People focus on optimistic scenarios and disregard pessimistic scenarios while predicting task completion times.
Task completion plans normally resemble best-case scenarios and yield overly optimistic predictions of completion times. The authors induced participants to generate more pessimistic scenarios and examined completion predictions. Participants described a pessimistic scenario of task completion either alone or with an optimistic scenario. Pessimistic scenarios did not affect predictions or accuracy and were consistently rated less plausible than optimistic scenarios (Experiments 1-3). Experiment 4 independently manipulated scenario plausibility and optimism. Plausibility moderated the impact of optimistic, but not pessimistic, scenarios. Experiment 5 supported a motivational explanation of the tendency to disregard pessimistic scenarios regardless of their plausibility. People took pessimistic scenarios into account when predicting someone else's completion times. The authors conclude that pessimistic-scenario generation may not be an effective debiasing technique for personal predictions.
Newby-Clark
I R
IR
Department of Psychology, University of Waterloo, Ontario, Canada. newby@uwindsor.ca
Ross
M
M
Buehler
R
R
Koehler
D J
DJ
Griffin
D
D
D000339:Affect; D001290:Attitude; D005260:Female; D005544:Forecasting; D006801:Humans; D008297:Male; D011795:Surveys and Questionnaires