原文：
A
Talkingon the phone while driving isn't the only situation where we're worse atmultitasking than we might like to think we are. New studies have identified abottleneck in our brains that some say means we are fundamentally incapable oftrue multitasking If experimental findings reflect real-world performance,people who think they are multitasking are probably just underperforming in all— or at best, all but one - of their parallel pursuits. Practice might improveyour performance, but you will never be as good as when focusing on one task at a time.
B
Theproblem, according to Rene Marois, a psychologist at Vanderbilt University inNashville, Tennessee, is that there's a sticking point in the brain. Todemonstrate this, Marois devised an experiment to locate it. Volunteers watch ascreen and when a particular image appears, a red circle, say, they have topress a key with their index finger. Different coloured circles require pressesfrom different fingers. Typical response time is about half a second, and thevolunteers quickly reach their peak performance. Then they learn to listen todifferent recordings and respond by making a specific sound. For instance, whenthey hear a bird chirp, they have to say “ba” an electronic sound should elicita “ko”, and so on. Again, no problem. A normal person can do that in about halfa second, with almost no effort.
C
Thetrouble comes when Marois shows the volunteers an image, and then almostimmediately plays them a sound. Now they’re flummoxed. “If you show an imageand play a sound at the same time, one task is postponed/5 he says. In fact, ifthe second task is introduced within the half-second or so it takes to processand react to the first, it will simply be delayed until the first one is done.The largest dual-task delays occur when the two tasks are presentedsimultaneously; delays progressively shorten as the interval between presentingthe tasks lengthens.
D
There areat least three points where we seem to get stuck, says Marois. The first is insimply identifying what we're looking at. This can take a few tenths of asecond, during which time we are not able to see and recognise a second item.This limitation is known as the "attentional blink,5: experiments haveshown that if you're watching out for a particular event and a second one showsup unexpectedly any time within this crucial window of concentration, it mayregister in your visual cortex but you will be unable to act upon itInterestingly, if you don’t expect the first event, you have no trouble respondingto the second. What exactly causes the attentional blink is still a matter fordebate.
E
A secondlimitation is in our short-term visual memory. Ifs estimated that we can keeptrack of about four items at a time, fewer if they are complex. This capacityshortage is thought to explain, in part, our astonishing inability to detecteven huge changes in scenes that are otherwise identical, so-called “changeblindness”. Show people pairs of near-identical photos - say, aircraft enginesin one picture have disappeared in the other - and they will fail to spot thedifferences. Here again, though, there is disagreement about what the essentiallimiting factor really is. Does it come down to a dearth of storage capacity,or is it about how much attention a viewer is paying?
F
A thirdlimitation is that choosing a response to a stimulus — braking when you see achild in the road, for instance, or replying when your mother tells you overthe phone that she5s thinking of leaving your dad — also takes brainpower.Selecting a response to one of these things will delay by some tenths of asecond your ability to respond to the other. This is called the “responseselection bottleneck” theory, first proposed in 1952.
G
But DavidMeyer, a psychologist at the University of Michigan, Ann Arbor, doesn't buy thebottleneck idea. He thinks dual-task interference is just evidence of astrategy used by the brain to prioritise multiple activities. Meyer is known assomething of an optimist by his peers. He has written papers with titles like"Virtually perfect time-sharing in dual-task performance: Uncorking thecentral cognitive bottleneck”. His experiments have shown that with enoughpractice - at least 2000 tries - some people can execute two taskssimultaneously as competently as if they were doing them one after the other.He suggests that there is a central cognitive processor that coordinates all thisand, what's more, he thinks it uses discretion: sometimes it chooses to delay onetask while completing another.
H
Maroisagi'ees that practice can sometimes erase interference effects. He has foundthat with just 1 hour of practice each day for two weeks, volunteers show ahuge improvement at managing both his tasks at once. Where he disagrees withMeyer is in what the brain is doing to achieve this. Marois speculates thatpractice might give us the chance to find less congested circuits to execute atask — rather like finding trusty back streets to avoid heavy traffic on mainroads ~* effectively making our response to the task subconscious. After all,there are plenty of examples of subconscious multitasking that most of usroutinely manage: walking and talking, eating and reading, watching TV andfolding the laundry.
