
…stomach, or other side effects, nocebo research shows they’re much more likely to experience them. “Expectation leads to perception, which becomes reality,” he says. “What we believe may happen becomes much more apt to happen.”
“Neuroscientists are starting to appreciate that the brain operates like a great Bayesian prediction machine,” he says. In statistics, Bayesian prediction describes a model or algorithm’s ability to anticipate an outcome based on incomplete data. And this is just what the brain does all the time. “The brain has all these inputs coming in from the senses, but there’s always missing info,” Napadow says. “So the brain has to fill in missing pieces, and how it fills those in becomes your reality or what you perceive.” This makes room for both placebo and nocebo effects.