The Journal ofGenetic Psychology, 149(1), 23-28 The Relationship Between Quality of Attachment in Infancy and IQ in Kindergarten

ABSTRACT. In this study, we hypothesized that securely attached infants would in kindergarten perform better on an intelligence lest than anxiously attached children. No difference was expected between children of working mothers (working more than 15 hours outside the home) and children of full-time homemakers. Mother-child pairs (N = 77; average age of child was 24 months) were observed during the Strange Situation procedure; three years later, 65 children completed the Leiden Di-agnostic Test for measuring intelligence level. Results showed that the securely at-tached reference group attained the highest IQ. The working Status of the mother did not appear to make a difference. IN ATTACHMENT THEORY, quality of attachment is supposed to have some consequences for future cognitive development: Securely attached chil-dren are expected to perform better in problem-solving situations compared to anxiously attached children. In longitudinal research, securely attached children have been more active in exploring the environment at age 2 i/2 (Ha-zen & Durrett, 1982) and at age 5 (Arend, Gove & Sroufe, 1979). They have also been more eager to learn (Waters, Wippman, & Sroufe, 1979) and more enthusiastic when solving problems (Matas, Arend, & Sroufe, 1978). Bus & Preparation of this article was supported in pari by a grant from the Nationaal Comite voor Kinderpostzegels. We gratefully acknowledge the assistance of Miriam Lambermon in collecting data. Requestsfor reprints should be sent to Marinus H. van IJzendoorn, Departmen