Using PPT to Correct for Inconsistency in a Speeded Task

Time pressure heuristics can improve performance due to increased consistency

Our goal is to demonstrate that potential performance theory (PPT) provides a unique type of methodology for studying the use of heuristics under time pressure. While most theories tend to focus on different types of strategies, PPT distinguishes between random and nonrandom effects on performance. We argue that the use of a heuristic under time pressure actually can increase performance by decreasing randomness in responding. We conducted an experiment where participants performed a task under time pressure or not. In turn, PPT equations make it possible to parse the observed change in performance from the unspeeded to the speeded condition into that which is due to a change in the participant's randomness in responding versus that which is due to a change in systematic factors. We found that the change in randomness was slightly more important than the change in systematic factors.

Using PPT to account for randomness in perception

According to many theories of decision making, of which signal detection theory is the most prominent, randomness is the main factor responsible for imperfect performance. These theories imply that correcting for attenuation due to randomness should result in perfect scores as long as the participants use nonextreme decision criteria. On the basis of a recent advance termed potential performance theory (Trafimow & Rice, Psychological Review 115:447-462, 2008), we performed auditory and visual detection experiments and corrected the scores for attenuation. Most participants in both experiments tended to perform at a less-than-perfect level, even after their scores were corrected. The findings demonstrate that at least one systematic factor influences detection that is not included in signal detection theory.