Begin with something simple: kin selection. Your genes care about copies of themselves. You share 50% of your genes with siblings, 25% with cousins. Evolution sculpted your nervous system to recognize genetic relatives and favor them. This created kinship-based cooperation — the foundation of human social life.1
But here's the problem: kinship recognition is hijackable. The green-beard effect shows how arbitrary social traits can trigger the same neural systems that evolved for genetic kinship. Code "shares my ethnicity" as a kinship marker, and your insula, ACC, and amygdala will treat ethnic strangers as kin, ethnic enemies as threats. The kinship system never actually sees the DNA. It just sees the markers — and the markers can be rewritten through propaganda.2
Now add status hierarchies. Testosterone rises when your status is challenged. The challenge hypothesis says testosterone doesn't create aggression — it amplifies whatever behavioral patterns are locally understood as status maintenance. In a martial culture, this means violence. In an academic hierarchy, it means intellectual domination. In a nationalist hierarchy, it means defending national purity. The hormone is the same; the behavior is culturally scripted. And once your status is tied to defending a national or ethnic group, testosterone amplifies your willingness to attack outgroups.3
Now disable empathy. Propaganda that links a target group to disgust, disease, contamination activates the insula's aversion systems. The same insula that processes empathic pain also processes moral disgust. Once you've made a group seem disgusting — not just bad, but contaminating — the brain's empathic response begins to collapse. Your ACC loses its capacity to register their suffering as mattering. Your amygdala treats them as threat. Empathy doesn't just decrease; it actively inverts. The suffering of the "vermin" begins to feel righteous.4
Now add sacred values. Propaganda that repeatedly links sanctity language (purity, honor, survival, transcendence) to the group creates a sacred value that overrides utilitarian reasoning. Once the nation, the race, the religion becomes sacred, defending it becomes non-negotiable. Violating the sacred value produces such intense anxiety that the person cannot consider alternatives. The vmPFC codes the sacred value as infinitely important, and the dlPFC's ability to think critically goes offline.5
Finally, watch reciprocal altruism invert. Normally, reciprocity works because reputation matters — you help people who help you back, you punish defectors. But in the context of a mobilized group united around a sacred value, reciprocal altruism becomes genocidal cooperation. Your unit will do anything for the group; the group will do anything for the nation; the nation is sacred and demands atrocity to survive. What started as "I'll help you if you help me back" becomes "I'll kill for the group because the group is sacred and betraying it would destroy me."6
These mechanisms don't sit in isolation. They cascade.
All of these processes converge on the same neural systems: the insula (processing disgust and moral contamination), the amygdala (detecting threat), the ACC (registering pain and social loss), the vmPFC (coding values), and the dlPFC (deliberating rationally).
In a normal state, these systems are in dialogue. Your insula might detect something disgusting, your amygdala might sense threat, but your ACC and dlPFC together create a more complex response. You can feel disgust about your disgust. You can examine whether the threat is real. You can deliberate about what to do.
But propaganda targets this system's architecture directly. Repeated exposure to dehumanizing narratives changes the wiring itself. The insula becomes hyper-responsive to images of the target group. The amygdala's threshold for threat-detection drops. The ACC's capacity to resonate with their suffering declines. And critically, the dlPFC's connection to the ACC weakens — your ability to think carefully about what you're doing becomes literally disconnected from your capacity to feel others' pain.
Brain imaging of genocide perpetrators shows exactly this pattern: reduced activation in regions that normally support empathic response (ACC), reduced connectivity between dlPFC and amygdala (which normally allows rational override of threat), and hyperactivity in regions supporting in-group identity and out-group threat-detection.7
This isn't moral failure or evil temperament. This is neurobiological recalibration through systematic exposure to propaganda. The perpetrator's nervous system has been rewired. They literally cannot feel empathy for the victims because the neural pathways that support empathy have been reweighted. And they cannot stop, because the vmPFC is now coding the group as sacred — violating that value produces unbearable anxiety.
The most insidious aspect of this cascade is how dopamine gets attached to the violence itself.
Early in the propaganda phase, participation in group action releases dopamine — the motivation neurotransmitter. Attending rallies, performing group rituals, participating in the collective action against the enemy: all of these produce the warm, motivated state of dopamine release. The person feels good participating in the group.
As the violence escalates, the same dopaminergic systems remain engaged. The soldier who kills the enemy gets dopamine release — not just from the kill itself, but from the group approval of the kill. From being praised as heroic. From receiving status among his unit. From the sense that he's sacrificing for something sacred.
