Sauce biarnaise syndrome

Learned taste aversion may be nature's way of keeping us away from deadly foods.

By Susan McCarthy
Published April 28, 1999 4:00PM (EDT)

As I lay on the bathroom floor, wracked with nausea, I knew exactly where to point the finger of blame, as soon as I was strong enough to point. If I was ever strong enough. If I lived.

I would point at the dinner my mother had served, an Italian dish. Manicotti. She had talked it up: hyped the difficulty of procuring the pasta; likened it to lasagna; boasted of its authenticity; and I had eaten. In fact -- horrible to recall my gullibility! -- I had praised it. We all did. My then-stepbrother engulfed platesful with cries of appreciation and galloped upstairs to top off his meal with a candy bar. Little did we suspect that we were about to become victims of sauce biarnaise syndrome.

As the night went on I began to feel sick and sicker, and finally crept to the bathroom to vomit. There was no question of leaving the bathroom, since it was clear that I would need to keep on vomiting, probably until death.

So I was thinking bad thoughts about manicotti (such an ugly word) when my stepbrother came stumbling in, also sick. After he had unburdened himself somewhat and slumped on the tiles next to me, I offered my sympathy to a fellow manicotti victim.

Incredibly, he defended the stuff. My stepbrother, a person perhaps overly concerned (i.e., more concerned than I) with cleanliness and freshness, declared that the candy bar he had eaten must have sat on the shelf too long and become toxic. He dismissed my arguments that candy bars do not do this, and that I had not had a candy bar, yet I also was sick. I reasoned that we had both eaten manicotti, and we were both dying. Therefore the manicotti had poisoned us. It now seemed clear that manicotti was distilled evil. My stepbrother groaned and disagreed. The manicotti was good, innocent: The candy was foul.

Time passed. We miraculously recovered. It turned out that even those who hadn't had manicotti got sick. It was a stomach flu. But my stepbrother was revolted by that brand of candy bar and, to this day, I loathe manicotti and become agitated if I think too hard about those bulging tubes of pasta, oozing ricotta, stained with tomato sauce, crusted with Parmesan ...

This hatred was caused by something called learned taste aversion, or, more snappily, sauce biarnaise syndrome, a phenomenon that was dismissed as impossible when it was first scientifically described in the 1960s.

Psychologist John Garcia, studying radiation sickness in rats, noticed that rats that got sick began rejecting their perfectly good rat chow. Even when they got better, they disliked it. In a series of experiments, Garcia discovered that even if their sickness isn't caused by the food but by radiation or an injection, and even if they ate the food many hours before they got sick, rats come to hate the food they eat before getting sick.

The dislike was specific to food. Getting sick to their stomachs didn't make the rats dislike their food dish, or a burst of lights and noise -- or the researcher. It was always the food or water they became averse to.

Rats can't actually vomit, being physiologically unable to talk to Ralph on the big white phone. But, as one researcher puts it, "They look like they feel sick. I'm certainly convinced that they feel crummy when we give them drugs that make other animals nauseated."

When Garcia reported his findings, another psychologist, Martin Seligman, was struck by how closely the rats' experiences matched an experience he'd had the month before, when he went out to eat, had steak with sauce biarnaise and then got violently ill.

Even though he learned the next day that "stomach flu was sweeping the department," Seligman writes, he now found sauce biarnaise loathsome. "[J]ust thinking about it set my teeth on edge." It was another ten years before he could eat the stuff again. Seligman, who has an ear for the memorable, coined the name "sauce biarnaise syndrome." It's well known to ship stewards, who learn that seasick passengers often blame the buffet.

Why was such a familiar phenomenon controversial? One authority reportedly called these results about as likely as "find[ing] bird shit in a cuckoo clock." Sauce biarnaise syndrome doesn't follow the rules of classic operant conditioning. Among the anomalies are the specific tie between food and nausea; the fact that just one episode is enough; and the fact that the aversion is so long-lasting. Most unusual is the fact that animals can learn to hate a food they ate hours before they got sick. In classic conditioning, two stimuli need to be seconds apart for learning to take place. After bitter wrangling in the journals, however, sauce biarnaise syndrome -- or rather, learned taste aversion -- is now accepted as a real thing, and is a staple of many introductory pyschology courses.

