TR#498 Understanding Expressive Action

Christopher R. Wren

Appears in: E.E.C.S. Ph.D Thesis Proposal

User interfaces make measurements of the user and use those measurements to give the user control over some abstract domain. The sophistication of these measurements range from the trivial keyclick to the most advanced perceptual interface system. Once the measurements are acquired the system usually attempts to extract some set of features as the first step in a pattern recognition system that will convert those measurements into whatever domain of control the application provides. Those features are usually chosen for mathematical convenience or to satisfy an {\it ad hoc} notion of invariance. The expressivity of any such interface is limited by the user's ability to overcome the reality of their bodies and perform in this arbitrary feature space.

The fact that people are embodied places powerful constraints on their motion. An appropriate model of this embodiment allows a perceptual system to separate the necessary aspects of motion from the purposeful aspects of motion. The necessary aspects are a result of physics, and are predictable. The purposeful aspects are the direct result of a person attempting to express themselves through the motion of their bodies. By taking this one thoughtful step closer to the original intentions of the user, we open the door to better interfaces. Understanding embodiment is the key to perceiving expressive motion.

Note: This abstract may not appear to be about Netrek, but much of this thesis proposal discusses this topic in the context of a testbed known as the Netrek Collective.

Last modified: Tue Jun 8 18:34:24 EDT 1999