Genetic and Environmental Influences on Reading and Listening Comprehension

We report preliminary behaviour genetic analyses of reading and listening comprehension from The Colorado Learning Disabilities Research Center. Although the twin sample with these new measures is still of limited size, we find substantial, and significant, genetic influences on individual differences in both reading and listening comprehension. In addition, word recognition and listening comprehension each accounted for significant "independent" genetic influences on reading comprehension. Together, they accounted for "all" the genetic influence on reading comprehension, indicating a largely genetic basis for the "simple model" of individual differences in reading comprehension proposed by Hoover and Gough (1990).