Few of us know more about the science of taste than what can be gleaned from that sixth-grade textbook illustration of the tongue segmented into the various kingdoms of sweet, salt, bitter and sour. If you went on to spend your lunch period wondering why you tasted salt on the tip of your tongue, a region clearly marked as the country of sweet, you, my little empiricists, win the prize.
The map was wrong, a slip-up in the otherwise painstaking scientific career of the psychologist Edwin Garrigues Boring, who published it in 1942 in his well-regarded “Sensation and Perception in the History of Experimental Psychology.” John McQuaid begins his new book, “Tasty: The Art and Science of What We Eat,” by debunking the tongue map so readers can start with a palate cleansed of misconception about a field popping with new discoveries.
Taste was long a neglected territory. The ancient Greeks considered it vulgar. Eighteenth-century philosopher Immanuel Kant said it was too idiosyncratic to study. When Boring wrote his nearly 700-page tome on sensation, only 25 pages were devoted to taste and smell. That we lagged in our knowledge of something so central to our being, a basic survival drive and our most common source of pleasure, seems preposterous in today’s foodie culture.
Consider, for instance, that science had not identified any receptors for taste until 1998, several years after the goal was reached for smell receptors. Note the addition of umami to the quartet of sweet, bitter, sour and salt came quite late in the game. It was 1907 before anyone even proposed the idea to label this savory flavor — although you can’t enjoy a hamburger without it — and it wasn’t until 1985 that the term met scientific acceptance. Today, people are only beginning to recognize fat as flavor No. 6.
McQuaid’s fresh approach to a savory subject takes readers on a surprising evolutionary journey, tracing the role taste played in the deep history of organisms, starting with the fossilized memento of the earliest recorded meal, a 480 million-year-old trilobite captured while munching a little worm. Probably not a lot of flavor involved in that meal from the Cambrian age, a time before dinosaurs and flowering plants, but in measured steps McQuaid shows how life’s evolving engagement with taste played a role in brain development, the acquisition of three-color vision, and even facial expression — think of the lives saved by the universal “Yuck” face.
“The senses, once mere detection-and-response mechanisms, had to grow more powerful in order to guide complicated behavior,” McQuaid asserts. “Flavor became the linchpin of this process.”
McQuaid’s name hasn’t been associated much with food writing, although he comes to the field with science writing credentials that include a piece of three Pulitzer Prizes from his years as a reporter for the New Orleans Times-Picayune. Readers of his environmental journalism or the book he previously co-authored, “Path of Destruction: The Devastation of New Orleans and the Coming Age of Superstorms,” wouldn’t have predicted this new preoccupation.
But McQuaid brings clarity and at times crackling prose to the topic. He portrays the newly evolved mammals’ need to keep fueling or die as “the crisp urgency of every meal.” In his description of umami he says, “The other four tastes boldly announce themselves, but umami operates by misdirection, helping other flavors bloom. It’s like the Wizard of Oz, putting on a tremendous show from behind a curtain.”
The book’s most entertaining chapters move beyond the evolutionary tale to examine the flavors in detail, with chapters devoted to sweet, bitter and potato chips — an examination of fat, salt and starch. There’s also a chapter on disgust, an essential part of taste, and a chapter about the newest addition to human cooking — heat, as in, chilies. A chapter on sweet features Chicago chef Homaro Cantu and his miracle berry paste made from the fruit of a West African shrub. Cantu hopes the berries may be one way to end the nation’s sugar binge. When their active ingredient hits the tongue, it blocks sweet receptors while making acids taste sweet, enabling us to satisfy sweet tooths without the calories real sugar packs.
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Still, for all McQuaid’s abundant focus on flavor, he often seems remote from his subject. It’s not until a chapter on chilies where one senses McQuaid the eater really taking an interest, when he and his heat-seeking son travel to South Carolina to meet Ed Currie, the creator of the world’s hottest chili.
This complaint aside, McQuaid’s thorough research, fresh insights and flavorful writing can’t help but enrich any eater’s appreciation of this complicated business of taste. As McQuaid writes, there are lingering mysteries. “Flavor remains frustratingly paradoxical. Like other senses, it’s programmed by genes; unlike them, it is also protean, molded by experience and social cues, changing over the course of a lifetime.” But as a map to these riddles, “Tasty” provides a enriching guide.
Jenni Laidman is a frequent Journal contributor.
“Tasty”
By John McQuaid, Scribner, 291 pages, $26