Perceptual mapping is like making a map of how people think about things. Think about how you might draw a map of your neighborhood to show where all your friends live, where the park is, and where your house is. Perceptual mapping is like that, but instead of places on a map, it shows how people see things in their minds.
Let's pretend you're trying to sell a new kind of soda. You would want to know what people think about different kinds of soda before you start selling yours. So you might ask people questions like "What do you like about Sprite?" or "Why do you drink Coke instead of Pepsi?"
Once you get answers from lots of people, you can put them on a map. The map will show where lots of people like Sprite, and where lots of people like Coke, and where lots of people like other sodas. You can use this map to figure out where your new soda fits in. If lots of people like Sprite where you live, you might want to make a soda that's similar to Sprite. Or if lots of people drink Coke in your area, you might want to make a soda that's really different from Coke so that people have more choices.
So perceptual mapping is like creating a picture of how people see things in their minds, so you can use that picture to make better choices about your product.