Sleep and Dreams
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127 free Sleep and Dreams trivia questions with answers — science & nature quiz, new questions added Oct 2026.
11 free Sleep and Dreams trivia questions with answers. Sleep and Dreams trivia lives in two places on BrainPickle. This page is the shorter set; the main quiz is Sleep trivia, with our deepest question pool on the topic and a source behind every answer.
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Q 01Slipping into REM within minutes of dozing off is a hallmark of which disorder?
Narcolepsy
Narcolepsy: most sleepers take an hour or more to reach REM, but people with narcolepsy often enter it within 15 minutes, which is why dream imagery and muscle weakness can spill into their waking hours.
Q 02Which colour of light, plentiful in phone and laptop screens, does most to delay the body's night-time sleep signal?
Blue
Blue: in a Harvard experiment it shifted the body clock about twice as far as green light, while dim red light disturbs the clock least, so red suits a night light.
Q 03Which inventor is said to have napped with a ball in each hand, so that the clatter cut each nap short?
Thomas Edison
Thomas Edison is said to have prized the ideas that surface at the edge of sleep, and a 2021 study backs him: as little as 15 seconds of that drowsy state nearly tripled volunteers' chances of cracking a hidden maths rule.
Q 04Roughly how long does one full cycle of adult sleep last?
90 minutes
About 90 minutes: sleep pioneer Nathaniel Kleitman argued the same rhythm keeps ticking through the day, nudging alertness up and down roughly every hour and a half.
Q 05Which pair of EEG features is characteristic of NREM Stage 2?
Spindles and K-complexes
Spindles and K-complexes: a K-complex is the single largest event in a healthy human EEG, and a sound or a touch can trigger one without waking the sleeper.
Q 06Which of these is secreted most heavily during NREM Stage 3, the deepest stage of the night?
Growth hormone
Growth hormone: its largest pulse of the day arrives about an hour after sleep begins, in the first stretch of deep sleep, which is why that stage matters for tissue repair and growth.
Q 07Which age group spends the largest share of its sleep in REM?
Newborn babies
Newborn babies spend far more of their sleep in REM than adults do, and the share falls as they grow; one theory is that REM supplies the stimulation a developing brain needs to wire itself.
Q 08As the night progresses, how does the proportion of REM sleep typically change within each sleep cycle?
It lengthens
It lengthens: the first REM period may last only a few minutes, while later ones can run for around an hour, so most of the night's REM, and its dreams, comes in the hours before waking.
Q 09What other name do sleep scientists use for NREM Stage 3?
Slow-wave sleep
Slow-wave sleep is named for the large, slow delta waves that sweep the brain in this stage; it is the hardest sleep to wake from, so an alarm that catches you in it leaves you groggy.
Q 10Which neurotransmitter is abundant during REM sleep while serotonin and norepinephrine are nearly absent?
Acetylcholine
Acetylcholine: cholinergic cells in the brainstem switch REM on while the serotonin and norepinephrine cells fall almost silent, and the missing norepinephrine is thought to be one reason dreams fade so fast.
Q 11What is the scientific study of dreams called?
Oneirology
Oneirology asks how the brain produces dreams, measuring the process rather than decoding meanings; that second job, dream interpretation, is a far older craft the Babylonians were already practising.
Q 12Added up over a whole night, roughly how long does a typical person spend dreaming?
About 2 hours
About 2 hours: the night's dreaming comes in episodes of roughly 5 to 20 minutes each, far more than most people would guess, because nearly all of it has faded by morning.
Q 13Across Calvin Hall's 50,000-plus dream reports, which emotion turned up most often?
Anxiety
Anxiety topped Hall's tally, and negative emotions as a whole outnumbered positive ones; he gathered the reports from children, older adults and people around the world, then coded their content by category.
Q 21Which marine mammal wraps itself in kelp so it will not drift away while it rests?
Sea otter
Sea otter: anchoring itself in kelp stops the current carrying it off as it rests at the surface, and a mother will wrap her pup in kelp so it bobs like a cork while she dives for food.
Q 22Dutch psychiatrist Frederik van Eeden coined which dream term in 1913?
Lucid dream
Lucid dream: van Eeden meant 'lucid' as clear-minded, not vivid; in such a dream, he wrote, the sleeper reaches full awareness and can act by free choice.
