Submitted to Science
Taylor et. al. (Science vol 328, April 23) compared identical twins in different classes in grades 1 and 2. The twin in a class that made better gains on a reading test made better gains than the co-twin in the other class. This shows, the researchers claim, that instruction is a stronger force than genetics for learning to read.
The reading test asked children to pronounce texts rapidly and accurately, without necessarily understanding them. Reading is about comprehension, not pronunciation. Prof. Elaine Garan (2001, Phi Delta Kappan 82(7), 500-506) has shown that the kind of reading instruction that is aimed at improving pronunciation without understanding does not help children much on tests in which they have to understand what they read.
Reading is about understanding, not pronouncing. The Taylor et. al. study does not tell us much about reading.