Why are the rich rich and the poor poor?

Is it simply because the rich work harder and longer? Is it because they are more willing to take risks and make sacrifices, while the poor go to sleep after 10 am and spend their money on online games? Or to be more specific, is it because the rich value education and opportunities, while the poor come from generation after generation?

In the United States, income inequality has grown for nearly three decades, according to the BBC. And that gap reached a record-breaking percentage in 2012, with the top 1 percent of Americans owning 19.3 percent of all household income. For some policymakers and members of the public, this is a serious problem - and it cannot be rationally addressed without looking at both the individual and the institutional aspects of why the rich are richer and the poor poorer.

A new study by a behavioral economist at Harvard University and a cognitive psychologist at Princeton University may help shed light on this persistent conundrum. In their most recent book, Scarcity: Why Little Owning Means Much, Seidhir Murainadhan and Elda Shafir argue that it is not because the Moonlighters are poor financially, and make them often in a state of no money, but because they are in a state of no money, they are not good at managing money. This is a subtle but significant conceptual shift.

Drawing on data gathered from numerous tests and experiments, the authors argue that constant debating about which credit card to pay for first, or which jar of peanut butter to put in a shopping cart based on sales, can cause mental damage that's not just draining. One’s cognitive resources also diminish the importance of planning for tomorrow, because today’s demands are so great. In other words, when you're struggling to tread water, the ability to calculate which coastline is closest becomes a luxury.

"Let your computer run 16 programs at the same time, and everything will slow down," says Shafir. "It's too much to do at once."

The metaphor is enough. Let's look at the experimental evidence.

In one experiment, the authors asked participants to imagine that it would cost $300 to repair their car, which they could pay immediately, with a loan, or ignore entirely. The authors then asked participants to answer a series of computer-generated questions designed to measure their logical thinking, cognitive function, and problem-solving skills. All participants, rich and poor, displayed similar levels of intelligence.

However, when the authors increased the maintenance cost to $3,000 and repeated the experiment, the poor's intelligence level fell far behind the rich, and some people's IQ even dropped to 13, or the value they sleep at night.

On a field trip, Shafir and Mullainathan asked sugarcane farmers in India to take psychological tests before they were ready to harvest (when most had little money) and just after harvest (when most had a lot of temporary money). The results were unsurprising: After the harvest, the farmers fared much better in the tests.

According to their findings, the presence of scarcity seems to create a narrow vision in the human brain. While it helps people focus on urgent issues, it also obscures appointments, errands, and wishes that are currently on the back burner. In this way, a life of poverty often perpetuates a state of poverty.

"We use intellectual bandwidth to focus, make decisions, and resist temptation -- what psychologists call 'active memory'," says Shafir. "We've always known that when working memory increases, it impairs active memory. For example, when you have to memorize a seven-digit number, you can't remember as many other things as you need to do. Increasing intellectual bandwidth and overloading your working memory can cause you to make frequent mistakes in doing things.

Nor are the authors' research limited to the poor and their lack of money. In A Sense of Scarcity, Shafir and Murainadhan argue that this shrinking mindset can arise in anyone for a variety of reasons, whether it's a lack of time, food, or friendship. No one is immune.

"We're careful to point out that it's not about the poor — it's about people living in poor conditions," Shafir said. "Think about what it's like to be hungry. If you're hungry, that's what you're thinking at the time. You don't have to spend For a long time - as soon as you feel hungry, you get this idea."

While some critics insist that the two writers completely confuse cause and effect — that the poor are poor because they lack intelligence and perseverance, not the other way around — Shafir doesn’t think it’s that simple.

"In a sense, the most exciting part of our study is that whatever you think is causing people to be poor, all the factors that we consider have a clear relationship with the poor environment," Shafir said. Not with the people themselves. In the same environment, the poor perform just as well as the rich, and when exposed to deprivation, the poor perform suddenly worse, despite the same group of people.”

But the circumstances described by the two authors are different from stress — a certain amount of stress helps us get things done — all of which are obvious to those who live in chronic poverty or who have experienced a period of financial hardship. Being broke is tough. Not only does a lack of money limit what you can do, it now puts your very existence at risk, entangled in the most basic goods and services. Going back to the bandwidth analogy, it's like browsing the internet while your computer downloads files, never-ending. When you have no idea how to pay your delinquent utility bills, you can't stop yourself from thinking about it.

But judging by the polarized political landscape in the United States, common sense for some is not the same for everyone. In this regard, Shafir said he hopes the data will build an "empathy bridge" between opposing camps and perhaps give some policymakers in Washington an understanding of the plight of the poor. The authors offer practical solutions, such as automatically depositing wages into accounts and pill bottles. Anything that helps free up bandwidth can be done.

"The United States has the most unequal distribution of income of all developed countries, and that inequality is growing rapidly," former U.S. Secretary of Labor Robert Leahy said on the occasion of the release of the documentary "Inequality for All." For some it means prosperity, for the rest it means destruction. While Shafir and Murainadhan's study doesn't address every aspect of the widening gap, it confronts the complex question of why it is so difficult for the poor to escape poverty on their own.