What the Nose Knows

Self-defined "smell scientist" Avery Gilbert is a man trained in evolutionary science, animal behavior and neuroscience who has made a career out of noticing, defining and creating odors. His commercial work includes both perfumes and kitty litter. In this book, his first, he provides a refreshingly unique look at odor perception and how it expresses itself in our culture.

"Cooking and spicing are behavioral adaptations with biological consequences. They have shaped out face and made mouth-based smelling a defining human trait," he points out in a chapter on how essential the sense of smell is to the experience of flavor in food.

In terms of sensory receptor genes, the human nose is relatively weak and our sense of smell has been degrading over time. But thanks to spicy cooking, this may be changing, according to Gilbert.

"In the last 5,000 to 10,000 years, genes for smell receptors, along with genes related to diet and metabolism, have been evolving faster than those in any other physiological system.

"In the recent evolutionary past we have evolved entire subfamilies of odor receptors not shared by the chimpanzee - our closest living relative. An intriguing possibility is that these new receptors are tuned to new smells - ones that only recently became important to human survival. It's speculation on my part, but I'd bet these receptors pick up the nuances of grilled meat - salmon filets and mastodon steaks - along with the volatiles of fermentation: not only milk products, but alcoholic drinks from beer to wine. On a daily basis we season food to please our palate, but over the long run our palate is evolving to match our menu."

An entertaining and informative read, Gilbert's book progresses from the basics of olfactory science to intriguing explorations of what makes for a good smeller, why some smells are malodorous, how odors affect memory, and whether subliminal smells can manipulate behavior.

Covering everything from Smell-O-Vision to scent sensitivity, this fascinating text will appeal to casual and serious readers alike.