People in cities all over the world shop in supermarkets. Who decides what you buy in the supermarket? Do you decide? Does the supermarket decide?

When you enter the supermarket, you see shelves full of food. You walk in the aisles between the shelves. You push a shopping cart and put the food in it.

You probably hear soft, slow music as you walk along the aisles. If you hear fast music, you walk quickly. The supermarket plays slow music. You walk slowly and have more time to buy things.

Maybe you go to the meat department first. There is some meat on sale, and you want to find it. The manager of the supermarket knows where customers enter the meat department. The cheaper meat is at the other end of the meat department, away from where the customers enter. You have to walk past all the expensive meat before you find the cheaper meat. Maybe you will buy some of the expensive meat instead of the meat on sale.

What is the purpose of the passage?