Discussion:
Neurological Foundations of Taste, Touch, and Smell
The way the brain perceives stimuli says something about how taste, smell and touch affect behavior. Most stimuli that are perceived positively are, in fact, good for people; food tastes and smells "good" because without some kind of psychological inducement to eat, people would not survive. Stimuli that are perceived negatively are those that people need to avoid; the fact that rotting foods smell "bad" is the brain's way of keeping one from eating something that might make one sick.