26 April 2010
ByAppeared in BioNews 555
Genetic influences are estimated to account for up to 82 per cent of a child's reading ability, but children can only make the most of their natural abilities if this is combined with excellent teaching, a study published in the journal Science last week has found. The study, which assessed reading progression among twins in different classrooms, is the first of its kind to try and pinpoint environmental influences on reading ability.
'When children receive more effective instruction, they will tend to develop at their optimal trajectory', said study lead author Jeanette Taylor, an associate professor in psychology at Florida State University in Tallahassee, in a prepared statement. 'When instruction is less effective, then children's learning potential is not optimised and genetic differences are left unrealised'.
The study involved 280 identical or 'monozygotic' and 526 non-identical or 'dizygotic' twin pairs entering either first or second grade in schools across Florida. Monozygotic twins share all their genes, and dizygotic twins share half (the same as siblings), providing a way for scientists to estimate the role that environmental influences play in determining reading ability.
After a year's teaching, children were assessed to see how many words they could read from a given paragraph in one minute, also known as an Oral Reading Fluency (ORF) test. Further ORF tests carried out on the twin's classmates were used to provide a benchmark for the overall quality of teaching in the class to which the twin's ORF score could be compared. If ORF scores improved across the class as a whole, it was taken as an indication that the teaching quality was good.
They found that twins who were in a good classroom environment, as assessed by the achievement of their classmates, generally did better than those gauged to be in a poor classroom environment. This suggested that teaching quality has a modifying affect on any genetic differences linked to an increased aptitude for reading.
But the researchers warned that the quality of teaching might not be the only explanation for the findings. Factors such as classmates' behaviour, availability of teaching resources, curriculum content and the suitability of the teaching style used for the individual in question are also likely to play a role.
Commenting on the study in the Miami Herald, Tim Shanahan, Professor of urban education at the University of Illinois, said: 'Good classrooms are all alike; they maximize kids' potential. Poor classrooms are not only poor in one way; they are poor in multiple ways'. Improving any of these factors can help to turn around a failing class, he argues.