Saturday, April 10, 2010

Racial differences in digit ratio

John Manning and colleagues have used the ratio of the length of the index to the ring finger (2D:4D) as a proxy measure of in utero exposure to relatively more estrogen and less testosterone. In other words, a long index finger compared to the ring finger is an indicator of "feminization" in the womb, and a comparatively short index is a sign of "masculinization."

 It turns out that there are large ethnic differences in the 2D:4D ratio. Manning is quoted as saying that, "There’s more difference between a Pole and a Finn than a man and a woman." According to the results of one study, "The Oriental Han had the highest mean 2D:4D, followed by the Caucasian Berbers and Uygurs, with the lowest mean ratios found in the Afro-Caribbean Jamaicans." In plainer language, Hans were the most feminized and Jamaicans the most masculine. You can read about a long list of characteristics associated with digit ratio here.

You gotta love citing studies that have Robert Trivers as a co-author.


  1. Anonymous2:50 PM


    My southern Han wife seems to have a highly masculine 2D:4D ratio ... she is feminine in all other ways ...

  2. Anonymous10:00 PM

    I thought Manning said something a bit different in his book.

    Though not especially motivated to study race – and thus apparently never having read any London School work – the empirical studies which he has found or organized have yielded a clear and interesting picture, bringing together Blacks and East Asians (Zulus, Jamaicans, Chinese and Japanese) as high-RFL and distinguishing them from the typically low-RFL Europeans (Polish, Spanish, English and Hungarian – with Germans and Gypsies scoring a little higher, intermediate with Chinese levels). For just what this means (if it replicates), Manning’s readers are left to refer to the book’s earlier claims. But the finding of a marked and allegedly important similarity between Blacks and East Asians will amaze many – and not just Rushton and Lynn. This is particularly because, having started his book by tending to play up the advantages of early testosterone (good for the heart, supposedly),


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