Free You May Also Like by Tom Vanderbilt

to a handful of networks playing the same old shows.
    But I have come to Pelchat’s office to talk about liking. Regardless of which part of my mouth and nasal cavities are telling me what the flavor is, what is telling me I like it? Virginia Woolf once wrote that “reading is a longer and more complicated process than seeing.” So too is the question of whether we like something more than feeling a sensory response to something we have put in our mouths.What welike is sometimes corrupted by what we know we like. A study that had consumers test pineapple varieties found those who preferred pineapples labeled “organic” and “free trade” tended to be those who were more fond of organic and free trade produce itself. Those less keen on organics were less happy about the pineapple. As the researchers noted, “The same cognitive information evoked opposite affective reactions in different subjects.”
    Pelchat, it turned out, did have some tea for me. But first she wanted me to take a capsule, which would contain either sugar or, simply, non-caloric cellulose. She wanted to show me the taste mechanism known as “flavor-nutrient” conditioning—the idea that we like what makes us feel good,
even if we do not know it
.
    The power of this conditioning has been shown in any number of studies on rats, our fellow neophobic omnivores. Typically, a rat will drink, ad libitum (as much as it wants), something like orange Kool-Aid. Rats, as a cursory glance at the scientific literature reveals, drink a
lot
of Kool-Aid. Meanwhile, sometime before, during, or after, a sweetener will be “infused,” via “intragastric catheter,” directly to its stomach. Later, the rat will sample grape Kool-Aid without getting the sugar drip to the stomach. When both flavors are later tested, rats will prefer the one that
was
sweetened, even when both flavors are now unsweetened. Sometimes they still cling to the old favorite when one of the
new
options actually tastes sweet in the moment.
    Curiously, the way the rat came to like one flavor over another had nothing to do with a taste preference. How do researchers know? “In fact,” Pelchat tells me, her voice lowering a bit, “the esophagus is externalized.” With the gullet sitting outside its body, the rat cannot taste the glucose, nor could he belch it back up into his mouth. Infused into the stomach, however, that sweetness still provides a hedonic payoff. “Something in the gut or the metabolic system is making them like that flavor,” Pelchat said.
    Pelchat wondered if humans’ sensory mechanisms could be similarly bypassed, without such extreme surgery. So she once swallowed a nasogastric tube for a day and tried to mainline glucose. “I thought, I know what I’m doing, I’ll pretend it’s food and I’ll swallow it, it’ll be fine. Instead, I was puking, tearing up.” Finally, she hit upon pills, which would or would not release sweetness into the gut. A placebo cellulose pill has no calories, no benefit for the body. Well, almost nobenefit. “Incidentally,” she noted with a laugh as I inspected a pill, “that will keep you regular.”In her study, people who downed the (tasteless) sugar pills ended up liking the flavor of tea more than the tea they drank with the unsweetened pills.
    So without even knowing why, people preferred one tea over another (
we are strangers to our taste
). They were getting “post-ingestive” signals, in the form of a nutritional reward, that predisposed them toward a flavor. “I always make a point of telling people that reward and pleasure are not the same thing,” she says. “Food can be rewarding without the conscious experience of pleasure.” How we have all known this, eating in front of the television. The reverse can happen as well. Cancer patients who sampled a novel ice cream flavor prior to chemotherapy,