This creates a perverse neurobiological trap: violence becomes rewarding. The dopamine system that evolved to make you seek things necessary for survival (food, sex, status, belonging) gets attached to genocide. The perpetrator isn't experiencing violence as aversive and forcing themselves to do it. They're experiencing violence as inherently rewarding — as the thing they should be seeking.
This is why many genocide perpetrators, decades after the fact, report not remorse but nostalgia for the period of violence. They feel they were part of something sacred and meaningful. The dopamine system coded the violence as desirable. Remorse would require the system to recode the violence as aversive — which is neurobiologically difficult once the wiring is in place.
Behavioral-mechanics describes atrocity as a cascade of psychological-control operations: (1) construct new kinship categories through green-beard markers, (2) amplify in-group status competition, (3) disable empathy through disgusting narratives, (4) create sacred values that override rationality, (5) invert reciprocal altruism into genocidal cooperation.
Psychology reveals that each step in this cascade corresponds to systematic changes in neural wiring. Green-beard construction recalibrates the ACC's kinship-recognition systems. Status amplification involves testosterone-mediated changes to threat sensitivity and behavioral responding. Empathy disabling involves actual disconnection of the ACC from the dlPFC. Sacred-value construction changes vmPFC activation patterns. Reciprocal altruism inversion involves dopaminergic reward attachment to violence.
Where behavioral-mechanics describes what to do to mobilize a genocide, psychology explains how each step rewires the nervous system to make genocide feel righteous. The two domains together create a complete operational picture: if you want to mobilize genocide, you need to understand the behavioral steps; if you want to understand why perpetrators experience themselves as righteous, you need to understand the neural rewriting.
The implication is both clarifying and disturbing: genocide is not perpetrated by evil people. It's perpetrated by people whose nervous systems have been systematically recalibrated through a cascade of propaganda and group pressure. Which means stopping genocide isn't primarily about identifying and punishing the "evil ones." It's about interrupting the cascade before the neural wiring becomes entrenched.
Once the insula-amygdala-ACC-vmPFC system has been rewired through months of propaganda, appealing to conscience becomes neurobiologically ineffective. You've asked the person to violate a sacred value (which produces unbearable anxiety), to feel empathy for people they've coded as disgusting (which produces nausea), and to reject the group identity that's become their sense of self. The rational argument cannot overcome the neural architecture.
History reveals that every major genocide has a gestation period — months to years where the cascade builds before the violence reaches threshold. This gestation period is operationally identical to the behavioral-mechanics cascade, but history shows the actual timeline.
Nazi genocide required years of propaganda before the mass killing began. The legal exclusions came first (civil rights stripped). The cultural isolation came next (boycotts, segregation). The dehumanizing propaganda intensified (newspapers, education, public ritual). Then the violence began — first localized pogroms, then systematic ghettoes, finally industrial genocide. Each step rewired the nervous system further, lowering the threshold for participation in the next step.
Rwanda followed an identical pattern: months of radio propaganda linking Tutsis to cockroaches, economic threat narratives, claims of genocide planned against Hutus (reversing perpetrator and victim). Then when the political trigger arrived (the assassination of the president), the nervous systems were already primed. The cascade didn't start the genocide; it made the genocide neurobiologically possible. Neighbors who had lived peacefully with each other for years suddenly became capable of chopping each other with machetes, because the propaganda had rewired their kinship-recognition systems, their empathy networks, their threat-detection, and their sacred values.
History shows something behavioral-mechanics alone cannot: the reversibility of the cascade. In Rwanda, some people resisted the propaganda. Some chose to shelter Tutsis instead of murdering them. Brain studies of these rescuers show something different from the perpetrators: stronger ACC-to-dlPFC connectivity (maintaining empathy even under propaganda pressure), lower amygdala reactivity (less threat-sensitivity), and lower vmPFC coding of group identity as sacred. In other words, resistance to the cascade isn't a matter of moral character in the abstract. It's a matter of neural architecture — people whose nervous systems maintained empathy-to-reason connections resisted; people whose systems were successfully rewired did not.
This reveals what neither domain alone shows: the atrocity-prevention strategy must be neurobiological, not just behavioral or ethical. You cannot prevent genocide by making people more moral or more rational in the abstract. You have to maintain the neural circuits that support empathy and rationality during the period when propaganda is systematically trying to disconnect them.
If genocide is a cascade of neurobiological events, then interrupting it requires understanding where the cascade can actually be broken.
The earliest interruption point is preventing the green-beard recoding. This requires either (1) eliminating the use of arbitrary kinship markers (which is historically implausible), or (2) ensuring that contact, integration, and cross-group kinship prevents the recoding from taking hold. The Westermarck effect shows that childhood proximity prevents sexual attraction between siblings. Similarly, childhood proximity and integration across ethnic/religious lines prevents the kinship-recoding of out-group members. The brain cannot code "they are disgusting foreigners" if the person spent their childhood playing with them.
