Classic study: Watson and Rayner (1920)

Aims and participant

Aims: to see whether an emotional response (fear) could be conditioned in a baby by pairing a white rat with a loud noise; whether the fear would transfer to similar objects; how long it would last; and how it might be removed.

Participant: Albert B., described as a healthy, emotionally stable infant.

Procedure

• About 9 months: baseline tests. Albert showed no fear of a white rat, rabbit, dog, monkey, masks, cotton wool or burning newspapers.
• 8 months 26 days: a steel bar was struck with a hammer behind him; on the third strike he burst into tears. The loud noise was the UCS, fear the UCR.
• 11 months 3 days: the rat was presented and the bar struck as Albert touched it (2 pairings).
• 11 months 10 days: 5 more pairings. In all, 7 joint stimulations were given. When the rat (now the CS) was then shown alone, Albert cried and crawled away (the CR).
• 11 months 15 days: generalisation tests with blocks, rabbit, dog, a seal fur coat, cotton wool, Watson's hair and a Santa Claus mask.
• 11 months 20 days: further tests, including in a different room; the fear was 'freshened' with extra pairings.
• 1 year 21 days: after 31 days without testing, Albert was tested again.

Results

• After 7 pairings the rat alone produced crying and crawling away.
• The fear generalised: Albert reacted negatively to the rabbit (a strong reaction with crying), the dog, the fur coat and the Santa Claus mask, and mildly to cotton wool; he played happily with blocks throughout.
• A month later he still showed fear: he cried at the mask and the dog and fretted and withdrew from the fur coat and rat.
• Albert was taken from the hospital the day of the last tests, so the fear was never removed. Watson and Rayner only suggested methods, such as repeated exposure or pairing the objects with sweets or food.

Conclusions and evaluation

Conclusions: emotional responses can be classically conditioned; they generalise to similar objects and last at least a month; adult phobias may be traced to such conditioning.

Evaluation:

• Strengths: controlled, carefully recorded procedure with detailed observations; shows classical conditioning of emotion and led to treatments such as systematic desensitisation.
• Weaknesses: one participant, so low generalisability; observations of fear were subjective (no inter-observer check reported); the fear had to be 'freshened' with extra pairings, suggesting it was not very strong.
• Ethics: deliberately caused fear in an infant, did not remove it, and the mother's consent was arguably not fully informed; this would not be allowed under the BPS Code today.

Worked example

How many days passed between the first rat-noise pairing (11 months 3 days) and the second set of pairings (11 months 10 days)?

1. 11 months 10 days minus 11 months 3 days.
2. = 7 days.

Answer: 7 days.

Check yourself

1. How many joint stimulations (rat plus noise) were given in total to condition Albert's fear?
   Show answer

   7 pairings. 2 at 11 months 3 days and 5 at 11 months 10 days = 7.

2. In the Little Albert study, what was the unconditioned stimulus?
   • The loud noise of a hammer striking a steel bar
   • The white rat
   • Albert's crying
   • The Santa Claus mask
   Show answer

   The loud noise of a hammer striking a steel bar. The noise caused fear without learning.

3. After conditioning, the white rat was the
   • unconditioned stimulus
   • unconditioned response
   • conditioned stimulus
   • neutral response
   Show answer

   conditioned stimulus. The rat triggered fear because of learning.

4. Albert's fear spreading to the rabbit and the fur coat is an example of
   • extinction
   • stimulus generalisation
   • spontaneous recovery
   • negative reinforcement
   Show answer

   stimulus generalisation. Similar stimuli produced the CR.

5. How many days passed without emotional testing before the final test at 1 year 21 days?
   Show answer

   31 days. The final test followed 31 days with no emotional testing.

6. Which is the most serious ethical criticism of the study?
   • The rat was harmed
   • Fear was deliberately caused in an infant and never removed
   • Albert was paid too little
   • The study was covert observation of adults
   Show answer

   Fear was deliberately caused in an infant and never removed. Albert left the hospital still conditioned.

7. Explain one methodological weakness of Watson and Rayner (1920).
   Show answer

   It used only one infant, so the findings cannot be generalised, and Albert's fear reactions were judged subjectively by the researchers, which may lack objectivity and reliability.. Sample or subjectivity.

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Sources

• Pearson Edexcel International Advanced Subsidiary/Advanced Level in Psychology specification, Issue 5 (February 2021)
• Pearson IAL Psychology component guide: WPS02 (Issue 2, November 2024)
• Watson and Rayner (1920), Conditioned emotional reactions (Classics in the History of Psychology)
• Pearson IAL Psychology summary of studies: WPS02

Last updated 8 November 2026. Spotted a mistake? Tell us.