Threat Detection

Over at the Times, Benedict Carey has a fascinating article on the crucial importance of intuition on the battlefield, where soldiers are often forced to make decisions without knowing why, exactly, they are making them:

The United States military has spent billions on hardware, like signal jamming technology, to detect and destroy what the military calls improvised explosive devices, or I.E.D.'s, the roadside bombs that have proved to be the greatest threat in Iraq and now in Afghanistan, where Sergeant Tierney is training soldiers to foil bomb attacks.

Still, high-tech gear, while helping to reduce casualties, remains a mere supplement to the most sensitive detection system of all -- the human brain. Troops on the ground, using only their senses and experience, are responsible for foiling many I.E.D. attacks, and, like Sergeant Tierney, they often cite a gut feeling or a hunch as their first clue.

Everyone has hunches -- about friends' motives, about the stock market, about when to fold a hand of poker and when to hold it. But United States troops are now at the center of a large effort to understand how it is that in a life-or-death situation, some people's brains can sense danger and act on it well before others' do.

The crucial element is experience, which endows the brain with a set of useful patterns: if this, then that. If a solider is driving down a familiar road in Baghdad then he or she expects to see a familiar landscape filled with familiar items, from the highway litter to the abandoned cars. So far, so obvious: experience gives us a form of practical, tacit knowledge. We don't need neuroscience to tell us that. But I think the brain can help clarify how experience actually cashes out in the real world, and why having a set of subtle patterns embedded in your neurons can be so useful.

The beauty of patterns, after all, is that they lead to predictions. More importantly, they allow us to act on our mispredictions, or those moments when our expectations are contradicted by reality, when the pattern we anticipate doesn't materialize. Perhaps the litter by the side of the road looks a bit different, or an Iraqi town seems unusually quiet: even the most subtle cues can lead soldiers to question the safety of their position. (This is known as the prediction error signal and it turns out to be a crucial component of learning. For more, check out my book or the work of Wolfram Schultz, et. al.) Such mispredictions not only generate actionable emotions - that feeling of inexplicable fear described by the soldiers is simply an awareness of a prediction error, or the vague sense that something is not right - but allow us to revise our internal models of the world, so that the next time our predictions are correct. The physicist Niels Bohr once defined an expert as "a person who has made all the mistakes that can be made in a very narrow field." From the perspective of the brain, Bohr was absolutely right. Expertise is simply the wisdom that emerges from lots and lots of cellular error.

This research has been noticed by DARPA, which is currently developing the Human-aided Optical Recognition/Notification of Elusive Threats, or HORNET. The fancy helmet will incorporate an EEG monitor, which will track the brain waves of soldiers as they scan their surroundings. The basic idea is that the prediction error signal - the brain's own early warning radar - is detectable via EEG before it enters conscious awareness. In other words, the electronics will accelerate our own sensory system, and make sure we don't miss any relevant threats.