Waiting for Flynn

[For updated estimates refer to: African National IQs, redux]
[For further discussion on African IQ, see: AfrIQ-Notes]

According to Wicherts et al. (2010), the average African IQ will markedly increase in the near-term due to the processes underlying the Flynn effect [1]. They show that there has been a steep score increase in the samples that they deem representative.

Is the African IQ really skyrocketing? Is the Congo student IQ really now around 120-something? Using Lynn’s IQ data bank, I plotted the increase in African IQs over time. There is disagreement about several of the sample scores. The graph on the left is based on a minimalistic exclusion criteria with judgement calls made by me. The graph on the right is based on a minimalistic exclusion criteria with judgement calls made by Wicherts et al. The rationale for using the complete data bank is that this presents a better picture of “the African IQ”; sampling bias at either ends (e.g., university students and tribal children) will cancel each other out. The overlap of the African Average calculated using the complete bank and the average derived from international assessments supports this contention. (Note: I used the un-weighted means, so the average IQs are slightly inflated in these graphs. The weighted means were 73.1 and 74.3 for the first and second graph, respectively.)

The regression lines show that the African IQs have been fairly constant across time relative to UK norms. If an accelerated Flynn effect was occurring in Africa, such that the African and Western averages were due to intercept in the near-term, we would expect a positive slope of a more than negligible magnitude. If the Flynn effect had yet to hit Africa, we would expect a negative slope, as the Western scores should have risen over time relative to the African scores. The mysterious Flynn effect seems to have occurred in African in tandem with the West. The massive African Flynn effect found by Wicherts et al. appears to have been a result of sampling bias.

For further confirmation of this, I plotted the international test score equivalents (calculated using equalization of the means) over time (K = 17). Were Wicherts et al. correct, see the figure at the top of the page, the African student scores should show an increase corresponding to their supposed IQ increase. They don’t. Rather, the African student scores show a decrease in tandem with increased enrollment and increased test sophistication.

[1] Wicherts, 2010. Raven’s test performance of sub-Saharan Africans: Average performance,
psychometric properties, and the Flynn Effect

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5 Responses to Waiting for Flynn

  1. KC says:

    Interesting. I remember Wicherts wrote in a 2004 paper that Flynn effect gains were qualitatively different to b-w differences in the US.

  2. Chuck says:

    Yes, Wicherts said that the Flynn effect gains were qualitatively different from the b-w differences in the US. He argued, elsewhere,that the African IQs would markedly rise due to the Flynn effect. His conclusion was that the African gap was wholly environmental; from this he reasoned that the African American gap was also wholly environmental. I dubbed this the “back door Flynn argument”; see point 15 (Reassessed international African Scores) in part 2 of my “race, genes, disparity” article. The above and other recent discussion of African IQ are just my attempt to fill out my counter-arguments.

  3. Meng Hu says:

    Some questions if you don’t mind.
    I finished reading this paper and I have a little doubt. Roberto Colom claims that “g” and “d” are strongly correlated. (d = generational changes) Ans this means that flynn effect occurs on g.

    But Rushton demonstrates (“The rise and fall of the Flynn Effect as a reason to expect a narrowing of the Black–White IQ gap”) that the contrary is true :

    “The relevant findings are: (1) the IQ gains on the WISC-R and WISC-III form a cluster, showing that the secular trend in overall scores is a reliable phenomenon; but (2) this cluster is independent of the cluster formed by Black–White differences, inbreeding depression scores (a purely genetic effect), and g factor loadings (a largely genetic effect).”

    • Chuck says:

      Colom suggests that the secular rise could represent a rise in “g”; this would imply that ‘g’ differences could be environmental.and, more specifically, cultural. It’s not clear, based on the paper, if the ‘d’ differences — in Spain — were in fact g differences. They didn’t use factor analysis to determine if strict measurement invariance held. Probably some of the secular rise in some countries represent rises in actual intelligence (‘g’). But clearly, it doesn’t in all countries. See, for example: http://www.iapsych.com/iqmr/fe/LinkedDocuments/Must2003.pdf
      (“The secular rise in IQs: In Estonia, the Flynn effect is not a Jensen effect”). Ultimately, one would need to do a meta analysis to see if the Flynn effect, on the whole, was a Jensen effect. Based on the literature available. it isn’t. When it comes to the Black-White gap in the US, based on the studies done (after Colom authored this paper), measurement invariance holds — which implies that the Black-White difference represent a g difference. It doesn’t for the Flynn effect in the US.

  4. Kiwiguy says:

    Hey, any new posts in the pipeline?

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