Tribalism is a double-edged sword

Reason is at the mercy of anger, but the same neurological responses that are helping to divide society could unite us

By R Douglas Fields

Follow R Douglas Fields on Twitter @rdouglasfields1


People are angry. The votes for Brexit in the UK and Trump in the US shocked the world and exposed deep fissures in society. Both events had rational explanations rooted in complex economic and social issues. But each event was also characterised by narratives of ‘otherness’. Fears of immigration, the notion that these countries should be ‘great again’ or should ‘take back control’, and talk of elites all ignited a sense of ‘us and them’ and spoke to a deep-seated tribal instinct. What are the roots of this rage against ‘others’ and why is it exploding now? For fresh answers, look past politics and see instead inside the human brain.

To a neuroanatomist’s eye the human brain has not changed since the stone age. The neural circuits of rage in our brain were forged in a survival-of-the-fittest struggle on the prehistoric open plains of Africa. What I see as a neuroscientist is an organ grappling to cope with an artificial environment that it was not designed for. Nature’s control mechanism, which keeps the biology of every species in check with its changing environment (natural selection), is outstripped by the furious pace of technological advancement that transforms the environment of human beings faster than the cycle of a generation.

From a biological perspective, the peril that we face is daunting because the success and survival of any species are at risk when its environment changes faster than genetics. As a consequence, the neural circuits of anger and aggression within the human brain are vulnerable to misfiring in the modern world.

What we see in politics today is tribalism played out in public arenas. Building a wall spanning the width of a continent, blocking people of certain religions from entry into the US, and breaking up the economic alliances between the European Union and the UK, are all representations of an ‘us vs them’ mentality.

From a biological perspective, the peril that we face is daunting because the success and survival of any species are at risk when its environment changes faster than genetics

However, tribalism is a double-edged sword. The ability of human beings to form tribes, to coalesce into cooperative groups, is the foundation of our success as a species. We do this so effortlessly that we fail to appreciate how remarkable and complex this behaviour is. Men divide arbitrarily into teams, ‘shirts and skins’, and instantly engage in intense athletic competition. Within a fraction of a second, they distinguish another person as either ‘us’ or ‘them’, and quickly divine their intentions. And this behaviour stretches well beyond the sports field. A mother could not recognise instantly the cry of her own child above all others unless her brain perceived the cries of other children differently.

The neurocircuitry of instantaneous discrimination is a vital part of our brain function, which, by necessity, operates faster than the speed of thought. Our conscious mind has an astonishingly limited capacity. We can hold on average no more than a string of seven digits in our working memory. This is such a pitiful limit that we must resort to pencil and paper just to carry out long division. Now consider a football player collecting and crunching all the diverse data necessary to determine in a flash if another person on the field is one of ‘us’ or ‘them’. In the most complex decisions we face, such as whom to marry or where to live, we tend to trust our feelings. That is because there is much more to decision-making than conscious deliberation.

The ability to distinguish instantly ‘us’ from ‘them’ evolved for the critical life-saving purpose of threat detection. In the face of a sudden threat there may be no time to think, so nature has equipped the human brain with high-speed neural pathways that send information from all of our senses to the brain’s threat detection centre before it goes to our cerebral cortex, where consciousness arises. This input from our senses eventually reaches our cerebral cortex by passing over a longer, slower and more complicated route. The brain’s threat detection circuitry is constantly analysing the vast amounts of data on our internal and external state, and is always on the lookout for danger.

There is much more to decision-making than conscious deliberation

Preconscious processing

You duck and put your arms out to deflect an errant ball streaking into your peripheral vision; only afterwards does your conscious mind kick in and ask, “What was that?” Your subconscious brain circuitry has already detected a threat and set you on an instantaneous, definitive course of action to protect yourself before you were consciously aware of the danger. Complex motor commands were shot to your muscles to evade or confront the danger and systems throughout your entire body were energised to propel you into action. Your heart pounds, your blood pressure skyrockets, your sweat glands pour out perspiration to cool you down, your muscles tense, ready to fight or flee, but you have already responded and evaded the danger before you are consciously aware.

The same threat detection circuitry is engaged any time we encounter another person. We size them up before we consciously realise what is happening. This ‘preconscious’ information processing can be studied in the human brain by detecting electrical signals in the appropriate brain regions, and these systems operate long before any signals develop in the cerebral cortex to provoke a conscious thought.

The outcomes of the votes in the UK and US were a surprise and bewildering to many, who watched people rage at elites who had deprived them of opportunity, then usher in economic instability. Equally, an angry backlash occurred against those voters, who were characterised as ignorant and ‘other’. But neuroscience provides some answers to these actions because rage and reason are different brain functions. Emotion and cognition are carried out in different brain circuits.

