Scholar Howard Gardner once proposed that there’s not one, but seven different intelligences (which is silly because we have only one brain).

Charles Murray described the enormous range of these seven abilities in his book Real Education:

Bodily-Kinesthetic: from someone who trips over his feet to Fred Astaire

Musical: from tone-deaf to Mozart

Spatial: from someone who gets lost two blocks from home to Daniel Boone

Linguistic: from unable to form sentences to Shakespeare

Logical mathematical: from unable to understand cause and effect to Aristotle

Interpersonal: from autism to Bill Clinton

Intrapersonal: from an undisciplined narcissist to Confucious.

I don’t agree that an undisciplined narcissist lacks intrapersonal intelligence, but more on that later.
Gardner also selected seven famous persons to personify each of his seven intelligences:

Linguistic (T.S. Eliot)
Logical-Mathematical (Einstein)
Spatial (Picasso)
Musical (Stravinsky)
Body-Kinesthetic (Martha Graham)
Intrapersonal (Sigmund Freud)
Interpersonal (Mahatma Gandhi)

Arthur Jensen once asked Gardner to estimate the lowest IQ one could possibly have and be included in a list of names such as this and he replied, “About 120.” On page 260 of the book The g Factor, Jensen writes:

Gardener has stated that the manifestation of one of his multiple “intelligences” at a level of scientific, artistic, or social significance such as illustrated by his list of famous exemplars depend on a threshold IQ of at least 120. This minimum IQ cutoff of 120, of course, excludes the 90 percent of the population who are below this level. (Many psychologists would probably set the threshold at IQ 130 or more, thus excluding 98 percent of the population.) It is noteworthy that so-called idiot savants who manifest one of the multiple “intelligences” despite having a very low IQ are never considered as outstanding mathematicians, musicians, artists or dancers; and exceedingly few, if any, are able to earn a living by their special talent. An average or above average level of g seems an essential condition for the intellectually or artistically significant expression of any special talent in the cognitive domain.

But does one really need an IQ of at least 120-130 to achieve extreme eminence in one of Gardener’s seven domains? Given that Gardener’s list reflects the best (mostly white) achievers of the 20th century in each domain, and given that roughly 1.22 billion whites have lived sometime in the 20th century, we can say that all of Gardener’s Geniuses are six standard deviations (SD) above the mean of a normalized white distribution in their particular domain. However some domains correlate more with g (general intelligence) than others.

Outstanding math achievement

Perhaps the most g loaded domain is “mathematical intelligence”. The best measure of raw fluid mathematical talent is probably the Figure Weights subtest on the WAIS-IV which has a g loading of 0.78.   However great achievement requires more than just raw talent. It also helps to have 10,000 hours of practice, among other things. Raw talent seems to explain 66%  to 70% of the variance in various cognitive performance, suggesting talent correlates 0.82 with performance.  If we assume that the correlation between g and math performance is caused simply by their shared correlation with math talent, then the correlation between g and math performance is simply the product of these two correlations: 0.78*0.82=0.64.

So if the greatest math achiever of the 20th century is +6 SD above the white mean in math achievement, he should be 6(0.64) = 3.84 SD above the white mean in IQ. Since IQ is scaled to have a mean of 100 and an SD of 15 in the white population, that equates to 158. With a correlation of 0.64, the standard error around the estimate would be 11.53, so we can say with 95% certainty that the greatest math achiever of the 20th century would have an IQ of 135 to 181. I suspect Einstein would be a lot closer to 135 than 181 given the small brain he had at autopsy.

There are also reports that Richard Feyman had an IQ of 125 but this might be because he was tested in childhood (many genes for IQ might not get expressed until puberty) and the test may have had a low ceiling, particularly in the areas where he excelled.

Outstanding linguistic achievement

But not every field requires a near genius IQ of 135+ to be a Genius. Let’s take “linguistic intelligence”, exemplified by T.S. Eliot. According to a study reported in the WAIS-IV technical manual, the written expression subtest of the WIAT-II correlates 0.6 with WAIS-IV Full-Scale IQ. 0.6 multiplied by the 0.82 correlation between talent and performance suggests a 0.49 correlation between IQ and writing achievement.

