harlow

• P: one criticism that has been made of Harlow's study is that the two stimulus objects varied in more ways tha being cloth-covered or not

  E: two heads were also different, which acted as a confounding variable because it varied systematically with the independent variable. it is possible that the reason the infant monkeys preferred one mother to the other was because the cloth-covered mother has a more attractive head
• link for confounding variable

  L: therefore, the conclusions of this study lack internal validity
• P: the ultimate aim of animal studies is to be able to generalise the conclusions to human behaviour

  E: humans differ in important ways because much more of their behaviour is governed by conscious decisions. nevertheless, studies have found that the observations made of animal attachment behaviour are mirrored in studies of humans.
• link for generalisation

  L: this demonstrates that, while animal studies can act as a useful pointer in understanding human behaviour, we should always seek confirmation by looking at research with humans