You are babysitting a 5-year-old child who does not want to eat his broccoli. He states that the broccoli tastes yucky. You tell him to hold his nose closed while he eats a piece of broccoli and see how it tastes. He says it doesn't taste as yucky when he holds his nose (although he still doesn't want to eat the broccoli). Why did the broccoli taste "less yucky" when the child held his nose?