5 AUG 2005
Can phony beliefs alter your behavior? In politics, the question answers itself. But can false beliefs about your personal history affect something as vital as food choice? Apparently.
In a series of experiments, Elizabeth Loftus, professor of psychology and social behavior at the University of California-Irvine, and colleagues persuaded college students that they had once felt sick after eating strawberry ice cream. When the mind games were over, up to 41 percent of college students fell for the suggestion that they had once gotten sick after eating strawberry ice-cream. These "believers" then said they were less interested in eating this flavor.
The untrustworthy nature of memories and beliefs is something that Loftus and others have long since proven, in the process helping to quell an avalanche of accusations of sexual, physical and mental abuse. Many of the malicious false memories were induced by misguided therapists. People went to jail and saw their lives ruined over these false memories.
A computer made me do it
But can false memories be used for beneficial purposes? Loftus says the question first occurred to her after she convinced some test subjects that eating dill pickles and hard-boiled eggs had made them ill. "We thought, 'Wow, if this would work with fattening foods, we could be on the brink of a new dieting technique,'" Loftus said.
But it wasn't that easy: the researchers could not associate potato chips with feeling ill.
Thinking about food aversions sparked by a bad experience with a particular food, Loftus realized that uncommon grub was usually to blame.
And so she tried again with strawberry ice-cream, and in a series of experiments, found that yes, she could convince a significant number of subjects that this knotty, pinko ice-cream had made them sick as a child. How? The experimenters had their human guinea-pigs fill out a series of questionnaires, which included some reference to strawberry ice-cream. A week later, at a second session, the subjects were told by the ultimate authority (a computer) that they had apparently gotten sick after eating strawberry ice-cream.
The subjects then answered another series of questions. What if they were offered strawberry ice-cream at a party? Twenty-two percent said they'd decline. To strengthen the association, the researchers asked some questions to cause a mental "elaboration" on the pseudo-experience of getting ice-cream sick:
"How old were you?
"Where did it occur?
"Who were you with?
"How did it make you feel?"
Afterwards, a higher percentage showed aversion to the innocent ice-cream. The phony beliefs about the past also intensified if the experimenters suggested that the "sickness" might have occurred at a restaurant or a birthday party. Using such manipulations, the researchers got up to 41 percent of their guinea-pigs to change their behavior -- or at least, say they would change it.
The point of the study, Loftus says, was not to invent a new diet, but to look at the real-world implications of false memories. "We were interested in looking at the outcome of developing a false belief or memory," she said. "In all the zillions of other studies that I and others have done, you plant the suggestion, look to see if it takes hold ...and the experiment is over."
This was the first effort, she says, to "look at the repercussions, at the idea that a false belief or memory can affect later intentions, actions. You come up with the false belief, and you want to avoid the food later."
In other recent studies, she suggested that subjects enjoyed a healthy food -- asparagus -- upon the first tasting, and some subjects reported greater interest in the food.
It's a long way
So could implanted memories help a dieter control eating? Loftus says yes, maybe. "We believe this new finding may have significant implications for dieting. While we know food preferences developed in childhood continue into adulthood, this work suggests that the mere belief one had a negative experience could be sufficient to influence food choices as an adult."
But one study does not prove that any technique will help at the local Slender Gender or Slim Gym. Will it last long enough to matter? Will it work when people are eyeing real food on the table?
And even if the deception works, how would you use it? I might retch at the thought of strawberry ice-cream, but be perfectly piggish with pistachio or peach. And the experimental subjects were being fooled, and Loftus acknowledges the obvious: People who know what's going on "will not fall for the deception."
Still, she suggests that parents of obese children might be able to "remind" their children about negative experiences with fattening food. "I'm sure your audience will at first cringe at the thought that parents would lie to their kids," she told us, "but parents do this all the time, with Santa Claus and the tooth fairy."
While you chew over the ethics, we see the study as more evidence for the frightening plasticity of memory. Even in the lab, it's fearfully hard to find factors that ferret for-real from phony, Loftus says. "People have looked at true and false memories and asked, do they have different characteristics? Are different regions of the brain active? Statistically, you can occasionally find differences between groups of true and false memories, but what is so striking is how similar they are."
Comparing people with real versus phony memories of getting sick from a particular food, she says, "we see very few differences. They use the same number of words to describe their experience, have the same level of wanting to avoid the experience in the future."
-- David Tenenbaum
- False Beliefs about Fattening Foods Can Have Healthy Consequences, Daniel M. Bernstein, Cara Laney, Erin K. Morris, and Elizabeth F. Loftus, PNAS online, Aug. 1, 2005.