How attribution-of-competence and scale-granularity explain the anchor precision effect in negotiations and estimations.

Precise numbers are more potent anchors than round ones. Two theoretical
mechanisms have been suggested to account for this anchor precision effect: (1) the scale granularity account postulates that individuals adjust away from the anchor in smaller steps on a finer-grained mental scale, and (2) the attribution-of-competence account postulates that people ascribe more competence to a precise-opening individual. Direct empirical evidence for both accounts is scarce, however, and exists mainly for the attribution-of-competence account in a negotiation context. In two experiments, we examined the two competing mechanisms simultaneously (Experiment 1) and contrasted them in a negotiation and in an estimation context (Experiment 2). Moreover, we developed and validated (Pilot Study) a direct measurement of scale-granularity. Mediation analyses showed that both attribution-ofcompetence and, for the first time, scale-granularity mediate the anchor-precision effect. The results refine our theoretical understanding of anchor precision. Implications for decisionmaking, negotiation, and estimation research are discussed.