How many human problems are, at base, neuroscience problems? Well, since all human problems are rooted in some way in human nature, and since human nature is rooted in our brains, I suppose all of them are in one way or another. However, sometimes the direct link between our behavior and our neurological predilections is clearer than others…

Take, for instance, the current subprime mortgage crisis. As Jonah Lehrer discusses at The Frontal Cortex, part of the explanation for why people take out subprime mortgages (which offer low introductory interest rates that quickly shoot up) that they won’t be able to afford can be found in the brain.

Lehrer explains:

So why do people take out sub-prime loans? Don’t they realize that they won’t be able to afford the ensuing 28 years of mortgage payments? I think a big part of the reason sub-prime loans remain so seductive, even when the financial terms are so atrocious, is that they take advantage of a dangerous flaw built into our brain. This flaw is rooted in our emotional brain, which tends to overvalue immediate gains (like a new house) at the expense of future costs (high interest rates). Our feelings are thrilled by the prospect of a new home, but can’t really grapple with the long-term fiscal consequences of the decision. Our impulsivity encounters little resistance, and so we sign on the bottom line.

It turns out that recent research give us a crystal-clear picture of what’s going on and where it’s going on:

The best evidence for this idea comes from the lab of Jonathan Cohen. Cohen’s clever experiment went like this: he stuck people in an fMRI machine and made them decide between a small Amazon gift certificate that they could have right away, or a larger gift certificate that they’d receive in 2 to 4 weeks. Contrary to rational models of decision-making, the two options activated very different neural systems. When subjects contemplated gift certificates in the distant future, brain areas associated with rational planning (the Promethean circuits of the prefrontal cortex) were more active. These cortical regions urge us to be patient, to wait a few extra weeks for the bigger gift certificate.

On the other hand, when subjects started thinking about getting a gift certificate right away, brain areas associated with emotion — like the midbrain dopamine system and NAcc — were turned on. These are the cells that tell us to take out a mortgage we can’t afford, or run up credit card debt when we should be saving for retirement. They are our impulsive pleasure seekers, the hedonists inside our head.

By manipulating the amount of money on offer in each situation, Cohen and his collaborators could watch this neural tug of war unfold. They saw the fierce argument between reason and feeling, as our mind was pulled in contradictory directions. Our ultimate decision — to save for the future or to indulge in the present — was determined by whichever region showed greater activation. More emotions meant more impulsivity.

Therefore, we essentially know the neural root of common financial errors. Does this mean we could create a drug or treatment to curb such impulsiveness? Does this mean subprime loans need to be regulated more strictly to compensate for people’s lack of self control? Does it mean lenders are ruthlessly exploiting holes in our brains to trap us in debt?

The problem, of course, is that each of us presumably has a slightly different tug of war going on. Some people are good at listening to their rational side; some people give in quickly to impulse.

I’ll admit I don’t quite know what the implications are of knowledge like this. We learn more every day about how irrational human beings are, despite our firmly held belief that we’re in control of our own minds. It’s seems clear, though, that these developments will force us to reconsider our concept of free will. And that, in turn, is a major threat to our concept of individual freedom.