A dream is the subconscious experience of a sequence of images, sounds, ideas, emotions, or other sensations, occurring predominantly during Rapid Eye Movement (REM) sleep – the period when the brain’s activity most resembles that seen in wakefulness. REM sleep accounts for approximately 20%-25% of total sleep. We typically have 4 or 5 periods of REM sleep during the night, with short periods at the beginning and longer ones as the night progresses.
Our dreams are made up of things we know, have experienced or can imagine. Yet what we dream about is also limited in certain ways. When we are asleep, we are vulnerable, so we need to remain vigilant about our environment. But because our dreams are essentially real, dream sensations that compromise our vigilance would be unhelpful.
For example, because we cannot see or move when asleep, vision and movement do not play a role in providing accurate information about the outside world. Vision and movement can therefore exist in dreams without compromising our vigilance. This accounts for the fact that the overwhelming majority of our dreams are visual. But experiencing things such as touch, smell or sound could compromise vigilance, by interfering with signals coming from the external environment. As a result, such sensations rarely occur in our dreams.
Anxiety is the most common emotion experienced during dreaming. Most of us have a recurring ‘stress’ dream that is usually about a stressful situation: events at school, being chased, falling, arriving late, failing an exam, etc. Men generally have more aggressive feelings in their dreams than women, whilst children’s dreams do not contain much aggression until they become teenagers.
But whatever you dream about, remember that your dreams are yours alone.
Dr. Neil Stanley
Dr Neil Stanley is an independent sleep expert who has been involved in research for over 35 years. After starting out at the R.A.F. Institute of Aviation Medicine, he moved on to the University of Surrey's Human Psychopharmacology Research Unit, where he was Director of Sleep Research. Today, he travels the world lecturing on various aspects of sleep to both healthcare professionals and the public at large.