The science of dreaming

Reader's Digest Editors

Dreams are amongst our most mysterious experiences. They can be strange, funny, frightening or stimulating. But what's the science behind them?

How are dreams and memories formed?

woman dreaming in a field of daisies

Thanks to modern science, it's now possible to see into a living human brain and observe the processes that occur there during sleep. Sometimes, modern medicine has even been able to bring people back from the threshold of death, and this has made the study of near-death experiences possible.

Despite medical progress and huge developments in the instruments used to observe human bodily functions, however, there are still many gaps in our knowledge about the nature of dreams and memories. As far as we know at present, for memories to be developed, genes in the brain’s nerve cells need to be activated, new proteins formed, and nerve connections changed. We know even less about the creation of dreams.

For a while it was assumed that dreams were closely linked to REM sleep—REM being the acronym of Rapid Eye Movement, a stage of sleep which is recognisable by the sleeper’s rapid eye movement. REM sleep was discovered in the mid-20th century, and has played an important role in explanations of dreams ever since. In addition to the rapid eye movement seen during REM sleep, there are other motor activities as well.

"There are still many gaps in our knowledge about the nature of dreams"

REM sleep occurs about every 90 minutes and lasts for about 20 minutes. Experiments conducted in sleep laboratories have shown that people who are woken while they are in a REM sleep stage are more likely to report having dreamt than those who were woken during nonREM sleep. However, scientists have now discovered that people dream during other phases of sleep as well, although these dreams have a different quality. They tend to resemble conscious thought sequences, whereas REM sleep dreams tend to be similar to cinematic narrative sequences.

The connection between dreaming and REM sleep seems to be looser than was initially assumed. REM sleep has even been observed in the very rare cases of people who no longer dream at all due to brain damage.

 

What are our dreams trying to tell us?

dreamcatcher

It has been suggested that dreams are some kind of mixture made up of originally unconnected information from different areas of the brain. However, scientists have noticed that people don’t usually dream at random and that their dreams do tend to have something to do with themselves and their lives.

Some people repeatedly dream that they have failed an exam, for example, or they dream of people and objects that they had dealings with during the day. Many researchers have therefore gone back to the idea that dreams are likely to be more than merely neurons stimulated at random.

Read more: How to get rid of nightmares

 

Which dreams do we remember most clearly?

girl remembering an unpleasant dream

We usually only remember the fact that we have had intense dreams when we wake. This makes sense since we usually have several dreams each night.

If we do remember a dream, it is likely to have occurred in the last stage of dreaming prior to waking, but for some people, its contents tend to fade as soon as we try to recollect it.

Only nightmares, or dreams of a particularly emotional nature, stick in our memories.

 

What were Sigmund Freud’s theories about dreams?

Sigmund Freud

For Sigmund Freud (1856–1939), dreams were a valuable tool that could be used to help us understand the working of our unconscious minds.

By interpreting his own dreams, as well as those of a number of other people, Freud developed a theory in which he claimed that dreams have meaning and that they are, in fact, the fulfilment of suppressed desires. However, when a suppressed desire appears in a dream it is disguised, with the substance of the dream being presented through a series of subtle shifts and transformations.

This is how Freud explained the well-known phenomenon where a dreamer is sure he or she knows a person in a dream but is quite unable to give that person a name. In cases like this, different people from the dreamer’s past and present have been transformed into a single composite individual. Shifts occur when images from the dreamer’s distant past find their way into dreams about places and events from the preceeding day.

According to Freud, it is because of these shifts and transformations that we often only remember fragments of our dreams when we wake the following day.

 

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