What is dreaming?
Although we usually think of the time we go to sleep as being the end of the
day, in one sense it is just another beginning. Scientists now know that our
minds are just as active when we sleep as when we are awake. Dreaming occurs
during periods of deep sleep during which the mind is especially active. These
periods are signalled by rapid eye movement (REM) and occur in cycles of up
to 25 minutes up to a maximum of around an hour and a half in adults. But as
to the significance of dreams, scientists still disagree.
Early theories about the significance of dreams
For the ancient Greeks, dreams were messages from the gods. Aristotle, however,
disagreed. He was perhaps the first person to offer a more pragmatic interpretation
of dreams, arguing that dreams were actually representations of images which
people had thought about or seen during the day.
Dreams and the unconscious
More recently, one of the first people to study dreams in a systematic way was
Sigmund Freud wno described dreams as 'the royal road to the unconscious'. Freud
argued that dreams express unconscious desires and wishes and that they can
be analysed on two different levels. On one level we can talk about the content
of our dreams (called the manifest content) and describe what actually
happened. However Freud suggested that dreams can be interpreted on a deeper
level (he called this latent content). At this level dreams are representations
of the unconscious, expressing the unconscious wishes and desires of the dreamer.
Freud argued that what we see and feel in our dreams are really symbols of the
unconscious.
Compensating for what we don't have
Another psychoanalyst, Carl Jung, agreed with Freud that dreams are meaningful
psychological communications, but suggested that the purpose of dreams was to
make up for things which were lacking in conscious life. Jung also argued that
dreaming allowed people to access information from a store of common human experience
which he famously called 'the collective unconscious'.
Dreams as problem-solving
Another perspective on dreams has been offered by cognitive psychologists. Cognitive
psychology argues that the key to understanding human behaviour can be found
through focusing on thought processes. British psychologist Christopher Evans
compares the brain to a computer, arguing that dreaming is a kind of information
processing. According to Evans, dreaming provides the brain with an opportunity
to sort through the information gathered during the day and store and order
it efficiently. Seen in this light, dreaming helps us to solve problems and
make sense of the world in which we live. Evidence for this theory comes from
a recent study that suggested that when people are asked to carry out new and
demanding tasks, the amount of time spent dreaming increased.
What to remember and what to forget
For others, far from helping us to process and learn, dreaming actually helps
us to forget! In 1983 Crick and Mitchison proposed a 'reverse learning' theory.
During our waking lives we are constantly bombarded with information. Crick
and Mitchison argued that dreaming is nothing more than a way of getting rid
of unnecessary information and modifying redundant connections in the brain.
Keeping the eyes healthy
A very different perspective comes from eye specialist David Maurice of Columbia-Presbyterian
Medical Center. Maurice has suggested that dreaming is a much more practical
activity than both psycholoanalysts and psychologists have proposed. Maurice
has hypothesized that REM is a means of maintaining a constant steady supply
of oxygen to the cornea during sleep. Without REM, the long period of time we
spend with the eyes closed would cause severe damage to the cornea.
The body's way of communicating problems
Maurice is not the only person to suggest a connection between the mental state
of dreaming and the physical body. Colin Shapiro of the University of Toronto
has suggested that dreaming can help people to stay in touch with their health.
One study found that people with severe heart disease experienced a dramatic
rise in dreams about separation and death – even before the full extent of the
illness had been diagnosed.