Q 23Lucid-dreaming pioneer Stephen LaBerge did his dream research at which Californian university?
Stanford
Stanford: LaBerge earned his doctorate there in 1980 for lucid-dream research, devised the MILD technique for entering one at will, and went on to found the Lucidity Institute to teach it.
Q 14Which Gothic novel grew from a 'waking dream' its 18-year-old author had beside Lake Geneva in 1816?
Frankenstein
Frankenstein: challenged by Lord Byron to write a ghost story, Mary Shelley lay awake one night and saw a 'pale student of unhallowed arts' kneeling beside the thing he had put together.
Q 15According to Freud, what purpose do dreams serve?
Prolonging sleep by presenting wishes as fulfilled
Prolonging sleep by presenting wishes as fulfilled: Freud called dreams the guardians of sleep, disguised fulfilments of repressed wishes, and cared more about interpreting them than explaining how they arise.
Q 16Which god of dreams, in Ovid's telling, takes human form to carry messages to sleepers?
Morpheus
Morpheus, one of the thousand sons of Sleep in Ovid's Metamorphoses, could copy any person's walk, face and voice; centuries later his name supplied the word morphine.
Q 17In 1964, 17-year-old Randy Gardner set a record by staying awake for roughly how long?
Eleven days
Eleven days: Gardner stayed awake 264 hours for a school science fair on nothing stronger than the occasional Coke, then slept for only about 14 hours before waking naturally.
Q 18Why did Guinness World Records stop accepting sleep-deprivation record attempts?
Safety reasons
Safety reasons: Guinness stopped monitoring the record in 1997, which froze Robert McDonald's 1986 run of 18 days 21 hours as its last official mark; nobody is known to have beaten it since.
Q 19Which leaf-eating mammal sleeps for up to 20 hours a day?
Koala
Koala: eucalyptus leaves are tough, toxic to most mammals and poor in calories, so the koala saves energy by sleeping up to 20 hours a day, often in the same tree it feeds in.
Q 20Which sleep pattern lets ducks at a flock's edge keep one eye open for threats?
Unihemispheric sleep
Unihemispheric sleep: one half of the brain rests while the other stays alert, so ducks on the edge of a flock do more of it and react to threats seen by the open eye.
Q 24In narcolepsy, the sudden loss of muscle tone triggered by strong emotion is called what?
Cataplexy
Cataplexy, the emotion-triggered loss of muscle tone, is the hallmark of type 1 narcolepsy, which is linked to low levels of the neuropeptide orexin in cerebrospinal fluid.
Q 25Which virus is thought to trigger the autoimmune process behind narcolepsy in susceptible people?
H1N1 influenza
H1N1 influenza: narcolepsy cases rose after the 2009 H1N1 pandemic and the Pandemrix vaccine, and the resulting immune attack destroys the neurons that produce orexin.
Q 26Sleepwalkers are not acting out their dreams; in which stage of sleep does sleepwalking usually begin?
Slow-wave NREM
Slow-wave NREM: sleepwalking is a partial arousal out of deep sleep, which is why it usually happens in the first third of the night, when deep sleep dominates.
Q 27What is the medical term for sleepwalking?
Somnambulism
Somnambulism: if you meet a sleepwalker, the advice is to steer them gently back to bed, because someone woken suddenly from it is confused and may be frightened or angry.
Q 28Which bringer of sleep is named in the titles of a Metallica hit and a Neil Gaiman comic series?
The Sandman
The Sandman: in folklore he sends children to sleep by sprinkling sand in their eyes, but in the German writer Hoffmann's tale of the same name a nurse describes a monster whose sand makes wakeful children's eyes fall out.
Q 29The word 'circadian' derives from Latin words meaning what?
Approximately one day
Approximately one day: Franz Halberg coined 'circadian' in 1959 from the Latin circa, 'around', and dies, 'day', choosing 'about' because the body's rhythms run close to 24 hours without always matching it.
Q 30In 1729, de Mairan found which leaf-folding plant kept its daily rhythm even in constant darkness?
Mimosa pudica
Mimosa pudica: shut away from daylight, its leaves still opened by day and folded at dusk, the first recorded hint of a body clock, though de Mairan himself stopped short of that conclusion.