WHEN I CANVASSED restaurant owners across the country, most said that customer opposition precludes any significant move away from tipping. “I like the idea of a service charge, and I’ve thought about having one,” says Hakan Swahn, the owner of Aquavit, a restaurant in New York that serves Scandinavian cuisine and has branches in Stockholm and Tokyo. Because tipping is negligible in Sweden and frowned upon in Japan, at these outposts the cost of service is factored into the bill. But that’s not possible at his Manhattan flagship, Swahn told me. “The customers would protest.”

Image ALL FOR ONE, ONE FOR ALL: At the Linkery, the staff, surprisingly, has embraced the no-tipping policy more readily than some of the restaurants customers. Credit... Jeff Minton for The New York Times

Eighty percent of Americans say they prefer tipping to paying a service fee, according to Zagat Survey. They do so, Leo Crespi’s surveys first demonstrated, primarily because they believe tipping provides an incentive for good service. But there is little correlation, in fact less than 2 percent, according to Michael Lynn, a Cornell professor of consumer behavior and marketing.

Economists have struggled to explain tipping. Why tip at all, since the bill is presented at the end of a meal and can’t retroactively improve service? And certainly there’s no reason to tip at a restaurant you will never revisit. “Using a rational and selfish agent to explain tipping, one reaches the conclusion that the agent should never tip if he does not intend to visit the establishment again,” Ofer Azar, the economist, writes. “Yet this prediction is sharply violated in practice: most people tip even when they do not intend to ever come back.”

The single most important factor in determining the amount of a tip is the size of the bill. Diners generally tip the same percentage no matter the quality of the service and no matter the setting. They do so, Lynn says, largely because it’s expected and diners fear social disapproval. “It is embarrassing to have another person wait on you,” the psychologist Ernest Dichter told a magazine reporter in 1960. “The need to pay, psychologically, for the guilt involved in the unequal relationship is so strong that very few are able to ignore it.” Ego needs also play a part, especially when it comes to overtipping, according to the Israeli social psychologist Boas Shamir.

These psychological factors also go a long way in explaining the steady rise of the average tip in the United States from 10 percent in the early 20th century to 18.9 percent today, with little regional variation. “To overtip is to appear an ass: to undertip is to appear an even greater ass,” Benjamin Franklin reportedly noted during his stint in Paris, and his quandary continues to vex American diners.

But not at the Linkery. Porter and his staff have found that most diners accept the no-tipping policy, which is explained on the restaurant’s Web site and menu as well as upon the presentation of the check. This doesn’t surprise Lynn, who says he believes consumer preferences for tipping are not as strong as Zagat Survey suggests. In a less-cited 1987 Gallup telephone survey, only 34 percent of American respondents said a 15-to-18 percent service charge was unreasonable. In Lynn’s own 2004 Internet survey, 44 percent of American respondents said they would prefer to have waiters paid higher wages instead of tips, while only 22 percent disagreed. “Given that consumers’ preferences appear to be weak and are unlikely to have strong effects on patronage behavior, they need not dictate tipping policies,” Lynn concludes.

That has already proved true at the antipodes of American dining  the fast-food restaurant and the private club  where tipping is not usually allowed. And with few objections, many full-service restaurants include service charges for groups of six or more diners. They do so because tip size is inversely proportional to the number of diners. One 1973 study at an Ohio restaurant revealed that individual diners tipped 19 percent on average, while groups of six left 13.5 percent. “[T]o the extent that many people contribute to a check, the responsibility of each to the waiter may be psychologically divided among the people present,” the researchers concluded.