.. have always thought deer and humans pretty similar in terms of "toughness" as pertaining to taking a round from a firearm.
I kind of have to say yes, and no, to that one. Physically, there is some correlation, mentally, there is none.
Deer don't know they have been shot. They may know something happened, and its time to get the heck out of there! Or they may not even realize they have been shot. I have seen both responses, and which one you get is flip a coin time.
With humans its also flip a coin time, but humans have the complication of KNOWING (subconsciously at least) what getting shot "means".
Anytime the physical hit does not incapacitate the target, the mental hit takes over, until the physical damage (blood loss, etc.) changes that, again.
Some people will simply collapse because "they got shot", no matter what their desires, their subconscious mind, trained by a life time of watching TV, takes over, briefly, anyway, and they drop.
Others don't seem to notice, and others essentially go into berserker mode, to get you (Or get away) before dying...
The mind play tricks with humans that generally don't apply to animals.
There are only two things that stop a person, their own choice (conscious, or not) and physically preventing the brain from sending signals to the rest of the body. (this covers both blood loss and nerve damage).
One or two large caliber hits COM often works, but NOTHING is guaranteed!!! People have even run away after taking two 12ga slugs to the chest. (they didn't run far, but they did run!, If their choice in that situation had been to pull a trigger, rather than run, they could have done it)
The only magic bullets are on TV and movie screens!