60秒科学:Brain Knows It's Duck Reason（在线收听）

When an Iraqi reporter threw his shoe at President Bush, University of Washington neurologists were delighted. But not because of politics. The fling was just real-world evidence of a theory they were testing. As the shoe flew, Bush ducked while Iraqi Prime Minister Maliki, who was standing right beside him, barely flinched. The reason, the researchers say, is that we have a dual vision system. Our brains "see" things well before our eyes do. Their report is in the June 11th issue of the journal Current Biology.

The scientists contend that Bush ducked because his brain’s action pathway categorized the trajectory of the shoe as a threat well before his perception pathway began to track its flight. Meanwhile, Maliki realized the shoe wasn’t headed his way and didn’t take evasive action. The scientists say this mirrors computer simulations where test subjects respond much faster to approaching visual stimuli when those objects are on a trajectory lined up with their heads. Basically, your brain will tell you whether an item is a threat even before you know you saw it. The findings could apply to everyone from ballplayers to loafers.

—Adam Hinterthuer