Reactive movements are indeed faster than intentional. During tests volunteer “gunslingers” were to “draw” on their opponents by pressing a row of three buttons. When doing this in response, they demonstrated an average 10% boost in speed as compared to their initiating the “duel”, winning by about 21 milliseconds.

Unfortunately for those thrill-filled duel scenes in the movies, the speed advantage was greatly offset by the reaction time, so in a real duel the first to draw is likely to be the winner.

“As a general strategy for survival, having this system in our brains that gives us quick-and-dirty responses to the environment seems pretty useful,” said researcher Andrew Welchman, an experimental psychologist at University of Birmingham in Britain.

“Twenty-one milliseconds may seem like a tiny difference, and it probably wouldn't save you in a Wild West duel because your brain takes around 200 milliseconds to respond to what your opponent is doing, but it could mean the difference between life and death when you are trying to avoid an oncoming bus!” he added.