smell

When you bite into a strawberry and experience something that feels like one unified sensation, you are experiencing the product of two entirely separate sensory systems — taste and smell — being fused by your brain into something that does not exist in the physical world. Flavor is a construction. The tongue detects five (or possibly six) basic chemical categories. The nose distinguishes potentially a trillion different molecules. Without the nose, the strawberry tastes like sweetened water. The neuroscience of how these signals combine reveals why eating is a fundamentally cognitive act.

Pinch your nose while eating a strawberry and the flavor nearly disappears — what remains is just sweetness with a hint of acid. Flavor, it turns out, is about 80% smell. The tongue detects only five basic tastes; the nose handles everything else through 400 distinct olfactory receptors, making smell the most molecularly diverse sensory system in the human body. Here is how these two ancient senses combine to produce the richness of what we call taste.