Hick’s law: Its limit is 3 bits

Abstract

Hick’s law states that choice reaction time is a linear function of the amount of information provided by the reaction stimulus. Thus a straight line is predicted for the function that relates choice reaction time to the logarithm of the number of response alternatives. Although some (but not all) studies have confirmed this relationship, the range of response alternatives has been almost completely limited to 2 to 8 choices. Three experiments now extend the range to 16 choices and beyond. In all of them, a curvilinear function is obtained. Longstreth’s power law better fits the data (Longstreth, El-Zahhar, & Alcorn, 1985). It is concluded that Hick’s law is an approximation to the complete power function and that it becomes noticeably deficient only beyond 3 bits of stimulus uncertainty (i.e., 8 choices). © 1988, The Psychonomic Soceity, Inc.. All rights reserved.