What are you going to do after you read this story? You may not know that yet, but your brain probably does. A new study shows that patterns of brain activity can reveal which choice a person is going to make long before he or she is aware of it. A team led by John-Dylan Haynes of the Bernstein Center for Computational Neuroscience Berlin scanned the brains of volunteers who held a button in each hand and were told to push one of the buttons whenever they wanted to. The scientists could tell from the scans which hand participants were going to use as early as 10 seconds before the volunteers were aware that they made up their mind.
Previous research has shown motor-related brain activity preceding conscious intent by a fraction of a second, but this study is the first to show unconscious predictive activity in a region associated with decision making—the prefrontal cortex—according to Haynes. The results support the notion that unconscious brain activity comes first and conscious experience follows as a result, says Patrick Haggard of University College London, who was not involved with the study. “We all think that we have a conscious free will,” he says. “However, this study shows that actions come from preconscious brain activity patterns and not from the person consciously thinking about what they are going to do.”