ABSTRACT
This chapter interprets what has been, and could yet be, done in the quantitative genetics of attentional disorders. Behaviour genetics is concerned with differences, rather than similarities, between people. Contemporary behaviour genetics has gone far beyond simply calculating “ the heritability” , using traditional formulae such as those provided by Holzinger or by Nichols, with all the problems and pitfalls these entail. The usual approach nowadays is by model-fitting, which provides a test of the adequacy of the genetic model as a parsimonious explanation of the data. Contemporary behaviour genetics is far more complex than simply testing a few sets of twins and comparing the resemblance in identical and nonidentical twins. The sophistication of the mathematical analysis in genetic research is such that very large numbers are needed to accurately estimate the genetic and environmental effects, and to ensure that all possible factors be tested.
