This study aims to identify the effect of familiarity among group members and their disagreements over decision-making under conditions of unshared information. As a research methodology we adopted a laboratorial quasi-experiment. The decision-making process has gone through reverse translation, cultural adaptation, and two validations. For the experimental application we developed a specific data collection system. In addition, the group discussions were watched by previously trained observers and recorded for later analysis. 144 college classmates participated in the experiment, divided into groups of three people. Among the results, it was found that familiarity between the participants contributed to a better decision-making process by the individuals under conditions of irregular unshared information. Also, from a quantitative and qualitative analysis of group discussion, we noted that there was a substantial exchange of information and disagreement among members about the choice alternatives, which contributes to obtaining better quality from group decisions. In general, we noted that irregular unshared information does not affect the quality of group decisions when there is an intensive exchange of information between the members.
group decision; irregular sharing of information; familiarity; disagreement
