The Year's Best Visual Illusions

Wooden balls roll up slopes as though pulled by a magnet? It seems impossible! What's actually happening is that the orientations of the slopes are perceived oppositely, and hence the descending motion is misinterpreted as ascent. It's one of the latest visual illusions, designed to trick the mind into seeing the impossible. <a href="http://illusioncontest.neuralcorrelate.com/cat/2010/" target="_blank">Watch the video</a> (Koukichi Sugihara / Neural Correlate Society)

In this illusion, four circular disks are simply translated back and fourth over a thin square outline. <a href="http://illusioncontest.neuralcorrelate.com/cat/2010/" target="_blank">See this illusion here</a> (Koukichi Sugihara / Neural Correlate Society)

It is well-known 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 is shown in ‘The Margaret Thatcher illusion. Now I give you The Fat Face Thin illusion. Compare the upside-down face on the left of the lower figure with the upright face on the right. The upside-down version looks much thinner, – altogether a longer shaped face than the upright version. (Peter Thompson / Neural Correlate Society)

Fix the colored image by looking at the spot for about 60 seconds. Now shift your eyes to the right spot, the one surrounded by rectangular outlines. If you attend to the vertical outline rectangle you will see the afterimage corresponding to it, and if you attend to the horizontal outline rectangle you will see the different afterimage corresponding to it. You can shift which afterimage you experience by attending to one rectangle and then the other. (Peter Tse / Neural Correlate Society)

This illusion is based on a billboard showing a bathtub shot at an angle. As we walk from one end of the picture to the other, the bathtub seems to stretch and shrink. <a href="http://illusioncontest.neuralcorrelate.com/cat/2010/%20" target="_blank">Watch the video</a> (Lydia Maniatis / Neural Correlate Society)

An array of moving spots lie at the heart of this illusion. Each spot travels in a spiral counterclockwise towards the center of the screen, but contains a grating that moves opposite to its direction of travel. <a href="http://illusioncontest.neuralcorrelate.com/cat/2010/%20" target="_blank">Watch the video</a> (Peter Meilstrup & Michael Shadlen / Neural Correlate Society)

<a href="http://illusioncontest.neuralcorrelate.com/cat/2010/%20" target="_blank">Watch this video</a>, you might be surprised at what you don’t see. (Daniel Simons / Neural Correlate Society)

Please move your eyes over the static red hearts on the blue background. The blurry heart wobbles whereas the sharp heart remains still.

Stationary and moving waves can be interpreted in all sorts of ways by the eyes. To explore all the possible perceptions, this illusion is really more an an application, with buttons to enable or disable a variety of colors and options. <a href="http://illusioncontest.neuralcorrelate.com/cat/2010/%20">See the illusion here</a> (Jan Kremlacek / Neural Correlate Society)

The appearance seems to change between matte and glossy, as the ruler illustrates. However, the surface is continuously rendered with matte reflectance.<a href="http://illusioncontest.neuralcorrelate.com/cat/2010/%20" target="_blank"> Watch the video</a> (Maarten Wijntjes & Sylvia Pont / Neural Correlate Society)