The surprise is that it is not an unreasonable question

Sometimes the world just begs for rank speculation.  I see an article this morning which I pair with the already well established uncanny valley effect.  The uncanny valley effect has been researched and discussed for more than fifty years.

The observation is that humans are reasonably comfortable as robots and other simulacrum of the human form move from the category of obvious simulations to the second category of indistinguishable from humans.  The progression is argued not to be a steady increase of acceptance as one might expect but rather, as long as it is in Category 1 (obvious mimic), there is a reasonably straight line increase in acceptability.

However, there is a proposed valley in the transition from Category 1 (obvious simulation 1) and Category 2 (indistinguishable simulation).  In that valley, when the simulacrum is not obviously Category 1 (robotic form) nor obviously Category 2 (human form), many people have a distinct aversion to the simulation, much lower than the best of Category 1.

At some point, the mimicry of the human form and function is so good, people emerge from the uncanny valley and back into high levels of acceptance in Category 2.  

There is discussion, at the fringes, as to why, from an evolutionary perspective, we should have developed a refined sensibility to near human forms and such a strong aversion to them.  At this point the conversation is likely to drift into discussions of space travel and aliens and very imaginative scenarios as to why we seem to have a weird capacity (distinguishing simulacrum of the human form) and aversion to near copies.  

Entertaining conversations and an intriguing question but more an exercise in imagination and creative thinking than actual reality.  

But then . . .

From Astronauts Have an Unexpected Ability That Helps Them 'Fly' Through Space by Clare Watson.  

The near-absence of gravity alters astronauts' motion perception such that they feel like they're moving faster than they really are when zipping around their cramped, weightless quarters. And yet they can still accurately judge how far they've traveled down a hallway in visual simulations, during and after spaceflight, the study found.

"Based on our findings it seems as though humans are surprisingly able to compensate adequately for the lack of an Earth-normal environment using vision," says Laurence Harris, sensory physiologist at York University in Toronto and senior author of the study.

Hmmm.

1) We appear to be oddly well adapted to discern and avoid near perfect simulacrum of the human form and function.  2)  We appear to be unexpectedly well adapted for movement in space.  

What are the evolutionary advantages for these capabilities and why do we have them.

I can come up with a few reasonable scenarios but that the question even exists is . . . intriguing.