Confounding variable
Type: Criticism
- The type of head was different for each wired mother
- The type of head may have acted as another independent variable
- Therefore the monkeys may have preferred the cloth mother because it had a more attractive head, not because of the cloth
- Therefore the study lacks internal validity
- The study doesn’t measure what it claims to measure
Ethics
Type: Criticism
- Harlow’s study created lasting emotional harm as the infant monkeys later found it difficult to form relationships with their peers
- However, some psychologists argue that animal research can be justified in terms of the effect it has on our knowledge of attachment
- i.e., Harlow’s research has been used to offer better care for human infants
- This suggests that the benefits of animal research into attachment may outweigh costs