Harlow's Research (AQA A-Level Psychology): Revision Notes
Harlow's Research
Background and context
Harry Harlow conducted groundbreaking animal research in the 1950s that fundamentally changed our understanding of attachment. Working with rhesus monkeys (which share greater similarities with humans than Lorenz's birds), Harlow challenged the prevailing view that attachment was primarily based on feeding.
Harlow's initial observations revealed a crucial insight: newborn monkeys kept alone in bare cages typically died, but survival rates improved dramatically when given something soft to cuddle, such as a cloth. This observation would become the foundation for his revolutionary research.
The study
Research Study: Harlow's Contact Comfort Study (1958)
Participants: 16 baby rhesus monkeys
Aim: To test whether a soft object could serve some of the functions of a mother and determine what factors are most important in attachment formation
Procedure: Harlow created two artificial 'mothers' from wire models. In one condition, the plain wire mother dispensed milk, while in a second condition, the cloth-covered mother dispensed milk. The baby monkeys were reared with both models present and their behaviour was observed.
Key Findings:
- Baby monkeys consistently cuddled the cloth-covered mother in preference to the wire mother
- When frightened, monkeys sought comfort from the cloth mother regardless of which model dispensed milk
- This demonstrated that contact comfort was more important than food provision for attachment behaviour
Long-term consequences of maternal deprivation
Harlow and his colleagues conducted longitudinal research, following the maternally deprived monkeys into adulthood. The findings revealed severe and lasting consequences of early maternal deprivation:
Severe Long-term Effects of Maternal Deprivation:
- Monkeys reared with only wire mothers showed the most severe dysfunction
- Even those with cloth substitute mothers failed to develop normal social behaviour
- As adults, these monkeys were more aggressive and less sociable than typically-reared monkeys
- They showed poor mating behaviour and bred less frequently than normal
- When these deprived monkeys became mothers themselves, many neglected their offspring
- In extreme cases, some attacked or even killed their own young
Critical period for attachment
Like Lorenz's concept of imprinting, Harlow identified a critical period for attachment formation.
Critical Window for Attachment
Harlow's research concluded that a mother figure must be introduced to an infant monkey within 90 days for normal attachment to develop. After this critical window, attachment became impossible and the psychological damage from early deprivation became irreversible.
Evaluation: Strengths
Theoretical value
Harlow's findings revolutionised psychological understanding of human mother-infant attachment. The research provided crucial evidence that attachment develops through contact comfort rather than feeding, directly challenging the prevailing 'cupboard love' theory.
The study highlighted the critical importance of early relationship quality for later social development, including the ability to form adult relationships and successfully parent children. This insight fundamentally changed how psychologists understood human development.
Practical value
The insights from Harlow's research have generated important real-world applications across multiple contexts. Social workers now better understand risk factors for child neglect and abuse, enabling more effective intervention strategies (Howe, 1998). The findings also inform proper care procedures for captive monkeys in zoos and breeding programmes, ensuring appropriate attachment figures are provided for young primates.
Evaluation: Weaknesses
Ethical issues
Harlow faced severe criticism regarding the ethics of his research procedures. The monkeys suffered considerably as a direct result of the experimental conditions.
Major Ethical Concerns
Since rhesus monkeys are sufficiently similar to humans to allow generalisation of findings, their suffering was presumably comparable to human-like distress. Harlow himself acknowledged the harm he caused, referring to the wire mothers as 'iron maidens' after a mediaeval torture device.
However, supporters argue that the research was sufficiently important to justify these effects, given the profound impact on understanding human development and childcare practices.
Generalisability to humans
Although monkeys are clearly more similar to humans than Lorenz's geese, they remain a different species. Psychologists continue to debate the extent to which studies of non-human primates can be generalised to human behaviour.
Arguments for generalisability:
- Monkeys and humans are both primates, suggesting similar attachment mechanisms
- Allows tight experimental control impossible with human participants
- Ethical constraints prevent creating deprivation conditions experimentally with human infants
Arguments against generalisability:
- Humans have significantly larger brains and greater psychological complexity
- Humans can make conscious decisions about social interactions to a much greater extent than monkeys
- The fundamental question remains: we simply don't know how similar attachment processes are between humans and monkeys
Summary
Key Points to Remember:
- Contact comfort is more important than food provision for attachment formation - monkeys preferred the cloth mother regardless of which provided milk
- Maternal deprivation has severe long-term consequences, including aggressive behaviour, poor social skills, and inadequate parenting abilities in adulthood
- There is a critical period of 90 days for attachment formation - after this window, normal attachment becomes impossible
- The research has high theoretical value by demonstrating that attachment is based on comfort rather than feeding
- Ethical concerns arise from the significant suffering caused to the monkeys, though this is balanced against the importance of the findings for human development