PRODUCTIVITY LOSS IN IDEA-GENERATING GROUPS - TRACKING DOWN THE BLOCKING EFFECT

Four experiments were conducted to identify the mechanisms that mediate the impact of production blocking on the productivity of idea-generating groups and to test procedural arrangements that could lessen its negative impact. Experiment 1 manipulated the length of group and individual sessions. Although Experiment 1 failed to find a closing of the productivity gap over time in equal man-hour comparisons, real 4-person groups produced more than nominal groups when given 4 times as much time. Because lengthening the time of session increases thinking as well as speaking time, speaking time was manipulated in Experiment 2. The finding that individuals who brainstormed for 20 min but were allowed to talk either for all or for only 1 4 of the time did not differ in productivity eliminates differences in speaking time as an explanation of the productivity loss in idea-generating groups. In Experiments 3 and 4, procedural strategies to lessen the impact of blocking were examined.