Ingrid Schoon (University of London) and her colleagues have just published a remarkable paper looking at the relationship between intelligence and social and political attitudes. The sample of their study was a huge (8804 individuals!) representative sample of the British population born in 1958. Each individual’s family socio-economic background and intelligence (g) was measured at age 11. Social attitudes and educational and occupational attainment (qualifications and occupational status) were then measured for each of these individuals 22 years later at age 33. Interestingly, they found a direct association between higher g at 11 and more liberal social attitudes and political trust at age 33. (Having a more ‘liberal social attitude’ means being more anti-racist, socially liberal (tolerant, with and in support of gender equality. Having more ‘political trust’ means having more trust in the country’s liberal democratic political system.) As far as socio-economic status goes, individuals from more privileged backgrounds showed more political trust, but did not differ in liberal social attitudes from those who came from less privileged backgrounds.
Structural equation model linking general cognitive ability at age 11 to social attitudes at age 33.
Strength of relationship (-1 to +1) for men (n = 4267) are shown on the left and for women (n = 4537) on the right.
This study’s results are consistent with other research showing that higher intelligence tends to be positively correlated with liberalism and negatively correlated with conservatism. A higher intelligence is also associated with the endorsement of alternatives (such as the Liberal ar Green party) to the two main political parties in the UK (Deary et al., 2008).
Schoon, I., Chenga, H., Gale, C.R., Batty, D. & Deary, I. J. (in press). Social status, cognitive ability, and educational attainment as predictors of liberal social attitudes and political trust. Intelligence.
The technique used in this study is ’structural equation modeling’. It is a ‘model driven’ (rather than exploratory or descriptive) approach, and it is ’causal’ rather than ‘correlational’ in its emphasis. It is a way of causally modeling the relationships between variables like g and liberal attitudes; it does not simply give you correlations which are difficult to interpret in terms of the underlying ‘causal arrows’. These causal links between g and liberal social attitudes and political trust are significant and meaningful but how strong are they? How are we to interpret the ‘path coefficient’ values in this diagram? Well, if there is a path coefficient of 0.20 between g (at age 11) and degree of liberal attitudes at age 33, this means that if g increases by 1 standard deviation from its mean (e.g. around 15 points on a typical IQ test, from 100 to 115), then the ‘liberal social attitude’ measure would be expected to increase by 1/5 of a standard deviation from its own mean (the assumed population mean for ‘liberal social attitudes’) – holding all the other coefficients in the model constant. If liberal social attitudes were measured like a psychometric IQ test, an IQ level of 115 in the population of 11 year olds, would predict (i.e. be causally instrumental in) a liberal attitude score of 103 in the population at 33 years of age – 3 points above the population mean for liberalism.
So as far as I can see these causal links are not that strong! Nothing like the relationship between IQ and educational attainment (in qualifications) for instance – with a path coefficient of around 0.5. There are many other factors that have an impact on liberal social attitudes other than IQ level. But it DOES have a causal role. IQ does tend to make people more liberal (and to a lesser extent less prone to conspiracy theories or cynicism about the political system).