Change blindness is the inability to see large changes in a visual scene that occur during some type of visual distraction. Elements of a scene can even disappear without detection unless one is paying particular attention to these elements. Change blindness therefore gives us a milieu that we can use to explore the neuronal mechanisms that underlie visual spatial attention. For a demonstration on change blindness, see ftp://lsr-ftp.nei.nih.gov/web/jc/cb_demo.htm. Also see the article by Cavanaugh and Wurtz for details.