The controversial study on African IQ levels conducted by psychologist Richard Lynn is deeply flawed. This conclusion is the outcome of studies by Jelte Wicherts, Conor Dolan, Denny Borsboom and Han van der Maas of the University of Amsterdam (UvA) and Jerry Carlson of the University of California (Riverside).

Their findings are set to be published in Intelligence, Personality and Individual Differences, and Learning and Individual Differences.

In an oft-quoted literature study conducted in 2006, Lynn concluded that black Africans have an average IQ of less than 70 (compared to an average western IQ of 100). Lynn suggested that these low IQs are indicative of a low intelligence level, claiming this offered an explanation for the low level of economic development in sub-Saharan countries.

Lynn's study is well known among psychologists, and has been referenced by academics such as Nobel laureate James Watson, and the authors of the controversial book The Bell Curve -- Intelligence and Class Structure in America (Richard Herrnstein and Charles Murray: Freepress, 1994).

African IQ scores prove flawed

Wicherts and his colleagues examined over 100 published studies, concluding that there is no evidence to back up Lynn's claims. Amongst other flaws, Lynn used selective data by systematically ignoring Africans with high IQ scores. The researchers also claim that African IQ test scores cannot be interpreted in terms of lower intelligence levels, as these scores have different psychometric characteristics than western IQ test scores. Until now, the incomparability of Western and African IQ scores had never been systematically proven.

The scientists point out that the average African IQ is currently comparable to the average level in the Netherlands around 1950. However, IQ scores in Western countries have risen sharply over the course of the 20th century. In view of this trend, Wicherts and his colleagues claim there are no reasonable grounds to conclude that sub-Saharan countries are poor due to the lower IQ scores of their populations. As it turns out, the average IQ of African adults is seeing a similar rising trend, which is expected to continue if living conditions in Africa improve in future.