Daydreams refers to a level of consciousness somewhere between sleep and wakefulness, a mild detachment from immediate surroundings often referred to in psychology as dissociation. As the mind begins to wander during lulls in concentration throughout the day, the level of conscious awareness can decrease and the imagination may create all manner of (usually pleasant and positive) imagined scenarios and fantasies, all without consciousness sinking to the level of actual sleep. A 2009 neurological study indicates that as much as half of our day-to-day thoughts are what are generally referred to as daydreams, and that more of our supposedly focussed thinking is interrupted and unstructured than we are wont to think.
Recent research is also attaching more and more importance to daydreaming. It claims that a wandering unfocussed mind is the brain’s default mode, to which it automatically tries to return given the oportunity. It even claims that some of our best thinking occurs when our minds are allowed to wander.
During these daydreaming episodes, our minds are more likely to tackle ongoing intractible life problems that we may be unwilling to work through in a more focussed way, thus providing an essential element of stress reduction. It also provides an opportunity for creativity and the incubation of new ideas without the usual inhibitory brake of our rational and prudent prefrontal cortex.
Lucid dreams are dreams in which, contrary to the normal situation, the sleeper is actually aware of dreaming, or at least that some event taking place in the dream cannot possibly be really happening. These dreams are generally extremely realistic and vivid. Usually, people automatically wake themselves up when they actually realize that they are dreaming, but it may be possible to consciously continue the dream. According to some people, it may even be possible to exert some control over the dream content, to become an active participant in the dream, making decisions and influencing outcomes. Some go even further, claiming that it is possible to train oneself to experience lucid dreams, although these are more contentious claims. It is thought that, in the case of lucid dreams, the lateral prefrontal cortex of the brain (the part associated with logic and common sense which is normally suppressed during REM sleep) is for some reason not suppressed, so that the dreaming and logic circuits are both active at the same time.
However, there does still seem to be some interface with the rest of the waking brain during lucid dreaming. An early researcher on the subject, the 19th Century French aristocrat Marquis d’Hervey de Saint-Denys, repeatedly tried to dream his own death by directing his lucid dreams towards suicide, but found that the dreams always changed scene and avoided the death. It also appears to be impossible to tickle onself or make oneself laugh in a lucid dream, suggesting a high level of awareness of bodily actions and sensations.
Recurring dreams are dreams that repeat themselves night after night with little variation. They may be positive in nature, but more often they have a nightmare-ish quality (see the separate section on Nightmares). The recurrence is thought to be because some conflict depicted by the dream (e.g. some life situation or emotional problem) remains stubbornly unresolved.
Progressive dreams are related dreams that occur in a sequence over several nights, with one night’s dream continuing where the previous night’s dream left off. This is relatively unusual, but it can occur when a particularly complex problem or situation needs to be worked out in great detail.