Unpacking, summing and anchoring in retrospective time estimation

Michael M. Roy, Elizabethtown College
Tatem Burns, Elizabethtown College
Joseph R. Radzevick, Gettysburg College


We examined whether or not interventions that have been used to try to influence predictions of future task duration – unpacking, summing and anchoring – had a similar effect on retrospective estimations of duration. In three studies, participants experienced a number of short stimuli, such as watching videos, before estimating the duration for each of the stimuli and the overall duration. The first estimation given served as an anchor for all following estimates. If the first estimation was highly biased in one direction, then subsequent estimates were more likely to also be biased in the same direction. Additionally, separate estimates for a number of individual tasks differed from the estimates for all of the tasks combined. This incongruity happened even though all estimates were given in sequence. Overall, results indicated that memories of past task duration could be influenced by the manner in which they were elicited.