Effects of Consensus Information and Task Demonstrability on Preference-Consistent Information Evaluation and Decision Quality in Group Decision Making

Abstract

Groups often fail to solve hidden profiles even when all information is exchanged. This is partly due to biased evaluation of information. We examined the effects of consensus information and task demonstrability on preference-consistent information evaluation and decision quality. The results showed that the evaluation of unshared but not shared information was moderated by consensus information and task demonstrability. For unshared information, majority members exhibited a higher evaluation bias favoring preference-consistent information than minority members. Task demonstrability reduced the evaluation bias only when group members received no information about the other members' preferences. Finally, majority members were less likely to solve the hidden profile than minority members, and this was partially mediated by the evaluation bias favoring preference-consistent unshared information.

Notes

¹In line with Laughlin and Ellis (1986), we propose that task demonstrability requires four conditions, namely, (a) a logical system that is commonly shared among the group members; (b) the availability of sufficient information for identifying a solution; (c) sufficient ability, motivation, and time for a group member to demonstrate the correctness of a solution to the other group members; and (d) the ability of all group members to recognize and accept a correct solution.

Note: Numbers refer to the amount of information.+ = supportive information; − = opposing information.

²The additional information sheets included more preference-inconsistent unshared items than preference-consistent unshared items in order to induce a hidden profile. The same logic of distributing preference-consistent and preference-inconsistent items was employed by Greitemeyer and Schulz-Hardt (2003).

³To demonstrate the homogeneity of the evaluations of shared information on the additional information sheets, we calculated Cronbach's alpha for the three evaluations of each shared piece of information (M = .88, SD = .05).