The paper was the first documented evidence that genetic influences on processes important for learning to read and spell, such as phonological sensitivity and knowledge of letters, are already at work prior to the start of formal schooling. This is important because once children learn to read, or fail to, the interactions between literacy levels and other cognitive and behavioral processes become clouded—do reading problems lead to difficulties in these other processes, or are those difficulties the cause of the problems?

By showing that genes have a hand so early in the growth process, we added to the evidence about what underlies difficulties in learning to read. The paper also showed that the home environment was more influential than genetic endowment in certain of these preschool skills, such as vocabulary growth.

  Does it describe a new discovery, methodology, or synthesis of knowledge?

This was genuinely a new discovery, because, at that stage, there were no other behavior-genetic data on such a broad range of preliteracy skills on children so young.

In a podcast audio interview with Brian Byrne, he talks about how genetic and environmental influences on processes important for learning to read and spell are already at work in children prior to the start of formal schooling. Podcast formats: mp3 | wma

Children arrive at school differently endowed, genetically, for the task of learning to be literate. They also come differently endowed as a result of home backgrounds, particularly in areas like vocabulary and other aspects of spoken language. The genetic and environmental influences behind these differences continue to play out in school literacy and language levels.

The research grew naturally out of earlier work into risk factors for learning to read, and how best to help children burdened by risk. My existing contacts with the first-rate scientists at the Institute for Behavioral Genetics at the University of Colorado, particularly Dr. Richard Olson, greatly facilitated the project. So did the cooperation of the Australian Twin Registry, directed by Dr. John Hopper and funded by the Australian National Health and Medical Research Council.

Subsequently, we were fortunate to recruit the cooperation of Dr. Stefan Samuelsson of Stavanger and Linkoping Universities in Norway and Sweden, respectively, who added a Scandinavian sample to those from Australia and the USA.

The project is ongoing. The 2002 report in the Annals of Dyslexia was just the first in what is now a substantial series of papers in which we document the growth of literacy and language in twins as we follow them through the first few years of school. The results apply, of course, not just to twins but to children in general, and indicate the need to delve more deeply into how genetic differences work through into the cognitive and behavioral processes that support or undermine further literacy growth. The project is attempting to do just that.

Teaching policies and practices need to take these observations into account, in two ways: Identification of the children less well-equipped to benefit from standard instruction, and modification of standard methods to afford these children every opportunity to achieve grade-average levels.

Given the importance of genes in shaping school progress, documented not just in our project for literacy but in others for other school subjects such as mathematics, educationists, from policy makers to classroom teachers need to develop an understanding of behavior-genetic research so that they can critically assess the burgeoning body of data coming from studies like ours.