雅思课外读物-- The inevitable and beneficial daydreaming？

2016年03月25日18:04 来源：小站整理

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今天要分享的雅思阅读文章是“The inevitable and beneficial daydreaming？千万别以为白日梦是讽刺那些不切实际的愿望，科学研究可是证明了，白日做梦可是有好处的，一起来看看这篇文章怎么讲的吧！文末有彩蛋，跟雅思写作相关的哦，所以答应我，一定坚持读到最后好吗？

Daydreaming has a bad reputation, but neuroscientists(神经科学家)are beginning to realise that a wandering mind is not only typical – it might be beneficial.

Sit down, relax and think of nothing. Struggling? There might be a good reason why your mind seems to wander even when you try very hard to switch off: your brain never really rests. And contrary to popular belief(与普遍观点相反), those idle daydreams might even be beneficial.

For years, neuroscientists worked on the assumption(假设;理论)that our brains work hard when given a specific job to do, and switch off when we’re not mentally stimulated(刺激). This is why you’ll read about experiments in which volunteers perform a task – tapping a finger, performing some mental arithmetic, looking at evocative(唤起记忆的)pictures – while their brain is scanned. The scan reveals which parts of the brain become more active during the task and which become less active. In this way it is possible to work out how our brain controls our behaviour.

Often the neuroscientists want to explore brain activity for a number of different tasks, so they need a way of getting the brain back to a neutral state(中性状态) between tests. This is typically done by asking the person to stare at a simple white cross(十字架)in the middle of a black screen. By thinking about nothing in particular, the theory goes, the brain should basically switch off.

There is just one problem: it doesn’t.

The first sign that a resting brain is surprisingly active came two decades ago. A student called Bharat Biswal was studying for a PhD at the Medical College of Wisconsin in Milwaukee. He was investigating(研究)ways to get a purer signal from a brain scanner, when he noticed that the resting brain isn’t doing nothing.(他正在研究如何从脑部扫描仪中提取一种更纯的信号，却发现休息的大脑并不是没有工作。) Even when people were told to clear their minds or to stare at a cross, activity in the brain continued. Not only that, the brain scans seemed to reveal this activity was actually coordinated(协调的).

Then in 1997 an analysis incorporating(包含，整合)the results of nine brain scan studies revealed another surprise. Gordon Shulman hoped his analysis would help identify the network that comes to life when people pay attention. But he discovered the opposite – the network which is activated when we do nothing.

It would make sense for the brain to become more active when volunteers shifted from resting to performing a task. Instead, Schulman noticed that some areas of the brain consistently(总是，一贯地)became less active when the resting period ended and the activity began. This suggested that while people were lying quietly in the scanner supposedly doing nothing, parts of their brains were in fact more active than when the volunteers were actively performing a task.(这表明，当志愿者静静地躺在扫描仪中，似乎什么都没做，其大脑的某些部分反而更活跃，甚至比他们积极完成一项工作时更活跃。)

It took a while for the idea that the brain never rests to catch on(变得流行，被人理解). For years neuroscientists had thought that brain circuits(线路)switched off when they weren’t needed. In 1998 the neuroscientist Marcus Raichle, now one of the leaders in the field, even had a paper rejected by a referee who said “the apparent activity must surely be down to an error in the data”.(神经科学家Marcus Raichle现在已经是该领域的领头人之一，但在1998年，他的一篇论文甚至被审稿人给拒绝了，理由是“大脑看起来很明显的活动状态一定是由于数据出现错误”。)

Today things are very different. Almost 3000 scientific papers have been published on the topic of the brain’s surprisingly busy “resting state”. Some object to(反对) this term for the very reason that the brain isn’t resting at all. They prefer instead to talk about the “default mode network”(默认状态网络) – the areas of the brain which remain active while we are apparently idle.

The big question is: why is the idling brain so active? There are plenty of theories, but no agreement yet. Maybe different brain areas are simply practising working together. Perhaps the brain is staying active like an idling car, just in case it needs to act suddenly. But it’s possible that those mind wanderings and replays of our day play a vital role in helping us to consolidate(加强) our memories. We know that our dreams seem to play a part in sorting out our memories – now there is evidence that it happens during the day too (in rats, at least).

We also know that when the mind is left to wander, it often focuses on the future. We start thinking about what we’re going to eat in the evening or where we’re going to go next week. All three of the chief areas of the brain involved in imagining the future are part of the default mode network. It is almost as though our brain is programmed to contemplate(思考)the future whenever it finds itself unoccupied(空闲的).

Moshe Bar from Harvard Medical School thinks there might be a very good reason for that. He believes daydreaming essentially creates memories of events that haven’t happened. This gives us a strange set of “prior experiences” we can draw on to help us decide how to act if the daydreams ever do come to pass. (这就给我们一套奇怪的“前经验”，如果白日梦真的发生了，我们可以利用这些经验来决定自己采取的行动。)For instance, many air travelers have wondered what it might be like to crash. Bar’s idea is that if the plane did actually crash, the memories of all those daydreams from previous flights would come into play and help the passenger decide how to behave.