Speed-Accuracy Tradeoff: A Formal Information-Theoretic Transmission Scheme (FITTS)

Описание: Speed-Accuracy Tradeoff: A Formal Information-Theoretic Transmission Scheme (FITTS)
Julien Gori, Olivier Rioul, Yves Guiard

CHI '19: ACM CHI Conference on Human Factors in Computing Systems
Session: Behaviour monitoring, changing, and modeling

Abstract
The rationale for Fitts' law is that pointing tasks have the information-theoretic analogy of sending a signal over a noisy channel, thereby matching Shannon's capacity formula. Yet, the currently received analysis is incomplete and unsatisfactory: There is no explicit communication model for pointing; there is a confusion between central concepts of capacity (a mathematical limit), throughput (an average performance measure), and bandwidth (a physical quantity); and there is also a confusion between source and channel coding so that Shannon's Theorem 17 can be misinterpreted. We develop an information-theoretic model for pointing tasks where the index of difficulty (ID) is the expression of both a source entropy and a zero-error channel capacity. Then, we extend the model to include misses at rate ? and prove that ID should be adjusted to (1??) ID. Finally, we reflect on Shannon's channel coding theorem and argue that only minimum movement times, not performance averages, should be considered.

DOI:: https://doi.org/10.1145/3290607.3313843
WEB:: https://chi2019.acm.org/

Recorded at the ACM CHI Conference on Human Factors in Computing Systems, Glasgow, Scotland, May 4 - 9 2019