First Bite: How We Learn to Eat by Bee Wilson Page B

four months). But all of the other basic mouth-tastes produced strong reactions. The sour swab made the babies pucker their lips. Bitterness provoked an expression of abject distress and an open mouth, as if trying to spit or vomit it out. As for the sweet swab, Steiner found that it produced a dreamy look of “relaxation” with an “eager licking of the upper lip” and even a “slight smile”—and this at an age when babies are not supposed to be capable of smiling. Such is the power of sugar.
    The test has since been repeated many times, with similar results. What it confirms is that, as we have seen, all human babies, from Sweden to China, have a strong innate preference for sweetness and a dislike of bitterness and sourness. Basic tastes are not a question of memory—we are hardwired to think sweetness is wonderful and bitterness is scary. No one has to learn these simple tongue reactions. But flavor is another matter. Flavors—these memories generated backward through our nose—are all learned. What we think about flavor in all its myriad forms, from toasted cumin to sea bass, from parsley to spaghetti carbonara, is not fixed. Each of us will have a different bank of memories and feelings about these; and it exists from day one, if not before.
    Taste buds appear at seven or eight weeks of gestation. Already, by thirteen to fifteen weeks, the taste buds are mature. A thirteen-week-old fetus weighs maybe an ounce, with no fat under the skin, no air in thelungs. Yet already he or she cannot only swallow but taste , and these sips of fluid leave memories.
    In 2000, some French scientists did a remarkable experiment showing that newborns arrive in the world with a memory of how their particular amniotic fluid tasted. The mothers studied came from the Alsace region, where strong-tasting anise sweets are a local delicacy. Some of the women had eaten anise regularly during pregnancy, but some had not. The babies were tested straight after birth and again four days later, having tasted nothing outside the womb but milk. When an anise odor was wafted in front of them, the babies born to anise-eaters showed a marked and “stable” preference for anise. They turned their heads toward the anise smell, sticking their tongues out with a licking gesture. They remembered it, and apparently, it pleased them.
    Further experiments have confirmed that other strong flavors, such as garlic, can also find their way into amniotic fluid. In one study, women agreed to swallow garlic capsules forty-five minutes before they were due for an amniocentesis; when it was tested, their amniotic fluid smelled garlicky. Babies born to voracious garlic eaters will have been floating in a sac of garlic water for nine months. It has been shown that babies exposed to garlic before birth are more likely to enjoy garlic in food later on. Likewise, mice whose mothers had been fed on artificial sweeteners when pregnant had an exaggerated taste for sweetness. Pregnant rats fed on junk-food chow—including savory snacks, sweetened cereals, and chocolate-hazelnut spread—had babies who also selected these foods over regular rodent pellets, though the babies’ preference for junk was lessened if the mothers switched to a healthier diet during lactation.
    The flavors our mothers ingest most regularly can become like mother’s milk to us. Julie Mennella and Gary Beauchamp, biopsychologists working at the Monell Chemical Senses Center in Philadelphia, have done a series of experiments on how flavor in utero and in breast milk leaves children with lasting memories and preferences for certain foods. One of their most celebrated studies, from 2001, involved carrot juice. The babies of a group of mothers who drank carrot juice during the last trimester of pregnancy and again during the first two months of breastfeeding were predisposed to like the flavor of carrot. When the babieswere weaned onto solid food, several months after the mothers stopped drinking the