“Dreams … are a training ground in which animals and people alike go over the behaviors that are key to their survival.”
- Antti Revonsuo

A recent project involved dream deprivation in rats. The rats were placed in an environment where they could get no REM sleep. Within several days, they lost their basic survival instincts — even when jacked up on amphetamines.

Finnish psychologist Antti Revonsuo believes the marooned rats lost their ability to defend themselves not because they were exhausted but because they were robbed of their dreams. Dreams, he contends, are a training ground in which animals and people alike go over the behaviors that are key to their survival. Prevented from dreaming, the rats were unable to rehearse their survival behaviors. In other words, they were defenseless because they were out of practice.

… In the ancestral environment, Revonsuo reasoned, our dreams served to protect us, teaching us how to respond when a wild animal was chasing us or when we got lost in the forest. That was why the dream world was so filled with peril: to simulate the potential threats and prepare us to react quickly ….

Revonsuo believes that by providing rehearsal, dreaming helps us recognize dangers more quickly and respond more efficiently. We don’t need to be aware of this rehearsal, just as you don’t have to recall exactly where you practiced your tennis serve in order to reap the rewards.

- Jay Dixit, Psychology Today: link.

Via SlashDot:

We have 300 to 1,000 threat dreams per year — one to four per night and just under half are aggressive encounters: physical aggression such as fistfights, and nonphysical aggression such as verbal arguments. Faced with actual life-or-death situations — traffic accidents, terrorist attacks, street assaults — people report entering a mode of calm, rapid response, reacting automatically, almost without thinking. Afterward, they often say the episode felt unreal, as if it were all a dream. ‘Dreaming is a sensitive system that tries to pay much attention to the threatening cues in our environment,’ Revonsuo says. ‘Their function is to protect and prepare us.’