causes of poverty, economics, poverty

The Causes of Poverty (73): Low IQ?

The brain, "the most complex human organ", and yet we think that 1 number based on a 100 or so short questions is a good measure of its ability

The brain, “the most complex human organ”, and yet we think that 1 number based on a 100 or so short questions is a good measure of its ability

This kind of reasoning is all too common: the poor are stupid and they are poor because they make stupid decisions. Unsurprisingly, it’s mostly the rich who indulge in this kind of pop-psychology, because if true it would also mean that they are wealthy because they are smart. They imagine a correlation somewhat like this:

income iq correlation

Had they cared to look up the actual data, they would have found that the rich don’t necessarily have higher IQ. There’s no correlation at all between wealth and IQ, not even a weak one:

iq and wealth correlation


And that’s not really surprising: a lot of high paying activities do not require high IQ (I’m looking at you, Sarah Palin). Conversely, it’s not uncommon for smart people to be poor.

So, if the wealthy aren’t making a living that is proportionate to their intelligence, then their wages are determined by other factors: specific skills if we want to be kind; networking, nepotism, degrees paid for by their parents if we want to be nasty. And the wages of the poor aren’t caused by their IQ either.

However, let’s just assume for a minute that the poor do indeed have lower IQ than average. Maybe all this would tell us is that the pressure and stress of poverty reduces our cognitive abilities. So, if there’s is an effect, the causation goes the other way: the poor aren’t poor because they are stupid; they are stupid – if they are indeed stupid – because they are poor.

dstupid2A more fundamental objection to the “poverty is caused by low IQ” narrative: IQ itself is a highly dubious notion. Children’s IQ scores are all over the places, changing almost overnight (up and down). Over longer periods of time, average IQ among populations rises (which is known as the Flynn effect). There is also no agreement on the heritability of IQ – the fluid nature of IQ results seems to argue against heritability. So intelligence is neither fixed nor obviously innate. Environmental factors – including education – change people’s IQ. Much has been made of the fact that African Americans score lower than European Americans on IQ test. However, when black or mixed-race children are raised in white rather than black homes, their test scores rise dramatically. And then I don’t even mention the cultural, gender or race biases inherent in a lot of the IQ test questions (for example, it’s clear that IQ tests are designed for very specific roles in a post-industrial advanced society).

Even more fundamentally: there is no one single and fixed quality or ability called “intelligence” that IQ tests could measure. What these tests do measure is one very particular type of intelligence. They don’t measure planning abilities, long term memory, creativity, emotional intelligence or any practical intelligence such as street smarts, and yet most of us would consider those abilities as essential parts of intelligence.

But again, let’s assume that the “poor = low IQ” claim is true, that the causation goes from low IQ to poverty and not vice versa, that IQ is a good measure of intelligence, that we have a good and objective definition of intelligence, and that the scientifically ascertained lack of innate intelligence among the poor is impervious to any social intervention such as education and redistribution. What would that imply? Inherited disadvantage is unfair and unjust. People should not suffer from inherited disadvantage. Even if the wealth of the rich and the poverty of the poor are the result of innate IQ, that would not lead to a conclusion favorable to the “poor = low IQ” crowd, because the conclusion would be that the poor need to be compensated.

More on poverty and IQ here. More posts in this series are here.


22 thoughts on “The Causes of Poverty (73): Low IQ?

  1. I thought lobotomy or growing up in wrong areas caused people to face poverty. I am in America and have seen poverty created by politicians whom I am compelled to say they have low IQ or they would make good judgments to ward off poverty….but they have failed dismally!

  2. bobbert says:

    wow, is this a competition to stuff as many half truths and popular misconceptions about IQ into a single post?

    have the humility to educate yourself on a subject before putting rubbish like this into the public domain. since your intellectual soth is pretty clear, i’ll start you off with a few facts and suggestions:

    1. IQ is fairly stable from the earrly teens onwards
    2. IQ tests seem rather colour blind. perhaps you’ll be surprised to learn that whites do not ave he highest average IQ
    3. Adoption studies have shown mixed results. think for a second about the case of GI children adduced in the observer article (sweet reference bro)
    4. explain the cultural/racial/gender bias in a raven’s matrix (you know what one of these is right?)
    5. no one has ever claimed that IQ is meaningful in every context

  3. realoldguy says:

    Real Americans will always come up with some ideological reason for kicking down the poor and brown-nosing anybody with wealth and power. It’s what we do here, it’s how we roll!

