Purpose of dreams

Dreams are so compelling, and they often seem so weird and strange -- surely they must have a "purpose"; that is, an "adaptive role" in the maintenance of our bodily or psychological health. Furthermore, all the famous theorists who talk about dreams claim that dreams do have one or another purpose (although the famous theorists disagree on just what those functions are), but the best current evidence suggests otherwise. Dreams probably have no purpose!

So let's review the arguments and the evidence. We'll start with the claims made by psychoanalysts and clinical psychologists in the first 50 years of the century based on their work with patients, then turn to more recent claims, some of which are based on work in sleep and dream laboratories that flourished in the 1950's and 1960's. The views presented here are those of research psychologists who have studied dreams inside and outside the laboratory, especially David Foulkes and Calvin Hall.

The first and most famous dream theorist of the modern era, Sigmund Freud, said that the function of dreams was to preserve sleep, but that theory from the year 1900 is contradicted by the fact that dreams happen very regularly at least five or six times per night in an active stage of sleep called REM sleep (after the rapid eye movements that are part of it, along with many other neurological and physiological changes). In other words, dreams don't just happen as we are about to wake up due to hunger pangs, sexual urges, or the need to go to the bathroom, as Freud thought way back when, before REM sleep was discovered in 1953.

The other famous dream theorist of the modern era, Carl Jung, an early follower of Freud who broke away to develop a very different theory, claimed that the function of dreams is to compensate for those parts of the psyche (total personality) that are underdeveloped in waking life, but Calvin Hall's studies of two-week dream series from students and longer dream journals from adults of all ages strongly suggest that dream content is continuous with waking thought and behavior. That is, if we are outgoing and active in our waking life, and not very introspective and reflective, then so too in our dream life, which contradicts Jung's view.

Still other dream theorists say that dreams have a problem-solving function. Dreams supposedly deal with problems we can't solve in waking life and offer solutions. But a variety of systematic studies find precious little support for this view. However, this is one of those places where we have developed "uses" for our dreams as part of our cultural lore. Looking at them in the light of waking day, and believing that they may be full of insight, we may sometimes come up with new ideas or insights while studying them. That is, we have invented a "use" for dreams, but that doesn't mean that problem solving is a psychological function of dreams built into us over evolutionary time.

So much for the claims by clinical theorists. Now we look at claims that have emerged in recent years, but are tied to no particular theory or famous theorist. They are the new "common sense" of our day, based on a reverence for physiological findings and the awesome capabilities of computers.

When REM sleep was first discovered, it was thought that dreams only occurred during that stage of sleep. This led to many functional theories about dreaming that were based on alleged functions for REM sleep. But we now have reason to believe that plenty of dreams happen in non-REM (NREM) sleep, especially late in the sleep period.

Furthermore, awakenings of children under age 5 in the sleep laboratory reveal that they only report dreams from REM sleep awakenings 20-25% of the time, so REM sleep does not automatically equate to dreaming. In addition, REM sleep can be found in all mammals, and it is unlikely that they are dreaming, i.e., imagining a world or story in which they are taking part and interacting with others. Dreams, as the pre-eminent American psychologist on dreams, David Foulkes, likes to say, are a "cognitive achievement." We only gradually develop the ability to dream. What all this adds up to is that REM sleep and dreaming are not the same thing, so whatever functions REM sleep may have cannot be taken as functions for dreaming and dreams.