You don’t think of yourself as someone who needs enemies. The science of us versus them thinking suggests your brain disagrees. Here’s the dark neuroscience behind why humans are wired to divide, exclude and oppose — and why understanding it might be the most important thing you do today.
You’re a reasonable person.
You don’t consider yourself tribal. You don’t think in us and them terms consciously. You believe in fairness, in judging people as individuals, in rising above the kind of primitive group thinking that causes so much damage in the world.
And yet.
You feel a specific satisfaction when a rival team loses. A quiet pleasure when someone you dislike fails. A tightening of loyalty when your group is criticised. A flash of suspicion toward the stranger whose worldview differs from yours.
Not because you’re a bad person.
Because you have a human brain. And the science of us versus them thinking reveals that your brain was built — deeply, specifically, neurologically — for tribal division. Not as a bug. As a feature. One that kept your ancestors alive and now quietly shapes nearly everything about how you see the world.
Your Brain Sorts People in Milliseconds
Here’s where the science of us versus them thinking begins.
Your brain categorises every person you encounter into in group or out group with extraordinary speed — research suggests the process takes as little as 170 milliseconds. Before you’ve consciously registered anything about a person your brain has already sorted them.
Same team. Different team.
Us. Them.
This categorisation isn’t neutral. It immediately activates different neural processing for each group. In group members receive automatic empathy, trust and positive attribution. Out group members receive automatic suspicion, reduced empathy and negative attribution.
The same behaviour — interpreted differently depending entirely on which side of the us them line the person doing it falls on.
Your in group member who was late had a good reason. The out group member who was late is unreliable. Same behaviour. Completely different neural processing. Completely different conclusion.
🔬 THE RESEARCH
Neuroscientist Jay Van Bavel at New York University has spent years studying the science of us versus them thinking in the brain. His research found that in group membership activates the ventromedial prefrontal cortex — the brain region associated with self representation and positive valuation — while out group perception activates regions associated with threat and negative evaluation. The brain doesn’t just prefer the in group. It neurologically processes in group and out group members as fundamentally different categories of human being. The science of us versus them thinking is not a social attitude. It is brain architecture.
Why Your Brain Needs the Out Group
Here’s the part of the science of us versus them thinking that most people find genuinely uncomfortable.
Your sense of group identity doesn’t just depend on who’s in your group. It depends on who isn’t.
Groups define themselves partly through contrast — through the explicit or implicit statement that we are not them. The out group provides the boundary that makes the in group coherent. Without something to be different from the group identity becomes fuzzy, uncertain, harder to feel.
This is why groups — social, political, religious, national — so reliably develop out groups even when none are strictly necessary. The enemy isn’t always a response to a genuine threat. Sometimes the enemy is constructed because the group needs one to maintain its own cohesion.
Henri Tajfel — one of the most important social psychologists of the twentieth century — demonstrated this in his minimal group experiments. He assigned people to completely arbitrary groups — based on nothing more than preference for one abstract painter over another — and found that within minutes people showed in group favouritism and out group discrimination.
No history. No conflict. No real difference.
Just the knowledge of group membership. And the brain did the rest automatically.
💡 SCIENCE OF US VERSUS THEM THINKING FACT
Research from Ohio State University found that sports fans watching a rival team lose showed activation in reward processing brain regions — the same areas that fire when you win something yourself. Your brain genuinely experiences the failure of an out group as a personal reward. The science of us versus them thinking suggests that schadenfreude — pleasure at another’s misfortune — isn’t a dark personality quirk. It’s a neurological response your brain produces automatically when the out group loses and the in group wins by comparison.
The Empathy Gap
Here’s one of the most practically significant findings in the science of us versus them thinking.
Empathy — your brain’s capacity to simulate and feel what another person experiences — is dramatically reduced for out group members compared to in group members.
Brain imaging studies show that watching an in group member experience pain activates your pain processing regions — you feel it with them. Watching an out group member experience the same pain activates those regions significantly less. In some studies — particularly where the out group is strongly defined as an enemy — it barely activates them at all.
You don’t lack the capacity for empathy. Your brain is selectively applying it based on group membership.
This is the neurological mechanism behind how ordinary people in extraordinary circumstances become capable of treating other humans in ways they would find unthinkable toward their own group. The out group stops being processed as fully human. Not through conscious decision. Through the gradual, automatic, neurologically driven reduction of empathy that tribal thinking produces.
Understanding this isn’t about assigning blame. It’s about recognising a mechanism that operates in all human brains — including yours and mine — and understanding what conditions allow it to become dangerous.
Why Threat Strengthens Tribal Thinking
The science of us versus them thinking has a specific and important relationship with threat.
When your group feels threatened — by competition, by criticism, by genuine danger or by perceived danger — in group loyalty increases and out group hostility increases simultaneously. Both effects amplify together.
This happens because threat activates the amygdala and the entire stress response system. Under threat your brain becomes more conservative, more pattern dependent, more reliant on familiar group structures for safety. The comfort of us becomes more neurologically urgent. The danger of them becomes more neurologically vivid.
This is why political and social polarisation tends to intensify during periods of economic stress, social uncertainty and perceived cultural threat. The brains involved aren’t becoming more irrational. They’re responding to threat in exactly the way they were designed to — by tightening tribal bonds and heightening out group suspicion.
The science of us versus them thinking suggests that you cannot reduce tribalism by arguing against it during periods of high threat. The threat response is running the show. The rational prefrontal cortex is largely offline.
What Actually Helps
Understanding the science of us versus them thinking doesn’t make you immune to it. But it opens specific and evidence backed possibilities for working against it.
Individuation deliberately. The out group empathy gap closes significantly when you engage with individual out group members as specific people rather than as category representatives. Your brain’s tribal processing operates on categories. Individual human contact disrupts categorical thinking by introducing complexity that the tribal system can’t easily file.
Find superordinate identity. Research found that reframing group membership at a higher level — not Democrat versus Republican but Americans, not rival sports fans but sports lovers — reduces in group out group hostility by shifting what the relevant us is. You’re still tribal. But the tribe just got bigger.
Recognise threat amplification. When you notice your tribal thinking intensifying — when us and them feels more urgent, more visceral, more certain — ask whether threat is driving it. Naming the mechanism doesn’t eliminate it but it creates enough distance to make a different choice.
Seek genuine contact. The most evidence backed intervention for reducing out group hostility is meaningful personal contact with out group members — not superficial exposure but genuine human encounter. Your brain’s empathy system responds to the individual in front of it. Give it the chance.
The Bottom Line
You don’t need enemies. But your brain thinks you do.
The science of us versus them thinking reveals a neural architecture so deeply wired for tribal division that it operates before consciousness begins, below rational awareness, in the most fundamental processing your brain performs about other human beings.
This doesn’t excuse what tribal thinking produces. It doesn’t make the harm it causes less real.
But it does mean that fighting tribalism starts not with condemning other people for their tribal thinking — which your brain will experience as confirmation that they are the out group — but with recognising the mechanism operating in your own mind.
The science of us versus them thinking lives in every human brain.
Including the one reading this.