MULTITASKING DEBATE
IS TRUE MULTITASKING POSSIBLE?
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A
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Talking on
the phone while driving isn’t the only situation where we’re worse at
multitasking than we might like to think we are. New studies have
identified a bottleneck in our brains that some say means we are
fundamentally incapable of true 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 improve your performance, but you will
never be as good as when focusing on one task at a time.
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B
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The problem,
according to Rene Marois, a psychologist at Vanderbilt University in
Nashville, Tennessee, is that there’s a sticking point in the brain. To
demonstrate this, Marois devised an experiment to locate it. Volunteers
watch a screen and when a particular image appears, a red circle, say, they
have to press a key with their index finger. Different coloured circles
require presses from different fingers. Typical response time is about half
a second, and the volunteers quickly reached their peak performance. Then
they learn to listen to different recordings and respond by making a
specific sound. For instance, when they hear a bird chirp, they have to say
“ba”; an electronic sound should elicit a “ko”, and so on. Again, no
problem. A normal person can do that in about half a second, with almost no
effort.
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C
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The trouble
comes when Marois shows the volunteers an image, and then almost
immediately plays them a sound. Now they’re flummoxed. “If you show an
image and play a sound at the same time, one task is postponed,” he says.
In fact, if the second task is introduced within the half-second or so it
takes to process and 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 presented simultaneously; delays progressively shorten as the
interval between presenting the tasks lengthens.
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D
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There are at
least three points where we seem to get stuck, says Marois. The first is in
simply identifying what we’re looking at. This can take a few tenths of a
second, during which time we are not able to see and recognize the second
item. This limitation is known as the “attentional blink”: experiments have
shown that if you’re watching out for a particular event and a second one
shows up unexpectedly any time within this crucial window of concentration,
it may register in your visual cortex but you will be unable to act upon
it. Interestingly, if you don’t expect the first event, you have no trouble
responding to the second. What exactly causes the attentional blink is
still a matter for debate.
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E
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A second
limitation is in our short-term visual memory. It’s estimated that we can
keep track of about four items at a time, fewer if they are complex. This
capacity shortage is thought to explain, in part, our astonishing inability
to detect even huge changes in scenes that are otherwise identical,
so-called “change blindness”. Show people pairs of near-identical photos –
say, aircraft engines in one picture have disappeared in the other – and
they will fail to spot the differences. Here again, though, there is
disagreement about what the essential limiting factor really is. Does it
come down to a dearth of storage capacity, or is it about how much
attention a viewer is paying?
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F
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A third
limitation is that choosing a response to a stimulus – braking when you see
a child in the road, for instance, or replying when your mother tells you
over the phone that she’ s thinking of leaving your dad – also takes
brainpower. Selecting a response to one of these things will delay by some
tenths of a second your ability to respond to the other. This is called the
“response selection bottleneck” theory, first proposed in 1952.
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G
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But David
Meyer, a psychologist at the University of Michigan, Ann Arbor, don’t buy
the bottleneck idea. He thinks dual-task interference is just evidence of a
strategy used by the brain to prioritise multiple activities. Meyer is
known as something of an optimist by his peers. He has written papers with
titles like “Virtually perfect time-sharing in dual-task performance:
Uncorking the central cognitive bottleneck”. His experiments have shown
that with enough practice – at least 2000 tries – some people can execute
two tasks simultaneously as competently as if they were doing them one
after the other. He suggests that there is a central cognitive processor
that coordinates all this and, what’s more, he thinks it uses discretion
sometimes it chooses to delay one task while completing another.
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H
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Marois agrees
that practice can sometimes erase interference effects. He has found that
with just 1 hour of practice each day for two weeks, volunteers show a huge
improvement at managing both his tasks at once. Where he disagrees with
Meyer is in what the brain is doing to achieve this. Marois speculates that
practice might give us the chance to find less congested circuits to
execute a task – rather like finding trusty back streets to avoid heavy
traffic on main roads – effectively making our response to the task
subconscious. After all, there are plenty of examples of subconscious
multitasking that most of us routinely manage: walking and talking, eating
and reading, watching TV and folding the laundry.
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I
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It probably
comes as no surprise that, generally speaking, we get worse at multitasking
as we age. According to Art Kramer at the University of Illinois at Urbana-
Champaign, who studies how ageing affects our cognitive abilities, we speak
in our 20s. Though the decline is slow through our 30s and on into our 50s,
it is there; and after 55, it becomes more precipitous. In one study, he
and his colleagues had both young and old participants do a simulated
driving task while carrying on a conversation. He found that while young
drivers tended to miss background changes, older drivers failed to notice things
that were highly relevant. Likewise, older subjects had more trouble paying
attention to the more important parts of a scene than young drivers.
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J
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It’s not all
bad news for over- 55s, though. Kramer also found that older people can
benefit from the practice. Not only did they learn to perform better, but
brain scans also showed that underlying that improvement was a change in
the way their brains become active. While it’s clear that practice can
often make a difference, especially as we age, the basic facts remain
sobering. “We have this impression of an almighty complex brain,” says
Marois, “and yet we have very humbling and crippling limits.” For most of
our history, we probably never needed to do more than one thing at a time,
he says, and so we haven’t evolved to be able to. Perhaps we will in the
future, though. We might yet look back one day on people like Debbie and
Alun as ancestors of a new breed of a true multitasker.
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Questions
28-32
The
reading Passage has ten paragraphs A-J.
Which
paragraph contains the following information?
Write
the correct letter in boxes 28-32 on your answer sheet.
28
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A theory explained delay happens when selecting one reaction
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29
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Different age group responds to important things differently
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30
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Conflicts
happened when visual and audio element emerge simultaneously
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31
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An experiment designed to demonstrates the critical part of the
brain for multitasking
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32
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A
viewpoint favours the optimistic side of multitasking performance
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Questions
33-35
Choose
the correct letter, A, B, C or D.
Write
your answers in boxes 33-35 on your answer sheet.
33
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Which one is correct about the experiment conducted by Rene Marois?
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A
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participants performed poorly on the listening task solely
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B
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volunteers
press a different key on different colour
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C
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participants need to use different fingers on the different coloured
object
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D
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they did a
better job on Mixed image and sound information
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34
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Which statement is correct about the first limitation of Marois’s
experiment?
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A
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“attentional
blink” takes about ten seconds
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B
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lag occurs if we concentrate on one object while the second one
appears
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C
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we always
have trouble in reaching the second one
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D
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the first limitation can be avoided by certain measures
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35
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Which one
is NOT correct about Meyer’s experiments and statements?
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A
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just after failure in several attempts can people execute dual-task
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B
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Practice
can overcome dual-task interference
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C
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Meyer holds a different opinion on Marois’s theory
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D
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an
existing processor decides whether to delay another task or not
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Questions 36-40
Do the following statements agree with
the information given in Reading Passage 3?
In boxes 36-40 on your answer sheet,
write
YES
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if the statement is true
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NO
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if the
statement is false
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NOT GIVEN
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if the information is not
given in the passage
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36
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The longer gap between the two presenting tasks means a shorter
delay toward the second one.
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37
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Incapable human memory cause people to sometimes miss the
differences when presented with two similar images.
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38
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Marois has
a different opinion on the claim that training removes the bottleneck
effect.
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39
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Art Kramer proved there is a correlation between multitasking
performance and genders.
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40
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The author
doesn’t believe that the effect of practice could bring any variation.
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