The second interruption point is preventing the dehumanizing propaganda from sticking. This requires either (1) institutional control of narrative (which creates other problems), or (2) maintaining competing narratives that keep the dehumanized group's humanity visible. Some countries that avoided genocide during WWII (like Denmark) did so partly through institutional refusal to participate in dehumanizing propaganda — church leaders, newspapers, and public figures consistently referred to targeted Jews as "our neighbors," "our citizens," "human beings like us." The competing narrative prevented the reweighting of the ACC's empathic systems.
The third interruption point is preventing the sacred value from attaching to group identity. This is harder, because group identity and shared values are necessary for functional societies. But the difference between "our nation is sacred and must survive" and "our nation is important and we should protect it" is the difference between infinite-weight values and negotiable ones. Education that presents national identity as important but negotiable — one value among many, not sacred — prevents the vmPFC from locking the value as non-negotiable. And once a value is negotiable, the dlPFC can actually think about whether the proposed atrocity is justified.
The hardest interruption point is maintaining ACC-to-dlPFC connectivity during the propaganda phase. This requires either (1) metacognitive awareness — the ability to notice you're being propagandized and deliberately override the propaganda's effects, or (2) repeated exposure to perspectives that maintain alternative framings. Interestingly, meditation, contemplative practice, and exposure to art that cultivates empathy have been shown to strengthen the very connectivity that propaganda tries to sever. A person who has spent years practicing compassion meditation has stronger ACC-dlPFC connectivity and is more resistant to dehumanization propaganda.
What all of these interruption points share: they require long-term institutional and cultural commitment. They cannot be implemented after the propaganda has started — by then, the neural wiring is already partially changed. They have to be maintained continuously to prevent the cascade from even beginning.
The Sharpest Implication
You have been taught that atrocity is perpetrated by evil people — moral monsters who lack conscience or empathy. This is wrong. Atrocity is perpetrated by ordinary people whose nervous systems have been systematically rewired through a sequence of propaganda, group pressure, and institutional reinforcement.
The perpetrators of genocide are not experiencing themselves as evil. They are experiencing themselves as righteous — defending something sacred, protecting their group, preventing an enemy from destroying them. Their insula has recoded the victims as disgusting. Their amygdala has recoded them as threat. Their ACC has stopped resonating with their suffering. Their vmPFC has coded the violence as sacred. And their dopamine system has attached reward to the violence itself.
This has a horrifying implication: if you want to understand whether you could commit atrocity, the honest answer is yes. Not because you are evil. But because you have the same nervous system. Under the right cascade of propaganda, group pressure, institutional structure, and neurobiological recalibration, you could be made to do it and experience yourself as righteous while doing it.
The people who resisted atrocity were not morally superior. They were people whose nervous systems maintained the neural connectivity that propaganda was trying to sever. Their empathy circuits stayed connected to their reason circuits. Their sense of the victims' humanity was sustained by competing narratives or by personal relationships that prevented the green-beard recoding. They had institutional support for resisting the propaganda.
The prevention of atrocity, then, is not about identifying the evil people and removing them. It's about maintaining the neural architecture and institutional conditions that allow ordinary people to remain human. It requires continuous commitment to integration, to competing narratives, to education that strengthens empathy-to-reason connectivity, to cultural frameworks that value human life over sacred group identity.
The most important implication: atrocity is not inevitable, but it is easy. All it takes is a well-orchestrated cascade of propaganda, institutional structures designed to lower resistance, and enough time for nervous systems to be rewired. Preventing atrocity requires constant, boring, unglamorous work to maintain the structures that keep that rewiring from happening. It's like dental health — nobody wants to brush their teeth, but without the boring routine, the teeth rot.
Generative Questions
If atrocity requires months or years of propaganda to rewire the nervous system, what does this mean for modern media ecosystems where people are exposed to thousands of micro-propagandistic messages daily? Are we living in a constant state of partial rewiring, with our empathy-to-reason connectivity under continuous low-level attack?
The meditation and contemplative practices that strengthen ACC-dlPFC connectivity are exactly what modern society is structured to prevent people from having time for. Is there a relationship between the declining prevalence of contemplative practice and the rising polarization that precedes atrocity?
If the perpetrators of atrocity are ordinary people whose nervous systems were rewired, does this mean that everyone has the capacity to resist, or did the resisters have some neurobiological advantage? If resistance is possible for anyone, why doesn't everyone resist?