A longitudinal study of 5- to 7-year-old twins from England and Wales January/February 2006 issue of Child Development concludes that the two problems are so interrelated that "targeting either reading achievement or antisocial behavior during the preschool and early primary school years is likely to produce changes in both behaviors.

The link between behavior and reading problems

"The development of reading achievement and antisocial behavior are intertwined: as one changes, so does the other," the researchers note. They emphasize that the association between reading difficulties and antisocial behaviors is most common in boys, and that educators should focus their interventions on boys.

Based on the study of more than 1,200 families with twins, the researchers conclude that the relation between reading achievement and antisocial behavior is primarily due to environmental factors, not genetic factors, and that the reciprocal impact that reading difficulties and antisocial behaviors have on one another is probably the most important environmental influence.

Participants were members of the Environmental Risk (E-Risk) Longitudinal Twin Study which investigates how genetic and environmental factors shape children's development.

The E-Risk sampling was from two birth cohorts (1994 and 1995) in a birth register of twins born in England and Wales. Of the 15,906 twin pairs born in these two years, 71% joined the register.

For this study about 1,116 families (93%) participated in home assessments within two months of the twins' fifth birthday, forming the base sample. With parents' permission, teachers were sent questionnaires. Children were individu- ally tested for reading (Test of Word Reading Efficiency), intelligence (Wechsler Preschool and Primary Scale of Intelligence-Revised) and reading disability. Children were assessed for antisocial behavior, conduct disorder and ADHD.

Homes were evaluated for family size, economic deprivation, mothers' reading, mother's age at first birth, maternal depression, child neglect, income, education, social class and stimulating environment.

To test whether there was a genetic cause, one twin's reading score was correlated with the other twin's antisocial behavior score for monozygotic (MZ) and dizygotic twins (DZ).

Intervention before school begins

"Our findings suggest two main implications for educational practices," the researchers state. "First, the finding that the association is reciprocally influenced and present during the first few years of formal schooling suggests that the association can be broken up by intervening before school begins.

"Second, the finding that boys' ability and behavior when they enter school influences changes in their reading achievement and antisocial behavior after 2 years of instruction suggests that the association can be broken up by intervening in the early stages of school."

In contrast to reading achievement and antisocial behavior, the researchers concluded that the relation between reading and ADHD is best explained by genetic influences that are common to both. "These results show that antisocial behavior and ADHD symptoms should not be considered equal, at least in terms of their relation with reading achievement," the researchers note.

"Revisiting the Association Between Reading Achievement and Antisocial Behavior: New Evidence of an Environmental Explanation from a Twin Study." Child Development Volume 77 Number 1 February 2006 pp. 72-88.

Published in ERN April 2006 Volume 19 Number 4