Thus, assuming TS Eliot is 6 SD above the white mean in linguistic achievement, he would likely have an IQ that is 6(0.49) = 2.94 SD above the white mean (IQ 144). We would expect, with 95% certainty that his IQ is anywhere from 118-170. So writing is a field where Genius level achievement seems to require a minimum IQ of about 120 although there are always freak exceptions. JD Salinger reportedly tested at 104.

Using the Jonathan Wai method on the 20 most recent white national book award winners for fiction, I found that 40% of them have IQs of 134+, suggesting an average IQ of about 130. Of course winning the national book award does not necessarily make one a literary Genius.

Outstanding musical achievement

In the book Real Education (pg 28), Charles Murray writes “Several studies of musical ability and g have been done, and they find a correlation of about +.3.” However in his book Race Differences in Intelligence, Richard Lynn writes:

The association between intelligence and musical ability has been shown in two studies carried out by Lynn, Wilson, and Gault (1986). In the first, a sample of 217 10-year-olds were given a number of tests of reasoning, vocabulary, visualization, and perceptual speed abilities together with four musical ability tests (pitch, memory, chords, and rhythm). All the tests were positively intercorrelated and loaded on the first principal component as a measure of general intelligence (g). The loadings of the four musical tests lay between 0.45 (cords) and 0.59 (rhythm). This shows that the musical tests are measures of g. In the second study 93 9-11-year-olds were given three tests of musical ability (pitch change, chord analysis, and memory) together with the Standard Progressive Matrices, a measure of g. The three musical tests were significantly correlated with the Progressive Matrices at 0.27, 0.40, and 0.37. This
confirms that musical ability is associated with intelligence. Further evidence for this association has been provided by Carroll (1993).

I think it’s likely that a composite score on a wide battery of musical tests would correlate about as well with IQ as the most g loaded musical abilities (i.e. rhythm 0.59) which is similar to the 0.6 correlating between writing talent and IQ. Once the correlation is reduced (by multiplying by 0.82, see above) for the non-talent aspects of musical achievement (i.e. practice), I would expect musical Genius achievement to require the same amount of IQ as literary Genius achievement.

Outstanding intrapersonal and interpersonal achievements

In the book Real Education (pg 28), Charles Murray argues there’s a moderate positive correlation between IQ and intrapersonal and interpersonal intelligence. Unfortunately he makes his case by citing studies showing a positive correlation between IQ and various personality traits such as leadership (+0.27), conscientiousness (+0.28), and extroversion (+0.31). Although I respect Murray’s work quite a bit, it’s very irritating how even the most learned experts in the field keep conflating personality traits with abilities. As commenter “Jorge Videla” noted:

indeed. the fictional character House, M.D. had very high social cognitive ability, but at the same time was a jerk, a cynic, selfish, etc.
in fact, i think this may be the usual outcome. in the case of dealing with people, one can be too smart. that is, if he sees people as they really are, he becomes a misanthrope and a cynic.
and it’s been my observation countless times that the “popular people” are not especially clued in to the motivations and “frame” of other people. they’re just the one’s for whom being liked is most important and at the same time have no gross defects like ugliness or poverty.
the first question for the socially intelligent isn’t, “is what this guy’s saying true?” it’s, “why does he care about this at all? why is he saying anything at all?”

Another example of a fictional character with an extremely high social IQ, but a completely dysfunctional personality is Hannibal Lecter

However Murray, to his credit, cited autism as an example of extremely low interpersonal intelligence. And it’s important to note that the reason autistics lack social intelligence is not because of dysfunctional personalities (since personality is NOT a cognitive ability) but because they lack Theory of Mind (which is a cognitive ability). Theory of Mind seems to correlate about 0.43 with (verbal) IQ. Reducing this correlation (multiplying by 0.82) for the non-ability aspects of achievement (i.e practice) puts it at 0.35.

