“Tribalism” as the term is frequently used by evolutionary biologists, means a human tendency to form groups larger than the personal network. What they are actually groping towards here is the way humans universally affiliate with others because they recognize they have important things in common. Seen as an evolved aspect of human nature, this tendency has nothing to do with any instinctive oppositional behaviour due to “coalitional” violence between competing “tribes”. Instead, it has everything to do with the extension of information exchange through networks that individuals forge. Unless they are taught to set group boundaries artificially by excluding people who look different, or speak a different language, or have different beliefs, humans have a tendency to curious about the exotic, not repelled. Or do you think tourism is about being more “relaxed” in foreign places?
Saying this is “caused” by empathy, or intersubjective compassion, does not explain it. Other species too have empathy and compassion. Raised together, or having experienced helpful interaction, other species, besides our own, can treat even members of another species with empathy and compassion: dogs and cats can be friends; an electric eel can become trusting and affectionate with a human diver.
“A theoretical model moreover suggests that evolution could not have made us any other way - if we are to deliberate at all. The authors find that, depending on parameter values, selection can favour all-out defectors, who never deliberate, or dual-process cooperators, who intuitively cooperate and who sometimes use deliberation to override their cooperative intuition, but it never favours dual-process defectors, who sometimes override their impulse to defect as they deliberate.”
(quote from “A general evolutionary framework for the role of intuition and deliberation in cooperation” by Stephan Jagau & Matthijs van Veelen)
Humans take this a step beyond: a brother is anyone we swear oath it is; two people who might have been strangers most of their lives are said to become “one flesh” because they vow it is so. Even a stranger should be helped if in trouble - this is the mark of true humanity in more than one religious belief system. Indeed, humans are even capable of perceiving their pets as “members of the family” and of dying to save a strange dog from drowning. We can even perceive, not only all humanity, as kindred, but all living things.
People in most cultures extend circles of acquaintance, friendship, and closer relationship well beyond those companions seen frequently over the course of a year. This networking uses our pre-existing capacity for extension of “fellow feeling” to expedite the spread of INFORMATION CODED SYMBOLICALLY. That information does not just pass between trusted companions in an individual network, it jumps from network to network and clear across continents and around the world across only six or seven degrees of separation.
This kind of inter-net evolved hundreds of thousands of years ago, modern written and digital communication systems merely add time depth and speed to a pre-existing gigantic cooperative effort enhancing accumulation and conservation of information.
That IS the whole magic trick of adding symbols – then language – to culture.
Culture is, in most species, that aspect of behaviour that represents the learned and shared: the cognitive niche that is COLLECTIVE. In our own genus, we see evidence that a collective cognitive niche was transformed: it became THE adaptation to every novel environment.
The vast extension of intersubjective communication across networks was a way of assuring the long term viability of any one local collective cultural niche. Like genetic information, cultural information can become too narrow, too homogenous; and this can be as dangerous as inbreeding depression leading to reduced evolutionary fitness.
Any one culture, adapting to it its local ecosystem, is vulnerable to over-specialization. A sea-coast people, whose food supply comes from marine resource, may lose the knowledge of bows and arrows; a mountain people might lose the knowledge of how to build sea-worthy boats. In both locations, people have a better chance of surviving long term upheavals in climate and geography if they share knowledge of boats AND archery.
Identifying with people on the basis of a common language, common customs, common sacred values, or even just common humanity, is NOT about politics or war between groups at all, although it can be exploited politically for just that purpose. No, it is about the human adaptation to a cultural environment: a culture too open to outside fashions and ideas can be swamped and lose the integration of the local adaptation to a particular geography and ecology. A fad for boating and shark fin soup is not going to have survival value among a mountain culture living at 6000 feet above the sea, now is it? We can enjoy learning about this without doing it.
Identifying yourself with humanity is – and always was – about remaining open to information flow between different streams of culture; but this has to be countered with love of one’s own ways of being and thinking. Therefore, this is what defends local adaptations from being swamped by tidal waves of novel ideas and exotic ideas and cuisines. We all do the same – and it is not a thing that shows hostility to “outside” ideas and identities.
Please understand, therefore, that tagging yourself with markers of of your natal or adopted group - by accent, dialect, language, dress, or decoration…is a normal way that each culture balances itself so it can persist within a meta-cultural sea. It does not mean we evolved to live in small groups or cultures that were automatically mutually hostile and/or competitive.
The fact that your cultural identity comforts you and makes you nostalgic when you are away from those who share a common heritage is a HIGHLY adaptive trait, as is the root of the conservatism that keeps old traditions alive.
Pan-human and ethnocentric sentiments need not cancel each other out, any more than novelty-seeking and nostalgia are mutually exclusive tendencies: in fact all of these are critical for the long term survival of any one local culture.
It is most unfortunate that these can be manipulated politically to seem so dichotomous and oppositional. I suppose “identity” is the original politics of mankind, but who said it was always weaponized?
Living in a young nation as a refugee in the aftermath of WWII, I was not alone in feeling wonderment at the joys of a multi-ethnic, multi-lingual society. It was at time austere and confusing, but it made me appreciate the benefits of membership “in-group” lets you sample a glorious rainbow without losing the pot of gold at the end - that is nestling down in the familiar scents and accents of home.
Sampling the rainbow together is more easily achieved when our first response to the arrival of strangers from faraway places is to prepare a feast of welcome; not to reach for weapons of war. Throughout most of our evolution, our rainbow was every new group encountered. The original out-group were not strangers, they were the coercive and violent bullies, the slick and selfish manipulators, the disloyal and cowardly liars, the freeloading and gas-lighting narcissists, and the murderers. They were – and still are – close to us.
It took communicative alliances to define and recognize such people WITHIN each society. The fact that human beings are swiftly inclined to punish, expel, or even to execute such non-cooperators is ancient; it may well be older than our species. But it can be used to incite racism and genocide and war against whole groups on the flimsiest of tags: Jane Elliot did it within two days, turning a class of cheerful friends into hateful factions purely on the basis of eye colour.
Why do you think there is Neanderthal and Denisovan and other “archaic” DNA in our genome today? Because, unlike today, people in the late Pleistocene recognized common humanity and acted accordingly. They did not worry about the size of brow ridges or eyes colour. Anyone who imagines “modern humans” raiding Neanderthal camps and “stealing women” - or that Neanderthal DNA got into “modern” humans by means of rape - has not thought it through.