I seriously doubt that is possible.
QUOTE
I read from a lot of websites that when you see a lot of moving shadows out of the corner of your eye (which i do), it might be a sign of undeveloped postcognition.
'A lot of websites' are really not good sources of information when it comes down to matters of the metaphysical nature. The large majority of them are ridiculous and written by people determined of conning teenagers out of money or by someone with an over active imagination.
Seeing shadows out of the corner of your eyes is a normal thing, I think it happens to pretty much everyone who can see.
I can't see any possible connection between seeing shadows and undeveloped postcognition. Not that I even fully understand what postcognition is.