In the southeastern corner of Kentucky, in the stretch of the Appalachian Mountains known as the Cumberland Plateau, lies a small town called Harlan.

The Cumberland Plateau is a wild and mountainous region of flat-topped ridges, mountain walls five hundred to a thousand feet high, and narrow valleys, some wide enough only for a one-lane road and a creek. When the area was first settled, the plateau was covered with a dense primeval forest. Giant tulip poplars grew in the coves and at the foot of the hills, some with trunks as wide as seven or eight feet in diameter. Alongside them were white oaks, beeches, maples, walnuts, sycamores, birches, willows, cedars, pines, and hemlocks, all enmeshed in a lattice of wild grapevine, comprising one of the greatest assortment of forest trees in the Northern Hemisphere. On the ground were bears and mountain lions and rattlesnakes; in the treetops, an astonishing array of squirrels; and beneath the soil, one thick seam after another of coal.

Harlan County was founded in 1819 by eight immigrant families from the northern regions of the British Isles. They had come to Virginia in the eighteenth century and then moved west into the Appalachians in search of land. The county was never wealthy. For its first one hundred years, it was thinly populated, rarely numbering more than ten thousand people. The first settlers kept pigs and herded sheep on the hillsides, scratching out a living on small farms in the valleys. They made whiskey in backyard stills and felled trees, floating them down the Cumberland River in the spring, when the water was high. Until well into the twentieth century, getting to the nearest train station was a two-day wagon trip. The only way out of town was up Pine Mountain, which was nine steep miles on a road that turned on occasion into no more than a muddy, rocky trail. Harlan was a remote and strange place, unknown by the larger society around it, and it might well have remained so but for the fact that two of the town's founding families-the Howards and the Turners-did not get along.

The patriarch of the Howard clan was Samuel Howard. He built the town courthouse and the jail. His counterpart was William Turner, who owned a tavern and two general stores. Once a storm blew down the fence to the Turner property, and a neighbor's cow wandered onto their land. William Turner's grandson, "Devil Jim," shot the cow dead. The neighbor was too terrified to press charges and fled the county. Another time, a man tried to open a competitor to the Turners' general store. The Turners had a word with him. He closed the store and moved to Indiana. These were not pleasant people.

One night Wix Howard and "Little Bob" Turner-the grandsons of Samuel and William, respectively-played against each other in a game of poker. Each accused the other of cheating. They fought. The following day they met in the street, and after a flurry of gunshots, Little Bob Turner lay dead with a shotgun blast to the chest. A group of Turners went to the Howards' general store and spoke roughly to Mrs. Howard. She was insulted and told her son Wilse Howard, and the following week he exchanged gunfire with another of Turner's grandsons, young Will Turner, on the road to Hagan, Virginia. That night one of the Turners and a friend attacked the Howard home. The two families then clashed outside the Harlan courthouse. In the gunfire, Will Turner was shot and killed. A contingent of Howards then went to see Mrs. Turner, the mother of Will Turner and Little Bob, to ask for a truce. She declined: "You can't wipe out that blood," she said, pointing to the dirt where her son had died.

Things quickly went from bad to worse. Wilse Howard ran into "Little George" Turner near Sulphur Springs and shot him dead. The Howards ambushed three friends of the Turners-the Cawoods-killing all of them. A posse was sent out in search of the Howards. In the resulting gunfight, six more were killed or wounded. Wilse Howard heard the Turners were after him, and he and a friend rode into Harlan and attacked the Turner home. Riding back, the Howards were ambushed. In the fighting, another person died. Wilse Howard rode to George Turner's house and fired at him but missed and killed another man. A posse surrounded the Howard home. There was another gunfight. More dead. The county was in an uproar. I think you get the picture. There were places in nineteenth-century America where people lived in harmony. Harlan, Kentucky, was not one of them.

"Stop that!" Will Turner's mother snapped at him when he staggered home, howling in pain after being shot in the courthouse gun battle with the Howards. "Die like a man, like your brother did!" She belonged to a world so well acquainted with fatal gunshots that she had certain expectations about how they ought to be endured. Will shut his mouth, and he died.

2.

Suppose you were sent to Harlan in the late nineteenth century to investigate the causes of the Howard-Turner feud. You lined up every surviving participant and interviewed them as carefully as you could. You subpoenaed documents and took depositions and pored over court records until you had put together a detailed and precise accounting of each stage in the deadly quarrel.

How much would you know? The answer is, not much. You'd learn that there were two families in Harlan who didn't much like each other, and you'd confirm that Wilse Howard, who was responsible for an awful lot of the violence, probably belonged behind bars. What happened in Harlan wouldn't become clear until you looked at the violence from a much broader perspective.

