crawl away so rapidly that he was caught with difficulty before reaching the edge of the table."

Classical Conditioning

The Little Albert experiment presents an example of how classical conditioning can be used to condition an emotional response.

Neutral Stimulus : A stimulus that does not initially elicit a response (the white rat).

: A stimulus that does not initially elicit a response (the white rat). Unconditioned Stimulus : A stimulus that elicits a reflexive response (the loud noise).

: A stimulus that elicits a reflexive response (the loud noise). Unconditioned Response : A natural reaction to a given stimulus (fear).

: A natural reaction to a given stimulus (fear). Conditioned Stimulus : A stimulus that elicits a response after repeatedly being paired with an unconditioned stimulus (the white rat).

: A stimulus that elicits a response after repeatedly being paired with an unconditioned stimulus (the white rat). Conditioned Response: The response caused by the conditioned stimulus (fear).

Stimulus Generalization

In addition to demonstrating that emotional responses could be conditioned in humans, Watson and Rayner also observed that stimulus generalization had occurred.﻿﻿ After conditioning, Albert feared not just the white rat, but a wide variety of similar white objects as well. His fear included other furry objects including Raynor's fur coat and Watson wearing a Santa Claus beard.

Criticism and Ethical Issues

While the experiment is one of psychology's most famous and is included in nearly every introductory psychology course, it is widely criticized for several reasons. First, the experimental design and process were not carefully constructed. Watson and Rayner did not develop an objective means to evaluate Albert's reactions, instead of relying on their own subjective interpretations.

The experiment also raises many ethical concerns. Little Albert was harmed during this experiment—he left the experiment with a previously nonexistent fear. By today's standards, the Little Albert experiment would not be allowed.

What Happened to Little Albert?

The question of what happened to Little Albert has long been one of psychology's mysteries. Before Watson and Rayner could attempt to "cure" Little Albert, he and his mother moved away. Some envisioned the boy growing into a man with a strange phobia of white, furry objects.

Recently, the true identity and fate of the boy known as Little Albert was discovered. As reported in American Psychologist, a seven-year search led by psychologist Hall P. Beck led to the discovery.﻿﻿ After tracking down and locating the original experiments and the real identity of the boy's mother, it was suggested that Little Albert was actually a boy named Douglas Merritte.

The story does not have a happy ending, however. Douglas died at the age of six on May 10, 1925, of hydrocephalus (a build-up of fluid in his brain), which he had suffered from since birth. "Our search of seven years was longer than the little boy’s life," Beck wrote of the discovery.

In 2012, Beck and Alan J. Fridlund reported that Douglas was not the healthy, normal child Watson described in his 1920 experiment.﻿﻿ They presented convincing evidence that Watson knew about and deliberately concealed the boy's neurological condition. These findings not only cast a shadow over Watson's legacy, but they also deepened the ethical and moral issues of this well-known experiment.

In 2014, doubt was cast over Beck and Fridlund's findings when researchers presented evidence that a boy by the name of William Barger was the real Little Albert.﻿﻿ Barger was born on the same day as Merritte to a wet-nurse who worked at the same hospital as Merritte's mother. While his first name was William, he was known his entire life by his middle name, Albert.

While experts continue to debate the true identity of the boy at the center of Watson's experiment, there is little doubt that Little Albert left a lasting impression on the field of psychology.