点击显示 收起
Jan. 5, 2007 -- Attention, shoppers: A battle between pleasure and pain may be going on in your brain.
When people are deciding whether to buy something, their brain apparently weighs the pleasure of making the purchase against the pain of spending the money.
That's according to research published in the January issue of Neuron.
The researchers included psychologist Brian Knutson, PhD, of Stanford University; economist George Loewenstein, PhD, of Carnegie Mellon University; and Drazen Prelec, PhD, of the Massachusetts Institute of Technology's Sloan School of Management.
Their findings defy an economic theory that purchasing decisions are a trade-off between current pleasure (buying something now) and future pleasure (buying something else later), Loewenstein tells WebMD.
"We suspected that that's not the way the brain solves the problem of how much to spend," Loewenstein says.
Spend Now or Later
"Suppose you're trying to decide should you go out to a nice dinner tonight," Loewenstein explains. "Do you really know what it is you're going to be giving up in the future? No. You don't have a clue."
"And suppose you did know what it was going to be," Loewenstein continues.
"Suppose it was going to be some tiny fraction of your child's education or something like that 20 years from now. That just wouldn't be very motivating."
So he and his colleagues tested another theory: that purchasing is a mental tug-of-war between pleasure and pain.
In the experiment, the researchers gave 26 healthy young adults $20 to spend.
But instead of shopping online or at a mall, participants made their purchases in a lab while having their brains scanned with functional magnetic resonance imaging (fMRI).
During the brain scans, The researchers showed participants a picture of an item such as gourmet chocolates, books, DVDs, clothes, clocks, and cameras.
Within a second or two, the item's price -- scaled to fit the participants' $20 budget -- appeared below the picture.
The participants quickly clicked "yes" or "no" buttons to buy the item or not, spending a total of four seconds each on 80 items displayed one by one.
Each participant bought, on average, 23 of the 80 items in the experiment, giving their opinions on the products and prices right after they finished the test.
The brain scans showed what participants' brains were up to as they considered each item.
When they liked an item, a certain brain area called the nucleus accumbens was particularly active.
But if they thought items were overpriced, another brain area (the insula) became more active and a third brain area (the mesial prefrontal cortex) became less active.
"The findings are consistent with the hypothesis that the brain frames preference as a potential benefit and price as a potential cost," the researchers write.
That is, the brain apparently weighs how much it likes an item with how hard it will be on the wallet to buy it.
The brain scans were capable of predicting whether or not participants would buy an item, the researchers report.
The researchers speculate that credit cards, which delay payment, may dull the sense of financial pain.
Loewenstein says that in his other research, many people say it is hard for them to spend money, even when they can afford it and would benefit from the purchase.
Loewenstein's advice to shoppers: "Make some executive decisions about what you're going to spend money on and what you're not going to spend money on."
As long as you stick by those decisions, you can spend without conflict, Loewenstein says.
"I think the key task for consumers is to make these executive decisions and then not fret about how much you're spending" as long as your spending falls in line with your decisions.
You can always revise those decisions, but "you probably should be thinking about it carefully if you do," Loewenstein says.
"Are there shopping centers in the brain?" asks neurologist Alain Dagher, MD, in an editorial in the same issue. Dagher works in Canada at McGill University's Montreal Neurological Institute.
"Certain questions remain unanswered," Dagher writes, noting that "in real life, purchasing decisions are also the result of planning, reflection, and deliberation."
The pace of spending during the experiment may be much faster than how people shop in the real world.
Also, participants had no distractions in the lab. They didn't window shop, clip coupons, or have a cooling-off period before deciding whether to buy.
Still, Dagher says "human financial behavior is often seemingly irrational." The brain's pleasure and pain network may explain questionable spending choices, he says.