题型：阅读理解 题类：模拟题 难易度：普通
河北省衡水中学2019届高三上学期英语二调考试试卷
What Cocktail Parties Teach Us
You're at a party. Music is playing. Glasses are clinking. Dozens of conversations are driving up the decibel (分贝) level. Yet among all those distractions, you can tune your attention to just one voice from many. This ability is what researchers call the “cocktail-party effect”.
Scientists at the University of California in San Francisco have found where that sound-editing process occurs in the brain — in the auditory cortex (听觉皮层) just behind the ear, not in areas of higher thought. The auditory cortex boosts some sounds and turns down others so that when the signal reaches the higher brain, “it's as if only one person was speaking alone,” says investigator Edward Chang.
These findings, published in the journal Nature last week, explain why people aren't very good at multitasking — our brains are wired for “selective attention” and can focus on only one thing at a time. That inborn ability has helped humans survive in a world buzzing with visual and auditory stimulation (刺激). But we keep trying to push the limits with multitasking, sometimes with tragic (悲剧的) consequences. Drivers talking on cellphones, for example, are four times as likely to get into traffic accidents as those who aren't.
Many of those accidents are due to “inattentional blindness”, in which people can, in effect, turn a blind eye to things they aren't focusing on. The more attention a task demands, the less attention we can pay to other things in our field of vision. Images land on our retinas (视网膜) and are either boosted or played down in the visual cortex before being passed to the brain, just as the auditory cortex filters sounds, as shown in the Nature study last week. “It's a push-pull relationship — the more we focus on one thing, the less we can focus on others,” says Diane M. Beck, an associate professor of psychology at the University of Illinois.
Studies over the past decade at the University of Utah show that drivers talking on hands-free cellphones are just as influenced as those on hands-held phones because it is the conversation, not the device, that is distracting their attention. Those talking on any kind of cellphone react more slowly and miss more traffic signals than other motorists.
Some people can train themselves to pay extra attention to things that are important — like police officers learn to scan crowds for faces and conductors can listen for individual instruments within the orchestra as a whole. Many more think they can effectively multitask, but are actually shifting their attention rapidly between two things and not getting the full effect of either, experts say.
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