Heritability of Selective Attention and Working Memory in Preschoolers

Abstract

In this study aspects of selective attention and working memory were tested in a large sample of nearly 6-year old monozygotic and dizygotic twin pairs, using a computerized test battery (Amsterdam Neuropsychological tasks). In the selective attention task the presence of a foil signal (target signal at an irrelevant location) resulted in more false alarms than a non-target signal. In the working memory task an increase in memory load lead to an increase in response times and errors. We analyzed variations in absolute performance parameters (overall speed and accuracy) and relative performance parameters (increase in errors and/or reaction time). The results showed clear familial resemblances on performance. It proved difficult to ascribe these effects to shared genes or to shared environment. An exception was memory search rate, which was clearly heritable.KEY WORDS: Attention-deficit hyperactivity disorder; endophenotypes; selective attention; twin study; working memory.In order to study the genetics of childhood psychopathologies such as ADHD it is of great importance to identify endophenotypes that predict the liability of the pathology of interest. The advantage of an endophenotypic approach to study complex disorders (or complex traits, such as IQ) is that it allows the identification of genes that by themselves make only a small contribution to the trait under study. A minimal requirement for suitable endophenotypes is that they yield continuously quantifiable measures; another requirement is that endophenotypes are anchored in neuroscience (e.g., Castellanos andTannock, 2002, andBoomsma, 2001). Indeed, researchers of psychopathologies often make use of neurocognitive tasks that are known to activate particular brain systems, and that yield quantitative performance measures, usually reaction times and percentage of errors. For example, Bush et al., (1999), using a counting Stroop task, found that children with ADHD showed underactivation in the anterior cingulate cognitive division (ACcd), and a concurrent increase in distractor interference, relative to controls. Stroop performance may thus qualify as a suitable (cognitive) endophenotype, indicative of ADHD. However, the search for endophenotypes should also be guided by the fact that many psychopathologies are highly heritable, and a recent line of inquiry has started to focus on the heritabilities of the endophenotypes themselves.Twin, adoption and family studies have shown that many psychopathologies are highly heritable (for review, see Acosta et al., 2004). For example, the heritability of ADHD is estimated to be around between 50% and 90% (e.g., Thapar et al., 1999). In a similar vein, the heritability of attention problems as

Biological Systems and the Development of Self-Regulation: Integrating Behavior, Genetics, and Psychophysiology

“…Research on the development of genetic influence on working memory mimics the pattern found for attention and effortful control, with modest and highly variable heritability estimates among younger children 70 and larger more consistent heritability estimates in samples of adolescents and adults. 71,72 That the development of heritability of attention and working memory parallel each other is not surprising given the close links between executive attention and working memory performance at the behavioral (described above) and neural (described below) levels.…”

Dopaminergic genotype biases spatial attention in healthy children

“…14 These lines of evidence led us to ask whether individual differences in the lateralized control of spatial attention are related to genotypic differences in potentially functional polymorphisms of the dopamine transporter gene (DAT1). Behaviour genetic studies have demonstrated a genetic contribution to visual cognition, 15,16 but few studies have examined the molecular genetic correlates of spatial attention. Two previous studies have reported an influence of allelic variation within a polymorphism of a nicotinic acetylcholine receptor gene and aspects of spatial attention.…”

The Role and Sources of Individual Differences in Critical-Analytic Thinking: a Capsule Overview

“…Although the number of quantitative genetic studies of EF is substantially smaller compared to the studies of fluid reasoning, crystallized knowledge, or general cognitive ability, there are some and they have generated a range of heritability estimates, indicating from negligible to substantial genetic influences (Anokhin et al 2003;Friedman et al 2008;Groot et al 2004;Kuntsi et al 2006;Polderman et al 2006;Stins et al 2005). Although the discussion of the different reasons for such a variation in heritability estimates (from methodological to conceptual and reflective of the psychological texture of a studied indicator) is highly important, such a discussion is outside the scope of this article.…”