Trump’s cranial capacity looks small compared to Bernie Sander’s, causing me to doubt Trump’s IQ

In one of the most popular posts in the history of this blog, I estimated Trump’s IQ to be a very impressive 125 (which would make him smarter than 95% of white America).

But as Trump struggles to adapt, trailing Hillary by double digits in the latest polls, I’m now wondering if I overestimated him.

One reason I thought Trump was so smart is that he’s a BILLIONAIRE with a B, and although I always knew he had inherited part of his fortune and brand,  I had assumed he had built most of it.

However according to an article at Ezra Klein’s

An analysis suggests that Trump would’ve been a billionaire even if he’d never had a career in real estate, and had instead thrown his father’s inheritance into a index fund that tracked the market. His wealth, in other words, isn’t because of his brains. It’s because he’s a Trump….That’s not really impressive. Worse, it suggests that his success is almost entirely the result of having inherited money from his father. His own actions might have even cost him money.

But even if Trump inherited much of his wealth, he likely also inherited the high IQ genes needed to make that much wealth in the first place.  However even that claim is undermined by regression to the mean, and by the fact that his father Fred Trump, suffered from dementia late in life.

Although about 30% of whites probably have dementia by 85, and it’s really completely normal for those who are lucky enough to live that long, it does make me doubt even his father was anywhere near as bright as the average gazillionaire.  The reason is cognitive functioning is very stable from about age 10 to old age, so if you’re in the bottom 30% at 85, it’s unlikely you were ever in the top 15% when you were young, let alone the top 1%.  So if Trump’s father, who actually created the empire from nothing, was perhaps not above average, what reason is there to think Trump himself is?

General knowledge is one of the strongest proxies for IQ, and New York Times columnist Thomas Friedman recently said this to Charlie Rose about Trump:

Yeah. From everything I’ve heard him say, I would say he is the least prepared person to run for president in my lifetime, in this sense, Charlie. You can have any position you want on globalization. I have no problem with that…But just tell me you did your homework. Just tell me that you actually studied the issues, that you really understood them.

Friedman’s claim is buttressed by Trump’s poor performance on a terrorism pop quiz:

But what really makes me wonder if I overestimated Trump’s IQ was this incident on Howard Stern’s show where Trump and two of his kids couldn’t multiply 17 by six (in their head).  In a recent study, mental arithmetic has emerged as the best measure of general intelligence (g) on the Wechsler scales, so this caught my attention.

Trump incorrectly answered 112 but that is only off by 10.  At least he was in the right general range, so perhaps he deserves some credit. I decided to find out.

Study method

In order to convert Trump’s performance on this question to an IQ equivalent, I needed to ask a representative sample of North American whites, in roughly the same age range as Trump, the same question.  I spent part of my day hanging out at two McDonald’s locations, one Tim Horton’s, and a grocery store, casually approaching white strangers with grey or white hair, and saying:

“Excuse me, do you happen to know what 17 times six is.  Sorry to bother you, but I don’t have a calculator”

Everyone I approached was more than happy to help.


I was quickly able to acquire a sample of 16 adults of roughly Trump’s generation.  About 63% were found in a lower middle class part of town.  About 19% were found in a middle class part of town.  And the remaining 19% were found in an upper middle class part of town.  About 88% of my sample was male like Trump, and 12% was female.


Exactly 50% of the sample gave the correct answer of 102.  About 6% missed the correct answer but came closer than Trump.  19% performed the same as Trump, missing the correct answer by 10.  The remaining 25% performed worse than Trump, either giving up, or being off by a huge amount.

Assuming my sample was representative, we can conclude that Trump’s performance was at the 35th percentile of North American whites in Trump’s age group, which equates to an IQ of 94 (white norms) or about 96 (U.S. norms).


A true measure of Trump’s IQ can only come from an in-depth exam consisting of dozens of items, so of course it’s laughable to try to gauge Trump’s IQ from his answer to a single question.  Nonetheless, the results of my little study do suggest that I may have been way too generous when I estimated Trump’s IQ to be 125.

One reason for doubting Trump’s IQ was his ridiculous response to the Kahn parents, who lost their Muslim son fighting in the Iraq war, and thus criticised Trump’s Muslim ban.  Anyone with even an ounce of common sense knows you don’t insult the grieving parents of a war hero when you’re running for President of the United States, even if they’re Muslim and your base is Islamophobic.  Because his base is ALSO the military.

By doing so, Trump turned the situation around to his disadvantage big time! The opposite of intelligent behavior.  What would have been a one day news story got dragged into a one week news story, with Trump looking incredibly insensitive, bigoted and disrespectful to the family of a soldier who gave his life in an American war, and now Trump’s sinking in the polls and the Khans are emerging as the most admired Muslims since Muhammad.

Trump should have known that picking a fight with grieving military parents isn’t smart politically

Indeed since the earliest days of IQ testing, there’s been a subtest called Comprehension which asks if you know the appropriate response to social situations.  An easy item might be:

“What is the thing to do if while running for president, the grieving parents of a dead war hero criticise you?”

The correct answer, which even a child would know, would be “respond respectfully”.  Trump would have failed such an easy item.

Or perhaps he knows what to do, but he just can’t control himself?

If Trump could just avoid making these very basic errors, over and over again, and just stay on message, he would actually win, but he seems incapable of evading traps the Democrats set for him.  Of course Trump has also proved over and over again that he’s not one to be underestimated, so maybe he’s several chess moves ahead of me and he’ll make another comeback.

But even if Trump’s IQ really is only 94, that doesn’t mean you shouldn’t vote for him if you share his values.  Although IQ is a major predictor of job performance, and the presidency is an extremely complex and important job, I’d much rather have an unintelligent president who shares my values than a brilliant president who opposes them.  IQ is only as good as the goals it serves.

And unlike his supposedly brilliant opponent Hillary, Trump passed the most important IQ test of their generation.  He opposed the unbelievably disastrous 2003 Iraq war before it began, or at least was very weak in his support.