Not black and white

The use of intelligence tests to justify prejudice is one of the uglier patches on psychology's history. Steve Woods of Aston Business School discussed a meta-analysis he's conducted which tested the idea that average differences in IQ between black and white people are caused by shifting sociocultural factors, rather than a reflection of inherent differences between the groups (as some psychologists claim).

The combined results from 91 samples, involving over a million participants across four decades (the 1960s to the 1990s) conveyed a positive message, Woods said, as they showed that black - white differences in average IQ rose from the 1960s to the 70s but then dropped through the 90s.

An additional detail was that the meta-analysis distinguished between so-called 'selective' and 'non-selective' samples - an example of the former would be employees and the latter would be job applicants; or in an educational context, high-school versus university samples. Results here showed that the narrowing in average IQ differences between black and white people was speeding up for selective samples but slowing down for non-selective.

'The headline is that the difference between black and white test takers appears to be eroding over time,' Woods said. 'Importantly our findings change the question from "if" these differences between ethnic groups are due to cultural/ developmental factors to "how much?".'

--Christian Jarrett