But I’m not sure I’ve seen it in real life, and I don’t think I’ve ever done it. But googling turns up:
“Scratching the back of your neck while thinking is often interpreted as a sign of stress, uncertainty, or discomfort while processing information; it’s a common body language cue that can indicate someone is deep in thought, trying to recall details, or feeling slightly anxious about a situation.”
My go-to tic is stroking my beard absentmindedly when I’m lost in thought. It’s the one thing I miss whenever I decide to shave it off and go bare-faced again.
People do scratch the back of their heads; sweat collects there and causing minor itching which feels good to scratch. Easing an annoyance may be conducive to thinking. Even if there is no active itching, most people like having their heads/hair stroked.
The chin acts the same way. Bringing a hand to the chin feels natural; no extra bending or stretching the limb needed. Beards are right there and like the attention. They’re like puppies.
Same here. I actually found it funny where after being clean-shaven most of my life I let my beard grow and almost immediately found myself absentmindedly stroking it in thought like I’d done it my whole life.