Niels Bohr once had a theory on why the good guy always won shoot-outs in Hollywood westerns. It was simple: the bad guy always drew first. That left the good guy to react unthinkingly 鈥� and therefore faster. When Bohr tested his hypothesis with toy pistols and colleagues who drew first, he always won.
Andrew Welchman of the University of Birmingham, UK, has now taken this a step further. Bohr may have won a Nobel prize for his work on quantum mechanics, but it turns out the answer to this puzzle is more complicated than he thought.
Welchman pitted pairs of people against each other. The task? Lift your hand off a button, push two other buttons, then return to the first. There was no start bell. 鈥淓ventually one decides it鈥檚 time to move,鈥� Welchman says. 鈥淭he other player will then try to move as fast as possible.鈥�
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The reacting players took 21 milliseconds less time to move, on average, than the first ones. Welchman thinks reaction movement involves a faster brain pathway than intentional movement. So Bohr was right? Not quite.
There was also a 鈥渞eaction time鈥�, a delay of 200 milliseconds before the players started to respond to their opponent鈥檚 actions. So although they moved faster, they never won.
Hotheaded villains
Is there any truth to the Hollywood version of the gunfight, where the last guy to draw is the winner? If there is, a gunslinger would merely have to wait for the hotheaded villain to move first. But that couldn鈥檛 have worked when two clued-up cowboys faced each other.
Now Welchman says neuroscience doesn鈥檛 support Hollywood鈥檚 portrayal either. The only way the last guy to draw could win is if the reactive part of the brain makes him move so fast that the time it takes him to draw, plus his reaction time, is less than the time it takes the first guy just to draw.
鈥淚t would be hard to get fast enough to recover the time it takes to react to your opponent,鈥� says Welchman. He thinks fast reactions evolved for avoiding unexpected danger, or for confrontations in which animals are in a face-off, and the second to move needs speed.
Fast but loose
鈥淰oluntary and reactive movements differ in basic ways,鈥� says , who studies movement at the University of Paris Descartes, France. The system has evolved so that reactions may be very fast but perhaps less accurate, Wasnak speculates.
Indeed, Welchman鈥檚 鈥渞eactive鈥� players hit the buttons less accurately than the 鈥渋ntentional鈥� players, another reason fast reactions may not win gunfights.
So it was all Hollywood legend. 鈥淚鈥檝e found little evidence for face-to-face duels on the streets of Dodge,鈥� Welchman says. And Bohr? 鈥淢aybe he was just a good shot.鈥� Or maybe everyone just expected the great Niels Bohr to win.
Journal reference: , DOI: 10.1098/rspb.2009.2123
