A03 Schaffer's stages of development

• Good external validity

  Study carried out in the families' homes and most of the observation done by parents. This means behaviour if babies is not affected by the presence of others. Babies behaved naturally - high validity
• Longitudinal design

  Same children followed up and observed regularly : longitudinal studies have thus, good internal validity as they do not have confounding variables of participant variables
• Limited sample charactersitics

  All families were from same social class and location and time of 50 years ago meaning results do not generalise well to other social/historical contexts
• Problem studying asocial stage


  Evidence cannot be relied on as babies are so young that they are generally immobile and have poor co-ordination so there is not much observable behaviour
• Conflicting evidence on multiple Attachments

  Not clear when children become capable of multiple attachments. Bowlby suggested most if not all babies form As to a specific carer before being capable of multiple As
• Van Uzerdoorn

  Suggested collectivist cultures cause children to create multiple As from the outset as families are constantly working together
• Measuring multiple attachments

  Bowlby stated children have play mates as well as A figures and may get distressed when the play mate leaves the room. Problem for Schaffer and Emerson as observation does not leave us a way to distinguish a way of behaviour shown towards secondary A figures and play mates
• Schaffer and Emerson used limited behavioural measures of attachment


  Carried out scientific study of attachment development because they used simple behaviours like separation and stranger anxiety to define attachment. Some critics believe these are too crude