Donald Norman was the founding chair of the Department of Cognitive 
Science 
at the University of California, San Diego, and a former Apple Fellow at 
Apple 
Computer. He is professor emeritus at the University of California, San 
Diego.

Norman is often quoted for the idea that effective interfaces render 
technology 
invisible -- we don't notice it because it works effectively. The design 
of an 
artifact (any man-made object) gives us cues to its use, Norman refers to 
these 
cues as "affordances."

 http://www.coe.ufl.edu/webtech/GreatIdeas/pages/peoplepage/norman.htm