What is ASMR?

According to Cal Newport:

Around 2010, a curious new term arose in obscure but energetic internet chatrooms: autonomous sensory meridian response. ASMR, as it was soon abbreviated, described a peculiar form of paresthesia experienced as a tingling that starts in the scalp and then moves down the back. It’s often triggered by specific sounds, like soft whispering or a paintbrush scraping canvas. Not surprisingly, those sensitive to ASMR sometimes found Bob Ross reruns to be a reliable source of the effect.

Examples include Charles Dickens’ writing room (above), Newt Scamander’s study (Harry Potter universe), and this strange collection of sights and sounds: