we are evolved from savannah primates for whom the ability to make eye contact and hold it was a signal of “you can trust me, I’m not about to bite you.”
Funny. Cats are the opposite. To them, unblinking eye contact says “I don’t trust you. I’m keeping my eye on you.” Hence the slow blink they’re famous for.
Paper and pen don’t signal “I have decided to break this evolutionary/social contract” in the same way a phone or open laptop does.
Why not? Either way, you’re breaking eye contact. When paper first became commonplace, people probably made the same argument, and there are photos of people on trains all looking at their newspapers and ignoring each other.