We tend to think of people's IQs as fixed, and indeed science shows your general mental horsepower is pretty fixed over time. But you can drive that engine at its maximum speed or you can let it sputter along in disrepair.

We can abuse our bodies and brains into performing at less than their best, including one major influence on intelligence that often goes overlooked. How broke you are and how broke you expect to be in the future has a giant effect on your IQ.

How to lower your IQ by 13 points

As entrepreneur turned 2020 presidential hopeful Andrew Yang points out in a short but fascinating recent Big Think video, studies show not being able to pay your bills is horrible for your cognitive performance. Whether scientists measured the IQ of the same farmers in the stressful pre-harvest period or after their crops went to market or just asked volunteers to imagine they had a bill they couldn't pay, being insecure about your finances had a dramatic effect on IQ -- a 13 point reduction to be exact.

"There's a mindset of scarcity that's associated with when you don't have enough money, or your don't have enough time, or you don't have enough food, or you don't have enough companionship and it actually decreases your functional bandwidth," Yang explains.

"It's different than stress. It makes you less reasonable, less rational, less generous, and more subject to bad ideas and bad impulses."

Being a politician, Yang's solution to the problems of the scarcity mindset are political. "78 percent of Americans are living paycheck to paycheck. 57 percent can't afford an unexpected $500 bill, so if there's a sense the United States is getting less reasonable, less rational... It's related to the fact that a mindset of scarcity has swept this country," he notes before arguing a universal basic income is the solution.

How to raise your IQ by 13 points

But you don't have to wait for politicians to get it together to come up with bold economic policies to alleviate Americans' financial insecurity (though agitating and voting for change would definitely speed things along).

As Yang explains the opposite of the scarcity mindset is the abundance mindset common among entrepreneurs. It involves optimism that the future can be improved and a belief that good outcomes are possible and hard work will be rewarded. You can legislate to encourage this mindset, but in the meantime experts insist it's also possible for individuals to cultivate it.

From Tony Robbins to Deepak Chopra to my Inc.com colleague Angela Zimmerman, various gurus insist that by practicing gratitude, focusing on learning, embracing generosity, and taking responsibility for your life you can shift your mindset away from scarcity and towards abundance, creating a virtuous cycle of opportunity leading to achievement leading to greater opportunity.

A change in attitude isn't enough for everyone certainly. If you're mired in poverty and struggling to access housing, healthcare, education, and other basic building blocks of prosperity saying positivity will solve all your woes is stupid and cruel. Yang is right that America has collective problems that need collective solutions.