Adaptive Decision Processes in Perceptual Comparisons: Effects of Changes in the Global Difficulty Context

Adaptive decision processes were investigated in experiments involving an unexpected change in the global ease or difficulty of the task. Under accuracy stress, a shift from an easy to a difficult context induced a marked increase in decision time, but a shift from a difficult to an easy context did not. Under speed stress, a shift to a more difficult context induced lower accuracy and rated confidence, depending on the difficulty of the decisions. A view of caution developed in D. Vickers's (1979) accumulator theory-whereby one seeks to base decisions on more information-is compared with a view based on slow and fast guessing theory ( W. M. Petrusic, 1992 ; W. M. Petrusic & J. V. Baranski, 1989a )-whereby one seeks to base decisions on more diagnostic information. On balance, the findings support the latter view.