Hmm, I wounder if the kid and his father took into account that D&D art is professionally designed, and therefor follows all the elements of design, including emphasis. Any art that they use will have a specific focal point that has been designated by the artist by contrast of colour, detail, and darkness; Not to mention directing shapes and lines. Any creature they show will draw the eye to a specific point on the drawing; very commonly the eyes/eye.
Granted they have removed the backgrounds, but the principle applies to the creature by themselves, and I still think there will be a flaw in their test. I don't suppose scientists and 12-year-olds would be likely to know the finer points of design but anytime someones eyes are draw somewhere it won't be because of unaltered human nature.