Warhead
How the Brain Shapes War and War Shapes the Brain
By Nicholas Wright
Category: Psychology | Reading Duration: 15 min | Rating: 3.9/5 (44 ratings)
About the Book
Warhead (2025) explores war from a neuroscience perspective. By studying the brain, we can gain a deeper understanding of why people fight each other, how people behave during conflict, and to what extent war is inevitable.
Who Should Read This?
- Anyone who wants to understand why war exists
- People interested in neuroscience
- Anyone who wants a better understanding of their own brain
What’s in it for me? Why we fight.
When Nicholas Wright told his friends he was writing a book about war, they laughed. “War? ” they said. “No one’s going to war anymore!
” And if one did break out, surely it wouldn’t be anything major. Just a few months later, in early 2022, Russia invaded Ukraine – igniting the largest war in Europe since the end of the Second World War. According to Wright, a neuroscientist and advisor to the Pentagon, human nature means that war is always a possibility. Throughout history, people have constantly been getting into conflict, and that doesn’t look likely to change any time soon. That’s why it’s so important that we gain a better understanding of ourselves – specifically, our brains – to learn how and why humans fight. What’s going on in our brains when we feel threatened?
The human brain is extremely complex, but we’ll look at some of the basics. In particular, we’ll be focusing on the lower parts of the brain, which control many of our instincts, and our drive to survive. Wright believes that self-knowledge is power. So, let’s get to know ourselves – our in-built inclination to fight, or fight back.
Chapter 1: Models and prediction errors
Before we begin our tour of the brain, we need to understand an essential concept: the model. All organisms, not just humans, benefit from having models. In basic terms, a model is a process describing how senses can be linked to actions. This helps the organism to achieve its goals, and stay alive.
For example, a bird has a model of where to locate its invertebrate prey, allowing it to find food. Human brains also use models to process data, and send commands. This happens in the very base of the brain: the brainstem. The lowest part of the brainstem is called the medulla. If the medulla dies, you die. That’s because it’s responsible for monitoring our life support systems, and sending messages to control things like breathing and heart rate.
It uses models to keep us alive. The brainstem also helps us to respond flexibly to situations – pain, for example. The capacity to feel pain is important – again, it helps us not to die. But there are some situations where it’s helpful to dial it down. During the Second World War, for instance, many injured soldiers claimed not to feel pain. Their brains were able to respond flexibly, protecting them from pain when it was helpful to do so.
Higher up in the brainstem is a group of cells that manufactures an important molecule: dopamine. Dopamine is often thought of as a “pleasure” chemical, something that makes us feel good, a reward. To some extent, that’s true. But as we look at another feature of the brain, we’ll see that the full picture is a bit more complicated. As we mentioned earlier, our brains use models to process data, and send commands. When they do this, they also make predictions about the data they’re receiving.
Sometimes, the predictions are wrong. The brain then uses these prediction errors to update its models – to learn, in other words. What does this have to do with dopamine? Well, prediction errors affect our dopamine, which means they can have a huge impact on how we feel and react. Let’s look at another example to understand this effect in the context of war. During the First World War, the German air raids on London were relatively small-scale attacks.
However, they were also totally unexpected, resulting in prediction error, and a devastating psychological impact. When London was bombed again, during the Second World War, people had been warned. The attacks were “predictable,” to a certain extent. So even though they were destructive, they were less damaging on a psychological level. Another example of prediction error can be seen in France’s response to the German Blitzkrieg, or “lightning war,” in 1940. The suddenness of the German attack – with a combination of tanks, airborne troops, and special forces – came as a total surprise.
The French army was caught off guard, and quickly surrendered. There are reports of military leaders in tears, in a state of psychological breakdown. According to the historian Ernest May, “The scale and suddenness of Germany’s victory has to be explained primarily, I believe, as a result of the surprise achieved. ” Or, from a neuroscience perspective – the French army was defeated by prediction error.
