Twenty years ago, meta-analytic results (k = 19) confirmed the association between caregiver attachment representations and child-caregiver attachment (Van IJzendoorn, 1995). A test of caregiver sensitivity as the mechanism behind this intergenerational transmission showed an intriguing "transmission gap." Since then, the intergenerational transmission of attachment and the transmission gap have been studied extensively, and now extend to diverse populations from all over the globe. Two decades later, the current review revisited the effect sizes of intergenerational transmission, the heterogeneity of the transmission effects, and the size of the transmission gap. Analyses were carried out with a total of 95 samples (total N = 4,819). All analyses confirmed intergenerational transmission of attachment, with larger effect sizes for secure-autonomous transmission (r = .31) than for unresolved transmission (r = .21), albeit with significantly smaller effect sizes than 2 decades earlier (r = .47 and r = .31, respectively). Effect sizes were moderated by risk status of the sample, biological relatedness of child-caregiver dyads, and age of the children. Multivariate moderator analyses showed that unpublished and more recent studies had smaller effect sizes than published and older studies. Path analyses showed that the transmission could not be fully explained by caregiver sensitivity, with more recent studies narrowing but not bridging the "transmission gap." Implications for attachment theory as well as future directions for research are discussed.

This meta-analytic review examines the association between attachment during the early life course and social competence with peers during childhood, and compares the strength of this association with those for externalizing and internalizing symptomatology. Based on 80 independent samples (N = 4441), the association between security and peer competence was significant (d = 0.39, CI 0.32; 0.47) and not moderated by the age at which peer competence was assessed. Avoidance (d = 0.17, CI 0.05; 0.30), resistance (d = 0.29, CI 0.09; 0.48), and disorganization (d = 0.25, CI 0.10; 0.40) were significantly associated with lower peer competence. Attachment security was significantly more strongly associated with peer competence than internalizing (but not externalizing) symptomatology. Discussion focuses on the significance of early attachment for the development of peer competence versus externalizing and internalizing psychopathology.