What Is the Correlation Between Head Size and IQ?

Mike Barnes writes:

For example, ~90% of the variation in human head shapes occurs within continental groups, and ~10% separates groups, with a greater variability of head shape among individuals with recent African ancestors ”

Note that the largest and the smallest Homo Sapiens brains would be found within Africa.

However brain size has a low correlation with intelligence (within humans) and this area of science is now largely discredited.

It is certainly interesting that the largest variation in head size is found among Africans, however, I am not certain that the largest and smallest Homo brains are found in Africa.

This is just wrong. The correlation between brain size and IQ is robust at ~.42. The research is not discredited at all, in fact, it is robust and ongoing. However, the correlation is not perfect. Eskimos have the largest heads of all, but their IQ’s are only 94*. Ugandans have heads bigger than Italians, but their IQ’s may be quite low; certainly they are lower than Italian IQ’s. Vietnamese have some of the smallest brains of all, but their IQ’s are quite high at 102.5*

*Setting US IQ at 100, which kicks US White IQ up to 103.

4 Comments

Filed under Intelligence, Psychology, Race/Ethnicity

4 Responses to What Is the Correlation Between Head Size and IQ?

  1. Mike Barnes

    The correlation between brain size and IQ is weak / moderate.

    You are correct the second statement is wrong – I meant brain size not head size! Thanks for pointing that out.

    The variation in head size may reflect greater African genetic diversity. However as I intended to state there is very weak correlation between head size and IQ .015 so this is a bit of speculation on my part.

  2. Mike Barnes

    head size not brain size! – clearly mine is not working

  3. Car Guy

    Robert,

    No way the Vietnamese have the smallest heads. Their heads look as big as their Cantonese counterparts.

    What study are you referring to?

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