Chapter 2: Vital drives
Now that we’ve learned about the brainstem – how it uses models and prediction errors, determining our responses – it’s time to move up to another part of the brain, to understand what drives us. Just above the brainstem is a structure the size of an almond: the hypothalamus. The hypothalamus contains groups of cells that manage five vital drives – thirst, hunger, sleep, warmth, and reproduction. Let’s look at some of these drives, which are essential for life, and understand how they play a part in war.
Without water, we die. And throughout history, thirst has made people vulnerable during wartime. During the Peloponnesian War, Athenian soldiers were so desperate for a drink that they went into the river, even though this made them easy targets for the Spartans on the opposite side. In 1940, during the Blitzkrieg, French troops were maddened by thirst as they traipsed through the woods. More recently, in 2014, Islamic State poisoned drinking water. Although people can survive for longer without food than without water, when we’re hungry, our brains can think of nothing else.
As well as obsessing over food, starving soldiers are likely to suffer from decreased strength, stamina, and heart rate. And like thirst, hunger can be weaponized to devastating effect. When the Germans invaded the Soviet Union in 1941, their strategy involved the “Hunger Plan,” deliberately starving people to death. While hunger and thirst take a toll on the body – and our mood – they don’t affect cognition as much as lack of sleep. Sleep-deprived soldiers are vulnerable to “micro sleeps”, missing responses entirely, which can result in combat catastrophe. So, during battle, it’s essential to manage these vital drives.
Military strategy isn’t just about attack and defense, but also logistics – keeping troops fed, watered, and rested, so their brains and bodies can function. Another vital drive, the drive to reproduce, may not have an obvious connection with war. But actually, indirectly, it’s a very strong motivator. Our brains want us to reproduce, creating offspring who will then reproduce themselves, and hormones motivate us to put in the work. For example, the hypothalamus produces hormones like oxytocin to create strong bonds between parents and children. Studies show that becoming a parent literally rewires the brain.
We’re designed to care deeply about our loved ones, which makes us more inclined to fight to protect them if necessary. Since the beginning of civilization, families have fought wars to maintain dynasties. Even today, monarchies still exist, and North Korea is ruled by Kim Jong Un – the third in the family dynasty. There’s something extremely powerful about family ties. Now, here’s something else to consider. Although there are some notable exceptions – the female warrior Boudicca, for example – wars and other acts of violence tend to be carried out by men.
A partial explanation can be found in the brain. Although male and female brains are fairly similar, there are some differences. And one of the most significant can be found in the hypothalamus, which influences the production of sex hormones such as testosterone. Testosterone influences men’s behaviour – it makes them more likely to compete for status, and can increase aggression. Perhaps this explains, in part, why starting and fighting wars is primarily a male activity.
Chapter 3: Fear and other visceral instincts
Have you ever wondered why people choose to fight, instead of running away? Fleeing might seem like the easier option, but humans tend to opt for self-preservation. If it increases our chances of staying alive, we fight. Fear is a major motivator.
In humans, fear is managed by an area of the brain known as the amygdala. If we didn’t have the amygdala, we wouldn’t experience fear. And while that may sound nice, it can actually lead to dangerous situations. Wright once worked with a woman who had lost her amygdala. She couldn’t feel fear, which made her very vulnerable. Unable to identify threats, she ended up as a victim of assaults and domestic violence.
Of course, an excess of fear can also be problematic, leading to anxiety disorders and PTSD. And in the context of battle, fear – worsened by factors such as sustained stress, unpredictability, and feeling cornered – can trigger impulsive, violent acts. A climate of fear contributed to the explosive conflict between China and Japan in the 1930s. In high-stakes situations, we tend to be guided by visceral instincts, fear and other emotions. But there’s something to be said for the “stiff upper lip. ” Like fear, strong emotions need to be managed appropriately.
When people lose control, the results can be catastrophic – particularly in the context of war, given that soldiers are already under pressure, and emotions are running high. During the Nanjing Massacre of 1937, Japanese troops were responsible for the mass rapes and murders of tens of thousands of Chinese civilians. This wasn’t a calculated act. Soldiers were hungry, exhausted, and enraged. They completely lost control, with appalling consequences. Fear and anger are visceral instincts that drive behavior.
