­Brain Pictures
­Brain Pictures

Americans like this young woman can't seem to get enough of shopping.  Is your brain to blame?

Jamie Grill/Iconica/Getty Images

If your jaw drops every month when your credit card bill arrives, as if you couldn't possibly have spent that much money and surely someone stole your card for a couple of hours and then snuck it back into your wallet without you noticing, you may not be that far off. Research published in January 2007 reveals that the brain chemistry of spenders and non-spenders, in the moments before a purchase, is so different that scientists are able to predict with pretty much complete certainty whether a person is going to buy an item or walk away from it. In essence, if you're a chronic spender, your brain is stealing your credit card and then sneaking it back in your wallet after buying a new 60" plasma TV.

Okay, so it's not exactly like that -- your brain chemistry is part of what makes you who you are. But the results of the study, published in the January 4 issue of the journal Neuron, imply that spenders have a chemical propensity to spend; and the thriftier among us experience chemical processes at the moment of potential purchase that make them far more likely to return an item to the shelf and leave the store empty handed. It's not a "get out of debt free" card, but it does help explain why some people can't seem to resist the urge to buy, while others seemingly wouldn't spend the money if their life depended on it.

­ Most of us like to believe that we make rational, conscious decisions about what we're going to purchase (the author actually has too many pairs of boots to maintain this belief, but let's call her the exception), and that these decisions are based on a combination of desire for the product and consideration of its cost. What a group of economists from Carnegie Mellon and psychologists from Stanford discovered is that desire and cost are indeed prominent factors in purchasing decisions, but that these decisions aren't necessarily all that rational or conscious. They appear to be first unconscious and emotional.

On the next page, we'll see how scientists can predict a person's shopping habits.