If you tallied up all the foods you like and dislike – and how much you like or dislike each one – you’d end up with an exhaustive list that was completely, uniquely yours. Kind of like fingerprints, if your fingerprints changed over time, and were also shaped by culture and family and everything you’ve ever done.
Let’s define the terms. Much of what we call “taste” is actually flavor, a trait that has as much to do with smell and texture as it does with our taste buds. Humans are born with the ability to detect five types of taste – sweet, bitter, salty, sour, and umami – though our individual sensitivity to each is determined largely by genetics. How we feel about a certain flavor, on the other hand, is much more up for grabs. In other words, you could be born with a higher-than-average sensitivity to the saltiness in, say, an everything bagel — but whether you’ll enjoy that saltiness also has to do with a mix of your past experience and cultural ideas about food.
There are three main ways we learn to like (or dislike) certain flavors, explains Michael Tordoff, a psychologist at the Monell Chemical Senses Center in Philadelphia. One is “flavor-nutrient learning,” where we learn to form positive associations between the flavor of a given food and what that food does to our bodies. If you regularly snacked on cherry-flavored fruit roll-ups as a kid, for example, you may have learned over time to associate cherry with the burst of energy that comes from the sugar hit: “You pair the taste in your mouth, that flavor that you’re getting, with the post-ingestive consequences,” he says.
There’s also what Tordoff calls “taste-flavor learning,” where we associate a given flavor with one we already like. In one 2007 study, for example, college students reported enjoying the taste of plain crackers more after eating them with high-fat versus low-fat cream cheese. Or consider coffee: If you’re brand-new to the beverage, it’s probably going to be more palatable if you load it up with milk and sugar than if you leap right into drinking it black.
And finally, there’s social learning, or the idea that we simply like what our friends and parents like. This one can be a lifelong learning process, but it starts early: Our flavor preferences begin to take shape in utero and continue forming as soon as we’re born, as the foods a mother eats during and immediately after pregnancy make their way to her child through amniotic fluid and then breast milk. In a 2001 study, Monell scientists found that babies who had previously been exposed to carrot juice through their mothers enjoyed carrot-flavored cereal more. And a 1994 study in Pediatrics found that breast-fed infants had an easier time accepting new foods that those fed on formula, possibly because they encountered a wider variety of flavors.
“There’s learning going on before a baby’s even born that this is appropriate food, because that’s what the mother’s eating,” says Gary Beauchamp, Monell’s director emeritus and a co-author of the 2001 study. In the paper, he and his colleagues argued that this early learning may even reinforce differences between regional cuisines, as certain preferences are transmitted from one generation to the text. “Those exposures probably have very long-term consequences,” he says. “It’s often said that one of the last things to change when you join a new culture is your food, your flavor preference and experience.”
That said, though, our preferences aren’t totally immutable. In fact, they tend to change in certain predictable ways as we age. Take sugar, for example. Enjoyment of sweetness is innate – nature’s way of making sure we take in calorie-rich foods – but we tend to enjoy it less as adults than we do as kids. The opposite is true for vegetables, which we tend to like a whole lot more in adulthood than we do in our earliest years.
How can we explain these trajectories? Not surprisingly, they’re often biological as well as cultural. Scientists believe one reason for kids’ love of sugar, for instance, may be that they seek out more calories to fuel their growing bodies, giving them an advantage when food is scarce.
As for vegetables, there’s a reason you willingly scarf down salads for lunch years after fighting all-out dinner table wars with your parents over broccoli. Evolutionarily speaking, we actually shouldn’t like veggies at all: We’re wired for an aversion to bitter tastes, a trait our ancestors developed to protect themselves against accidental poisoning. The problem with this, of course, is we’ve generally figured out by now which plants will kill us and which won’t, yet the aversion remains – even though plenty of bitter compounds, like those found in vegetables, are actually important sources of nutrition.
So how do we get that bitterness aversion to tolerate, and even enjoy, eating our greens? Mostly, by just eating them. Part of it is social learning: We hate vegetables as kids, we see adults eating vegetables, we become adults and learn to like them, too. Another part of it is the simple fact that eating a food enough times will make it more appealing.
But the question that naturally follows – why does exposure eventually negate our dislike? – doesn’t have a clear-cut answer, Beauchamp says. One possibility, though, may be that each encounter with a given food chips away at our natural suspicion of newness: “We’re sort of built to be very wary of novel things. You can see it in species like rats: They’ll take a little bite of something and wait and see if anything happens to them, and then take a bigger bite,” he says. “That’s the whole idea behind gradually introducing foods. It’s not a conscious thing. You’re not thinking, ‘This might be dangerous.’ But the repeated exposure supposedly gets rid of this wariness.”
In some cases, though, repeated exposure might not be enough to negate the deeply held dislike that can result when we associate a negative experience with a given taste. It’s called “conditioned taste aversion,” Tardoff explains, and it can stay with us for our entire lives. One especially bad night with margaritas, for example, may be enough to turn you off tequila forever.
Sometimes, on the other hand, taste preferences feel like complete mysteries. I can’t stand the taste of Coca-cola, for instance, even though I can’t recall any particularly traumatic experiences with it. When I asked Beauchamp where this dislike may have come from – it can’t be social learning, since I grew up with parents who downed Coke like water – he offered that maybe I’d had a formative experience with it when I was very young. Maybe I once saw a family member get sick shortly after drinking one, or had a sip myself and then tripped and skinned my knee, and those negative impressions were enough to cement an aversion that stayed with me.
Even the smallest of experiences, in other words, can shape our food likes and dislikes in ways we don’t even realize – and sometimes these fleeting moments can override culture, evolution, and everything else. That’s one reason, perhaps, why taste preferences are still such a tricky thing for scientists to understand. “I have two kids and I could never figure out why one liked one thing and the other liked something else,” Beauchamp says. “And I’m supposed to be a professional.”