[MUSIC]. When we enter a supermarket on any given day, we come in with a set of goals. Maybe we want to get the things we need to make the next meal or the next few days of meals. Sometimes we might be stopping in to pick up just one or two things like eggs or milk. No matter what the goal of our shopping trip, the supermarket has been designed to make us buy more than we came to buy. And to make us consider buying the most expensive versions of those items. So, let's look at how this is done. In general, people buy perishable items most frequently here in the U.S., things like milk and eggs. And these items are usually located at the back of the store, so this means that we often have to walk through the store to find what we need. And usually, the most direct routes to those items will be stocked with the most heavily processed foods, things like cereals, chips, and sodas. And these items also tend to have the greatest mark-ups. The more processed a food is, the more a company can charge for the final product. So, even within the processed food aisles, the heavily processed versions of a food will be placed at eye level, and will be easier for us to reach. For example, if you go to the baking aisle, the cake mixes and ready-made frostings will be easier to reach than the less processed baking goods, which are also less expensive. If you look at foods specifically marketed to young children, they'll be placed at two levels. One is low down at the level of a typical three year-old and the other is exactly at the level of a child who's sitting in a shopping cart. So that's just the low shoulder level for an average height adult. So, highly processed food aimed to appeal to children, is also going to be easy for them to see, and easy for them to ask for. Then, a lot of research has gone into the music that's played in a supermarket throughout the day. There's evidence suggesting that instrumental music with a slow tempo actually slows down the flow of traffic in the store, and this increases the daily sales volume of the supermarket. Some stores even use artificial aromas that are released by machines designed to deliver a constant smell of things like freshly baked bread in the bakery section and chocolate in the candy aisle. There's evidence to suggest that these scents make customers hungrier, and in this way, they increase sales. Now, one easy rule to follow in the supermarket is, in general, try to stick to the periphery of the store, where fresh whole foods, like fruits and vegetables, eggs, meat, and dairy products, are usually displayed. If possible, try and make a shopping list before you go to the store, and, when you're there, try to stick to that list. And finally, try not to go shopping when you are hungry. Because if you enter the supermarket hungry, you are much more likely to be tempted by the unhealthy, high calorie and highly processed foods.