Groups of 4 brainstormed on computers for 20 min. In some groups infor
mation about the number of ideas generated was exchanged every 5 min.
Some groups verbalized their ideas as they were typed, and others only
typed their ideas. Exchange of information about number of ideas incr
eased group performance, but verbalization decreased performance. Both
information exchange and verbalization increased the favorability of
performance perception. These results are consistent with the Paulus a
nd Dzindolet (1993) social influence model of group brainstorming.