Action and Reaction - He who draws first Loses

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 – 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. "Eventually one decides it's time to move," Welchman says. "The other player will then try to move as fast as possible."

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 "reaction time", a delay of 200 milliseconds before the players started to respond to their opponent's actions. So although they moved faster, they never won.