This optical illusion is one of the weirdest, freakiest brain phenomenon I've ever experienced. It's called the flashed face distortion effect, but just follow the instructions in the video and experience it for yourself, then read the description:

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). This new method of image presentation, based on alignment and speed, could provide a useful tool for investigating contrastive distortion effects and face adaptation.

My question is: how did Jason M Tangen, Sean C Murphy and Matthew B Thompson—the authors of this scientific study—come up with their thesis and the experiment to prove it? I'd like to know, but I'm too mesmerized playing this video once again. [Perception via Metafilter]