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.
However, the rich don’t necessarily have higher IQ. There’s no correlation at all between wealth and IQ, not even a weak one.
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.
A 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.