Abstract: Fourteen groups of college students (in total of 68 subjects) were dichotically appointed with two different group tasks: discussing an open-ended (OE) question or a close-ended (CE) question. The group work was assessed in the procedure, pattern, and features: the time used for different working stages, the object that each speaking directs against, the continuity of group discussion, the method and intensity of reasoning, the group conflict and supporting, and expressing style. Results showed that CE needed more time to clarify the question and was more likely to cite examples to support the opinions. OE adopted inductive method whereas CE adopted deductive method. Both groups were more likely to talk to individual members than to the whole group, and more likely to express agreement nonverbally than orally. The results were also discussed referring to the design of videoconference system and computer surpported co-operative work.

Key words: group work, interpersonal interaction, social behaviour, tele-video- conference system, human-machine interaction