A GIF version of the Flashed Face Animation Effect has been making the rounds recently, prompting us to ask: why the hell do these faces look so grotesque and distorted when we're not focusing our eyes on them? We spoke to a neuroscientist to find out.
The answer may have to do with the lack of information going to our visual cortex. Neuroscientist Mark Changizi explained it to me this way:
Because the faces are in the periphery, there's not enough information for the brain to realize it's a bunch of different people's faces appended one after another — something that's very non-natural. Instead, the brain presumes the reasonable: that it's a single person's face in the periphery, and then the face-changes are treated as this person's facial expression changes. Basically, each of those photographs has a different resting face expression, relative to the one before it, and these become drastic, cartoon-like, facial expressions on a single dynamic monstrously cartoon-like expressive creature.
Changizi knows a thing or two about vision; he's developed a wearable eyeglass device that effectively cures red-green colorblindness.
This optical illusion was first described last year by University of Queensland researchers Jason Tangen, Sean Murphy and Matthew Thompson. Interestingly, Murphy discovered the effect by accident when skimming through faces aligned at eye-level.