The first critical fact about Harlan is that at the same time that the Howards and the Turners were killing one another, there were almost identical clashes in other small towns up and down the Appalachians. In the famous Hatfield-McCoy feud on the West VirginiaKentucky border not far from Harlan, several dozen people were killed in a cycle of violence that stretched over twenty years. In the French-Eversole feud in Perry County, Kentucky, twelve died, six of them killed by "Bad Tom" Smith (a man, John Ed Pearce writes in Days of Darkness, who was "just dumb enough to be fearless, just bright enough to be dangerous, and a dead shot"). The Martin-Tolliver feud, in Rowan County, Kentucky, in the mid-1880s featured three gunfights, three ambushes, and two house attacks, and ended in a two-hour gun battle involving one hundred armed men. The Baker-Howard feud in Clay County, Kentucky, began in 1806, with an elk-hunting party gone bad, and didn't end until the 1930s, when a couple of Howards killed three Bakers in an ambush.

And these were just the well-known feuds. The Kentucky legislator Harry Caudill once looked in a circuit court clerk's office in one Cumberland Plateau town and found one thousand murder indictments stretching from the end of the Civil War, in the 1860s, to the beginning of the twentieth century-and this for a region that never numbered more than fifteen thousand people and where many violent acts never even made it to the indictment stage. Caudill writes of a murder trial in Breathitt County-or "Bloody Breathitt," as it came to be known-that ended abruptly when the defendant's father, "a man of about fifty with huge handlebar whiskers and two immense pistols," walked up to the judge and grabbed his gavel:

The feudist rapped the bench and announced, "Court's over and ever'body can go. We ain't agoin' to have any court here this term, folks." The red-faced judge hastily acquiesced in this extraordinary order and promptly left town. When court convened at the next term the court and sheriff were bolstered by sixty militiamen, but by then the defendant was not available for trial. He had been slain from ambush.

When one family fights with another, it's a feud. When lots of families fight with one another in identical little towns up and down the same mountain range, it's a pattern.

What was the cause of the Appalachian pattern? Over the years, many potential explanations have been examined and debated, and the consensus appears to be that that region was plagued by a particularly virulent strain of what sociologists call a "culture of honor."

Cultures of honor tend to take root in highlands and other marginally fertile areas, such as Sicily or the mountainous Basque regions of Spain. If you live on some rocky mountainside, the explanation goes, you can't farm. You probably raise goats or sheep, and the kind of culture that grows up around being a herdsman is very different from the culture that grows up around growing crops. The survival of a farmer depends on the cooperation of others in the community. But a herdsman is off by himself. Farmers also don't have to worry that their livelihood will be stolen in the night, because crops can't easily be stolen unless, of course, a thief wants to go to the trouble of harvesting an entire field on his own. But a herdsman does have to worry. He's under constant threat of ruin through the loss of his animals. So he has to be aggressive: he has to make it clear, through his words and deeds, that he is not weak. He has to be willing to fight in response to even the slightest challenge to his reputation-and that's what a "culture of honor" means. It's a world where a man's reputation is at the center of his livelihood and self-worth.

"The critical moment in the development of the young shepherd's reputation is his first quarrel," the ethnographer J. K. Campbell writes of one herding culture in Greece. "Quarrels are necessarily public. They may occur in the coffee shop, the village square, or most frequently on a grazing boundary where a curse or a stone aimed at one of his straying sheep by another shepherd is an insult which inevitably requires a violent response."

So why was Appalachia the way it was? It was because of where the original inhabitants of the region came from. The so-called American backcountry states-from the Pennsylvania border south and west through Virginia and West Virginia, Kentucky and Tennessee, North Carolina and South Carolina, and the northern end of Alabama and Georgia-were settled overwhelmingly by immigrants from one of the world's most ferocious cultures of honor. They were "Scotch-Irish"-that is, from the lowlands of Scotland, the northern counties of England, and Ulster in Northern Ireland.

The borderlands-as this region was known-were remote and lawless territories that had been fought over for hundreds of years. The people of the region were steeped in violence. They were herdsmen, scraping out a living on rocky and infertile land. They were clannish, responding to the harshness and turmoil of their environment by forming tight family bonds and placing loyalty to blood above all else. And when they immigrated to North America, they moved into the American interior, to remote, lawless, rocky, and marginally fertile places like Harlan that allowed them to reproduce in the New World the culture of honor they had created in the Old World.

"To the first settlers, the American backcountry was a dangerous environment, just as the British borderlands had been," the historian David Hackett Fischer writes in Albion's Seed.

Much of the southern highlands were "debatable lands" in the border sense of a contested territory without established government or the rule of law. The borderers were more at home than others in this anarchic environment, which was well suited to their family system, their warrior ethic, their farming and herding economy, their attitudes toward land and wealth and their ideas of work and power. So well adapted was the border culture to this environment that other ethnic groups tended to copy it. The ethos of the North British borders came to dominate this "dark and bloody ground," partly by force of numbers, but mainly because it was a means of survival in a raw and dangerous world.*

The triumph of a culture of honor helps to explain why the pattern of criminality in the American South has always been so distinctive. Murder rates are higher there than in the rest of the country. But crimes of property and "stranger" crimes-like muggings-are lower. As the sociologist John Shelton Reed has written, "The homicides in which the South seems to specialize are those in which someone is being killed by someone he (or often she) knows, for reasons both killer and victim understand." Reed adds: "The statistics show that the Southerner who can avoid arguments and adultery is as safe as any other American, and probably safer." In the backcountry, violence wasn't for economic gain. It was personal. You fought over your honor.

