科学美国人60秒 SSS 测量凝视的力量（在线收听）

This is Scientific American — 60-Second Science. I'm Karen Hopkin.

You're at a party and you suddenly feel someone looking at you. But how can it be possible to feel another person's gaze? I mean, it's not like people shoot actual beams out of their eyes. Yet...a new study suggests that, unconsciously, we actually do believe that looking exerts a slight force on the things being looked at. That eye-opening finding appears in the Proceedings of the National Academy of Sciences.

Vision depends on light entering the eye...a form of ocular intromission, if you will. But kids...even those in college...often express a belief in "extramission"...the idea that the eyes emit a form of invisible energy.

To probe this perception, researchers at Princeton asked volunteers to look at a computer screen and gauge the angle at which a cardboard tube...shown being slowly tilted on its side... would finally topple over. Now, in some of the tests, they included an image of a young man watching the tube as it tilted toward him.

What the researchers found is that, when there was someone staring at the tube, subjects thought that the tube could tilt a little further before it toppled toward the fella looking at it. Which means that, unconsciously, the volunteers must have imagined that the guy's gaze exerted a slight force on the tube, keeping it from falling.

But this force was not strong. When the researchers replaced the cardboard tube with a brick, the subjects felt that the Jedi eye beams wouldn't support the added weight...they said the brick would fall at the same angle, whether or not there was someone there to watch it.

Interestingly, when the participants were explicitly asked about eyeball extramission, only 5 percent of them fessed up to believing in some sort of force being exerted by the eyes. But deep down, it looks like many of us put stock in the awesome power of the stare down. Just don't depend on it if something weighty is about to fall your way.

Thanks for listening for Scientific American — 60-Second Science. I'm Karen Hopkin.