I think somehow our body is pre-wired for some smells.
Healthy food is nutritious, so it smells good.
In the same way our body knows "dead person" is a very terrible smell, even if we have never encountered it in our life.
Maybe the uncanny valley is the same thing for vision -- we are wired to be wary of sick or dead people, who look "off" because of an expression, their posture, skin color, etc.
Just a theory.
> Mate selection. Automatic, stimulus-driven appraisals of uncanny stimuli elicit aversion by activating an evolved cognitive mechanism for the avoidance of selecting mates with low fertility, poor hormonal health, or ineffective immune systems based on visible features of the face and body that are predictive of those traits.
“Looks human, but not quite what I’m used to.”
Seems like a decent way to quickly spot nonmembers of a social group. I wonder if an experiment could classify the revulsion and compare/contrast it to something like, when a person meets someone of an unfamiliar subculture.
This is a result of millions of years of biological evolution. Bodies that were "less" wired for certain smells were likely at some sort of disadvantage. After a lot of generational churning, the average body appears to be "prewired" for the most important smells.
> In the same way our body knows "dead person" is a very terrible smell, even if we have never encountered it in our life.
Again, Darwinian evolution can explain this.