It’s hard to see some line of people who were extremely high or low in any of the big five traits reproducing more successfully than those who had all five in a healthy moderation.

For the purposes of blogging, here’s a weird theory as to why high levels of neuroticism could have helped in the evolutionary past. We know from animal research that even highly monogamous species (some birds) cheat on their mates, essentially, females want to make babies with a bird that sings pretty songs but they want to build a nest and care for the babies with often a much duller mate, a mate who is going to be faithful and see the offspring to maturity so they can continue the line. That’s pretty similar to what humans do too. A neurotic male might be highly protective of his mate thus cutting off her opportunity to cheat (and smashing babies that he fears might not be his own, this was big back then no jk), this way he ensures paternal certainty and keeps the pair-bond going until the child reaches sexual maturity. Males low in neuroticism would prolly just raise the cuckold’s baby and chill on a vine somewhere until his line was all but wiped out.

Another weird theory could be that gossiping and perspective taking (I’m assuming people who are highly neurotic do this…) could have lead to more complex thinking and rapid brain development.

Crude example perspective taking ->
“I’m gonna kill that boar aagghhhh” < - Low neuroticism (dies).
"If I sneak up behind the boar, he won't see me" <- High neuroticism (kills boar, shares boar, gets mates).

Crude example gossiping ->
“K, see you later honey!” <- Low N (she’s going to cheat on her mate, have other dude’s baby, his genes get passed, not yours)
“K, see you later honey!”…(to Grog) “Where she going Grog?” <- High N (Grog tells him, he intercepts)

Anyways, I’m prolly wrong but just sayin’

Alec