Language arises from the cerebral cortex, so our brain’s threat-detection mechanism in the amygdala and hypothalamus does not have language to set out all the reasons for the perceived danger. Instead, the output of our brain’s threat-detection circuitry is communicated to our conscious awareness by multicoloured emotions that convey very specific messages about the threat. Fear, sadness, envy, regret, anger and all the other subtle emotions we experience are the result of our brain’s assessment of our current state. This is why, when our threat detection mechanism identifies differences in a stranger, we feel a visceral reaction. And emotions are powerful motivators of behaviour. Whether we fully understand what sparked them or not, emotions move our decision-making and our behaviour.

Rage and reason are different brain functions. Emotion and cognition are carried out in different brain circuits

The emotion of anger serves one purpose: to prepare us to fight. Humans have language, so verbal battles can be substituted for physical combat, but the two are twin gears of the same mechanism; each one moves the other. Violence is necessary for survival so our brain is equipped with the neural circuitry to launch this behaviour, but engaging in violence simultaneously puts survival at risk. Therefore, violent behaviour is highly controlled, initiated by distinct neural circuits that are triggered by a few specific provocations. The instantaneous aggressive reaction of a mother to protect her young, for example, is triggered by a different neural circuit than other provocations that result in sudden aggression.

One of the nine triggers of rage that provoke this reaction in the brain is called ‘T’, for tribe. Early in human evolution our species lived in small groups, where everyone likely knew each other. An encounter with a strange group represented a threat to survival from competition for resources, and violence is how social animals defend their group. This is true for most vertebrates and especially so for primates. Males are equipped by nature with physical strength for defence and aggression, which is why they carry out most of the violence and aggression.

The problem today is that, while this Neolithic neural circuitry was balanced to the level of threat our species experienced when our brain evolved in an environment of relatively infrequent interactions with strange groups, this circuitry is not so well calibrated for the modern world. Technology has enabled the tremendous increase in numbers of homo sapiens by providing the means to house and feed large populations living in huge social groups. In addition, high-speed transportation and instantaneous communication in the modern world result in constant pressure on the ‘T’ trigger. People of different cultures, classes, values and races do not live in complete isolation any more. We rub elbows because we can cross the globe in a matter of hours, and we interact over the internet and through broadcast media instantaneously and incessantly.

To be part of a group is a fundamental human need

Unfortunately, those who do not find affinity and success as a member of society will find a group that will embrace them. This is the appeal of gangs that can suck inner-city youth into a self-destructive and violent life that offers nothing but membership for a person who has none. To be part of a group is a fundamental human need. Moreover, the internet brings anonymity and superficiality in place of face-to-face interactions. Just as anonymity inside a car diminishes the ability to see those in other cars as people, causing drivers to rage on highways, so too is the case on the information superhighway.

Reason or rationalisation?

The message here is not that anyone who voted for Brexit or Trump is a caveman. Tribes are necessary and must be protected. If what drove a vote was deliberation, then the neural circuitry of ‘us vs them’ is not pertinent. The difficulty here is to discern reason from rationalisation. The telling indicators are whether the arguments are directed at what is wrong rather than whom, and whether anger and violence fuel the rhetoric. “If you see somebody getting ready to throw a tomato, knock the crap out of ’em, would you? Seriously. Okay? Just knock the hell — I promise you, I will pay for the legal fees. I promise. I promise,” said the US president on his successful campaign to the White House. And this is what disturbs people about Brexit and Trump: the anger and hostility, and the attacks directed at people rather than their arguments. Cogent arguments cannot be laid out in 140-character ejaculations, and there is so much vicious violence against ‘others’.

But the paradox is that the same neural circuitry that divides us also unites us with the realisation that we share affinity as members of a larger group. Republican or Democrat, both are citizens of the US, and immigrant or resident, all have families they love. So the photograph of a lifeless child washed up on a beach in Greece touches us all, and the ‘T’ trigger unites us.

I hope that, in time, the increasing encounters that new technology enables between people will diminish perceived differences and strengthen the things we share as human beings. The media has done this for sports figures of different nationalities. Technology makes them familiar to us and then we embrace them as a valued member of ‘our’ group. However, the rewards of this positive change will not be felt if we choose to separate because we are angry.


This article first appeared in the RSA Journal Issue 4 2016–17

R Douglas Fields is a neuroscientist and author of the book, ‘Why We Snap: Understanding the Rage Circuit in your Brain’

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