Thus we’d expect someone who is 6 SD above the white mean in interpersonal achievements to be 6(0.35) = 2.1 SD above the white mean in IQ (IQ 132) with 95% falling between 104 and 160. Thus one needs to be only slightly above average (IQ 104) to be a Genius in the interpersonal range (though being brilliant helps), and possibly also in the intrapersonal range since (as a commenter pointed out) self-awareness is sometimes described in the academic literature as Theory of Mind directed at one’s own mind. “First-order Theory of Mind”, I believe, is the technical term.

The relatively low correlation between “social intelligence” and IQ can be seen from the fact that many autistic people are extremely intelligent, with some even winning Nobel prizes in fields like literature and economics and there is constant speculation that some of the greatest minds in the history of science and Silicon Valley were/are autistic. Conversely, some mentally retarded people seem to function quite well socially. On page 28 of the 1962 book Know Your Own IQ, H.J. Eysenk writes:

The case is recorded of at least one mental defective with an I.Q. of just under 70 who was released from an institution on the application of his wife and who became a successful salesman owning a large house in town, a villa at the seaside, several cars, with all his children away at the university.

Outstanding spatial achievements

The type of spatial reasoning tasks on an IQ test are probably quite g loaded, however the type of spatial talent for which folks like Picasso are considered Geniuses probably are not. The Draw a Person IQ test only correlates about 0.5 with more accepted IQ tests, and although it’s not designed to measure artistic skill, but rather accurate knowledge of the human form, a good artist is an accurate artist.

Multiplying by 0.82 to reduce this correlation for the non-ability aspects of achievement (i.e practice) puts it at 0.41, and so a recognized Genius in the visual arts who is +6 SD above the white mean in artistic achievements, should have an IQ of 0.41(6 SD) = 2.46 SD above the white mean, or roughly IQ 137, with a 95% chance of falling anywhere from 110 to 164. Thus one needs to be only somewhat above average (IQ 110+) to be a Genius in the visual arts, though being a brilliant as always, increases the odds.

Outstanding Bodily-Kinesthetic achievements

Of all of Gardner’s seven intelligences, the one that least belongs is bodily-kinesthetics ability. Since physical coordination is controlled by the brain, Gardner feels justified in labeling it an intelligence, however just because something is controlled by the brain does not mean it’s controlled by the mind, which is the higher part of the brain that came later in evolution. Only the abilities of the mind are mental abilities.

Nonetheless, since the mind is part of the brain and since the brain controls the body, there is about a 0.35 correlation between IQ and physical coordination according to technical studies by the U.S. Department of Labor. Multiplying by 0.82 to reduce this correlation for the non-ability aspects of achievement (i.e practice) puts it at 0.29 and so a recognized physical Genius who is +6 SD above the white mean in bodily-kinesthetic achievement, should have an IQ of 0.29(6 SD) = 1.74 SD above the white mean, or roughly IQ 126, with a 95% chance of falling anywhere from 97 to 155.

And since most “Geniuses” in the bodily-kinestheic domain are black, and blacks tend to score 15 points lower than whites in Western countries, we might reduce the likely IQ range of bodily-kinesthetic Genius by 15 points to 82 to 140. The range might be lower in fields like boxing which require, in addition to physical coordination, extremely high weight/height ratio, violent behavior, and self-danger (three variables negative correlated with IQ). The fact that at least two boxing Geniuses reportedly had IQs in the borderline retarded range (though the validity of the testing was questionable) indicates this is a field with minimal IQ requirements (assuming one has other traits).

Conclusion

The assertion that one needs an IQ of 120, or possibly 130, to be a Genius in any of Gardner’s seven domains is mostly false. Although some of his domains require a vaguely minimum IQ of 135 (logical mathematical) or 118 (lingustic (writing) and musical), the spatial (visual arts) seems to require only 110, and inter-personal and intra-personal require only 104, with body-kinesthetic requiring only about 82.

This demonstrates that even people like Howard Gardner, who have devoted their lives to undermining the importance of IQ, greatly overestimate the importance of IQ. I wonder what intrapersonal Genius Freud would say. Of course, I of all people think IQ is hugely important, but given that the average IQ of Northwestern Europeans is 100, and the average IQ of the entire World is about 90, it’s absurd to think greatness is the exclusive property of the 120+ IQ.