Dion McGregor was a songwriter who wrote for stars like Barbra Streisand, but he ended up being much more famous for recordings he made in his sleep. McGregor, who died in 1994, is known as the world’s most talkative sleeper. In the ‘60s, his New York City roommate began recording his nighttime speeches—bizarre narratives where he used different voices and described things like playing roulette with poisoned eclairs and taking a hot air balloon to the Moon—resulting in a total of 500 sleep-talk recordings that were published as albums.

In 2015, a set of Harvard researchers coded almost 300 of these “somniloquies” using the Hall and van de Castle Content Scales, a system scientists use to analyze dreams, to see how McGregor’s sleeping narratives stacked up to traditional dreams. The scale tallies how often different types of people pop up in dreams (family, strangers, children, adults, etc.) and the kind of emotions and actions involved in the narrative (aggression, friendliness, misfortune, success, sexuality). Their study published in Imagination Cognition and Personality also analyzed McGregor’s recordings with the Hobson Bizarreness Scales, a framework developed in the ‘80s to quantify exactly how bonkers your dreams get.

While many people’s sleep mumbles are just a few incoherent words, many of McGregor’s clocked in at more than 100 words, and they tended to have a narrative to them, with “basic elements such as characters and social interactions,” as the researchers write. They caution that “given what is known about the physiological state involved in sleep talking, [it] is not entirely accurate” to call these “dream” recordings. But the ramblings do contain enough dream-like imagery that researchers can compare them to what we know many people dream about, giving us insight into what was going on in McGregor’s mind. The sleep talking seemed to arise from a state halfway between sleeping and waking, as the researchers note, which might explain why they’re a little different than people’s dreams.

Compared to the typical dream on the Hall and van de Castle Scales, McGregor’s sleeping speeches were more likely to feature female characters than male, and more likely to feature friends and acquaintances rather than family members, the study found. They were less bizarre than the typical dream, and in them he seemed less passive than other dreamers report being.

Some of the differences in McGregor’s imaginings might be due to his particular personality. The study notes that he was well known to be obsessed with actresses, perhaps accounting for how many women he talked about in his sleep.

Other differences might be due to the unique physiological circumstances involved in sleep talking. Because it’s a state between waking and sleeping, it’s closer to a daydream than a dream in REM sleep, for instance. McGregor’s narratives were more likely to involve him as an active participant (e.g., the aggressor) than a true dream, where people tend to be passive and unable to control the narrative—lucid dreamers being the exception. The part of the brain associated with having a sense of agency is suppressed during REM sleep, so McGregor’s odd sleep state likely gave him a little more control over his actions in his unconscious tales.

McGregor was just one person, so it’s hard to generalize about sleep-talkers from his somniloquies. Plenty of people talk in their sleep—up to 60 percent of kids and 20–45 percent of adults do it at least an occasionally. But because McGregor was so carefully recorded, he is one of the richest sources of sleep-talking content out there. If you want to hear him ramble, you can listen to some of the recordings on Bandcamp.

[h/t BPS Research Digest]