Category Archives: IQ

IQ is Highly Heritable

Source: Association for Psychological Science, 2016

 the heritability of intelligence has been shown consistently to increase linearly throughout the life course in more than three decades of research in longitudinal as well as crosssectional analyses and in adoption as well as twin studies (McGue, Bouchard, Iacono, & Lykken, 1993; Plomin, 1986; Plomin & Deary, 2015). For example, as summarized in Figure 3, an analysis of cross-sectional data for 11,000 pairs of twins—larger than all previous twin studies combined—showed that the heritability of intelligence increases significantly from 41% in childhood (age 9) to 55% in adolescence (age 12) and to 66% in young adulthood (age 17; Haworth et al., 2010). 

Some evidence suggests that heritability might increase to as much as 80% in later adulthood independent of dementia (Panizzon et al., 2014); other results suggest a decline to about 60% after age 80 (Lee, Henry, Trollor, & Sachdev, 2010), but another study suggests no change in later life (McGue & Christensen, 2013).

Learning Without Questioning –Why Asians do not win Nobel prizes

Source: James Thompson blog, Apr 2014

Asians (Chinese, Koreans, and Japanese) are supposed to have higher IQs (about 105 on average) than North Europeans (100), while sciences have been developed overwhelmingly by Europeans and their offshoots. Why Asians are lacking in scientific success might relate to two factors:

1. Low curiosity, which is expressed by lower Openness to experience (-.59 SD) as shown in various cross-cultural personality comparisons.

2.  Collectivism, which is captured by various individualism-collectivism indices such as the Hofstede individualism index (IDV), or Hofstede and Triandis individualism index (about -2 SD). The genetic underpinnings for these traits, such as DRD4, 5HTTLPR, and OPRM1 have also become increasingly apparent.

To integrate these psychological traits, a “q” factor is constructed by factor analysis on measures of Openness and Collectivism, which are then correlated with variables measuring academic achievements and also student assessments. It is found that IQ scores coupled with “q” factor scores neatly predict racial scientific achievements and also world-wide student assessments.  

Google DOC presentation: 

A Century of Research on Gifted Kids

Source: Psychology Today, Jan 2017

… advanced educational stimulation matters for gifted individuals to fully develop their talent and actualize their intellectual potential. One study from SMPY showed that grade skipping is a highly effective intervention on later achievement, and another study showed that it may not necessarily be one specific intervention that matters for the development of gifted youth but rather the right mix and intensity of interventions—the appropriate educational dosage—to keep them intellectually stimulated and engaged. Additionally, findings from SMPY have also shown that the willingness to work long hours varies greatly among the gifted population and thus is also likely connected to long-term development of expertise.


Genetic Scores and Average IQ

Source: Infoproc website, Oct 2016

This graph was in the comments

Database of IQ Studies

Source: Psychological Comments, Oct 2016

The database gives the Country, the age of the testees, the N, the test, the IQ, the short and the full reference, and then a column indicating whether we have an copy  of the reference (Y or N). Occasionally there are question marks where a reference has not been traced.

Database LINK

Rationality and Intelligence

Source: NYTimes, Sep 2016

irrationality — or what Professor Stanovich called “dysrationalia” — correlates relatively weakly with I.Q.

A person with a high I.Q. is about as likely to suffer from dysrationalia as a person with a low I.Q. In a 2008 study, Professor Stanovich and colleagues gave subjects the Linda problem and found that those with a high I.Q. were, if anything, more prone to the conjunction fallacy.

Sex Differences in IQ – Richard Lynn

Source: Psychological Comments, Sep 2016

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