If you were a member of a super race and you had the technology to blend in with the target race, undetected.
I'm talking about individuals from the super race randomly choosing this option, would you be able to spot them? Even if you cannot prove it?
I am super race. Did you spot me? laugh
You can always suspect anyone, but without knowing what you're looking for you'd just be throwing dice and saying "this characteristic is not human". So, unless you're a scientist, I don't think that would be really accurate and correct.
The success of the superior species in hiding would depend on their purpose and the type of interactions they had with regular humans. In one story I read vampires were a predator race, just a little more intelligent than average humans. They would hibernate for long periods to avoid having the predator/prey ratio too high, and could quickly adapt to whatever technology and culture they woke up in. It was quite interesting how our superstitious stories about vampires fit well into the consequences of their lifestyles.
In another story, the purpose of the visitors was scientific study with the intent of eventually sharing their culture. They "hid" quite well; in fact when someone caught them using advanced technology they sometimes told the truth, knowing that the story would be considered a silly conspiracy theory within a short time. I believe that on was called the Bobo chronicles and is probably still available online. Bobo was an anthropologist who took menial jobs and felt free to violate Star trek's "prime directive" with impunity.
It would make an interesting thing to read about. I'm not quite sure that it is going on but who really knows.
You can use statistics.
Someone you never knew before comes up and starts asking you questions or spends longer around you for no apparent reason.
If your suspicions are raised..
Is this person a "drop in"? IE have they any traceable history. Where are their roots? etc etc
I'm not saying it's happening but (In the event it is) it won't be like the good old hollywood films where the hero "discovers" the secret. The reality would be that there would be no hope of the "peepers" ever being discovered.
However, if you are a person of interest you can use statistics and you might consider making this a stimulating private study...
If they are really that smart it would be hard to spot them. They would know how to blend in and not get caught. At least thats what I think would happen.
Lets face it if they somehow came up with the technology to blend in with us they would know how to get past our detection.
Maybe we all are a super race that has taken over from the original homo sapiens race that once lived here on earth. So how did we manage to blend in you might wonder. Easy! We just changed our DNA to be identical to homo sapiens so now we are even fooling ourselves.
That just made my head hurt a bit. Again this would make an excellent movie.