SSS 2008-06-11（在线收听）

This is Scientific American's 60-Second Science. I'm Christopher Intagliata. Got a minute?

At a crowded party, seems like you will be hard to hear the person you are talking to over all the clinking glasses, the chatter, the laughter but somehow your brain filters out all the noise. Scientists have known about this useful ability for over 50 years, it's called the cocktail party effect. But they're still trying to figure out how the brain does it. A new study in the journal Public Library of Science Biology hints at an answer.Neuron scientists played one repeating tone to volunteers along with a bunch of louder distracting tones of different pitches. The participants pressed a button if they heard the right tone. Meanwhile, the researchers are monitoring the subjects' brain activity. Turns out, even when the subjects didn’t think they can detect the repeating tone. It's still traveled from the inner ear to the auditory cortex.Somewhere after that initial processing though, it got discarded before the person was consciously aware of it. So all those other conversations at a party probably likewise make it into your brain. But they got thrown away before you are aware of them. Unless of course, you are eavesdropping. 

Thanks for the minute, for Scientific American's 60-Second Science. I am Christopher Intagliata.