# Does intelligence correlate with any measurable physical attribute? **URL:** \ **Category:** Factual Questions\ **Created:** [June 16, 2013, 1:32pm UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120 "2013-06-16T13:32:55Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Nars\_Glinley](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nars_glinley/32/8177_2.png) [@Nars\_Glinley](https://boards.straightdope.com/u/Nars_Glinley)\ **Post date:** [June 16, 2013, 1:32pm UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/1 "2013-06-16T13:32:55Z")
Brain mass? Neuron density? (if that’s even a thing) Anything? ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [June 16, 2013, 1:44pm UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/2 "2013-06-16T13:44:05Z")
[http://news.yahoo.com/brains-connections-may-predict-intelligence-study-210612856.html](http://news.yahoo.com/brains-connections-may-predict-intelligence-study-210612856.html) How connected the lateral prefrontal cortex is to the rest of the brain plays a role, but I don’t know how big. ---
**Author:** ![Terr](https://avatars.discourse-cdn.com/v4/letter/t/839c29/32.png) [@Terr](https://boards.straightdope.com/u/Terr)\ **Post date:** [June 16, 2013, 1:52pm UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/3 "2013-06-16T13:52:16Z")
[http://www.mankindquarterly.org/spring\_summer2009\_karlsson.html](http://www.mankindquarterly.org/spring_summer2009_karlsson.html) Nearsighted persons excel in terms of intelligence, several studies in developed countries having indicated a gain of 7 IQ points over the general population. It also appears that visually normal heterozygous carriers of one myopia gene enjoy brain enhancement, probably of a somewhat lower degree than occurs in homozygous myopes. **It is concluded that the proposed myopia gene is primarily an intelligence factor.** ---
**Author:** ![si\_blakely](https://avatars.discourse-cdn.com/v4/letter/s/d9b06d/32.png) [@si\_blakely](https://boards.straightdope.com/u/si_blakely)\ **Post date:** [June 16, 2013, 2:23pm UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/4 "2013-06-16T14:23:18Z")
Probably not. Intelligence (in so far as it can be attributed to genetic factors) is due to a [combination of a number of genes](http://www.newscientist.com/article/mg21829204.600-finding-the-players-in-the-symphony-of-iq-genes.html#.Ub3ILJysM7U), and the effect is small. Of course, similar statements could be made about most other physical characteristics, like height, hair colour, eye colour etc. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [June 16, 2013, 2:54pm UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/5 "2013-06-16T14:54:22Z")
You know what they say, big feet … oh. Never mind. ---
**Author:** ![Jake](https://avatars.discourse-cdn.com/v4/letter/j/f475e1/32.png) [@Jake](https://boards.straightdope.com/u/Jake)\ **Post date:** [June 16, 2013, 2:55pm UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/6 "2013-06-16T14:55:24Z")
I’ve always thought that intelligence (or lack of) was the result of chemical balances in the brain. I guess that’s what I get for thinking… 😃 ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [June 16, 2013, 2:58pm UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/7 "2013-06-16T14:58:26Z")
Intelligence is highly associated with walking erect, relatively fine hair, opposable thumbs, certain configurations of the mouth, tongue and larynx, there must be many more. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [June 16, 2013, 4:02pm UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/8 "2013-06-16T16:02:25Z")
Baldness. ---
**Author:** ![D18](https://avatars.discourse-cdn.com/v4/letter/d/c57346/32.png) [@D18](https://boards.straightdope.com/u/D18)\ **Post date:** [June 16, 2013, 4:09pm UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/9 "2013-06-16T16:09:33Z")
[Height.](http://en.m.wikipedia.org/wiki/Height_and_intelligence) But Weakly. ---
**Author:** ![Washoe](https://avatars.discourse-cdn.com/v4/letter/w/ecae2f/32.png) [@Washoe](https://boards.straightdope.com/u/Washoe)\ **Post date:** [June 16, 2013, 8:40pm UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/10 "2013-06-16T20:40:52Z")
> [@si\_blakely](#): > > Probably not. Intelligence (in so far as it can be attributed to genetic factors) is due to a [combination of a number of genes](http://www.newscientist.com/article/mg21829204.600-finding-the-players-in-the-symphony-of-iq-genes.html#.Ub3ILJysM7U), and the effect is small. Of course, similar statements could be made about most other physical characteristics, like height, hair colour, eye colour etc. Thanks—I need to shove some idiot’s nose in this. BTW, I found free [full text](http://www.chabris.com/Rietveld2013-GWASEducation-Science.pdf) of the report. I doubt very much that the statement contained in the last sentence is true, though. I would venture to guess that environmental contributions to all of those phenotypes, and particularly eye color, is negligible. ---
**Author:** ![si\_blakely](https://avatars.discourse-cdn.com/v4/letter/s/d9b06d/32.png) [@si\_blakely](https://boards.straightdope.com/u/si_blakely)\ **Post date:** [June 16, 2013, 9:47pm UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/11 "2013-06-16T21:47:15Z")
> [@Washoe](#): > > I doubt very much that the statement contained in the last sentence is true, though. I would venture to guess that environmental contributions to all of those phenotypes, and particularly eye color, is negligible. On re-reading, my comment wasn’t quite clear - my point was that those characteristics (height, hair colour, eye colour) are not just the result of single genes, but are likely to involve a number of genes to produce the final result. I wasn’t implying that there was a similar ratio of environmental contribution in all those cases. [QUOTE=wikipedia] [Human Hair Color](http://en.wikipedia.org/wiki/Human_hair_color): The two-gene model does not account for all possible shades of brown, blond, or red (for example, platinum blond versus dark blond/light brown), nor does it explain why hair color sometimes darkens as a person ages. Several gene pairs control the light versus dark hair color in a cumulative effect. A person’s genotype for a multifactorial trait can interact with environment to produce varying phenotypes [/QUOTE] ---
