时差N小时:跑步机与意识

Lots of people these days get their exercise at gymsand health clubs, oftentimes by walking or runningon treadmills—that is to say, running without goinganywhere. If you've ever been on a treadmill forsome time and then suddenly stepped off it, you'veprobably experienced the weird sensation that youare suddenly moving much faster than you think youshould be. Why?

这些天很多人去健身房、健康俱乐部锻炼身体，时间大多花在跑步机上——也就是说原地不动行走或者跑步。如果你在跑步机上跑了一段时间，突然停下时，你心头可能会出现一种古怪的感觉：你移动得比实际要快。为什么?

This deceptive sensation is the result of sending your brain two different signals at once. Thefirst signal is the one coming from your legs; during exercise they are in rapid, regular motion,and the brain understands by this fact that the body is moving through space. The secondsignal comes from the eyes, which are seeing that the objects around you are not passing by,and hence you are standing still. In a sense your eyes are disagreeing with your legs. The resultis that after about ten minutes of this input disparity, the brain recalibrates its internal senseof motion.

这种欺骗性的感觉实际上是大脑一次传递两种不同信号的结果。第一种信号来自于你的双腿，在锻炼的时候它们快速，有规律地移动，然后大脑把这个事实理解成在空间里穿行。第二种信号来自于你的眼睛，眼睛看到的周围的物体并没有远去，因为你是站着不动的。在意识里，你的眼睛和你的腿是不一致的。结果，在这种输入分歧之后大约十分钟，大脑开始重新调整内心的动作感。

In simple terms, your brain tells itself: this is how fast objects move by when I'm walking atthis rate, as opposed to what was formerly the case. That means when you step off thetreadmill and begin actually moving through space again, your recalibrated brain is now sentthe incorrect message that you have suddenly increased your speed significantly. Once again,what the legs say and what the eyes say is out of sync. The sensation of accelerated motion isonly temporary, though, and the ever-adaptable brain soon readjusts itself once more—untilthe next time you step up on that rolling, immobile track.

单纯意义上来说，大脑告诉自己：当我以这样的速度行走时，身边的物体也以同样的速度在移动，不同于先前那种情况。这意味着，当你跳下跑步机再次开始真正的空间运动时，你调整过一次的大脑将会发送错误的信息：你突然加度了。腿和眼睛传达的信号再一次不同步。尽管加速运动的感觉只是暂时的，能不时顺应的大脑很快又会再次调整，直到下次你再踩在那滚动着但稳定的轨道上。