Mid Sweden University

The main purpose of this thesis was to study the circumstances under which anchoring biases occur for estimation of age, weight and height. Paper I investigated accuracy and biases in age estimates made by salespersons with experience in age estimation, compared to a control group without any similar experience. The accuracy in age estimates of young target persons (15-24 years old) made by salespersons was higher than that of control persons. Moreover, the salespersons demonstrated less overestimation of the age of younger target persons, and whereas the control group own-anchored in their age estimates, the salespersons did not. Paper II and IV investigated gender differences in the tendency to own-anchor in within- and cross-gender estimates of age, weight and height. Both papers found that women own-anchor spontaneously both within and across gender, whereas men for the most part own-anchor only in their estimates of other men. Paper IV also investigated the possibility to increase own-anchoring by priming the participants’ use of their own characteristics in their estimation of age, weight and height. Elaborated similarity priming (asking the participants to state their estimates in relation to their own characteristics) did influence the estimates, by increasing the participants’ tendency to own-anchor. Paper III aimed to investigate whether standard anchoring effects (i.e., assimilation towards explicit, experimenter-provided comparison values) occur for estimations of age and quantities – estimations based on visual stimuli and made with a higher degree of certainty as compared to the judgments traditionally used in the standard anchoring paradigm. Anchor effects were found for both age estimations and quantity estimations, and were not affected by neither cognitive load nor source credibility.