The mustard battle starts at quarter after. Do we have everybody lined up for it?”
“We’re playing food roulette, food roulette! Yes, there’s a poisoned eclair on there.”
“Edwina didn’t even cry when that crocodile popped off her leg.”
All of the above are direct quotes from the absurd, unconscious world of Dion McGregor, an American songwriter and prolific sleep talker. McGregor was well known among his social circle for lengthy, sleep speeches about food, off-beat characters, and bizarre imagined scenarios. His nighttime monologues were so notable (and disruptive) to his roommates and friends that they recorded them and made them into an album, initially released by Decca Records in 1964. Decades later, a team of psychology researchers formally analyzed the content of his sleep talking episodes.
Most of us probably won’t achieve a sleep talk record deal nor be the subject of a scientific study for fantastical, nocturnal soliloquies. But that doesn’t mean we’re sleeping silently. Sleep talk is surprisingly common.
Estimates vary, but up to 65 percent of people report having sleep-talked at least once in their lives. And somewhere between 3 and 30 percent of the population report regularly sleep-talking, Luigi De Gennaro, a psychologist and sleep researcher at Sapienza University of Rome in Italy, tells Popular Science. The habit is most often documented in children (potentially because of the prevalence of parents as observers), but can persist well into adulthood, he notes. Sleep talking is “one of the most frequent” sleep behaviors,” De Gennaro says.
So why can’t we shut up for our shut eye, and what is it our sleeping selves are so desperate to share?
What are we saying when we snooze?
Sleep talk ranges from unintelligible mumblings to full-throated rants. But the only way the vast majority of us ever find out we talk in our sleep is because someone else tells us. “People are entirely amnesic or unaware that they are talking,” De Gennaro says.
All the data we have on what’s said comes secondhand, from recordings or sleep studies. A handful of research efforts have attempted to catalog the content of our sleep talk. After closely looking at McGregor’s nighttime musings, the study authors found his monologues were similar in bizarreness to the average, self-reported dream. They differed slightly in character makeup and emotional quality, but the psychologists chalked that up to personality.
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In larger samples, more trends are apparent. Deirdre Barrett, author of the 2001 book The Committee Of Sleep, and a psychologist and dream researcher at Harvard University, led the research on McGregor’s sleep-talking episodes. In a follow-up study, she conducted a not-yet-published analysis of thousands of peoples’ sleep talk, recorded at home using an app. She compared the sleep talk with existing studies of self-reported dream content and waking speech, and found that it was significantly different on a few fronts. Sleep talk seemed to convey more negative emotions, anger, mentions of bodily functions, food, and sex than either dreams or waking speech, she tells Popular Science.
The most notable difference between waking speech and sleep talk was the amount of profanity. In Barrett’s sample data, sleeping people cussed about six times as often as they normally would. “Some of these vocalizations really just sound like somebody having a swearing fit,” she says.
These observations are bolstered, in part, by a 2017 study in the journal Sleep, which catalogued 883 nighttime utterances from 232 people. The researchers observed that “no” was the most common, understandable word, and that negations as a whole represented more than 21 percent of clauses. Question words and phrases also made up more than a quarter of sleep talk. Finally, the study notes that about 10 percent of sleeping statements contained curse words, and that a significant proportion of sleep talk involved insulting someone or something.
But that doesn’t mean we’re all secretly dying to swear like sailors or cuss people out. There is no evidence that sleep talk is inherently more truthful or revealing than what we say when we’re awake, says Barrett. In most cases, sleep talkers “are just not very in touch with reality,” she notes. Often, the intelligible statements sleep talkers make simply aren’t that sensical, let alone deep, emotional confessions.
Why do we sleep talk?
Sometimes sleep talk is clearly linked to self-reported dream content. When someone wakes up from a dream, occasionally they will be able to verbatim quote what they had just been saying aloud, Barett says. But that’s not always the case.
Sleep talk happens at all stages of sleep, including REM—when most dreams occur. Yet, the majority of sleep talk occurs during the three non-REM sleep stages, she explains, according to the authoritative book on the subject, Sleep Talking, by the psychologist Arthur Arkin.
During non-REM sleep, verbalizations are shorter and less clear, says Jing Zhang, a neuroscientist at Harvard Medical School who studies sleep and memory. In contrast, during REM, sleepers are known to say longer, more easily understood phrases, Zhang tells Popular Science. One 2021 study even reported that some people are capable of coherently responding to spoken questions and carrying out conversations when they’re in the midst of REM sleep. In Barrett’s unpublished data analysis, she even noted rare instances of couples sleep-talking in conversation with each other.
Scientists don’t understand exactly what’s going on inside the brains of sleep talkers. But there are clues. A 2022 paper co-authored by De Gennaro measured differences in brain activity between people sleep talking and people making non-verbal sleep sounds like laughing, crying, or moaning. De Gennaro and his colleagues observed a distinct pattern in a brain region associated with waking speech and motor function during sleep talk bouts. Specifically, the types of regular brain waves associated with deep sleep broke down during speaking episodes—more closely resembling the awake brain. The finding indicates a link between waking speech and sleep talk.
More broadly, people tend to babble more during sleep-wake transitions, when the brain is shifting states, Zhang says. It’s possible that parts of the brain remain relatively active, while other parts sleep, she explains. And, because sleep talk is more frequent at the borders of sleep stages, people with disrupted sleep are more likely to chatter. Sleep talk is more commonly reported during periods of stress, sleep deprivation, or following alcohol consumption, Zhang adds.
“I think it’s a glitch,” says Barrett—just something gone a little wrong in the move from one phase of sleep to another. Sleep talk is also associated with other types of “parasomnias” like sleep walking and night terrors. If you engage in any one of these behaviors, you’re more likely to experience others. Our genes may also play a role in our likelihood to sleep talk, sleep walk, or have other parasomnias.
Yet that doesn’t mean it’s a concerning disorder. Except in very extreme cases (routinely waking up your partner, roommates, neighbors, or self), sleep talk is not generally anything to worry about. For most people, occasional sleep chit chat is a normal part of a nighttime rest. Though, if you’re at McGregor’s level, it might be worth a visit to a sleep lab. For his part, he found that, later in life, when he was more settled and resting better, he quieted down.
