I boinked my forehead on the corner of a cabinet door when I turned around quickly, a few days ago. I cried freely. Did no good, I was home alone. I think one of the cats may have looked up. It was particularly painful for some reason. I thought for sure, my brains were hanging out as I ran to a mirror. Just a small bump that bruised up the next day.
OTOH, when a stray dog bit me really bad on my hand requiring an ER visit and stitches. Nary a tear was shed. I tried to cry in a effort to milk sympathy. I moaned alot;)
Experience both physical and emotional definitely play a roll. Grown adults will cry if the pain is something they haven’t experienced before or they think it’s life-threatening. What I found interesting and baffling about getting my strawberry was that it was neither of the above. It just plain hurt and I cried! :eek: Not making a sound, but quietly, trying to get home a soon a possible to wash it out. Maybe a piece of gravel was hitting a certain nerve, but it’s a true mystery.
I’m neither a complete wuss or he-man, but I can withstand a far amount of pain. A few years ago I had a cavity drilled out on a tooth without novacaine and the dentist keeping asking me if I was okay because I didn’t flinch even when she got to close to the root. I kind of self-hypnotized myself mentally and spiritually and at one point caught myself starting to snore. Even the dentist was surprised and mentioned the snoring after. 
BTW, she was kinda hot and that probably helped! 
I agree that we are generally conditioned not to cry as we get older.
We are also more used to experiencing minor pains, and managing them.
But hurt an adult real bad and they will still often cry.
As read in the many accounts of WW1 battles resurfacing due to the centennial. Battlefields were full of crying and weeping soldiers regardless of any social conditioning.
Occasionally you see toddlers after a fall look around to see whether there anyone saw it before deciding to cry. I guess that is the changeover from alway crying to crying only if anyone is around to offer comfort to eventually generally suppressing th crying:
An adult understands pain is temporary, a child, not so much.
Also, when one hurts themselves, say from falling off a bike, they also have to deal with a bruised ego. Which adults are better at compartmentalizing.
It genuinely seem to me that we feel things differently as adults than as children. There is a level of emotional distance I have as an adult that I was entirely incapable of as a child. When I was hurt as a child (emotionally or physically), I was completely unable to focus on anything else, even with the small stuff.
I also do not remember ever intentionally crying as a kid. It never felt like a choice. But, as an adult, I usually feel something like I could cry, but then have to choose. When it comes to physical pain, I usually choose not to, since it doesn’t tend to make that feel better.
And I never choose to sob–it only seems to help when it happens on its own.
Regardless of age, too. I once saw a human male child stub his toe badly on a rock embedded in his path. He stumbled, regained his balance, turned back to the stone and angrily denounced it:
“StupidJackassPoopoo!!”
This was 55 years ago and I still use his eloquent curse when it’s appropriate.