SUPPOSE you had to predict which kids in a roomful of 3-year-olds at your local preschool were likely to grow up to be violent criminals. How would you decide?
Most of us would probably round up the usual sociological suspects, and check whether a child comes from a broken or abusive home, is part of a family living below the poverty line, or has a parent who is a convicted criminal.
But there's an easier way, says Adrian Raine: just measure their resting heart rate.
His research shows that lower heart rates are a better indicator of criminal behaviour than smoking is of lung cancer.
In "The Anatomy of Violence" Raine, a criminologist at the University of Pennsylvania in Philadelphia, uses this and other evidence - much of it unearthed by himself over decades of research - to build a convincing case that violent criminals are biologically different from the rest of us.