The effect of expected difficulty on psychophysical judgment

Abstract

The effect on psychophysical judgments of pretask instructions that indicated the degree of task difficulty was studied. Prior to estimating the midpoints of various line lengths, one experimental group was told that the judgment task was difficult and to expect large errors, while another group was instructed that the task was easy and to expect few judgment errors. The average deviations of midpoint judgments from the measured midpoint of various line lengths was reliably larger for the group instructed to expect large deviations.