Tribalism is human nature
The default human wiring segregates the world into two groups: “my people” and “not my people.” Unity can only succeed to the extent that it overcomes this tendency.
From Influence – Cialdini (2021), ch. 8 “Unity: The ‘We’ Is the Shared Me’”:
The range of circumstances and settings where “we” relationships affect human responding is impressive and varied. Nonetheless, three constants have emerged. First, members of “we”-based groups favor the outcomes and welfare of fellow members over those of nonmembers—by a mile. For example, members of rival work groups (that each included two humans and two robots) not only held more positive attitudes toward their own teammates but also went so far as to hold more positive attitudes toward their own team’s robots than toward the rival team’s robots—and humans! Second, “we”-group members are highly likely to use the preferences and actions of fellow members to guide their own, which is a tendency that ensures group solidarity. Finally, these partisan urges to favor and follow have arisen, evolutionarily, as ways to advantage our “we” groups and, ultimately, ourselves. Indeed, after reviewing decades of relevant scientific work on the point, one set of scholars concluded not just that tribalism is universal but that “tribalism is human nature.”
From Team of Teams – McChrystal, et al. (2015), ch. 6 “Team of Teams”:
Though any given SEAL was, like the entirety of our Task Force, on paper fighting the same fight, he was really fighting for his squad. The men on a squad prepare, deploy, and operate together. They spend four-month rotations in the alien, hostile deserts of Iraq or the arid plains of Afghanistan, and they rarely have meaningful, friendly interaction with anyone outside this circle. Imagine the closest roommate relationship you’ve ever had and multiply that by one hundred. The bonds within squads are fundamentally different from those between squads or other units. In the words of one of our SEALs, “The squad is the point at which everyone else sucks. That other squadron sucks, the other SEAL teams suck, and our Army counterparts definitely suck.” Of course, every other squad thought the same thing.
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