Peter Thompson from the University of York (UK) discovered an amazing optical illusion that will shock you! By now we have all learned that faces are more difficult to recognize when they’re upside-down and that sometimes we misperceived the facial expressions of upside-down faces (as was shown in Margaret Thatcher Illusion).
What I have prepared for you today is a slightly different example called The Fat Face Thin illusion. Your assignment is to compare the upside-down face on the left of the lower figure with the upright face on the right. Have you noticed how the upside-down version looks much thinner?! Moreover it appears longer shaped than the upright version. Of course, there is no need to mention how both pictures are identical. This illusion illustrates the internal features of the face (eyes, nose, mouth) can distort our perception of face shape. To boost up the effect, cover the right photo with your palm, and concentrate on the left photo for a while!