Cerebral Combat

 

“Warhead

 

By Nicholas Wright

 

St. Martin's, 400 pages, $32

 

Defense Secretary Pete Hegseth has promised a military dedicated to "maximum lethality." He may have his work cut out for him.

 

It turns out that the parts of our brain that govern emotion and risk make even seasoned soldiers hesitant to kill. One Army study found, for instance, that during World War II the share of soldiers who fired their weapons in typical close-fought infantry actions was only 15% to 25%.

 

But the human brain is also remarkably susceptible to social pressure. In weapons operated by multiple people, such as crew-served machine guns, firing rates were nearly 100%.

 

Nicholas Wright, a British neuroscientist who has advised the Pentagon Joint Staff, believes these sorts of insights can help Western democracies avoid losing wars. "Warhead: How the Brain Shapes War and War Shapes the Brain" is his primer on brain anatomy and function, made specific and relatable with examples from military history.

 

Mr. Wright guides us through the brain's layers one by one, starting with the primitive life-and-death processes controlled by the medulla and increasing in sophistication until we reach the most elevated levels of consciousness rooted in the frontal pole. Common across these regions is the production of what Mr. Wright calls "models": ways of connecting what we sense about the world to how we should act in pursuit of some goal. The model produced by the sensory cortex of an inexperienced radar operator in north Oahu, Hawaii, for example, might say that two pulses on the display signal an expected flight inbound from California, and that therefore no action need be taken.

 

Key to understanding the brain, Mr. Wright posits, is the fact that these models are flexible and can change with new inputs. When the models' anticipated outcomes do not occur -- when the pulses instead represent scores of Japanese Zeros about to destroy Pearl Harbor, for instance -- the brain experiences "prediction error," which it then uses to update the model and learn. The greater the prediction error, the stronger its influence over brain processes such as memory and emotion.

 

Extreme reactions provoked by these failures of anticipation can take the form of the panicked collapse of the French army in 1940, when its collective model held the Ardennes to be impassible, only to be met with the prediction error of Blitzkrieg. More constructively, prediction error can be used to influence negotiations for peace -- as Egypt's Anwar Sadat did in 1977 by surprising Israelis with an offer to speak before the Knesset.

 

The ability to manipulate models and prediction errors has toppled regimes and forged new nations. Rooted in the insula cortex, for instance, is an expectation that others act fairly, which is why Mao Zedong's Red Army, we are told, was instructed to treat peasants equitably to win popular favor over Chiang Kai-shek's Nationalists. Mr. Wright points to Horatio Nelson's superb navigation of space and time to show how the British admiral used his "impressive hippocampal-entorphinal brain region" to master positioning across a vast ocean and triumph over Napoleonic France. Hamas hid fighters in complicated urban terrain and underground, Mr. Wright suggests, as a way of sidestepping Israel's surveillance technology, which improves upon the perception capabilities of the sensory cortex.

 

"Warhead" focuses on examples from World War II and the early Cold War. Still, its neuroscientific approach addresses many timeless questions. How do grievously wounded combatants power through to achieve extraordinary feats of heroism? They're enabled, we learn, by the periaqueductal gray, which adjusts the sensation of pain to improve our odds of survival. More fundamentally: Why do humans stand and fight at all, rather than run away to safety? Yes, the amygdala generates a fear-driven flight response in the face of imminent threat. But we also have the insula, which processes risk, including the risk of social ostracization -- to which the parietal cortex makes us extremely sensitive. We stay and fight lest we disappoint our comrades in arms.

 

Where "Warhead" does look ahead, it is by turns thought-provoking and terrifying. Contemplating how nuclear warfare might be affected by the brain's decision making processes -- and by whose brains' decision making processes -- Mr. Wright warns that it may all come down to, say, a Russian lieutenant colonel having the perspicacity to ignore alarms indicating an imminent U.S. nuclear first strike (as happened in 1983, when a Soviet satellite misread the sunlight reflecting off cloud tops).

 

But not all of "Warhead" is so grim: The author, while refraining from full-on prescription, does offer hopeful suggestions. Personalized nutrition could help soldiers improve performance. Training focused on reducing prediction error could lessen post-traumatic stress disorder. Figuring out how to mimic hibernation, allowing the human body to husband resources during long stretches of transport, could contribute to superiority in space.

 

And what of artificial intelligence? Will human brains matter, if our wars are fought by robots with algorithmic ones? Mr. Wright asserts, almost as an article of faith, that war will always involve some human intervention. He also notes that while AI is good at the sorts of computational processes required for computerized chess, it remains more resistant to our efforts to re-create humanlike motor skills. Fertile areas for investment, then, may be in the places where AI augments, rather than replaces, human intelligence, and where human bodies and AI intersect.

 

"Warhead" is too meandering and superficial to serve as a manual for anyone professionally involved in warmaking. Still, with its broadly applicable insights, it's a useful guide for readers interested in learning about the brain -- or mocking the French.

 

"Warhead" can also help those of us not on the front lines fulfill our civic duty. The book showcases the considerations that go into keeping America safe, as well as the threats -- particularly from China -- that loom on the horizon. One of Mr. Wright's important messages is that much of what leads to success in war is set in motion well before the first shot (or keystroke). The leaders a nation chooses, the domestic cohesion it fosters, the technological investments it prioritizes -- all help determine preparedness for war. "Warhead" prompts Americans to ask: What about us?

 

---

 

Ms. Kruger is a writer living in Maryland.” [1]

 

1. Cerebral Combat. Kruger, Meghan C.  Wall Street Journal, Eastern edition; New York, N.Y.. 11 Dec 2025: A13.