Bowlby's attachment theory, maternal deprivation and the 44 thieves

Attachment theory

• Attachment is innate and evolved because it keeps infants close to a caregiver, which aids survival.
• Monotropy: infants have an innate need for one primary attachment, usually the mother; other attachments sit in a hierarchy below it.
• Critical period: Bowlby first proposed roughly the first two and a half years; if no attachment forms, later attempts are much less successful. He later treated this as a sensitive period.
• Internal working model: the first attachment becomes a mental template for later relationships: whether others can be trusted and whether the self is valuable.

Maternal deprivation hypothesis

Deprivation means losing or being separated from an attachment figure once a bond has formed. Privation means never forming an attachment at all.

Bowlby claimed that frequent or prolonged separation from the mother in the critical period causes long-term harm to intellectual, social and emotional development: delinquency, lower intelligence, aggression, depression and affectionless psychopathy (lack of guilt or concern for others).

The 44 Juvenile Thieves (Bowlby, 1944)

• Sample: 88 children from the clinic where Bowlby worked: 44 thieves (referred for stealing) and 44 controls (children at the same clinic referred for emotional problems who did not steal).
• Procedure: Bowlby (psychiatrist), a psychologist and a social worker interviewed each child and their parents about early life, including separations.
• Results: 14 thieves were classed as affectionless psychopaths, and 12 of those 14 had been separated from their mothers for six months or more before the age of five. Of the other 30 thieves, 5 had such separations. Only 2 of the 44 controls had prolonged separations, and none were affectionless psychopaths.
• Conclusion: early maternal separation was linked to affectionless psychopathy and offending.

44 Juvenile Thieves results (Bowlby, 1944); the 14 and 12 figures are confirmed in The Psychologist (BPS)

Evaluation

• Retrospective interview data about early separations may be inaccurate (reliability and validity problems).
• Correlation, not causation: Rutter argued other factors (why the separation happened, family conflict) could explain the link.
• Privation, not deprivation: some children may never have formed an attachment, which Rutter argued is more damaging.
• Researcher bias and subjectivity: Bowlby knew which group each child was in when diagnosing.
• Strength: practical application: the theory changed hospital and childcare practice (for example, parents staying with children in hospital).

Worked example

Using the 44 thieves data, what percentage of the affectionless thieves had a prolonged early separation, compared with the controls?

1. Affectionless thieves: 12 / 14 x 100 = 85.7%.
2. Controls: 2 / 44 x 100 = 4.5%.
3. The difference is large, which Bowlby took as support for maternal deprivation.

Answer: 85.7% versus 4.5%.

Check yourself

1. What is monotropy?
   • An innate tendency to form one primary attachment
   • Forming attachments to many people equally
   • Learning to attach through feeding
   • Never forming an attachment
   Show answer

   An innate tendency to form one primary attachment. One special bond, usually with the mother.

2. What is the difference between deprivation and privation?
   • Deprivation is never forming an attachment; privation is losing one
   • They mean the same thing
   • Deprivation is losing an attachment that formed; privation is never forming one
   • Privation only applies to adults
   Show answer

   Deprivation is losing an attachment that formed; privation is never forming one. Rutter drew this distinction.

3. The internal working model is
   • a mental template from the first attachment that shapes later relationships
   • a model of working memory
   • the stage at which attachment begins
   • a type of insecure attachment
   Show answer

   a mental template from the first attachment that shapes later relationships. It guides expectations about others and the self.

4. In Bowlby's study, 14 of the 44 thieves were classed as affectionless psychopaths. What percentage is that? Give your answer to 1 decimal place.
   Show answer

   31.8 %. 14 / 44 x 100 = 31.8%.

5. How many of Bowlby's 44 control children had experienced a prolonged early separation?
   Show answer

   2. Only 2 of the 44 controls.

6. Why might Bowlby's data about early separations lack validity?
   • He used brain scans that were unreliable
   • The children were tested in a laboratory
   • He used too large a sample
   • They came from retrospective interviews, so memories may be inaccurate
   Show answer

   They came from retrospective interviews, so memories may be inaccurate. Recalling events years earlier can be wrong.

7. Explain why the 44 thieves study cannot show that maternal deprivation causes affectionless psychopathy.
   Show answer

   The data are correlational: the separations were not manipulated, so other factors such as family conflict or poverty, or the reason for the separation, could explain both the separation and the delinquency.. Correlation plus an alternative cause.

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Sources

• Pearson Edexcel International Advanced Subsidiary/Advanced Level in Psychology specification, Issue 6 (November 2024, first assessment January 2026)
• British Psychological Society, The Psychologist: Looking back, making and breaking attachment theory
• Bowlby (1944), Forty-four juvenile thieves: their characters and home-life, International Journal of Psycho-Analysis 25 (PEP-Web record)

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