Sauce biarnaise syndrome has been found in creatures as simple as the slug. It's easy to see why the complex has been preserved by evolution, since it protects even the dumbest bunny from repeated poisoning. If it only takes one episode of illness to cure you of eating the fruit of the salmonella tree, you are much more likely to survive and leave descendants than if you keep eating it while you try to figure out why you feel so rotten. And if the side effect is that you can't bear to eat the fruit of the biarnaise tree, well, that's the trade-off.

The reverse also happens. If you feel poorly, and eat a certain food, and then feel better, you will come to like that food. (Yes, more coffee, please.) Rats that felt horrible due to a low thiamine diet were offered sweetened water, and then given thiamine shots. The rats got better, and acquired a strong liking for sweetened water. Wild animals sometimes appear to be eating certain plants for medicinal reasons. It seems that the reason is not that they instinctively sense the plants are good for them, but that they've learned to like them -- because they feel better after eating them.

The syndrome is of interest from the standpoint of pure research. "It's a wonderful paradigm for looking at the neurobiology of learning," says Dr. Ilene Bernstein, of the University of Washington. "It's incredibly powerful to generate a memory trace in neurons that lasts so long."

Naturally, applied science has also attempted to harness this powerful reflex. But, like the telephone that runs off hiccups, the laptop that runs off a treadmill, and the sneeze-powered radio, it remains mostly in the realm of speculation.

One attempt to use learned taste aversion was a project to make coyotes disgusted with the taste of lamb so that they would gag at the sight of sheep. It worked, especially if the coyotes and the sheep were penned up together, but hasn't panned out on a large scale.

Others have hoped that the phenomenon can be used to make alcoholics disgusted by drink, and it's true that many people despise the first kind of alcohol they got truly smashed on. "Tequila shots," a former enthusiast confirms grimly.

"Cointreau," groans another friend, recalling an evening of browsing a bar menu laden with must-sample beverages like Pink Cadillacs and Dirty Jellybeans, culminating in the dread liqueur.

"Old Smuggler," snarls a third. "All blended Scotch whiskey. Mediocre. Blended. Scotch."

Unfortunately, switching to another form of alcohol is usually all it takes. (Rat work on this subject has not progressed very far, since rats are teetotalers. Indiana researchers have bred rats that let their hair down a little -- "They drink enough so that they couldn't drive a car legally," quips Bernstein -- but the parallel doesn't seem to be exact.)

Bernstein has worked with children getting chemotherapy for cancer. Since chemo usually causes nausea, many patients develop aversions to foods if they eat them before treatment. This is upsetting for parents worrying about sick children's weight loss. Bernstein gave children ice cream of an obscure "nutty maple-y" flavor before chemotherapy and had some success in getting the kids to dislike that ice cream instead of their usual foods.

Once the syndrome kicks in, the high-class intellectual part of the mind often rationalizes it. Rather than acknowledge that the body reflexively rejects the food in question whether good or bad, the mind comes up with ingenious reasoning to prove that the food is genuinely bad: The candy bar was tainted! Manicotti is an evil food! That rat chow is toxic!

My friend Sarah takes a more aesthetic approach toward a certain kind of frozen cheesecake she has spurned since a traumatic episode some years ago, saying delicately: "It just strikes me as so nasty the way it has whipped cream on top."

Whatever the intellect may say, that's what it really comes down to when your stomach tries to dig a hole and crawl in: the neurons, determined to save your life, that scream "so nasty!"

Susan McCarthy

Susan McCarthy is a San Francisco freelance writer and the author, with Jeffrey Masson, of "When Elephants Weep: The Emotional Lives of Animals."

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