Across species eye contact is a thing for both carnivore/herbivore dynamics and also dominance hierarchies so if you intentionally wanted to create a weird theo

Across species eye contact is a thing for both carnivore/herbivore dynamics and also dominance hierarchies so if you intentionally wanted to create a weird theory I'd suggest mixing those in weird ways. So if a hunter gets hurt while hunting he could screw up the hunt for everyone by being hurt except for crying messes up his eye to eye stare down so he temporarily falls to the bottom of the dominance hierarchy allowing the overall tribe better luck hunting and more meat for everyone including himself, therefore cry in pain, in the long run equals more delicious meat. Stalking being more a carnivore behavior than herbivore I'd theorize crying is extremely manly and women carried the trait originally rather than directly benefiting by expressing the trait. The vegan types can be very vociferous when presented with commentary about the biology of the human body appearing to have evolved to support meat eating, so be careful, its very politically incorrect to look into things like cross species carnivore eye contact behaviors or apparently evolutionary evidence of stalking and hunting biological technologies.