Weird! You may have heard the theory of shopping for groceries with a basket, rather than a full-size shopping cart, as a trick to limit spending, especially on impulse purchases. Logically, this makes sense: With less space to carry groceries, there’d seem to be less chance for making bad decisions. But a new study shows that shoppers gathering groceries in baskets are more likely to make unhealthy, wasteful purchases.
Why might this be? The research of a group of European professors indicates that, oddly enough, the answer has something to do with how the basket shopper must flex his or her arm carrying the groceries. According to the study, in the Journal of Marketing Research:
We demonstrate that arm flexor contraction makes individuals more likely to choose immediately pleasing options.
That’s another way of saying “instant gratification.” The tension and strain on the arm (and presumably, back and shoulders as well) makes shoppers more likely to pick up “vice products” such as candy and soda, apparently as some sort of unconscious counterbalance to the hassles of carrying a shopping basket. When pushing a shopping cart on wheels, there is no “arm flexor contraction” necessary.
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The researchers make their case through a number of studies. In the first, they simply followed around random shoppers in a supermarket, noting who was shopping with a cart, who had a basket, and what they brought to the register. What the data indicated is that:
The odds of purchasing vice products at the cashier for a basket shopper is 6.84 times the odds of purchasing vices for a cart shopper, all other things being equal.
Wow. Those baskets seem to bring out the worst in people. But, generally speaking, aren’t the people shopping with baskets just plain different than those shopping with carts? Think about it. The individual shopping with a cart is probably not an amateur randomly looking for something to fill his belly. If you’ve grabbed a cart, you’re probably shopping for more than yourself. You probably have a list. You probably don’t want to have to visit the store more than once a week. You’re probably careful about what goes into the cart. The basket shopper, on the other hand, would seem to be more likely to be going to the store for one or two specific things—but who, when tempted or bored, might mindlessly toss a few other items into the basket.
In other words: Blame the shopper, not the shopping basket.
Yet, another study conducted by the researchers indicates that shopping basket shoppers—specifically the “arm flexion” involved in holding a shopping basket—tends to result in people choosing vice over virtue at the grocery store. In the experiment, participants were given a shopping list in which they had a choice of snacks—some healthy (apple, orange), some not to healthy (Twix, Mars bar).
You know where this is going: The shoppers holding baskets were more likely than the shopping cart shoppers to pick the candy bars over the fruit. And why is this so? Researchers say that uncomfortable body sensations, such as the strain of holding a shopping basket, induce a “present-biased preference.” For grocery shoppers, that means wanting chocolate asap. At least you shouldn’t have room in the basket for too many of them.
(MORE: The Sneaky Art of Getting Consumers to Spend More at the Supermarket)
Brad Tuttle is a reporter at TIME. Find him on Twitter at @bradrtuttle. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.