The intensity of domain knowledge exchange among group members is an important factor that directly influences group decision quality. The more frequent information is exchanged among group members, the higher the quality of the corresponding decision. In this paper we present results of an empirical study conducted with groups of students – the task of each group was to take a decision regarding the exam topics the group prefers. This group decision had to be taken on the basis of a group decision support environment with included recommendation functionality and a discussion forum that allows for information exchange among group members. Depending on the included variant of the group recommendation algorithm, groups received recommendations that varied in terms of recommendation diversity. The results of the study show that increased recommendation diversity leads to an increased degree of information exchange among group members.