the sense of smell does far more than provide information about a mouthful of food Smell detects whatever volatile molecules are in the air It therefore tells an animal about its surroundings: the air, the ground, the plants growing in the ground, other animals moving nearby that might be enemies, mates, or a meal This more general role explains why we’re sensitive to aroma notes in foods that are reminiscent of the world: wood, stone, soil, air, animals, flowers, dry grass, the seacoast and the forest It’s also essential for animals to learn from experience, and therefore to associate particular sensations with the situations they accompany This may be why odors are so evocative of memories and the emotions associated with them The Variety of Gathered Foods, the Monotony of Agriculture Our earliest human ancestors were omnivores: they ate whatever they could find worth eating on the African savanna, from meat scraps on an animal carcass to nuts, fruits, leaves, and tubers They relied on taste and smell to judge whether a new object was edible — sweetness meant nourishing sugars, bitterness toxic alkaloids, foulness dangerous decay — and to help identify and recall the effects of objects they had encountered before And they ate a varied diet that probably included several hundred different kinds of foods They had a lot of flavors to keep track of When humans developed agriculture around 10,000 years ago, they traded their diverse but chancy diet for a more predictable and monotonous one Now they lived largely on wheat, barley, rice, and corn, all concentrated sources of energy and protein, and all relatively bland They had very few flavors to keep track of But they still had their senses of taste and smell Spices Haven’t Always Gone with Foods ... on wheat, barley, rice, and corn, all concentrated sources of energy and protein, and all relatively bland They had very few flavors to keep track of But they still had their senses of taste and smell Spices Haven’t Always Gone with Foods... — and to help identify and recall the effects of objects they had encountered before And they ate a varied diet that probably included several hundred different kinds of foods They had a lot of. .. flavors to keep track of When humans developed agriculture around 10,000 years ago, they traded their diverse but chancy diet for a more predictable and monotonous one Now they lived largely on wheat, barley, rice, and corn, all