This effect was discovered in 1990: portrait, synthesized computer out of 16 persons evaluated subjects are much higher than each of the 16 ordinary "original" people.
The same effect applies to our perception of the dogs, cars ... even a wristwatch. Dr. Winkelman and colleagues from the University of Otago (New Zealand) and the University of Denver (USA) conducted an experiment that showed that a generic prototype is attractive for us because the brain more easily recognize it. So, if the "prepare" the brain to perceive a certain object, that will resonate in the soul. This explains the cultural differences in the perception of beauty. Nice what we are used to seeing, and that "it is clear" our brain.