Illusions can often reveal or provide an insight into perception and our ability to construct models - even incorrect ones - to explain our world
Part of this process requires us to ignore information unimportant to the situation, and resolve conflicting channels of information
The "Margaret Thatcher Illusion" (Thompson, Perception, Volume 9, pp. 483-484), illustrates that modelling is not necessarily robust to rotation, look at the picture up-side-down (http://www.wesleyan.edu/psyc/scheibe.htm)
point lights and biological motion (G. Johansson 1973)
Visual perception of biological motionWatch this short video on Daniel Simons page and count the number of times the ball is passed. When you have finished check your answer here.
Prediction in humans has a consequence, the abililty to ignore information not relevant to the prediction.
For an example, run this video.