Have you ever noticed that the first cowboy to draw his gun in a Hollywood Western is invariably the one to get shot? Nobel prize–winning physicist Niels Bohr did, once arranging mock duels to test the validity of this cinematic curiosity. Following Bohr's example, researchers have now confirmed that people move faster if they are reacting to another person's movements than if they are taking the lead themselves. The findings may one day inspire new therapies for patients with brain damage, the team speculates.
Bohr was seemingly unhappy with the Tinseltown explanation that the good guy, who never shoots first, always wins. Legend has it that he procured two toy pistols and enlisted the aid of fellow physicist George Gamow. In a series of duels, Bohr never drew first but won every time. The physicist suggested that the brain responded to danger faster than it carried out a deliberate intention. Experimental psychologist Andrew Welchman of the University of Bristol in the United Kingdom recently learned of the duelling conundrum and also wondered whether it might reveal something about the way our brains are wired to respond to danger. "It would be sensible for the brain to have a reactive system that went a bit faster than a system based on decisions or intentions," says Welchman.
Welchman's team organized simulated "gunfights" in the laboratory, with pairs of volunteers competing against each other to push three buttons on a computer console in a particular order. The researchers observed that the time interval between when players removed their hands from the first button and when they pressed the final button was on average 9% shorter for the players who reacted to an opponent moving first. However, those who reacted to a first move were more likely to make an error, presssing the buttons in the wrong order. Welchman speculates that this rapid, if somewhat inaccurate, response system may have evolved to help humans deal with danger, when immediate reaction is essential and the risk of an error worth taking.
The study, published  today in the Proceedings of the Royal Society B, is part of a larger research project examining how the brain coordinates the movement of muscles. "We're doing a lot of work trying to understand how we time and produce our movements and working with patients who've had some kind of motor impairment through, for instance, a stroke," says Welchman. We are "trying to retrain abilities."
"It's a nice paper--it's not oversold. It's a very small effect, and they admit that," says computational neuroscientist Roland Baddeley of the University of Bristol.
For devotees of Hollywood Westerns, however, the results might be disappointing. Although players reacting to an opponent's draw completed the sequence more quickly, they still didn't win the duel because the increase in speed wasn't sufficient to make up the time they lost by starting later. In this experiment, the good guy lost. So how do the researchers explain Bohr's repeated triumphs over Gamow? "Our data make it unlikely that these victories can be ascribed to the benefits associated with reaction," the team concludes. "Rather, they suggest that Bohr was a crack shot, in addition to being a brilliant physicist."