Reverse motion illusion creates pigeon neck walk

As a pigeon moves through a forest of stripes, it appears to bob its head back and forth. But the motion is an illusion caused by the background made up of bands of opposite contrast. The brain trick is similar to the kickback illusion but in this case the stripes are thicker. The effect was one of the finalists in the Illusion of the Year contest. The Neural Correlate Society (c) 2014