today in "well, that explains a lot"

via star-anise, this post:

TIL there are nerve endings that exist only to recognize a gentle stroking touch. Their activation decreases the heart rate and activates the smile muscle. Their optimal speed is 3-5 cm/s, which means we are genetically wired to cuddle and caress each other at predetermined velocities.

[Pawling et al., 2017.]