Ulterior Motives

How goals, both seen and unseen, drive behavior

Art Markman is a cognitive scientist at the University of Texas whose research spans a range of topics in the way people think. See full bio

September 18, 2009, Behavioral Economics

Take a list to the supermarket, because you’re on autopilot

Food will leap off the shelf at you when you're hungry.

Shopping list It is possible that there are people who really relish a trip to the local mega-supermarket. As far as I can tell, though, most people do not. On a typical weekend afternoon, the supermarket is crowded with people (sometimes with kids in tow) moving through the aisles at speeds that NASCAR drivers would envy, expertly throwing things into their carts as they try to do a week's worth of shopping in 30 minutes.

Marketers who study shopping know that most of what people do at the store is done on autopilot. Whenever you use one of those loyalty cards at the supermarket, the market is tracking your purchases. They have statisticians analyze the purchases of all of the people with the loyalty cards so that they can better understand the effects of changes in price or other promotions on purchases. In order to do these analyses, the statisticians first have to pull out your habits. That is, they figure out what you usually buy, and then factor that into the analysis. As it turns out, about 9 out of every 10 things you buy in any trip to the supermarket fit the pattern of what you get habitually.

That makes sense, of course. You're in a hurry, and so you move through the supermarket on autopilot. You wander through the aisle, grab the things you need, and move on.

The positive thing about being on autopilot is that you get out of the store in a hurry. The downside is that lots of things can affect what you end up putting in your cart beyond what you are consciously thinking about buying.

Muffin For example, Dan Gilbert and Tim Wilson describe a study they did in a supermarket. They manipulated how much people needed to eat by having some participants eat a quarter pound of blueberry muffins before shopping, while others ate no muffins. Some of these shoppers were allowed to keep their shopping lists, while others were not. At the end of the shopping trip, the experimenters looked at what the shoppers bought, and compared it to what was on the shoppers' lists.

Shoppers who ate muffins bought fewer things that they did not intend to buy than shoppers who did not eat muffins. That is, being hungry in the supermarket made lots of things in the store look really appealing. Because people were on autopilot, they often grabbed those things that looked good and bought them.

Here's the potentially good news, though. The shoppers who were allowed to bring their shopping lists into the store did not buy that many things that they did not intend to buy, even if they were hungry in the store. The shoppers with the list had a strategy for being on autopilot: they focused on what was on their list.

More generally, the idea is that there are lots of things that may make things look attractive to you at the supermarket. Being hungry will make some foods seem more appealing. Advertising will also have more of an affect on your purchases when you are not really thinking carefully, because you are likely to choose products that are familiar without really thinking about why you are making that purchase.

So, do yourself a favor at the store. Bring a list and stick with it.