A less obvious, but equally powerful instinct, is a social motivation – the rejection of unfairness and injustice. You might think that this is a moral issue, but actually, it’s biological. Rejecting unfairness is a deep-rooted drive, something that influences our responses. This has been shown in scientific experiments, where participants rejected offers of money or water that they perceived to be unfair. And looking at world events, we can also see that perceived inequalities often inspire people to fight. Just think of the cry of the French revolutionaries – “Liberté, égalité, fraternité” – or the uprisings of the Arab Spring.
Now, let’s take a moment to consider the big picture – or part of it, at least. Vital drives and instincts are processed in lower parts of the brain, including the brainstem, hypothalamus and amygdala. They work in coordination with higher brain areas such as the prefrontal cortex, which is responsible for more sophisticated cognition. There’s a lot going on, and this is just part of the story. But it gives us an idea of just how much is happening in our brains when we make split-second decisions, such as whether to fight or flee.
Chapter 4: The inevitability of war
What if we could make a collective decision never to fight again? No more war. Is that a realistic prospect? Wright sees war as something inevitable, not for one reason, but because of many different factors.
To a great extent, our brains are wired for conflict. And unfortunately, there will always be a small minority of humans – the Putins and Hitlers of the world – who deliberately start wars. When that happens, others will be forced to respond. But while this may seem like a pessimistic conclusion, Wright is actually optimistic about the future. Through self-knowledge, and a wiser approach to war, it’s possible to create a more peaceful world. Just think of leaders like Churchill and Eisenhower.
During the Second World War, they were able to see the bigger picture, using not just aggression, but also teamwork, alliances, magnanimity, and restraint. After all, there’s more to the brain than our vital drives and visceral instincts. While we’ve mainly been focusing on these aspects, let’s remember just how complex and multi-faceted the brain is. The frontal pole, for instance, which sits at the end of the prefrontal cortex, is responsible for metacognition. It allows us to think about our own thinking, enabling wiser decision-making. So, to sum up – Wright thinks war is an inevitable part of life.
In fact, he thinks that during his children’s lifetimes, there’s about a one in three chance of a catastrophe on the scale of one of the World Wars. But despite this gloomy prediction, Wright remains hopeful. The way he sees it, humans have an incredible capacity for self-knowledge. We can continue to learn more about ourselves – that includes why we fight wars, and why we win or lose. By harnessing the power of our brains, we can work together to build a better, more peaceful world.
Final summary
In this Blink to Warhead by Nicholas Wright, you’ve learned that different parts of the human brain shape behavior, including behavior in war. The brainstem, for instance, governs basic survival. It builds internal “models” that link sensation to action, allowing us to adjust responses based on prediction errors. This explains why unexpected attacks, such as early German air raids on London, or the Blitzkrieg in France, had such profound psychological effects.
Above the brainstem, the hypothalamus controls vital drives like thirst, hunger, sleep, warmth, and reproduction. These basic needs influence combat effectiveness and can be weaponized, as seen in historical strategies that deprived soldiers of water or food. The amygdala manages fear, a key force in motivating humans to fight rather than flee. Excessive fear and uncontrolled emotions can lead to breakdowns or brutality. In part, the Nanjing Massacre was caused by rage and a loss of control. Wright concludes that war is likely an inevitable part of life, rooted in deep neurological drives, yet he remains hopeful.
With self-awareness and wise leadership, humanity can better manage conflict, building a more peaceful world. Okay, that’s it for this Blink. We hope you enjoyed it. If you can, please take the time to leave us a rating – we always appreciate your feedback. See you in the next Blink.
About the Author
Dr. Nicholas Wright is a neuroscientist who works both with governments and the private sector. He does research at University College London and Georgetown University, and also works at the Center for Strategic and International Studies in Washington DC, as an advisor to the Pentagon Joint Staff. Wright’s work has appeared in Foreign Affairs, Foreign Policy, and The Atlantic.