For James Calvin Smith, it's lime Jello.|
Just the sight of the stuff in a cafeteria line can give him the woozies.
We humans are funny about the things we eat and drink—and the things we don't. The connection between what we put into our mouths and our sense of well being afterward is so powerful that it doesn't take much to make us turn what once may have been a delectable treat into toxic waste.
When he was nine, FSU neuropsychologist Jim Smith spent the night with a boyhood pal whose parents fed the boys all the lime Jell-O they could hold before bedtime. During the night, Smith thought he was going to die. Nearly 60 years later, Smith still mightily hates the mere sight or smell of lime Jell-O—all memories of taste are deeply suppressed.
For Smith it's an artificially green, quaking desert of dubious distinction in the culinary arts. For others its oysters Rockefeller, Hershey bars, cantaloupes, pate fois gras, shrimp, scrambled eggs, rye bread, green beans, vichyssoise, ham salad, chicken livers, steak tartar, boiled peanuts, banana pudding, guacamole, stewed tomatoes, Cracker Jacks, margaritas, sangria. Name a food or drink, and chances are someone somewhere gets nauseous just at the sound of it.
Morbid repulsion to a particular food, clinically known as taste aversion (also known as "the Garcia-effect," after John Garcia, the UCLA psychologist who was the first to quantify it), is a common psychological phenomenon well known to dieticians, food manufacturers, pesticide manufacturers, restaurateurs, and physicians. The condition has been observed for centuries, but only in the past 30 years has it been studied in depth by scientists.
As irony would have it, among them is Jim C. Smith. With a good personal model to guide him, Smith has earned a reputation as one of the pioneers in the study of conditioned taste aversion. Psychologists now recognize the phenomenon, one of many evolutionary adaptations that no doubt helped animals survive, as one of the most powerful means by which animals learn anything.
Before the 1950s, the few scientists who studied the phenomenon knew well how to condition a lab rat to avoid any diet—simply give them a small taste of poison just after feeding time. Rats subjected to such experiments quickly associated the food with a stomach ache, and wouldn't touch the food again for days, even months.
To psychologists, such learned behavior is fascinating because it defies the standard Pavlovian rules for conditioned learning, says Smith. Pavlov, the famed Russian physiologist, showed how animals could be trained to do most anything given the right stimulus, or motivating factor. The sound of a bell would make dogs salivate because they knew food was soon on its way. But there couldn't be much lag time between the bell and the treats, otherwise the dogs would forget the association between the two.
That's not the case in conditioned taste aversion, where hours can pass between a stimulus (e.g. a bellyful of lime Jell-O) and an adverse reaction (throwing up). And amazingly, subjects (nine-year-old boys or lab rats) can learn the connection after only a single experience. So extraordinarily powerful is this form of learning, in fact, that psychologists like Smith and his FSU colleague Tom Houpt are drawn to it as a means of studying how the brain perceives, stores and processes information for learning.
Taste aversion in humans is generally not considered debilitating, although the condition sometimes is associated with anorexia. (Some anorexics say they simply hate the taste of food, period.) A common fallacy about aversions is that they typically are caused by eating contaminated food, which quite often is not the case, says Smith.
"A taste aversion is not nearly so strong if you're real familiar with the taste to begin with," he said. "For example, if you're a fan of roast beef and mashed potatoes, but eat some and suddenly get sick, you may develop an aversion to that when in fact it was a virus that made you ill. Chances are if you remember how well you liked something, you'll eventually start eating it again."
It's unfamiliar taste that typically makes for lifelong disgust of a particularly food or beverage, he said. "If you get sick after eating something you've never tried before, let's say guacamole, then nothing can persuade you that it wasn't the guacamole that did you in."
In the 1960s, Smith became one of the first scientists to prove that lab animals could develop strong taste aversions just by being exposed to relatively small doses of radiation. His work was controversial because few scientists at the time believed that radiation was something animals couldn't feel, see, smell, hear or taste.
Smith showed that he could induce taste aversion in animals by irradiating them either before or after a feeding session, and the aversions could be just as strong as if the animals had been given poison. To this day, neither he nor any other scientist has a good physiological explanation for this remarkable phenomenon.
His passion for this line of research eventually led him to look at electromagnetic radiation—magnetism—as a stimulus. His instincts have now opened up a beckoning new field of inquiry that may hold the answer to fundamental questions about how we animals perceive, adapt to and use our world, awash as it is in electromagnetic information.
And perhaps even show us all how to like lime Jell-O. — Frank Stephenson