- not globally representative = Africa, South America, Eastern European socialist countries were not represented
- findings are misleading due to disproportionate number of studies e.g in the USA the study was conducted 18/32 times which was more compared to other countries like Great Britain which was conducted 1/32 times which distorts the findings
- culturally biased = strange situation was developed in america it may be more suitable for western cultures, attachment behaviour differs for each culture so may lack validity when used to compare samples from non-western cultures