The end is nigh…for the Flynn Effect

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Of course, you knew this, but now so do others.

TangoMan Adds: See the related post – Intelligence in UK declining?


  1. Perhaps they scandinavian researches should’ve taken into account significant rise in third world immigration.

  2. haf, 
    I added the related post in anticipation of your hypothesis.

  3. basic algebra seems a problem for many GNXP readers :( or at least the instinct to go back-of-the-envelope. definitely no flynn effect here….

  4. Jelte Wicherts and I both had American data that showed little-to-no gains in the US, although his research was much more comprehensive as he used the WJ norming samples. I am in the midst of resubmitting my article/data, and I imagine Jelte is as well.

  5. Although the apparent demise of the Flynn effect is bad for the world, it is a relief to me, as every attempt at logical explanation for it fails. In reality humans should be getting dumber; the birth rate is higher and the generation size is smaller at the low end of the curve. If there is a hereditable component to intelligence – even a non-genetic one – the differential birth rates and generation sizes should result in a lowering of the mean.

  6. The Flynn effect couldn’t have been related to changes in abortion practices, could it? But then I don’t see why it would stop.

  7. Hi – I’ve been trolling this site for the last few days. This discussion reminded me of a Doonesbury cartoon from a few months back as well as study by Philip Longman. Enjoy! 

  8. I stumbled across this ‘analysis’ of the Flynn effect by John Horgan, a former senior science writer at Scientific American, and thought that some here might find it amusing: 

  9. I thought it was well established that the Flynn Effect worked on the left side of the distribution only. Is this being ignored or did I miss it? 
    There is a well known correllation between height and IQ but it is also well known that this phenomenon is a product of confounding two populations: the “normal” and the defective. Those who have no genetic diseases or have not had a severe envioronment that stunted them, have no correllation between height and IQ. Those with bad genes/aneuploidy or a midieval peasant upbringing will likely be short and stupid. 
    I have long assumed that the elimination of these factors was what was powering the Flynn Effect. Obviously this sort of reform can’t go on endlessly. The irony is that the as these problems are cleared up the phenotype comes to ever more closely express the genotype. This is sometimes called the Hernstein Effect I believe.

  10. I realize that General Social Survey vocabulary data is not the best way to measure IQ, but my analysis shows a recent increase in the U.S., especially for blacks:

  11. it is also well known that this phenomenon is a product of confounding two populations 
    I’m sure including the residual population with pathologies would strengthen the correlation, but I believe the effect remains even when they are eliminated. See here for example (top hit if you google for ‘correlation between height and IQ’).

  12. If you buy the heritability of intelligence at all, you have to guess that the Flynn effect represents the sum of at least two different forces: Dysgenic forces pushing the average scores down by X, and some other set of forces pushing the average scores up by Y, where Y>X. The end of the Flynn effect might just be those dysgenic forces overpowering the other forces–the pool at the bottom has expanded so that X>Y, say.