Many years ago, the southern newspaperman Hodding Carter told the story of how as a young man he served on a jury. As Reed describes it:

The case before the jury involved an irascible gentleman who lived next door to a filling station. For several months he had been the butt of various jokes played by the attendants and the miscellaneous loafers who hung around the station, despite his warnings and his notorious short temper. One morning, he emptied both barrels of his shotgun at his tormenters, killing one, maiming another permanently, and wounding a third.... When the jury was polled by the incredulous judge, Carter was the only juror who recorded his vote as guilty. As one of the others put it, "He wouldn't of been much of a man if he hadn't shot them fellows."

Only in a culture of honor would it have occurred to the irascible gentleman that shooting someone was an appropriate response to a personal insult. And only in a culture of honor would it have occurred to a jury that murder-under those circumstances-was not a crime.

I realize that we are often wary of making these kinds of broad generalizations about different cultural groups-and with good reason. This is the form that racial and ethnic stereotypes take. We want to believe that we are not prisoners of our ethnic histories.

But the simple truth is that if you want to understand what happened in those small towns in Kentucky in the nineteenth century, you have to go back into the past-and not just one or two generations. You have to go back two or three or four hundred years, to a country on the other side of the ocean, and look closely at what exactly the people in a very specific geographic area of that country did for a living. The "culture of honor" hypothesis says that it matters where you're from, not just in terms of where you grew up or where your parents grew up, but in terms of where your great-grandparents and great-great-grandparents grew up and even where your great-great-great-grandparents grew up. That is a strange and powerful fact. It's just the beginning, though, because upon closer examination, cultural legacies turn out to be even stranger and more powerful than that.

3.

In the early 1990s, two psychologists at the University of Michigan-Dov Cohen and Richard Nisbett-decided to conduct an experiment on the culture of honor. They knew that what happened in places like Harlan in the nineteenth century was, in all likelihood, a product of patterns laid down in the English borderlands centuries before. But their interest was in the present day. Was it possible to find remnants of the culture of honor in the modern era? So they decided to gather together a group of young men and insult them. "We sat down and tried to figure out what is the insult that would go to the heart of an eighteen-to-twenty-year-old's brain," Cohen says. "It didn't take too long to come up with 'asshole.' "

The experiment went like this. The social sciences building at the University of Michigan has a long, narrow hallway in the basement lined with filing cabinets. The young men were called into a classroom, one by one, and asked to fill out a questionnaire. Then they were told to drop off the questionnaire at the end of the hallway and return to the classroom-a simple, seemingly innocent academic exercise.

For half the young men, that was it. They were the control group. For the other half, there was a catch. As they walked down the hallway with their questionnaire, a man-a confederate of the experimenters-walked past them and pulled out a drawer in one of the filing cabinets. The already narrow hallway now became even narrower. As the young men tried to squeeze by, the confederate looked up, annoyed. He slammed the filing cabinet drawer shut, jostled the young men with his shoulder, and, in a low but audible voice, said the trigger word: "Asshole."

Cohen and Nisbett wanted to measure, as precisely as possible, what being called that word meant. They looked at the faces of their subjects and rated how much anger they saw. They shook the young men's hands to see if their grip was firmer than usual. They took saliva samples from the students, both before and after the insult, to see if being called an asshole caused their levels of testosterone and cortisol-the hormones that drive arousal and aggression-to go up. Finally they asked the students to read the following story and supply a conclusion:

It had only been about twenty minutes since they had arrived at the party when Jill pulled Steve aside, obviously bothered about something.

"What's wrong?" asked Steve.

"It's Larry. I mean, he knows that you and I are engaged, but he's already made two passes at me tonight."

Jill walked back into the crowd, and Steve decided to keep his eye on Larry. Sure enough, within five minutes, Larry was reaching over and trying to kiss Jill.

If you've been insulted, are you more likely to imagine Steve doing something violent to Larry?

The results were unequivocal. There were clear differences in how the young men responded to being called a bad name. For some, the insult changed their behavior. For some it didn't. The deciding factor in how they reacted wasn't how emotionally secure they were, or whether they were intellectuals or jocks, or whether they were physically imposing or not. What mattered-and I think you can guess where this is headed-was where they were from. Most of the young men from the northern part of the United States treated the incident with amusement. They laughed it off. Their handshakes were unchanged. Their levels of cortisol actually went down, as if they were unconsciously trying to defuse their own anger. Only a few of them had Steve get violent with Larry.

But the southerners? Oh, my. They were angry. Their cortisol and testosterone jumped. Their handshakes got firm. Steve was all over Larry.