Abstract: Brainstorming is a technique that helps to overcome the restriction of evaluation that takes place in most business meeting and one of the most popular idea-generating methods. Results of previous research on brainstorming and related idea-generating methods generally showed that interacting groups produced fewer ideas than equivalent numbers of nominal groups. Evaluation apprehensions, production blocking and free riding were said to be the three major causes for explanation of this fact. Some forms of production blocking were the primary impediment to generating ideas of groups. With expansion of IT in the world, computer-aid and computer-support systems have emerged rapidly in individual and group decision-making. Electronic brainstorming (EBS) is such a technique of computer-aid systems that focuses primarily on eliminating production blocking. It is expected to promote group idea-generation, and much evidence of both its effectiveness and why such effectiveness occurs has been presented.
This study investigated into the effects of group size (six-persons vs. three-persons), group types (nominal vs. interacting) and kinds of communication media (compute-mediated, CM, vs. face-to-face, FTF) on the number and the quality of unique ideas produced by decision-making groups with simulated experiments in the laboratory. 144 Zhejiang University undergraduates were involved in this study. Subjects in each condition were given a task to help a poor student to earn enough money for studying and living in the school.
The results showed: (1) The number of effective ideas produced by CM groups was much more than that of FTF groups under every condition of the experiments; The number of effective ideas produced by CM nominal groups was more than that of FTF nominal groups. The number of creative ideas was influenced primarily by production blocking and evaluation apprehensions. Production blocking existed in the face-to-face groups. As the size of the face-to-face group increased, the production blocking in the group was very obvious. Evaluation apprehensions also existed in the face-to-face group, but were not influenced by group size. (2) Both of breadth and the depth of idea-generation in each experimental condition were not affected by kinds of communication media, but were affected by types and size of groups. Because anonymity and parallelism in communication are two important ways for group members to contribute creative ideas, computer-mediated groups were thought to be the best ones for group members to contribute creative ideas. In the view of the breadth of the ideas, six-person groups were better than three-person groups, and nominal groups were better than interacting groups. (3) FTF groups were better than CM groups in terms of member’s confidence on the quality of ideas produced by himself or the group he belongs to

Key words: idea-generation, face-to-face group, computer-mediated groups, electronic brainstorming