If you are absolutely determined to contain your spending this Christmas, start your next shopping trip by buying yourself a nice little treat. This is the first lesson of the physics of shopping.
Make the mistake of having your first purchase of the day be something dull and boring, much as you might need it, and you are asking for trouble. This is the moment the gravitational field takes hold.
Next thing you know, your wallet is empty, your credit cards are full, you're hauling home a bulging shopping bag and you're asking yourself, "What was I thinking?"
You don't have to blame yourself. Perhaps buying more than you want or can afford is more force of nature than weakness of character. You may be just one more victim of "the shopping momentum effect," according to an about-to-be-released study by researchers from Yale and Duke universities.
It works like this: Once you decide to buy that first utilitarian item and put it in your cart, you have matter, it is moving, and it is taking you for a ride. Force equals mass times acceleration, and what you have is an unstoppable force.
Ravi Dhar, co-director of the Center for Customer Insights at the Yale School of Management, began noticing the phenomenon a couple of years ago. Turning to Amazon.com for a book he needed, he would quickly find himself checking out with a shopping cart stacked with books he hadn't planned to buy.
He mentioned this behavior to Joel Huber, who was giving a talk at Yale. Huber, a professor at Duke's business school who specializes in modeling consumer choice, realized he did the same thing. They decided to find out why.
Dhar says a shopper looking for something utilitarian, such as an umbrella, sets off quite rationally, considering price and value. But as soon as he decides to buy it, something happens. He shifts gears, lurching into buying mode.
"It's a change in mindset," Dhar says. "You go from carefully weighing pros and cons to buying. You don't stop to think. You get into a frenzied mindset. You start looking for things to buy."
That utilitarian purchase, he says, apparently gives you the justification to do something fun. "Essentials drive momentum," he says.
