American politics, we are told incessantly, has become “tribal.” It is not meant as a compliment. References to tribalism are intended to capture how Western, and especially American, political life has regressed in recent years into a more primitive state, one characterized by polarization, insularity, vengefulness, and lack of compromise. New York Times columnist Thomas Friedman asserts that the politics reigning over “tribalized” societies is “‘rule or die’ — either my tribe or sect is in power or we’re dead.” The psychologist Steven Pinker speaks of “our impulses of authoritarianism and tribalism,” while his Harvard colleague the biologist E.O. Wilson flatly declares that “the true cause of hatred and violence is faith versus faith, an outward expression of the ancient instinct of tribalism.” Even former U.S. President Barack Obama, whose mother was an anthropologist, has stated that “the power of tribalism” to which people may naturally revert is “the source of a lot of destructive acts.” As popular rhetoric, the tribalism metaphor, given its sheer pervasiveness, must be judged a success. But as an attempt to illuminate our present moment, it represents the worst kind of failure. It draws its force from a legitimate scientific insight that it distorts beyond recognition. From an anthropological perspective, Western politics has, it may be argued, become more tribal. Tribes are distinguished from other human groups by their relatively clear social boundaries, often defined by kinship and demarcated territory. It’s clear that our political groups are increasingly based on single aspects of common identity with unambiguous boundaries, such as race and educational status. Equally undeniable, however, is that most commentators vastly misunderstand the nature of tribes. The mistaken view of tribes as primitive, violent, and insular is already having pernicious effects on our response to this new era of politics. Tribalism, contrary to popular belief, is not atavistic. But American political rhetoric, by suggesting otherwise, has become essentially fatalistic; it suggests that tribalism marks a reversion to some natural and ancestral mode of thinking and, thus, even if tribes can be temporarily transcended, their pull remains inexorable. If we hope to live productively in this new political era, it helps to understand what tribes actually are — and how, rather than simply being the cause of our political problems, tribalism can also contribute to the solution.

Our colloquial evocation of tribalism mostly reflects outmoded anthropology. Scientists once believed that tribes were defined by their rigid social structures. Their traditional social practices — such as habitual rejections of private property — were understood to be instinctual and impervious to change. Meanwhile, the structure of their social relationships was believed to be coercive; tribes were thought to be able to integrate their individual members only through the stultifying and imposed repetition of social customs.

The political implications of this armchair anthropological analysis are clear enough. If tribalism is both instinctual and exclusionary, then we should treat our present-day tribes — our identity groups or even political parties — as a natural refuge from otherwise inevitable social conflict. We should also treat the restoration of a more inclusive form of social cohesion as an impossibility, absent some social or political revolution.

But present-day anthropologists know better. Years of empirical studies of actual tribes show that even as they are defined by relatively narrow identities, they are also characterized by porous boundaries. Tribes continually sample one another’s practices and social forms. Speaking about American Indians, James Boon, a Princeton anthropologist, noted that “[e]ach tribal population appears almost to toy with patterns that are fundamental to its neighbors.”

Tribes also frequently adopt outsiders. North American tribes commonly invited captured whites into their communal life. (The subsequent process of integration was so effective that even when captives were liberated, many chose to remain with the adopting tribe.) In other instances, among certain tribes in North Africa, members could voluntarily leave their own tribe and join another.

Reciprocity, too, is a central part of traditional tribal life. Tribesmen constantly create forms of mutual obligation, both within and across tribes. Moral or material indebtedness, they know, can serve as the foundation of a strong relationship. It is common across various tribes in different cultures — including the Berbers of North Africa, for example — for leaders to be chosen or ratified by the group’s opponents on the theory that one’s current enemy may later be an ally. When Berber tribes find themselves in a dispute, one group may call on the leader of the other to settle the claim, in the knowledge that he will not risk his ability to form later alliances by simply supporting his own side.

Many tribes — among them the Mae Enga of Papua New Guinea and the Lozi of Central Africa — also share the common practice of marrying members of enemy tribes to reduce the likelihood of internecine warfare. For the same reason, tribes also frequently develop residence patterns to ensure that grandchildren are raised in a different kinship group. As a result of intermarriage and trading relations, a high proportion of tribes are multilingual.

Nor are tribes inherently authoritarian. Tribes often do not like too much power in too few hands for too long a period of time. To that end, they employ a wide variety of practices that redistribute power, whether by appointing multiple “chiefs” for limited periods and tasks or using gossip, humor, intoxicants, and ritual reversals to undermine anyone who might claim pervasive power. Perhaps most important: Historically, tribes generally have avoided claims of moral superiority, both within and among tribal groups. Most tribes, as the Oxford anthropologist Paul Dresch says of Yemeni groups, practice an “avoidance of any absolute judgment, a kind of moral particularism or pluralism.” For members of these tribes, each situation must be judged independently, with no claim to absolutes governing all eventualities and relationships.

This might sound quite distant from the partisan tribes of our present politics, which seem mostly to be characterized by their pugnaciousness. But the point is that, anthropologically, narrow identity groups such as tribes — or political parties in our hyperpartisan era — aren’t defined by exclusionary traits. The existence of narrow group identities doesn’t imply hostility among such groups.

Indeed, there is a reason that tribes historically have not embraced the rigid structural identities and institutions evident in our politics today. Excluding immigrants or cultural outsiders in the name of social solidarity comes at a price. Actual tribes know that social isolation or claims of moral superiority limit their flexibility. But we can only sustainably avoid paying such costs when we understand that resorting to defensive boundaries, even when we have gone “tribal,” is not our natural default position.