For the experts, the term “red wine” carries countless associations. Each one points to further questions; each question leads them further off the trail. By contrast, the amateurs’ ignorance keeps them from exploring subtle byways. Seeing only one question  “what do you think of this wine?”  they can’t wander far.

The catch is that, when it comes to food, we all think of ourselves as experts. But we taste with both our tongues and our minds, and it’s easy to lead minds astray. Brownies taste better, for example, when served on china rather than on paper plates, research has shown. And we prefer wine with a pedigree, even if it’s a phony one. Sometimes all it takes is an alluring name. Until a few decades ago, Patagonian toothfish was a trash fish not worth trying to give away. Renamed Chilean sea bass, it sold so fast that it nearly disappeared from the sea.

Expectations are everything. In one recent test, psychologists asked 32 volunteers to sample strawberry yogurt. To make sure the testers made their judgments purely on the basis of taste, the researchers said, they needed to turn out the lights. Then they gave their subjects chocolate yogurt. Nineteen of the 32 praised the strawberry flavor. One said that strawberry was her favorite flavor and she planned to switch to this new brand.

The volunteers knew the taste of strawberries perfectly well. That was the problem. The associations that came with the word “strawberry” overwhelmed the taste of chocolate. Every trickster’s hope, says Jim Steinmeyer, who designs illusions for magicians, is “finding smart people who bring a lot to the table  cultural experience, shared expectations, preconceptions. The more they bring, the more there is to work with, and the easier it is to get the audience to make allowances  to reach the ‘right’ conclusion and unwittingly participate in the deception.”

In the case of the fish forgery, discovered by a pair of high school students armed with DNA tests, a nice presentation and a lofty price tag probably helped restaurants palm off tilapia as white tuna. That left diners poised for a fall. But in the end they weren’t pushed. They jumped. Maybe their own ignorance or carelessness did them in. More likely it was overconfidence.