Undertook meta-analyses of previous attachment research examining the relative importance and relationship between the mother-infant and father-infant attachments.

They found that:

1. Infant attachment to mother was only modestly similar to infant attachment to father. This strongly suggests that attachment is relationship specific rather than generalized within the family or for the infant.
2. Mothers and fathers individual attachment styles were only modestly correlated.
3. Fathers contribute to the shaping of infant attachment style but to a lesser extent than mothers.