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

breakfast you were given for a weekend treat, and the way bread tasted in your house. These are the memories that still have emotional force years or even decades later.
    Such memories, conscious or unconscious, are what drive us to seek out the old habitual foods—particularly packaged foods—even if, judged objectively, they do not really taste nice or do our bodies any good. Experiments have been done with rats and mice where the animals weregiven dopamine blockers, drugs that interfere with the part of the brain that governs reward. These drugs take away much of the chemical reward of eating food. Yet the dopamine blockers do not extinguish the rodents’ food-seeking behavior, at least not straightaway. At first, the animals continue to press the lever (or run through the alleyway, or whatever the task might be) and eat the pellets, even though the dopamine blocker means that the food no longer offers the same gratification. Next, they carry on pressing the lever to earn the pellets, but do not eat them. Finally they stop pressing the lever, indicating that at last their desire for the pellets has gone away. The interesting thing is that it takes so long for the desire to fade. As the neuroscientist Roy A. Wise has observed, it is only when “the memory of the reward is degraded through experience that the desire is lost.” The craving for the pellets is more a function of memory than of how they taste. Memory propels human food urges in much the same way. As we traverse the supermarket aisles in a trance-like state, we are like rats in an alleyway, steered to this or that food by memories of rewards long gone.
    One of the reasons that we do not usually think of our tastes as learned is that most of the learning tends to happen in the very early years of life—and then it stops. For those of us who believe in personal development, it is depressing to learn that a person’s food “likes” at age two generally predict their tastes at twenty. In 2005, researchers in Turkey interviewed nearly seven hundred undergraduate students and their mothers. The mothers were asked about their children’s eating habits when they were two, and the students were asked about how they ate at the time of the experiment. There was a remarkable continuity between past and present. The students who were “picky eaters” as children still described themselves as picky eaters. The ones whose mothers recalled that they always ate too much still did so. And the three people in the study who “never” ate vegetables as children still had no vegetables in their diet. So much for putting aside childish things.
    When we talk of memory and food, we generally assume that nostalgia is a phenomenon that occurs late in life—as when Marcel Proust was transported to his youth by a madeleine dipped in lime-blossom tea. But food-memory is there from the start. Even babies have nostalgia! It’s a large part of how we learn to eat. The foods parents give to babies providethem with powerful memories that trigger lasting responses to certain flavors. This process begins before birth. We are all born with echoes of our mother’s diet, which means that no one is a totally blank slate when it comes to flavor. We arrive predisposed to respond to certain foods by our experiences in utero.
    It’s hard to know what newborns think about taste, since we can’t exactly ask them. Or rather, they can’t exactly answer. But in 1974, the Israeli doctor Jacob Steiner realized that babies’ reactions to the basic tastes of sweet, sour, salty, and bitter could be gauged by their facial expressions, which are vivid and mobile, even in the first week. Steiner took babies just a few hours old and offered them a range of tastes on a cotton swab, filming their facial expressions. When given salt, which you’d think might make them cry, the babies, surprisingly, showed little reaction, continuing to look expressionless (a liking for salt only emerges later, around