  4. crf says:

    You linked to a graph of “IQ and net worth” and compared it to an graph of what some people might imagine as the relation between “IQ and income”. But the web page you linked to containing the graph “IQ and net worth” actually has a graph on the relation between “IQ and income” (

    This graph “IQ and income” shows a positive correlation. Though not as strong as your graphed imaginary relationship, which many people probably believe, and which you seek to dispel.

    Your post could have been just a bit more honest. There is a correlation between IQ and income. It’s in the data. It just isn’t as super-strong a correlation as many people might imagine.

    • Yes, I saw that one coming. Ultimately, it’s wealth and not income that counts. You know that as well as I. Talk of income in this setting only serves to perpetuate the myth that I want to undo. If there’s dishonesty in this debate it’s by those who use income rather than wealth data.

      • hannesmalmberg says:

        No; the main source of wealth is the discounted value of your future labor income. Income is MUCH more important than wealth for the vast majority of people. Most people have a net worth below $100,000. This doesn’t support you for more than a few years without income.

        • This is true only for the lower end of the income distribution. For the wealthier the main source of wealth is NOT the discounted value of their future labor income but returns on investment, savings, capital gains etc. Wage income is less important. And don’t forget we’re comparing the rich to the poor here. It doesn’t matter how the “vast majority” make their living.

          • hannesmalmberg says:

            Define “wealthier” and “lower end of the income distribution”. We are talking about more than 90% of the working age population. Wealth is distributed very unevenly so only a few percent of working age Americans have so much capital that it can support them.

            Curiously enough, that group is not included in your graph. The x-axis stops at $230k, which corresponds to about $12000 in capital returns, well below the poverty line. No one can live off the wealth in your graph.

            The correct part of your entry is the last paragraph. Cognitive ability is very important for your opportunities in life; some of it is determined in childhood — a lot of it is inherited. Yes, this is unfair, so yes, that provides an argument for redistribution.

          • The issue is not whether people can or cannot support themselves on the basis of their wealth or lack of it. The issue is whether the amount of wealth or net worth they have – be it 0 or negative – is what they have on account of their IQ. Whether their *income* as well is linked to their IQ is less important since that’s a flow and not a stock, hence concerns about desert are less relevant.

            But even if income were what matters, the correlation is pretty weak as opposed to nonexistent. So my point would still stand.

          • hannesmalmberg says:

            Ok, my measured net worth is negative, as I have loads of student loans after a long education. I have reasonably high IQ as I have managed to finished a degree in Mathematics at a good university. My future income prospects look quite OK. Do you consider me rich or poor?

            I just want to convince you that your measure of rich vs. poor is fundamentally flawed.

            Your point does not stand. Even though the correlation is not that strong in income (do you have a figure..?), people with below $25,000 are very concentrated below 100 in IQ.

            Also, a people rich over a lifetime often go to college we would expect the correlation to be weaker in yearly income than in lifetime income.

            I have myself at great pains come to the realization that inherited IQ is an important determinant of lifetime successes. Not extremely important, but quite. The reason it took so long was that I bought bad arguments to support my preferred belief.

          • hannesmalmberg says:

            For an article dealing with the issue:


            They say that a good estimate of the effect of IQ directly, and indirectly through more schooling, is 0.266. This means that increasing your IQ with one standard deviation increases your income by 26%. This is not enough to explain most of the intergenerational inheritance of income, but a fair bit.

            Question to you: Why do you think these economists (having written a lot about inequality and intergenerational transfer of wealth) use income and not wealth?

            Is it because they’re fundamentally misguided, or is it you who are wrong?

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  8. I am having a hard time finding the early posts in this series. When I click on the link for more in the series, it only goes back as far as number 24. Yet, I have a direct link to number 9. It would be nice if you had a search mode on your blog and an archive listing by month and date (a drop down menu is helpful). I would like to read your whole series…in order.

      • YES! Thank you!

        I am starting a blog about living in poverty (which we are) and want to share articles and such about it. I also want to give those living with this a voice to safely share what they experience, how they are treated and how they really feel. There are things my family want to share about how we are made to feel that we cannot openly share because people would misunderstand. But we can share anonymously and, hopefully, open people’s eyes to the truth of what people are going through. I will definitely be putting that list on my Articles and Studies page.

        If you have any ideas as to how to get the word out so that it will show up on searches, I will gratefully appreciate hearing them. One of the things I want to share are ways to really help the poor, particularly the chronically poor. But people need to read about it in order to, again hopefully, actually DO some of them!

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