Speaker:

Prof. Peter Killeen

Title:

"Subsumption Psychophysics I. Signal Detection as Information Transmission"

Abstract

Subsumption psychophysics is a theory of human information processing that starts with minimal assumptions about covert processes. When the most general assumptions fail, the next most general are brought into play. In this talk the framework for detection and discrimination called Signal Detection Theory (SDT) is reanalyzed from an information-theoretic perspective. Receiver-operating characteristics (ROCs) for the iso-informative processor describe arcs in the unit square, and lie close to those described by constancy of A'. Necessary and sufficient conditions for performance to fall on these arcs is that the payoff matrix be honest, and that changes in the equivocation expected from yes responses are complemented by those expected from no responses, as bias shifts. Asymmetric ROCs require the imputation of additional structure. The resulting maximum-entropy distributions on the evidence axis are exponential, and yield power-law ROCs which cover most data. The success of ROCs constructed from confidence ratings shows that more information is often available from the signal than the experimenter's binary classification suggests; this enables an additional inference concerning structure in the discrimination task. Comparisons are made with the theory of the ideal receiver. The full-blown, traditional N-N SDT analysis has not been found necessary for any data yet analyzed.

Lyrics by Johny Mercer and Peter Killeen
Bass and scat by Tom Taylor
Cindy on cembali