Heritability of Intelligence

Abstract

This article discusses findings of two recent studies conducted in collaboration with the East Flanders Prospective Twin Survey in the field of cognitive ability. The first study examined the effect of chorion type on heritability estimates of intelligence in children. The second study investigated the causes of association between child psychopathology and lower cognitive ability. Findings of these studies are discussed in the light of the current view on cognitive ability (or ‘g’) and recommendations for future research are made.

Genetic foundations of human intelligence

“…The heritability of g increases with age (McCartney et al 1990;McGue et al 1993;Plomin 1986;Wilson 1978). Again we cite older studies because it is well established that heritability increases from about 30% in very young childhood (Spinath et al 2003) to as much as 80% in adulthood (Edmonds et al 2008;Jacobs et al 2007;Johnson et al 2007). More recent studies have tended to focus on measuring the extent to which genetic influences contribute to stability and change in g. For example, using Dutch twin pairs assessed at ages 5, 7, 10, 12, and 18 years, Hoekstra et al (2007) found that the heritability of verbal ability increased from 48% at age 5 to 84% at age 18, while the heritability of nonverbal ability increased from 64% at age 5 to 74% at age 18.…”

The neuroscience of human intelligence differences

“…The heritability of general intelligence increases with age [22][23][24] . It is about 30% in very young childhood 25 , and grows to as much as 70% to 80% in adulthood 17,26,27 . Because this is now well established, recent studies have shifted to investigating how genetic influences on various mental abilities are related and how they change with development.…”

Extending Brain-Training to the Affective Domain: Increasing Cognitive and Affective Executive Control through Emotional Working Memory Training

“…Perhaps the most persuasive of these is Jaeggi et al's [6] demonstration that systematic training on a complex WM task – a dual n -back task – accrues transferable benefits in G f , over and above any gains in WM capacity (indexed by an increase in digit span). This finding merits particular attention because G f has traditionally been viewed as highly heritable and stable [9], [10] and is positively correlated with a large number of desirable outcomes including academic success, and neurological, psychological and physical health [11]–[14]. Evidence showing change in G f through WM training, therefore, has far reaching implications.…”