Speed and accuracy in comparative judgments of line length

The paper presents an extension of Henmon’s (1906) finding that RT decreases as the difficulty of discriminating a difference between two line segments decreases. It is shown that, when an E RT deadline is imposed on the experimental task, RT remains constant with respect to changes in discrimination difficulty, but that correct response probability increases with increasing difference between two line segments. The data are examined in terms of current theories for the speed-accuracy trade-off.