Why do I always spend a lot in the supermarket?
Don't you feel like often you spend more than you wanted in a supermarket (or in a shopping center)? Well, it's not just you, and there are many "tricks" supermarkets can use to make you spend more money.
Did you ever notice the floor is slippery (or at least looks like that)? Well, this way you'll be careful and walk slower, and so will spend more time browsing. Have you ever thought the time flew by you while you were shopping? Pay attention: there are bright lights everywhere to make it feels like it's still day, and the few windows (if any) are usually dark, mirrored or frosted, so you don't notice how much time you spent inside until you leave.
In Economics, two things are perfect substitutes when they can be used for the same purpose without affecting the result. Coke and Pepsi are perfect substitutes in Economics - both are fizzy cola drinks - but might be imperfect substitutes for a customer who perceives the difference in taste. However, for a specific person, apple juice and orange juice might be perfect substitutes on one occasion, if they're simply looking for juice. One other example: what is the perfect substitute for salt? You may use other spices, but there's no substitute for salt. I had a professor in college who would say "if the supermarket is selling salt on sale, immediately hand out your CV, they have a bad economist working for them". Why would you need a price reduction to sell salt? 😅
Perfect complements are products that need one another to be used - think of toothpaste and toothbrush, for example. If you buy just one of them, you won't be able to use it (unless you use your finger to brush your tooth or brush your teeth with no toothpaste).
Now think of how products are displayed in supermarkets: perfect or imperfect substitutes and complements are always near each other. You think "hmm I'm going to make some meat tonight", you look for meat and you'll also find grills, charcoal, lighters, and of course, alcohol. Sometimes, you buy something, get home and notice you miss its complement. You go back to the market, only to find out it was right next to the first product you bought.
You're going to pay for everything you picked and you see something is on sale. If the person in charge of displaying products around is smart, they'll put products on sale on the way to the checkout, as that's where you purchase products on impulse. Well, not only items on sale but other products we purchase on impulse - chocolate, candies, snacks and whatnot.
There is also the "instinctive factor". In the book Sapiens, I believe in the very first chapter, it's said that in the wild, animals (including our ancestors) would find a tree full of fruit and eat them all, even though it is too much. That's why we do the same when we buy chocolate, for example: instinctively, we are programmed to eat all the food when we find it because we don't know the next time we will find food.
Similarly, you get to the supermarket and see a huge variety of food and goods - you want to buy them all, especially if they're on sale.
Learn more:
Yuval Noah Harari - Sapiens: A Brief History of Humankind - buy on Amazon.de, Amazon.com
― Why do I always spend a lot in the supermarket?
Supermarkets know how you'll behave, and display products in a way you'll purchase more - for example, products on sale near checkout.
Similar products and products that need each other to work are displayed together.
Supermarkets keep you from seeing daylight, so you don't notice how much time you're spending indoors. Similarly, they make floors slippery so it takes longer for you to walk (you don't want to fall down, do you?).