Thus, your brain receives no signal identifying the odor, and everything you eat tastes much the same. The odor molecules remain trapped in your mouth. Of all our senses, smell is our most primal. Animals need the sense of smell to survive. Although a blind rat might survive, a rat without its sense of smell can't mate or find food.
Smells can also signal danger, fear, or dread.
Although our sense of smell is our most primal, it is also very complex. To identify the smell of a rose, the brain analyzes over 300 odor molecules. The average person can discriminate between 4,000 to 10,000 different odor molecules. Much is unknown about exactly how we detect and discriminate between various odors. But researchers have discovered that an odor can only be detected in liquid form.