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The Little Albert experiment

In 1920 John Watson and Rosalie Rayner made a loud noise behind an 11 month old child each time he reached for a white rat. Within a few sessions the rat alone was enough to upset him.

Published November 3, 2026. 3 sources at the foot of the page.

What it says

The study is a demonstration, not a theory. Watson wanted to show that an emotional reaction in a person could be built by classical conditioning, the way Pavlov had built a salivation response in dogs.

The rat was the neutral signal and the noise, a hammer struck on a steel bar behind the child, was the thing that upset him on its own. After the pairings the rat produced the reaction by itself.

The part Watson made most of was the spread. The reaction appeared with a rabbit, a dog, a fur coat and a mask with a white beard, none of which had ever been paired with the noise. That is generalization, and it is the reason the study is still taught.

What happened, in order

The sequence as Watson and Rayner reported it in 1920.

  1. Before

    The child was shown a rat, a rabbit, a dog and masks, and reached for them with no sign of fear.

  2. The pairings

    A steel bar was struck behind him as he reached for the rat, across a small number of sessions.

  3. After

    The rat alone produced crying and moving away.

  4. The spread

    Similar furry things produced it too, though more weakly, which is the generalization the paper rests on.

  5. The end

    The child left the hospital before anything was done to undo the reaction. Watson and Rayner wrote that they knew he was leaving.

Where it came from

Watson ran it at Johns Hopkins and published it with Rayner, then a research assistant, in the Journal of Experimental Psychology in 1920. It arrived in the middle of his campaign for a psychology built on observable behavior alone.

Four years later Mary Cover Jones showed the other direction. She worked with a child who was already afraid of a rabbit. Pairing the animal with food, and with other children who were not afraid, brought the fear down. That study is much less famous than the one that created a fear.

What holds up, and what does not

What survives is the general point: emotional reactions in people can be conditioned, and they generalize to similar things. That has been shown many times since under conditions that could be approved.

What does not survive is the strength of the claim. There was one child and no control condition. The reports of how upset he was come from the experimenters' own notes and a short film, which later authors read very differently. The ethics would stop the study today: an infant was made afraid and sent home that way. Henry Beck and colleagues traced the likely identity of the child in 2009. What they found about his later life is part of why the study is now taught as a caution as much as a result.

What it does not mean

It does not show that every fear is learned this way, and Watson's wider claim that any child could be made into anything went far past his evidence. One infant in one laboratory is a demonstration that something is possible, not a measurement of how often it happens.

Check yourself

Three questions on what is above. Each answer says why.

  1. In the 1920 study, what was the conditioned stimulus?

    1. The loud noise
    2. The white rat
    3. The child's crying
    Show the answer

    Answer: B. The rat started out neutral and came to produce the reaction. The noise was upsetting on its own, which makes it the unconditioned stimulus.

  2. What does the spread to a rabbit, a dog and a fur coat demonstrate?

    1. Generalization
    2. Extinction
    3. Spontaneous recovery
    Show the answer

    Answer: A. A response that appears to similar signals that were never paired with the noise is generalization.

  3. Pick the honest summary of what the study proves.

    1. All fears are built by conditioning
    2. A fear response in a person can be conditioned, in one child, with no control condition
    3. Fears cannot be reduced once learned
    Show the answer

    Answer: B. It is a single case demonstration. Mary Cover Jones showed four years later that a fear could also be brought down.

Sources

  1. Watson, J. B., and Rayner, R. (1920). Conditioned emotional reactions. Journal of Experimental Psychology, 3(1).
  2. Jones, M. C. (1924). A laboratory study of fear: The case of Peter. Pedagogical Seminary, 31.
  3. Beck, H. P., Levinson, S., and Irons, G. (2009). Finding Little Albert: A journey to John B. Watson's infant laboratory. American Psychologist, 64(7).

Practice it on Learn

Learn teaches this study in Four more studies that changed the field, the second unit of the Landmark studies track. The unit reads it beside Pavlov's dogs, learned helplessness and the minimal group studies, each against its original paper.

Practice the Little Albert experimentSee what Learn is

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