Co-author Shanker Krishnan, via email, confirms my initial reservations.
There is quite a bit of evidence that groups in fact exhibit social loafing, which could make their joint performance lower. On the other hand, the brainstorming literature would suggest that groups can build off each others' comments, so the output could be higher.I'd like to focus on two interesting parts of the study's format:
Our perspective was to suggest that when groups are exposed to external cues, they inhibit memory more so than they would an individual. The reason is the group gets "stuck" on that external cue, and keep going back to it (what we call double cueing). The implication is that if it is a memory task where the group may be exposed to some information that might serve as a cue, the kinds of inhibition that we document are likely....
I wouldn't extrapolate beyond these conditions and memory, because the task seems to be important.
[T]riads consisted of groups of virtual strangers. In many consumption situations, group members know one another.... Finally, the current experiments used one member of the collaborative group to record the group’s responses.Many teachers--myself included--use small groups frequently, to help students get to know each other, fostering a collaborative dynamic in the classroom, which might reduce the phenomenon of "social loafing."
Also, I've noticed that in a brainstorm, when only one student holds the marker, that student tends to dominate the conversation and the shape of the "thinking map" produced. I've noticed similar effects when one student acts as the note-taker in small group discussion. That role, minor as it may seem, is powerful.
Years ago, one of my fellow Evergreen master's-in-teaching candidates theorized that education is just another form of aggressive marketing. No surprise, then, that a marketing researcher would prod me to critically analyze a teaching method I use all the time.
I thank Dr. Krishnan for his generosity in responding to questions and providing access to a copy of the study.