Dreams

Every night we lie down to rest, we spend about two hours traveling through seemingly real experiences as dreams bubble up from our subconscious during various phases of sleep. Despite the ubiquity of the experience, where dreams come from—and what their purpose is—remains largely unanswered.

In the mid-1900s, dream scientists would tape study participants' eyes open, wait for them to fall asleep, and attempt to influence their dreams by shaking, tickling, and more. Now, advanced techniques like MRIs have shed new light on what’s happening in the brain as we sleep.

Many people equate "random" with "well-spaced," creating a cognitive bias that influences how people interpret events. This article explains how people tend to assume a generative force behind the patterns produced by randomness. This phenomenon, known as pareidolia, is seen in claims ranging from backward messages hidden in reversed audio recordings to tea leaf readings.

Most people dream for about two hours every night and recall about two dreams per week, and memory encoding is especially fragile upon waking. Alarms can knock dreams right out of one's head, and dream recall may be influenced by personality, interest, and socialization.

Austrian psychologist Sigmund Freud believed dreams should be interpreted using personal symbolism and free association, meaning relaxing the mind and waiting to see what concepts spontaneously erupt. Interpreting and unraveling these "involuntary ideas" is a precursor to understanding the psychology of neuroses, according to Freud.

Sleepwalking, or somnambulism, occurs most frequently in children who are in the deepest stages of sleep. REM, the sleep stage in which most people dream, often causes temporary muscle paralysis, so it’s only when sleepers pass to the deeper stages of sleep that sleepwalking—and sleep talking—can occur.

Sleep is a natural process that is critical to maintaining life—a process conserved throughout evolution across just about any animal with a brain. Generally speaking, the first three stages involve increasingly deep phases of non-REM sleep, followed by a roughly 90-minute period of REM sleep that repeats throughout the night.

The first venture into modern dream interpretation may have been when ancient Greek philosopher Heracleitus proposed dreams were created within the mind. In the late 1800s, the rise of psychoanalysis theorized that dreams content revealed truths about one's psyche, while the invention of the electroencephalogram linked dreams to brain functions.

When the body falls into a deep enough phase of sleep, it paralyzes certain parts of itself so the brain can't force it to physically act out dreams. This well-known but little-understood phenomenon happens when the brain awakens early and typically results in haunting hallucinations and reports of supernatural terrors.

Every night, most of us dream, but about 20% of people experience lucid dreaming at least once a month. In these rare moments, dreamers are aware they're dreaming, and can even control their actions. Though linked to increased frontal lobe activity, why this state occurs remains a mystery.