For the holidays, a brief history of manners According to Emily Post, "All rules of table manners are made to avoid ugliness." They exist to shield us from other people's effusions and emissions - and to conceal our own. Manners can act as a lubricant, minimizing social friction, but mostly their purpose is protective. They muffle our primal urges. In effect, they turn our natural warrior-like selves into elegant courtiers. That may be something to keep in mind today, especially if you find yourself seated between fastidious Uncle Eric and belligerent Cousin Kenneth at the Thanksgiving table. Early guides to manners were fixated on proper behavior at table. In medieval England, meals were occasions not only for celebration, but also for diplomacy. A leading arbiter of manners was Petrus Alfonsi, who served at the court of King Henry I. He urged his readers (male, aristocratic) not to speak with their mouths full or let crumbs shower from their lips. King David I of Scotland, who spent time in Henry's household, proposed that any of his subjects who learned to eat more neatly should get a tax rebate. PHOTOS: The Macy's Thanksgiving Day Parade's most controversial attractions Disappointingly, that idea never caught on. Yet the prescriptions of writers such as Petrus Alfonsi endured. They were amplified by later writers such as Desiderius Erasmus, a Dutchman who produced a systematic account of manners in the early 16th century, in which he gave guidance on how to share a bed (don't steal all the blankets for yourself) and how to pass wind (mask the sound with a well-timed cough). Later that century it was Italians who dominated the field. None was more influential than Baldassare Castiglione, who wrote suavely about the need to control one's social space. His key concept was sprezzatura, a stylishly effortless excellence: The truly decorous individual must be both self-possessed and unassertive. Castiglione thought of manners as a technology, and during the Renaissance there were real technical developments that changed notions of correct behavior. None of these was more significant than the introduction of the table fork: Previously there had been large crude forks for hoicking food from a shared dish, but now the fork became an implement for the individual. It was the traveler Thomas Coryat who introduced the table fork to Britain. When he returned from Italy in 1608 with this fancy novelty, he met with a torrent of ridicule. Twenty-five years after Coryat's Italian jaunt, the first table fork reached America - a gift for John Winthrop, governor of the Massachusetts Bay Colony. In the accompanying missive, the sender suggested Winthrop use his discretion in handling this precious item, and Winthrop saw fit to keep it in a special leather case. Gradually, as forks became popular, they brought finesse to the act of eating, making it possible, for instance, to consume berries without staining one's fingers. Nearly 300 years later Emily Post reflected on the need for forks (though "If you are able to eat a peach in your fingers and not smear your face ... [you may] continue the feat"). Parsing such matters, she was the inheritor of traditions at once profuse and prolix. She had to concede that among those rules of the table "there are a number of trifling decrees of etiquette that are merely finical, unreasonable, and silly." She cited as an example the insistence that one shouldn't cut salad into small pieces. She went on to damn those who choose to "condemn the American custom of eating a soft-boiled egg in a glass, or cup, because it happens to be the English fashion to scoop it through the ragged edge of the shell." It was George Bernard Shaw, of course, rather than this doyenne of American social niceties, who supposedly observed that Americans and Britons are "divided by a common language." That assessment may be a little less apt where manners are concerned than in questions of vocabulary. Yet while most of the essentials are the same on both sides of the Atlantic, there are a few clear differences between what's normal in Los Angeles and what holds true in London. Comment on this gap tends to veer into rueful specifics: A Californian friend of mine complains that the British have no grasp of the potluck dinner. Alternatively, it drifts toward generalizations about American directness and British reserve, or Americans' comparatively fluid sense of social class. But there is one really salient difference - and we observe it at table. In the U.S., when food needs cutting with a knife, you cut a bite, then lay aside the knife and transfer your fork to your right hand. Then, with the fork's tines pointing upward, you pick up one bite at a time. By contrast, the British keep the fork in the left hand and don't lay the knife down. The American cut-and-switch method, which Post termed "zigzag," may have been influenced by fashionable French practices in the early 19th century. Other theories abound. The zigzag technique may stem from the fact that early American forks were unwieldy and needed careful manipulation, or from the belief - a hangover from medieval culture - that it is best to put down a knife when it's not in use. It may also have been calculated to draw attention, as Coryat once did, to the sheer magnificence of one's modish fork. As globalization fosters a new international standard of manners - pragmatic rather than necessarily refined - the zigzag method seems to be in the first stages of decline. Those who stick with it are preserving something distinctively American. They are also hanging on to a form of behavior that, like so much in the realm of manners, favors tortuous delicacy above blunt efficiency. Henry Hitchings is the author, most recently, of "Sorry! The English and Their Manners.