This is because most of what we perceive as “taste” is due to our sense of smell. Our brain combines the information from both scent and taste to create the overall flavor of food or drink. When we plug our nose, we block our sense of smell and impair the connection between our nasal cavity and brain. This makes it hard to identify the flavor of food, which consists of smell, taste, temperature, texture, spiciness, and so on. Therefore, apples potatoes and onions may taste similar if we eat them with our noses plugged.