Infant Behavior & Development 27 (2004) 417–433 Differences in attachment security between African-American and white children: ethnicity or socio-economic status? Marian J. Bakermans-Kranenburg ∗ , Marinus H. van IJzendoorn, Pieter M. Kroonenberg Center for Child and Family Studies, Department of Education and Child Studies, Leiden University, Wassenaarseweg 52, 2333 AK Leiden, The Netherlands Received 12 December 2003; received in revised form 27 January 2004; accepted 4 February 2004 Abstract The NICHD Early Childcare Research Network data set was used to examine differences in attachment security between African-American children (n = 142) and white children (n = 1002). African-American children’s mean score on the Attachment Q-sort (AQS) [Monographs of the Society for Research in Child Development 60 (1995) 234] was substantially lower (.20) than that of white children’s (.30). The pattern of covariation between attachment security and predictor variables was similar in the African-American and white subgroups. In both groups, maternal sensitivity was the strongest predictor of attachment security. A mediational model explaining the difference in attachment security included income and sensitivity: African-American ethnicity was related to low income which through (in-)sensitivity affected the quality of the infant–mother attachment relationship (family stress model). Our findings on African-American mother–infant dyads support one of the basic tenets of attachment theory: the association between maternal sensitivity and attachment security. Children of African-American and white families in the USA may be exposed to culturally specific experiences, but these do not alter the relation between attachment security and pertinent predictor variables. Poverty may, however, seriously hamper maternal sensitivity. © 2004 Elsevier Inc. All rights reserved. Keywords: African-American; Attachment; Attachment Q-sort; Ethnicity; Cross-cultural; Socio-economic status ∗ Corresponding author. E-mail address: bakermans@fsw.leidenuniv.nl (M.J. Bakermans-Kranenburg). 0163-6383/$ – see front matter © 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.infbeh.2004.02.002