Monday, September 1, 2008

What do our dreams mean?

What did you dream about last night? Were you chased by some unseen phantom through dark woods; did you get intimate with a Hollywood film star; or were you simply doing some shopping in your local supermarket? According to new research that has analysed more than 22,000 dreams, you're most likely to have dreamt the latter.

The dreams, some dating back to the late 19th century, are stored on the Dreambank at the University of California. The facility, which relies on people phoning the university to report their dreams, is giving researchers new insights into the nature and content of dreams.

The research suggests claims that dreams are top heavy with sex and religion might be wrong, and that most - as many as eight out of ten - are about mundane everyday concerns and interests such as parents, friends, driving, shopping and sport. Men might think about sex every seven seconds, it seems, but don't dream about it anywhere near as much.

Dreams have long been a source of fascination because of their surreal content, our lack of control over them, and the absence of a universally accepted explanation for exactly what they are and whether or not they have any purpose.Although there is no consensus on the purpose, if any, of dreams, there are many theories. One suggests that dreams are random images created by the brain as it reworks the previous day's events, while another proposes that dreaming is simply the brain keeping itself occupied with home-made B movies while the body sleeps.

Yet another theory is that they are part of a survival strategy that evolved in early Man to help him to learn while he slept so he could recognise and deal with threats in a hostile world. Others suggest that dreams have a kind of mulling-over effect, helping to solve problems that cannot be dealt with while awake, or that they are part of the process of memorising the previous day's events, or that they can somehow foretell the future.

Do dreams have a function?

Although there are many of these theories, they broadly split into two camps: those that suggest a function for dreams; and those that propose they have no purpose. “The fact that we remember so few of our dreams, a few per cent at best, argues against any function for dreams. If they are so important, why don't we remember more of them? If dreams are important, why aren't the recallers of them better off in some way?” says Dr Bill Domhoff, of the University of California, Santa Cruz, home of the Dreambank. “We are thinking creatures because thinking is a valuable adaptation, but that doesn't mean that all forms of thinking have a function. Dreams at this moment in the collective findings of dream researchers seem to be a throwaway production, an offhand story to while the night away.''

Dr Domhoff and his colleagues have used new search tools to investigate the content of the individual dreams in the Dreambank, a database whose contributors range from scientists and academics to teenagers, middle-aged women and pensioners. It includes 86 dreams from a physiology graduate student at Massachusetts Institute of Technology that date back to 1897, and 900 dreams from a psychologist recorded between 1913 and 1965. When the psychologists searched the bank for keywords, they found that references to sexual intercourse and religion were relatively rare. Sexual intercourse references were 2 per cent for men and 0.4 per cent for women. Only 3.3 per cent of the dream reports mentioned churches, cathedrals, temples and chapels, and only 0.8 per cent referredto specific religions or denominations.

“The findings from this search raise the general question: why is thinking about sexuality more pervasive in waking thought than it appears to be in dreaming?” say the researchers. “Although dreams and sexuality are often closely related in popular culture, perhaps in part due to Freud's theory concerning the hidden sexual meanings said to be present in most dreams, studies suggest that there is little explicit sexual content in dreams.''

The findings also raise questions about what people dream about. According to the research, as many as 75 to 80 per cent of dreams deal with everyday personal concerns and interests. A dream series from one man that they analysed in detail showed that his mother and father appeared in 23.9 per cent of dream reports, friends in 53.9 per cent, driving 24.5 per cent, outdoor activities 17 per cent, eating 13.7per cent and sport 6.1 per cent.

The theory that dreams are not full of magical worlds and bizarre fantasies but are about events in our day-to-day lives has been bolstered by other research. For example, researchers at the University of Florence found that musicians dream of music more than twice as often as non-musicians. Other research has shown that the number of women dreaming about work has increased at the same time as the proportion of women in the workforce has risen.

An evolutionary purpose

But although the everyday content seems to support the idea that dreams have no function, other researchers have shown otherwise. Researchers at the University of Turku in Finland have found support for an evolutionary purpose of dreams. When they analysed nearly 600 dreams they found that two thirds contained at least one threat, and that more than 60 per cent of these threats were likely to be experienced in real life.

The idea is that during dreaming the brain builds up a model of the world, taking into account what happened in the real world so that strategies can be planned and problems solved.

“The hypothesis is that the biological function of dreaming is to simulate threatening events and to rehearse threat perception and threat avoidance,'' says Dr Antti Revonsuo, a psychologist at the University of Turku. “In the ancestral environment human life was short and full of threats. A dream-production mechanism that tends to select threatening waking events and simulate them over and over again would have been valuable for the development of threat-avoiding skills.'

An aid to daytime learning?

Research at Harvard University has found support for another idea, that sleeping and dreaming boost daytime learning. Researchers found that when they woke people as soon as they had fallen asleep and then analysed the content of their dreams that the subjects were already processing images from a computer game that they had been playing beforehand. That, say the researchers, suggests nocturnal brain processing was helping them to play the game better.

Jim Horne, the director of the Sleep Research Centre at Loughborough University and author of Sleepfaring, is sceptical about the value of analysing the dreams of others. “People who obsessively record their dreams probably are not normal dreamers. Most normal dreamers don't remember dreams because they are junk basically. Most dreams last for 20 minutes or longer, so recall is often of the distorted end of the dream,'' he says.

The idea that dreams have an essential function is further undermined, he adds, by research showing that people taking some drugs, including certain antidepressants, do not dream at all for months. Dreaming, he suggests, is a consequence of the brain not wanting to be switched off for eight hours and its needs to be stimulated. The job of dreams, it seems, may be to keep the brain entertained and the body asleep. “They are the cinema of the mind where the brain creates junk B movies that are entertaining, but which mean little and arebest forgotten.”

Factbox: What do our dreams mean?

The stuff of nightmares

According to the dream specialist Dr Patricia Garfield, a past president of the Association for the Study of Dreams, there are 12 basic nightmares that are universal, including being chased or being naked in public, as well as drowning, falling or being menaced by the dead.

Personality and dreams

People with conservative personalities dream more about being chased, fall from high buildings with greater frequency, and are prone to themes of discontent and unhappiness. They also have far fewer sexual dreams, according to research by the Santa Clara University, California.

Be careful what you read

People who are attracted to fantasy novels are more prone to nightmares, while children who read scary books are three times as likely to have scary dreams, according to research at Swansea University. It also shows that the dreams of those who prefer romantic novels are more emotionally intense.

Flying high

Nearly one person in 12 has had a recent dream about flying, according to a study at Mannheim University in Germany. “The increase in people who report flying dreams might reflect the increasing amount of air travel,'' they say.

Don't watch the news

Dream topics change in response to what we worry about. According to dreams filed at the World Dream Bank, a library of 1,500 dream texts and images (, more people seem to be dreaming about climate change, while a study at Tufts University in Boston disclosed that the dreams of dream diarists immediately after the 9/11 attacks were different from those just before.

Dreams in numbers

5-30 minutes the average length of a dream

Every 90min how often we dream at night

33% of dreams convey misfortune

25% of dreams take place in a known location

50% of social interactions in dreams are aggressive, usually towards the dreamer

95% to 99% the proportion of dreams that we forget

Source: Times database, Sleepfaring by Professor Jim Horne

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