Why do we dream?.

This documentary looks at the lastest developments in our understanding of the origin and function of dreams. We look back at the history of dream research and meet a man who acts out his dreams at night due to a rare REM sleep disorder. Latest research has shown that dreams occur in both REM and non-REM sleep and tests by dream therapist Erica Harris show that REM sleep tends to produce a more negative state of mind than non-REM sleep. It is possible that depressives get too much REM sleep and that this affects their state of mind during their waking hours. Professor Mark Solms works with people who do not have dreams, usually due to damage to the brain following a stroke or brain injury. He believes that dreams are a way of keeping us asleep. Antonio Zadra is a dream researcher in a Montreal sleep lab who has collated thousands of dreams and created statistics from them. It seems that, for instance, two thirds of our dreams are negative and that we rarely dream about sex with our own partners. Can we manipulate our dreams to affect our performance during the day? Robert Stickgold believes that in dreams we are bringing new experience to bear on old memories and that this is how we learn. Antti Revonsuo studies children's nightmares - he believes that many children's dreams about monsters and aggressive animals have been inherited from our ancestors and are a 'rehearsal' of things that might threaten one in the day. Traumatic memory can be reinforced by repetitive dreams leading to post-traumatic stress disorder; on the other hand lucid dreaming is a state in which one has self-awareness within one's dreams. Both areas are covered with examples.