Projection bias

Projection bias is the habit of shopping for the person you are right now. When you are hungry, cold, sunburned or freshly inspired, you assume you will feel the same way next week, and you buy for that feeling. Then the feeling passes, and the purchase stays.

That gap matters most for things that outlast a mood: a membership, a season’s gear, a full kit for a hobby you started yesterday. Plenty of returns, unused passes and closet regrets begin with a decision made at the peak of a feeling. That peak is exactly when sellers try to reach you.

The office snack order

In 2003, the economists George Loewenstein, Ted O’Donoghue and Matthew Rabin published “Projection bias in predicting future utility” in the Quarterly Journal of Economics. They gathered evidence from many corners of life, built a formal model and gave the bias its name. Their definition is precise. People know which direction their tastes will change, but they underestimate how much. So they expect their future tastes to look more like their current ones than they will.

The scene that shows it best is a study run by Read and van Leeuwen, published in 1998 and reported in the 2003 paper. Office workers chose a snack they would receive a week later. They could pick something healthy (apples and bananas) or something unhealthy (crisps, snack nuts and candy bars). Some would get the snack late in the afternoon, when they would expect to be hungry. Others would get it just after lunch, when they would expect to be full. And they made the choice either late in the afternoon, while hungry, or just after lunch, while full.

The results followed their stomachs. Among people who were hungry when choosing and would be hungry when eating, 78 percent picked the unhealthy snack. Full when choosing but hungry when eating: 56 percent. Hungry when choosing but full when eating: 42 percent. Full both times: 26 percent.

The workers clearly knew their appetite would change, which is why the time of delivery mattered. But how they felt while choosing still leaked into a decision about next week. Loewenstein and his colleagues drew the wider lesson: the bias can lead to misguided purchases of things that last, and with habits it leads people to spend more and save less than they planned.

Cold days and convertibles

Later work found the same pattern in real spending. In a 2007 paper, the economists Michael Conlin, Ted O’Donoghue and Timothy Vogelsang studied catalog orders of cold-weather items. Ordering decisions were over-influenced by the weather on the day. When the temperature on the order date was 30 degrees Fahrenheit lower, the chance the item was returned rose by 3.95 percent.

In 2015, the economists Meghan Busse, Devin Pope, Jaren Pope and Jorge Silva-Risso looked at more than 40 million vehicle sales. Whether people bought a convertible or a four-wheel drive depended strongly on the weather at the time of purchase. They found no rational explanation that fully accounted for it, and pointed to projection bias and salience, meaning what feels vivid at the moment.

Why today’s feeling places the order

We use how we feel now as a guide to how we will feel later. Most of the time that works well enough, because tastes do not swing wildly from hour to hour.

The trouble is the size of the change. We know hunger fades after a meal and a cold snap ends, so we adjust a little. We just do not adjust enough. The present state is vivid and the future one is a guess, so the present wins. That is why even the full office workers underrated how much a hungry afternoon would want candy.

One great class, one full kit

Say you take a cycling class and love it. That evening you buy a $300 bike, because of course you will ride every day. The bike makes the rest feel necessary: $150 of clothes and shoes so you look the part, then a $100 rack so you can take it to the trail. All of it lands in the first week, while the excitement is fresh, and most of it gets a month of use. This is how a burst of enthusiasm feeds the Diderot effect, where one purchase makes the next one look required. When the thrill wears off, as the hedonic treadmill predicts, you own $550 of gear sized for a feeling. Projection bias bought the whole kit at once.

Where sellers catch the peak

Sellers have good reason to sell to you while the feeling is high.

• Memberships at the first visit. Gyms, golf clubs, time shares and ski resorts offer long commitments right after an enthusiastic first visit. In one study of three New England health clubs, members on monthly contracts paid about $17 a visit when a $10 per-visit option was available.
• Displays and store music. Enticing displays, mood music and sales hype raise how much you want something while you are standing in front of it.
• One-click checkout. Fast purchase buttons let you act before the feeling has time to pass.
• Seasonal goods on the extreme day. Heaters, fans and rain gear tempt most on the day the weather is at its worst, when an ordinary day is hardest to picture.
• Fresh-start gear. The new year brings a wave of “new you” equipment for habits that are a few days old.

How to shop for your ordinary self

1. Name your state before you pay. Hungry, cold, hot, tired or just inspired? If one applies and the purchase will outlast it, leave it in the cart and come back when the feeling has passed. Our seven rules that stop a chain build on the same pause.
2. Eat before the grocery run. Write your list on a full stomach, bring it, and buy what is on it.
3. Pay per visit for a month. Before signing up for a gym, a class pass or a season ticket, pay as you go for four weeks and count how often you actually went.
4. Buy seasonal items mid-season. Shop on an average day, not the hottest or coldest, and check the return policy before you buy.
5. Price it for an ordinary week. Run the item through the Cost per Wear Calculator using the uses you would expect in a normal week, not this one. If it still looks good, let the 30-day rule confirm it.

When the mood is the right guide

Sometimes how you feel now is exactly the right guide. If you are cold this week and the blanket is for this week, buying for your current state is just buying for the moment you will use it. The same goes for a snack you will eat in ten minutes. Projection bias only costs money when the purchase outlasts the feeling.

So the test is simple. Picture an ordinary day, in an ordinary mood, with ordinary weather. Would you still want this, at this price? If yes, buy it. If you can only want it while hungry, cold or freshly inspired, let the feeling pass first.