More likely deep code from prior evolution. Similar, but not right, is the difference between life and death for a lot of species. That'd get built in long before anything resembling 'human' existed.

I think it's a pattern recognition issue. We have brain areas specialized for facial recognition. There is a cognitive dissonance where something is almost but not quite a face. This is distinct from pareidolia where the pattern system recognizes that something resembles, but is definitely not a face.

My favorite theory is that it's about corpses. You know what looks similar to a person but isn't one? A dead person. People who don't like being around human corpses tend to live longer because you know, something killed that guy and it might kill you too

It wasn't very long ago we lived with australopithecus and neanderthals and other hominins that looked like us.

It also can apply to humans that have something wrong with them, like visible signs of severse contagious illness, or just dead people, where being around can risk disease for oneself

Or it can mean that our mind is flawed.
Unless cats fearing cucumbers mean that they once had to fight cat-hunting cucumbers.

If your brain sees something that isn't human, that isn't human.. there needs to be a theory about that?

We shared the planet with several different human species in the past. We also fucked most of them into extinction.

Cucumbers could easily be triggering feline responses to snakes, which are most certainly a danger to them.

Are you some kind of carnivorous cucumber truther? The evidence is incontrovertible. Trust the science. This isn't the kind of thing you can meaningfully do your own research about. Watching YouTube videos where weirdos rehash the same three articles about how carnivorous cucumbers were not an apex predator for a million years isn't a personality. Touch grass. Get a fucking hobby.

And we won’t stop until we’re done.

Wake up sheeple! There were no big cat eating cucmbers! All evidrnce is made up!

Neither of my cats give a shit about a cucumber.

Yeah, that's a perfect example of mind being wrong because of faulty pattern recognition triggering unconscious responce.

Personal anecdote: I've experienced uncanny valley once with perfectly human human, just some guy that had unfortunate experience of being meat crayon on a motrocycle some time in the recent past, i was absolutely terrified until he came really close and I understood what exactly was wrong.

Be careful you don't drive off the side of the world on your way to buy horse paste you troglodyte

This is my hypothesis. Brain doesn't know what to do with what its seeing so it just goes "yuck"

Riker would approve of this message.

Rabies.

The ultimate "other".

Not all mutations that survive are beneficial. Beneficial mutations are simply more likely to survive.

It wasn't that long ago on the cosmic scale that homo sapiens lived alongside humans that were not the same species as us.

I think it's less likely to be an evolutionary advantage and just a side effect of having really good pattern recognition. Because the uncanny valley does not only trigger with humans. Anything that is close to something recognizable but not quite right can trigger it. It's what makes liminal spaces feel creepy.

Wait, y'all feel creepy at those hallways and such? Maybe something is lost in the photos, but I don't see it.

No, it doesn't.

Definitely enhanced when in person. I get the strongest sensation being anywhere staff-only after hours (usually when I’m tagging along with a friend who works somewhere). There’s normally an implied force pushing you out of those places, but when left empty, it’s like a weird energy vacuum.

That’s my take, anyway.

They said "could". So more like a fun thought than a statement of fact.

Well, think about walking through the forest. That large branch just doesn't look right. Oh shit, theres a predator on that branch. Seems reason enough for the trait to exist.