**Author:** ![Desolation\_Island](https://avatars.discourse-cdn.com/v4/letter/d/9fc29f/32.png) [@Desolation\_Island](https://boards.straightdope.com/u/Desolation_Island)\ **Post date:** [June 17, 2013, 2:48am UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/12 "2013-06-17T02:48:49Z")
> [@Terr](#): > > [Mankind Quarterly](http://www.mankindquarterly.org/spring_summer2009_karlsson.html) > > Nearsighted persons excel in terms of intelligence, several studies in developed countries having indicated a gain of 7 IQ points over the general population. It also appears that visually normal heterozygous carriers of one myopia gene enjoy brain enhancement, probably of a somewhat lower degree than occurs in homozygous myopes. **It is concluded that the proposed myopia gene is primarily an intelligence factor.** People who read more tend to develop myopia. People who are smart tend to read a lot. [“How genetic is school myopia?” Progress in Retinal and Eye Research, Vol. 24 (2005):](http://w3.csmu.edu.tw/~pcl/handout/optometrynews/How%20genetic%20is%20school%20myopia.pdf) > [@](#): > > Myopia is of diverse aetiology. A small proportion of myopia is clearly familial, generally early in onset and of high level, with defined chromosomal localisations and in some cases, causal genetic mutations. However, **in economically developed societies, most myopia appears during childhood, particularly during the school years. The chromosomal localisations characterised so far for high familial myopia do not seem to be relevant to school myopia.** …There is in fact strong evidence for rapid, environmentally induced change in the prevalence of myopia, associated with increased education and urbanisation. ---
**Author:** ![candle67](https://avatars.discourse-cdn.com/v4/letter/c/a3d4f5/32.png) [@candle67](https://boards.straightdope.com/u/candle67)\ **Post date:** [June 17, 2013, 3:23am UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/13 "2013-06-17T03:23:48Z")
> [@Nars\_Glinley](#): > > Brain mass? Neuron density? (if that’s even a thing) Anything? I’d say the eyes. Smart people always seem to have a certain look in their eyes. ---
**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Post date:** [June 17, 2013, 3:33am UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/14 "2013-06-17T03:33:30Z")
I do know that with dogs, horses, racing piigeons etc. Many behavioral traits can be somewhat accurately predicted based on physical types and features. Good breeders have gotten very good at pickng out these subtle differences. ---
**Author:** ![zombywoof](https://avatars.discourse-cdn.com/v4/letter/z/9e8a1a/32.png) [@zombywoof](https://boards.straightdope.com/u/zombywoof)\ **Post date:** [June 17, 2013, 3:51am UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/15 "2013-06-17T03:51:42Z")
Weren’t there some studies that supposedly found the ratio of index finger length to ring finger length was correlated to intelligence (and other things)? ---
**Author:** ![Surreal](https://avatars.discourse-cdn.com/v4/letter/s/eada6e/32.png) [@Surreal](https://boards.straightdope.com/u/Surreal)\ **Post date:** [June 17, 2013, 4:10am UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/16 "2013-06-17T04:10:51Z")
Intelligence (as measured by IQ tests) is positively correlated with brain volume. ---
**Author:** ![tomndebb](https://avatars.discourse-cdn.com/v4/letter/t/b9e5f3/32.png) [@tomndebb](https://boards.straightdope.com/u/tomndebb)\ **Post date:** [June 17, 2013, 6:04am UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/17 "2013-06-17T06:04:18Z")
A number of people have attempted to link intelligence to [Reaction Time](http://en.wikipedia.org/wiki/Mental_chronometry). (Of course, this is one of several reasons why I tend to dismiss efforts to quantify intelligence: I test pretty well on “IQ” tests, but tend to fail miserably on tests of Reaction Times.) ---
**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\ **Post date:** [June 17, 2013, 6:47am UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/18 "2013-06-17T06:47:52Z")
I read somewhere that (contrary to many wishful stereotypes) it is fairly well correlated with physical attractiveness. I guess, then, that I must be dumber than I like to think. ☹ ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [June 18, 2013, 10:09pm UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/19 "2013-06-18T22:09:15Z")
This study (from 2010) from various universities working together found the g factor is based on both activity in certain regions, and the connections between them. The distributed neural system for general intelligence revealed by lesion mapping [http://www.pnas.org/content/early/2010/02/05/0910397107](http://www.pnas.org/content/early/2010/02/05/0910397107) [http://www.caltech.edu/content/caltech-neuroscientists-find-brain-system-behind-general-intelligence](http://www.caltech.edu/content/caltech-neuroscientists-find-brain-system-behind-general-intelligence) > **[Brain map reveals biology of intelligence](https://www.futurity.org/brain-map-reveals-biology-of-intelligence/)** > > The brain regions important for general intelligence are found in several specific places (orange regions \[…\] ---
**Author:** ![iamthewalrus\_3](https://avatars.discourse-cdn.com/v4/letter/i/258eb7/32.png) [@iamthewalrus\_3](https://boards.straightdope.com/u/iamthewalrus_3)\ **Post date:** [June 18, 2013, 10:52pm UTC](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120/20 "2013-06-18T22:52:05Z")
This is sort of a facile answer, but it is valid. Since some genetic disorders impact both intelligence and physical characteristics, on average I’d expect intelligence to be correlated with the lack of those physical markers. For example, pick any of the common physical markers that people with Down Syndrome have, and intelligence is probably inversely correlated with that. [Next page](https://boards.straightdope.com/t/does-intelligence-correlate-with-any-measurable-physical-attribute/661120.md?page=2)