For a smart material to be able to send out a more complex signal it needs to be nonlinear. If you hit a tuning fork twice as hard it will ring twice as loud but still at the same frequency. That's a linear response. If you hit a person twice as hard they're unlikely just to shout twice as loud. That property lets you learn more about the person than the tuning fork.

Neil Gershenfeld

Neil Gershenfeld is a professor at MIT and the head of MIT's Center for Bits and Atoms, a sister lab spun out of the popular MIT Media Lab. His research interests are mainly in interdisciplinary studies involving physics and computer science, in such fields as quantum computing, nanotechnology, personal fabrication, and other research areas. His lab is currently located in the E15 building at MIT, but he has received funding to build a substantial extension to the building, shaped like a castle, which will house his lab in the future. His books include When Things Start to Think, The Nature of Mathematical Modeling, The Physics of Information Technology, and Fab, The Coming Revolution on Your Desktop - From Personal Computers to Personal Fabrication (ISBN 0-465-02745-8). In 2004, Gershenfeld was named to the Scientific American 50. The magazine has also named him Communications Research Leader of the Year. Classes at the Center include "How To Make (almost) Anything" (MAS 863) and "How To Make Something That Makes (almost) Anything" (MAS 961)

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