Abstract
Ratings of time savings when increasing an original assumed mean speed to a higher one were collected for different distances and combinations of velocities in 2 experiments. 24 and 35 undergraduates, respectively, served as Ss. The spontaneous process leading to estimate formation was accounted for by a multiplicative combination of 2 components, 1 related to physical distance and the other proportional to the difference in speeds divided by the larger speed. This use of the information of velocities leads to systematic discrepancies between predicted and real-time gains. (PsycINFO Database Record (c) 2006 APA, all rights reserved)