The Little Albert experiment was a controlled experiment showing empirical evidence of classical conditioning in humans and operant conditioning in humans. The study also provides an example of stimulus generalization. It was carried out by John B. Watson and his graduate student, Rosalie Rayner, at Johns Hopkins University. The results were first published in the February 1920 issue of the Journal of Experimental Psychology.

The Experiment

After observing children in the field, Watson hypothesized that the fearful response of children to loud noises is an innate unconditioned response. He wanted to test the notion that by following the principles of the procedure now known as "classical conditioning", he could use this unconditioned response to condition a child to fear a distinctive stimulus that normally would not be feared by a child (in this case, furry objects). The aim of Watson and Rayner was to condition a phobia in an emotionally stable child. For this study they chose a nine-month old infant from a hospital referred to as "Albert" for the experiment. Watson followed the procedures which Pavlov had used in his experiments with dogs. Before the experiment, Albert was given a battery of baseline emotional tests: the infant was exposed, briefly and for the first time, to a white rat, a rabbit, a dog, a monkey, masks (with and without hair), cotton, wool, burning newspapers, and other stimuli. Albert showed no fear of any of these items during the baseline tests.

Who Was
Little Albert?

Little Albert was the subject of Watson’s experiment. Many of the facts of the experiment are somewhat sketchy and over the years there have been conflicting reports as to whom Little Albert actually was, but it is generally believed that he was a 9 month old baby boy born and raised in a home for Invalid Children. At 8 months old, Watson tested the child to see if he showed a fear response to a loud noise. Initially the child was startled, but not afraid, but by the time he heard the loud noise for the third time, he was extremely frightened. For the next baseline stage of the experiment, Watson introduced a series of random objects to the boy: a white rat, a monkey, a rabbit, burning newspapers, cotton wool, plus others. At this point the boy was unafraid of the objects. Next, Watson introduced the white rat to the child. Initially he was happy to play with the rat and showed no fear, but in subsequent tests, each time the child reached out to touch the rat, he heard a loud noise. Before long the child exhibited a fear response and became extremely distressed whenever he was exposed to the white rat, even when he heard no loud noise. From this, Watson concluded the child had been conditioned to feel an emotional response (fear) to a neutral stimulus.

For the experiment proper, Albert was put on a mattress on a table in the middle of a room. A white laboratory rat was placed near Albert and he was allowed to play with it. At this point, Watson and Rayner made a loud sound behind Albert's back by striking a suspended steel bar with a hammer each time the baby touched the rat. Albert responded to the noise by crying and showing fear. After several such pairings of the two stimuli, Albert was presented with only the rat. Upon seeing the rat, Albert got very distressed, crying and crawling away. Apparently, the infant associated the white rat with the noise. The rat, originally a neutral stimulus, had become a conditioned stimulus, and it was eliciting an emotional response (conditioned response) similar to the distress (unconditioned response) originally given to the noise (unconditioned stimulus).

"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."

Criticisms of the Experiment

While the experiment is one of psychology’s most famous and is included in nearly every introductory psychology course, it has also been criticized widely for several reasons.

First, the experimental design and process were not carefully constructed. Watson and Rayner did not develop an object means to evaluate Albert’s reactions, instead relying on their own subjective interpretations.

Secondly, the experiment also raises many ethical concerns. The Little Albert experiment could not be conducted by today’s standards because it would be unethical.


In further experiments, Little Albert seemed to generalize his response to the white rat. He became distressed at the sight of several other furry objects, such as a rabbit, a furry dog, and a seal-skin coat, and even a Santa Claus mask with white cotton balls in the beard. However, this stimulus generalization did not extend to everything with hair.

It should be noted that Watson's experiment had many failings by modern standards. For example, a single subject and no control subjects. Most importantly, such an experiment would never be allowed under current law and regulations, as it clearly subjected the infant to severe stress and potential long-term psychological damage.

"Now he fears even Santa Claus"

Identifying Little Albert

Douglas Merritte

In 2009, psychologists Hall P. Beck and Sharman Levinson published an article in which they claimed to have discovered the true identity of “Albert B.” After reviewing Watson’s correspondence and publications, as well as research in public documents (such as the 1920 United States Census and state birth and death records), Beck argued that “Albert B.” was a pseudonym for Douglas Merritte, the son of Arvilla Merritte, then a woman who appears to have been a wet nurse at the Harriet Lane Home. Recent research has shown, however, that Douglas Merritte may not have been “Little Albert”, who may in fact have been young William Barger.

William Barger

The identity claimed by Beck, Levinson, and Irons has been contested by psychology researchers, Russ Powell and Nancy Digdon, as well as Watson scholar, Ben Harris, who offer an alternative identity based on available data. William Barger had been born within a day of Merritte, was known by friends and family as “Albert” (even though his given name was William), and his mother had also worked at the hospital where the experiment was conducted. In addition, his size and developmental condition much more closely matched the experiment’s documentation of the subject baby’s condition.