Three-year-old-Joshua spits out his broccoli, scrunches his face, and shouts, "Yuck!" His mother can't understand why he has such a distaste for broccoli, because she finds it to be rather bland. Why might Joshua and his mother have such different reactions to the taste of broccoli?

This situation happens because each person has differences in the number and type of taste receptors (found in taste buds). It is possible that Joshua has more chemical receptors present in food than his mother, for that reason he perceive the taste of broccoli as more intense. It is also possible that he has a particular broccoli bitterness receptor and his mother does not have it.