Nub of the problem: If the question is, what helped prehumans survive, there really aren’t any prehumans around. So we don’t know how they differed from current ones. If the question is how early humans survived, we don’t have a good reason to suppose that their psychology was much different from ours.
Evolutionary psychology likely got started when psychologists wanted to get in on the popularity of findings in evolution. But whatever evolutionary thinking may have done for the tyrannosaur or the trilobite, it can’t really do for humans. So far as we know there has been no real evolution of any kind, of which we have a clear record, in human psychology.News, “Evolutionary psychology: When we looked in, no one was there…” at Mind Matters News (December 2, 2021)
Takehome: Evo psych likely got started when psychologists wanted to get in on illuminating findings in evolution, like the Cambrian Explosion. Trouble is, there aren’t any prehumans around. And we don’t have a good reason to believe that early humans differed much from us in psychology.
You may also wish to read: Philosopher flattens evolutionary psychology: There is no such thing as a fossil mind. Rejecting evolutionary psychology means realizing that we cannot both claim to represent “Science!” and refuse to be bound by its standards.