The researchers looked at the proportions of secure, insecure-avoidant, and insecure-resistant attachments across a range of countries.
They also looked at the differences within the same countries to get an idea of variations within a culture. They yielded results for 1,990 children and meta analysed them.
Secure attachment was the mostcommon, but ranged from 50% in China to 75% in Britain.
van Iljzendoorn and Kroonenbergs's meta-analysis: their findings
In individualist cultures rates of insecure-resistant attachment were similar to Ainsworth's original sample (under 14%), but this was not true for the collectivist samples from China, Japan, and Israel where rates were above25%.
This suggests that there were cultural differences in the distribution of insecure attachment.
The variations between results of studies within the same country were actually 150%greater than those between countries.
Simonelli's key study
Assessed 76 one year olds using the strangesituation to see whether the proportion of attachment types stillmatched previous studies in Italy.
Mothers were reasonably varied in terms of their education levels.
Researchers found that 50% were secure, with 36% insecure-avoidant. This was a lower rate of secure attachment than found in previous studies. They suggested this was due to the increasing number of mothers working long hours and using professional childcare. Culturalchanges can make dramatic differences in the patterns of attachment.
A strength of meta-analysis is that you can end up with very large samples.
In Kroonenberg's study there was a total of nearly 2000 babies and their primary attachment figures. Even Simonelli's study had large comparison groups. This is a strength because large samples increase internal validity by reducing the impact of biased methodology or very unusual participants.
Another limitation is the StrangeSituation's method may be biased towards American/British culture.
The study was designed by an American researcher based on a British theory. This theory and assessment may not be applicable to other cultures. Trying to apply a theory or technique designed for one culture to another is known as imposed etic which disregards the notion of cultural emic. The idea that a lack of pleasure on reunion indicates insecure attachment is an imposed etic. In Germany, this behaviour might be seen more as independence than avoidance and not a sign of insecurity.
A further limitation is there is an alternative explanation for the similarities found between cultures.
Bowlby's explanation for cultural similarities was that attachment is innate and universal so produces the same kind of behaviours all over the world. Kroonenberg proposed an alternative possibility. They suggest that small cross-cultural differences may reflect the effects of mass media. Many books and TV programmes are broadcast around the world and create parenting norms, so similarities in child-rearing have become more common.