TL:DR – The flashed face distortion effect leads to some ugly faces in your peripheral vision.
A while ago there was a meme that went viral, it showed images of people one after the other, but if you stared at a spot just to the side of the faces flashing past something very strange happened – you got the impression that the faces were monstrous, ghouls, with distorted features. Gizmodo and many others covered the original concept. The concept emerged from research by University of Queensland scientists Jason Tangen, Sean Murphy and Matthew Thompson who call it the “flashed face distortion effect”.
Earlier this year, a similar “video” was published where the pairs of faces were celebrities and Mark Changizi recently brought it to the attention of his circles on Google+. It’s like watching the celebs in a hall of mirrors, but the distorting mirrors are all in your mind…
If you look at all the faces individually, although some of these people are considered particularly handsome not one of them has a “perfect” face, especially with regard to symmetry. There are thus deviations from what one might consider the norm, the ideal. Somehow, by not looking directly at the pair of faces, the brain is emphasising the differences we perceive in our peripheral vision, making the fairly normal looking individuals seem like trolls and ogres when viewed this way. Could this odd effect underpin some of our monstrous fairy tales and the caricatures we enjoy of other people and even ourselves where deviant features are usually emphasised or taken to the extreme?
Changizi discusses his explanation of the effect as relating to the flashing of the photos itself, that the brain assumes it’s the same person in our peripheral vision and as the images change our brain interprets actual differences as changing expression. That’s not what it “feels” like to me though as it seems to still work even if the images are not flashing past. [I also noticed the effect when looking in the mirror, but slightly to the side]
I think it’s more to do with the deviations from the idealised norm of a face we have in our heads and for some reason the deviations are emphasised when compared in peripheral vision with another face. This would tie it into other studies where researchers “average” out hundreds of photos of ordinary people and we end up seeing androgynous and yet attractive faces as a result.
From the original paper by Tangen et al:
“We describe a novel face distortion effect resulting from the fast-paced presentation of eye-aligned faces. When cycling through the faces on a computer screen, each face seems to become a caricature of itself and some faces appear highly deformed, even grotesque. The degree of distortion is greatest for faces that deviate from the others in the set on a particular dimension (eg if a person has a large forehead, it looks particularly large).”
Tangen J.M., Murphy S.C. & Thompson M.B. (2011). Flashed face distortion effect: Grotesque faces from relative spaces, Perception, 40 (5) 628-630. DOI: 10.1068/p6968