standardised procedure - meaning that it has high reliability
Weaknesses of the 'Strange situation' design
only designed for the USA - may not provide valid date in other countries
only measures attachment to oneperson (mother) - it should look at the infant's attachment type to other people as well (like dad) and take an average as infant may be securely attached to mum but insecurely attached to everyone else
not all infants fit into the 3categories of attachments - e.g Main and Cassidy who identified a 4th group
