Beyond Belief

In the brain science lab at the University of Colorado Boulder, associate research professor Marta Ceko looks through a glass wall at a functional magnetic resonance imaging (fMRI) machine with two feet poking out of it. The subject inside is hooked up to a device built to inflict pain via a quick heat zap to the finger, so Ceko can see what’s happening in her brain. “The stimulus isn’t torturous, but it hurts,” says the scientist. However, if this unsuspecting person responds as Ceko thinks she might, the cream that’s been slathered on her right index finger will quell the throb.

Ceko gives the air a fist pump as she watches exactly that happen. It’s a powerful result, considering the catch: while the study participant was told the cream was a potent pain reliever, it’s just moisturiser – pure placebo. And when the same cream