From a sample of middle-class mothers and their 3-year-old children,
a selected group
of 36 mothers were divided into 2 groups according to the quality of their
responses to the
Adult Attachment Interview as a Questionnaire (Crandell, Fitzgerald, &
Whipple, 1997).
Twenty mothers provided coherent accounts of their early parent–child
relationships (secure)
and 16 mothers provided idealised, entangled, or otherwise incoherent accounts
of their early
parent–child relationships (insecure). The mothers were administered
an abbreviated version
of the WAIS-R and the children were given an abbreviated version of the
Stanford-Binet
Intelligence Scale. The quality of mother–child interactions was
assessed by videotaping a
20-minute play episode and clean-up period, and by rating the degree of
synchrony
according to a modified version of the Belsky Parent–Child Interaction
System (Whipple,
Denburg, & Davies, 1993). The results were that children of secure
mothers scored 19 points
higher on the Stanford-Binet test compared to children of insecure mothers.
(The adjusted
mean difference was 12 points when maternal IQ, education, and family SES
were taken into
account.) The group difference in the children's IQ remained significant
when comparisons
were made between a subgroup of 12 secure and 12 insecure mothers who were
matched for
maternal IQ. Finally we examined the subgroup of 16 cases where child IQ
scores were either
10 points higher or lower than maternal IQ. In all 6 cases where child
IQ was at least 10
points below maternal IQ, the child had a mother who was insecure; in contrast,
only 4 of
the 10 children who had IQ scores 10 points higher than maternal IQ had
an insecure mother.
In terms of parent–child interaction patterns, there was suggestive
evidence that the degree
of parent–child synchrony was also related to child IQ. The results
suggest important social-developmental contributions to young children's performance on standardised
tests of
intellectual ability.