大学英语精读听力第一册 unit9

[00:00.00]Unit Nine　Text
[00:23.33]Throughout the ages different ideas’ve been expressed about the workings of the human brain
[00:23.43]It is only recently,however,
[00:26.10]that science has begun to give us some idea of how the brain really works.
[00:30.85]THE BRAIN 　THE MOST POWERFUL COMPUTER IN THE UNIVERSE
[00:36.28]Man still has a lot to learn about the most powerful andcomplex part of his body--the brain
[00:43.52]In ancient times men did not think that the brain was the centre of mental activity.
[00:49.37]Aristotle the philosopher of ancient Greece
[00:52.87]thought that the mind was based in the heart.
[00:55.54]It was not until the 18th century　that man realized
[00:59.61]that the whole of the brain was involved in the workings of the mind.
[01:03.76]During the 19th　century
[01:06.09]scientists found that when certain parts of the brain were damaged
[01:10.16]men lost the ability to do certain things.
[01:13.33]And so,
[01:14.48]people thought that each part of the brain controlled a different activity.
[01:19.20]But modern research has found that this is not so.
[01:23.15]It is not easy to say exactly what each part of the brain does.
[01:28.92]In the past 50 years there has been a great increase
[01:33.35]in the amount of research being done on the brain.
[01:36.59]Chemists and biologists have found that the way the brain works
[01:40.43]is for more complicated than they had thought.
[01:43.38]In fact many people believe that we are only now
[01:47.82]really starting to learn the truth about how the human brain works.
[01:52.16]The more scientists find out,
[01:54.82]the more questions they are unable to answer.
[01:57.49]For instance,
[01:58.84]chemists found that over 100000 chemical reactions take place in the brain every second
[02:05.79]Mathematicians who have tried to use computers
[02:09.63]to copy the way the brain works
[02:11.67]works have found that even using the latest electronic equipment
[02:16.03]they would have to build a computer which weighed over 10,000 kilos.
[02:20.89]Some recent research also suggests
[02:24.44]that we remember everything that happens to us.
[02:24.55]We may not be able to recall this information,
[02:27.71]but it is all stored in our brains.
[02:30.74]Scientists hope that if we can discover how the brain works,
[02:35.37]the better use we will be able to put it to.
[02:38.32]For example,how do we learn language?
[02:41.66]Man differs most from all the other animals
[02:45.14]in his ability to learn and use language
[02:48.48]but we still do not know exactly how this is done.
[02:52.53]Some children learn to speak and read and write
[02:56.68]when they are very young compared to average children.
[03:00.24]But scientists are not sure why this happens.
[03:09.60]They're trying to find out whether there's something
[03:12.86]about the way we teach language to children
[03:15.71]which in fact prevents children from learning sooner.
[03:19.34]Earlier scienists thought that during a man's lifetime
[03:23.60]the power of his brain decreased.
[03:26.26]But it is now thought that this is not so.
[03:29.42]As long as the brain is given plenty of exercise it keeps its power.
[03:34.65]It has been found that an old person
[03:37.70]who has always been mentally active has a quicker mind
[03:41.86]than a young person who has done only physical work.
[03:45.41]It is now thought that the more work we give our brains,
[03:51.24]the more work they are able to do.
[03:53.38]Other people now believe
[03:55.63]that we use only 1% of our brains' full potential.
[03:59.97]They say that the only limit on the power of the brain
[04:03.65]is the limit of what we think is possible.
[04:06.89]This is probably because of the way we are taught as children.
[04:11.46]When we first start learning to use our minds we are told what to do,
[04:16.53]for example,to remember certain facts,
[04:19.90]but we are not taught how our memory works
[04:23.35]and how to make the best use of it.
[04:25.78]We are told to make notes
[04:28.00]but we are not taught how our brains accept information
[04:32.02]and which's the best way to organize the information we want our brains to accept
[04:37.95]This century man has made many discoveries about the universe--
[04:42.89]the world outside himself.
[04:45.13]But he has also started to look into the workings
[04:49.18]of that other universe which is inside himself
[04:52.55]--the human brain.