it has to do with mirror nerves and empathy, and is also related to how yawning is contagious and why people smile/frown back at one another. no fear; this is common in everyone (excluding many autistic children)
Awesome. Wasn’t sure if I was developing a tic or something. Guess I just never noticed before. Huzzah!
That was where I was watching. Love that site.
… I need a hobby…