Friday, April 29, 2011

Living in the Past - Neurology

I've spoken to this before: Humans live a half-second or so in the past, and the reason seems to be that the brain's internal editor does this so we can make sense of the world. 

There's a fascinating article in The New Yorker, The Possiblian, by Burkhard Bilger, profiling neuroscientist David Eagleman, and in it, a quick and easy experiment to show you how your brain dispenses with what it considers useless clutter. It deals with saccades, or rapid eye movements, and how it works is simple. Go look in the mirror. Shift your gaze to your left eye, then to your right, then back again. What happens is this: Your eyes (your brain) won't register movement. Even if you close one eye and try it, it still doesn't pick up motion. This is entirely subjective, because if you record this, the camera will see it. The little vid up top, I couldn't detect any movement when I shifted my focus from eye-to-eye, none. But plainly, it is there.

I confess I find this somewhat spooky, but my brain thinks this kind of input is a waste of cognition, and simply edits it out. And this isn't the only thing it estops.

The reason they use a gun to start a sprint instead of a bright light? At close range, hearing works faster than sight. The human ear can tell where a growling tiger is by the milliseconds of difference it takes the sound to reach one ear ahead of the other ear. 

An expert drummer can keep time better than a click-track, and can register differences most of us can't come close to hearing.

That fight-or-flight slowing of time? Subjective–they devised a way to test it, and you don't objectively slow down incoming data, you only think you do. The brain marks life-or-death events so as to be sure to remember them, and maybe avoid them in the future. 

I find all this kind of stuff fascinating. 

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