I
Itprobably comes as no surprise that, generally speaking, we get worse atmultitasking as we age. According to Art Kramer at the University of Illinoisat Urbana- Champaign, who studies how ageing affects our cognitive abilities,we peak in our 20s. Though the decline is slow through our 30s and on into our50s, it is there; and after 55, it becomes more precipitous. In one study, heand his colleagues had both young and old participants do a simulated drivingtask while carrying on a conversation. He found that while young drivers tendedto miss background changes, older drivers failed to notice things that werehighly relevant. Likewise, older subjects had more trouble paying attention tothe more important parts of a scene than young drivers.
J
It’s notall bad news for over-55s, though. Kramer also found that older people canbenefit from practice. Not only did they learn to perform better, brain scansshowed that underlying that improvement was a change in the way their brainsbecome active. While if s clear that practice can often make a difference,especially as we age, the basic facts remain sobering. "We have this impression of analmighty complex brain, says Marois,"and yet we have very humbling andcrippling limits.” For most of our history, we probably never needed to do morethan one thing at a time, he says, and so we haven't evolved to be able to.Perhaps we will in future, though. We might yet look back one day on peoplelike Debbie and Alun as ancestors of a new breed of true multitaskers.
答案解析：
28-32
28 F【原文参考依据--F段】Selecting a response to one of these things will delay by some tenths ofa second your ability to response to the other. This is called the ''responseselection bottleneck'' theory, first proposed in 1952.
29 I
【原文参考依据--I段】....We get worse atmultitasking as we age.....He found that while young drivers tended to missbackground changes older drivers failed to notice things that were highlyrelevant. Likewise, older subjects had more trouble paying attention to themore important parts of a scene than young drivers.
30 C
【原文参考依据--C段】''show valunteers animage then ....plays them a sound.''关于视觉和听觉的实验!
31 B
题干修改订正： Anexperiment designed todemonstrates the critical part in brain for multitasking
【原文参考依据--B段1-2行】The problem,according to....is that there's a sticking pint in the brain. To demonstratethis, Marois devised an experiment to locate it.
32 G
【原文参考依据--G段】...He thinks dual-taskinterference is just evidence of a strategy used by the brain to prioritisemultiple activities. Meyer is known as something of an optimist by his peers.
33-35
33 C
【原文参考依据--B段第3行】'
34 B
【原文参考依据--G段倒数3行】'原文见D段第1行
35 A
【原文参考依据--G段】A错的原因是不知只通过几次尝试便可做到，而是足够的练习。注意a的表达，just after severalattempts和原文的enoughpractice至少两千次的尝试是不同的哦。35的d在最后一句话有提到是对的，Hesuggeststhatthere is a central cognitive processor that coordinates all this and, what’smore, he thinksituses discretion: sometimes it chooses to delayone task whilecompleting another.
36-40
36 YES
【原文参考依据--C段末句】The largestdual-task delays occur when the two tasks are presented simultaneously; delaysprogressively shorten as the interval between presenting the tasks lengths.3637都是定位处的同意转换
36shorten 对应shorter lengthen 对应longer as随着对应means意味着。
37 YES
【原文参考依据--E段第4行】'...changes inscenes that are otherwise identical, so-called''change blindness''原文见E段第4行37changes 对应differences similar 对应identical。
38 NO
【原文参考依据--H段第1行】Marois agrees thatpractice can sometimes erase interference effects.
39 NOT GIVEN
【原文参考依据--I段】文章说的是Art Kramer 研究的是age 方面的，说明是和AGE的关系; 而问题说的是和性别有联系但文章没有提到任何排除 ArtKramer 研究 了 performance 和 gender 关系的可能。因此是，NOT GIVEN 而不是 NO
40 NO
【原文参考依据--J段第4行】While it's clearthat practice can often make a difference, especially as we age.最后一段之前描述了Kramer的观点说“从我们的历史来看，我们或许从未被需要同时做一件事以上，他说，所以我们就不需要这方面的进化”。作者便说perhapswe will in future,though.意思还是说表示最好是能够进化的，最后还举了个例子
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发表于 2020-7-27 17:58:23
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