Most modern research measures reading habits using what is known as an Author Recognition Test (ART). This measure is simply a list of names, with respondents being asked to indicate with a check mark those names that they recognize as belonging to actual authors. Importantly, they are told that some of the names on the list are fake, or foils, so they cannot simply guess or check indiscriminately in order to mis-represent their own reading habits. The ART constitutes an indirect measure of what is known as exposure to print, since it is not a direct indication of what people read. What it does indicate are general reading habits, and from these measures it can be inferred the types of reading material that people engage with. A recent study investigated what is the genetic contribution of print exposure (Martin et al., 2009). These researchers administered the ART along with other measures to a group of identical twins (monozygotic twins), fraternal twins (dizygotic), and those not part of a twin pair, known as singletons. By comparing the similarity in scores between identical twins to the similarity for fraternal twins, the contribution of genetic make-up to lifetime exposure to print can be inferred. What these researchers found was that print-exposure was moderately heritable (h = .67), and that the same genes appeared to also account for scores on other measures of reading and verbal ability. They also discovered that a separate set of genes accounted for really high scores on the ART, separate from those genes associated with low ART scores and reading ability. These are very interesting results, as they indicate that a separate process or ability could explain those who read a lot, compared to those who read a moderate amount or less. As with any study that employs this method (i.e., looking at twins to infer genetic contribution), it is important to stress that heritability is not equivalent to genetic cause, but more like a correlation or association between genetic variance and variance in tests scores (in this case the ART). So, one cannot conclude that genes cause a moderate amount of the variability in ART scores, nor can any conclusion be made about how pre-determined or amenable to change these ART scores are. It is very exciting to see a diversity of methods being employed with regard to our understanding of reading habits. As with any of the papers we discuss here at OnFiction, please contact me if you would like a copy of this paper (e-mail in profile).
Martin, N. W., Hansell, N. K., Wainwright, M. A., Shekar, S. N., Medland, S. E., et al. (2009). Genetic covariation between the Author Recognition Test and reading and verbal abilities: What can we learn from the analysis of high performance? Behavioral Genetics, 39, 417–426.