Kevin Allocca, head of culture and trends at YouTube and author of “Videocracy,” a book about the cultural impact of viral videos, says the phenomenon of Oddly Satisfying has always existed — we just didn’t have a name for it.

“You started to have a nomenclature around it and you started having a taxonomy, and you were able to explain a thing you’d always seen and enjoyed,” he said, “which allowed it to flourish.”

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But just what makes Oddly Satisfying so oddly satisfying? While the videos have yet to become the subject of major scientific inquiry, there are some theories. It may have to do with symmetry, patterns and repetition, which our brains seem to find inherently pleasing. It may have to do with a sense of “flow” — the state of being completely absorbed in an experience. Or it may be related to the “autonomous sensory meridian response,” or A.S.M.R., the phenomenon of deriving a pleasurably tingly sensation from certain auditory stimuli, like tapping or whispering or crinkling, which is itself a bit of a mystery.

“There may be something in the physical exploration of slime, or soap, or frosting in these videos that scratches a need to learn about how those materials behave,” Emma Barratt, a British psychology researcher who wrote one of the earliest papers about the autonomous sensory meridian response, told me. “Getting that information may be what’s innately satisfying.”

Whatever the neuropsychological explanation, it’s clear that Oddly Satisfying videos serve as a form of self-care, to use another term that has spiked in recent years . While it’s a journalistic cliché to talk about “our anxious times,” it does seem that the early 21st century is doing something to our heads.

Self-reported anxiety rates are high and growing. Geopolitics and economics aside, some of this probably has to do with the internet itself. Much of the online world is designed to agitate, thriving on fear and anxiety and anger — outrage clickbait, disaster porn, FOMO-inducing social media. The medium itself is stressful, with its red dot alerts and needy open tabs. Oddly Satisfying is everything the rest of the internet isn’t — soothing, slow-paced, non-interactive, noncommercial.