The quick answer is that nobody knows. The long answer is that are lots of different theories. So, if you're interested, read on!

Some theories of the purpose of dreams
Freud believed that we dream so that we can release the deep, secret desires that we are not allowed to express in real life because of the rules of polite society. Most people know about Freudian dream analysis - a dream about a train going into a tunnel is a dream about sexual intercourse. But couldn't it just be a dream about travelling on a train?

Another theory is that dreams allow us to solve problems that we can't solve in real life. We go to sleep with a problem and wake up with the answer. This may be more of a way to ‘use' our dreams than a ‘purpose' of dreaming. If you believe that your dreams are important then analysing them may help you to focus your mind on the problem and help you to find the solution.

The modern image is that dreams are the brain's way of cleaning up the computer's hard disk, organizing the events of the day into folders and deleting the rubbish that it doesn't want to keep. But we all know that very little of what we dream every night is concerned with what happened to us that day.

Another idea is that dreams are the brain's way of practising the behaviour that we need to survive. So we dream about being chased by a monster because one day it might happen! It's a bit like a pianist practising her scales every day even though she doesn't need to use them at that moment.

Others believe that dreaming is the brain's way of exercising the pathways between the brain cells. This may be an important element in why we sleep rather than why we dream. We die if we don't sleep but we can live without dreaming. Some patients with brain injuries lose the ability to dream but don't seem to suffer any ill-effects.

REM and dreaming
Scientists used to think that dreaming only happened during Rapid Eye Movement sleep (REM). REM sleep is essential for all mammals. We all become irritable and depressed without it. If we don't have enough REM one night, we will compensate by having more the next. REM is generated by the brainstem - the oldest and most primitive part of the brain. So scientists used to believe that dreaming was also caused by activity in the brainstem. We now know that dreaming can happen at any time during sleep. The only difference seems to be that it's easier to remember dreams that happen during REM.

Babies have a lot more REM activity than adults, but research shows that they dream less. The same may be true of animals. We know that they have REM activity but that doesn't mean they dream.

It also seems that dreaming is a skill that develops as you get older, like language for example. Young children's dreams are very different from older children's or adult's dreams.

New research
Modern technology has allowed scientists to map the parts of the brain that are active when we dream. The primitive brainstem is very active, but so are other important areas at the front of the brain. These are the frontal lobes that control emotion, memory, and experiences that come through the senses like hearing and vision. If these areas are injured, the person stops dreaming. On the other hand, the areas that control rational, logical thought are not active at all. This could explain why dreams are so strange. They have no logical sequence or time, which makes them very difficult to explain to other people when we wake up. Dreams combine recent events with long past events and our emotions while we are dreaming are often very strong.

Psychologists have also done studies on people who kept dream diaries for long periods of time (up to fifty years in some cases) and have found that what we dream is very much connected with how we think and behave when we are awake. So an extrovert, adventurous person will have extrovert, adventurous dreams. A shy person will be a shy person in her dreams. People who are important to us will often be in our dreams and so will things that worry us or make us happy.

So what's the conclusion?
Well, nobody really knows. But scientists are now suggesting that dreams have absolutely no purpose at all. When we are awake we are ‘thinking' all the time. Some of this thinking is useful and has a purpose. But we often just ‘think' about nothing in particular while we're waiting for the bus or walking to work. And that's what the brain is doing when we are asleep - just thinking. Sometimes it's interesting and sometimes it's boring.

Vocabulary

5 words/phrases from the text:

1. analysis: the process of studying the nature of something by examining its features
2. to focus: to concentrate on something
3. irritable: easily annoyed or impatient
4. extrovert: a person who is outgoing
5. embarrassing: making you feel ashamed

Exercise one.

Vocabulary gap fill. Now use the 5 words/phrases to fill the gaps in the sentences below:

1. Try ................. on what I am saying and forget about everything else.
2. After making an initial ..................... of the situation, the firemen decided to enter the building.
3. It was very ................ for James to see his wife singing in the karaoke competition; she had an awful voice!
4. She was being more .............. than usual and was starting to get angry with me.
5. Invite Sally to the party; she's ................. so she'll get everybody dancing and singing.

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Exercise two.

Comprehension. Decide whether these sentences are TRUE or FALSE according to the article:

1. Freud believed that dreams were a way of expressing things like sexual desire.
2. Some people believe that dreams are a way of organising our business while we sleep.
3. Evidence shows that babies dream more than adults.
4. As we get older, our dreams get more sophisticated.
5. Psychologists believe that we change aspects of our personality while we are dreaming.

Grammar.

British English and American English

British people and American people can always understand each other - but there are a few notable differences between British English and American English

Grammar
Americans use the present perfect tense less than speakers of British English and a British teacher might mark wrong some things that an American teacher would say are correct.
US Did you do your homework yet? Brit. Have you done your homework yet?
US I already ate. Brit. I've already eaten.

In British English, ‘have got' is often used for the possessive sense of ‘have' and ‘have got to' is informally used for ‘have to'. This is much less common in American English.
Brit. I've got two sisters. US I have two sisters.
Brit. I've got to go now. US I have to go now.

There are a number of other minor grammatical differences.

Vocabulary
There are a lot of examples of different words being used in British and American English. Here are a few of the commonest.

Brit. US
angry mad
autumn fall
boot (of a car) trunk
chemist's drug store
cupboard closet
flat apartment
lift elevator
nappy diaper
pavement sidewalk
petrol gas/gasoline
rubbish trash
tap faucet
trousers pants

There are British words which many Americans will not understand and vice versa. There are also words which exist in both British and American English but have very different meanings.

Spelling
There are also a number of different spelling rules between British English and American English.

1 Some words that end in ‘-tre' in British English end in ‘-ter' in American English.
US theater, center Brit. theatre, centre

2 Some words that end in ‘-our' in British English end in ‘-or' in American English.
US color, labor Brit. colour, labour

3 Some words are shorter in American English than in British English.
US catalog, program Brit. catalogue, programme

Exercise

Decide whether these sentences were said by an American or a British person.

1. I already took the trash out.
2. I've got to put some petrol in the car.
3. I just spilt wine on my pants.
4. Take the elevator up to my apartment.
5. Have you changed the baby's nappy yet?

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Quiz Question 35

What are dreams for? - key

Vocabulary

1. to focus
2. analysis
3. embarrassing
4. irritable
5. extrovert
   

Comprehension

1. True
2. true
3. False
4. True
5. False

Grammar

1. US
2. Brit
3. US
4. US
5. Brit