The rationale for the inspection time index

Abstract

The inspection time (IT) index proposed and tested by Vickers, Nettelbeck and Willson [Perception 1, 263-295 (1972)] imposed a number of experimental constraints in order to measure the time required by the S to make a single observation of the sensory input, the constraints in question being determined by certain general assumptions regarding the decision process mediating the S's responses. These constraints are re-examined in the light of recent experimental evidence which necessitates some modifications to the underlying conceptualization, particularly with reference to the assumptions concerning the sensory classification of observations and the factors influencing performance change. I..