Not just humans - I think it's not unusual to see a sick animal, notice that it's "moving wrong", and feel a revulsion that motivates staying away from it. It's a very handy instinct if, for example, that animal might have rabies...

Edit: I agree with you, I'm just expanding on what you said.

Could also have been cannibals, a lot of folklores talk about people who aren't really people that kill and eat people. Some versions of the tale of the wendigo feature whoever encounters them in their human forms noting that they knew they must be wendigo because they looked like normal people but something just felt wrong about how they behaved.

Uncanny valley could be at play in the ick you feel when you can tell for no apparent reason that someone's a psychopath or dangerous in some other way, the unconscious response to the things your brain noticed that you didn't.

IIRC Sapiens, Neanderthals and Denisovans coexisted for some time, so it could be not about things that aren't human, but humans that are different. To this day, xenophobia and ethnocentrism are common attitudes.

I just saw this meme, though it was funny. Showed it to my friend and he said almost exactly this.

It makes perfect sense now that I hear it.

And mentally ill / under the influence. You could say sick includes those. The danger was real.

/thread

Also corpses, I see it debunked pretty much every time it’s posted

See e.g. https://en.m.wikipedia.org/wiki/Interbreeding_between_archaic_and_modern_humans

Corpses, illness, "bad genes" (asymmetry etc) seems like a more reasonable explaination in my ears, with interacting/breeding in mind.

Humans as a whole have never had any trouble killing other humans who looked just like them. I don't think such an instinct would have been necessary. And anyway the uncanny valley has more to do with revulsion than aggression.

We did fuck with Neanderthals too, though. There's still traces of their DNA in modern humans, I think

Being lactose intolerance implies that at some point there was some deadly form of milk and squirting shit out of your arse at 400mph is an appropriate way of dealing with it.

I've always understood it as the perception that something isn't quite right (usually with a person, but I've seen it used in non-human contexts too) without being able to immediately describe why.

A great example is Grand Moff Tarkin in Rogue One - the actor who played him on the original trilogy died in 1994, so they just deep-faked him into the scenes he was needed. When I saw Rogue One initially, I didn't know that actor was dead, and didn't connect the dots that even if he wasn't dead, he'd look like a zombie this many years after filming the OT... but in Rogue One, he just looked like Tarkin. Mostly. The scenes that featured him gave a kind of uncomfortable "what the hell is wrong with that guy" feeling, but I still didn't connect the dots and couldn't put my finger on why it looked so wrong.

Then later I learned is was a deep-fake, and now it just looks like a deep-fake; the uncanny valley sensation went away once I finally understood why he looked the way he did.

The internet is full of creepy looking 'examples' of uncanny valley, but they're all shit imo, cuz they're all just blatantly creepy shit; well beyond the uncertainty that goes along with uncanny valley.