When are two (or more) heads better than one?

We must believe that groups produce better results than individuals — why else do we have so many “teams” in the workplace, and so many meetings. But many of us also, of course, hold the opposite belief: that most meetings are a waste of time; that teams might be better for some tasks (and for other people!), but not for all tasks. So what do we know about the circumstances that make groups better value?

A recent study involving some 700 people, working on a wide variety of tasks in small groups (two to five), found that much of the difference between groups’ performance (specifically, around 40% of the variation in performance) could be explained by a measure called “collective intelligence”.

It was called that (I assume) on the basis that it was such an important factor in predicting performance on such a wide range of tasks (from visual puzzles to negotiations, brainstorming, games and complex rule-based design assignments). But the intriguing thing about this collective intelligence is that it didn’t seem to reflect the individual intelligence of the groups’ members. Instead, the most important factor in a group’s collective intelligence appeared to be how well its members worked together.

There were two (or three) factors that seem particularly important for this. The main one is the “social sensitivity” of the members — meaning how well the individuals perceive each others’ emotions. The number of women in the group also enhanced collective intelligence, but this may not be a separate factor — it may simply reflect the tendency for women to be more socially sensitive.

The other factor was the extent to which everyone contributed — groups where one person dominated were less collectively intelligent. This fits in with a review of workplace teams that found that teams that spent time sharing new information performed better overall in their tasks — even though a lot of the information was already known by everyone in the group. (Although it must be added that bringing in new information was even better!). It also fits in with the same review’s finding that teams whose members had more similar backgrounds tended to share more information than those with greater diversity.

That’s a depressing finding, but it’s not insoluble.

The review (which looked at studies totally some 4800 groups, involving over 17,000 people) also found that teams communicate better when they engage in tasks where they are instructed to come up with a correct / best answer rather than a consensual solution.

Previous research (see reports here and here) has suggested that brainstorming actually produces fewer ideas than would be produced by the same individuals working individually, and that groups working together to remember something recall more poorly than the same individuals would working on their own. One big reason for these findings, it is thought, is that hearing other people's ideas disrupts your own retrieval strategy. However, this is less likely to occur in a structured situation, where turns are taken.

So groups can have inhibitory effects (which are apparently worse when the information being recalled is more complex), and it seems likely that is one of the problems that social sensitivity helps fight against. And indeed, previous research has indicated that, when the meeting is unstructured, with everyone chipping in as they feel like it, the specificity of the suggestions is important — with this being affected by how well the group members know each other. (If turns are taken, on the other hand, it is waiting time that’s important.)

Another recent report (which I reported on a few weeks ago, which is what triggered this post), found that although two people working together can make better decisions than either one could make alone, this is only true when the participants were able to accurately judge their level of confidence in their information. If one of them is working off inaccurate information and doesn’t realize that it is inaccurate, then (unsurprisingly!) the one with accurate information is better off without him.

Again, we can surmise that a group where members know each other well is one where they have a good understanding of the confidence they can put in each other’s judgments and claims.

Perhaps relatedly, another study indicates that problems can be exacerbated when information is shared, if the people have different viewpoints. People mentally organize information in different ways, and cues that help one person recall may inhibit another.

So where does all this leave us?

How effective a group is depends a lot on how attuned its members are to each other’s emotions and capabilities. Information sharing is a positive process that enhances group productivity even when the information is already familiar to members, and therefore strategies to encourage information sharing are useful.

There are three classes of strategies that could be used:

  • Providing structure to the discussions (e.g. taking turns, setting time limits, having a moderator that encourages suggestions to be specific and novel)
  • Providing instruction in how to become more socially sensitive (e.g. learning about physical cues to emotion)
  • Encouraging informal conversation and “team-building” exercises that help team members become more familiar with each other (bearing in mind that the point of such exercises is to help members become more aware of each other’s emotions and capabilities, and designing them accordingly).

The first of these strategies is most important for groups who have come together for a specific occasion, or only meet rarely. The second of these is useful for individuals who are (as most everyone is!) going to sometimes work collaboratively — that is, it is not dependent on a particular group. The third class of strategies is useful for long-term groups.

In all these cases, such strategies are most needed when a group contains more diverse members, who are not well-known to each other.

There is also a fourth class of strategy, that relates to assessing the effectiveness of group collaboration for particular tasks. For example, the difficulty or complexity of the task is an important factor — more complex tasks are more efficiently learned or processed by groups, while low-complexity tasks are better left to individuals. But greater complexity also requires a group that works well together.

Type of task is another likely factor. For example, organizational or memory retrieval tasks may be best left to individuals or small, similarly-inclined groups in the early stages, because our ways of approaching these tasks is quite idiosyncratic and can be hampered by contrary approaches. Of course, diversity is needed at a later stage to ensure thoroughness and/or wide applicability.

References: 

Bahrami, B., Olsen K., Latham P. E., Roepstorff A., Rees G., & Frith C. D. (2010).  Optimally Interacting Minds. Science. 329(5995), 1081 - 1085.

Basden, B.H., Basden, D.R., Bryner, S. & Thomas, R.L. III (1997). A comparison of group and individual remembering: Does collaboration disrupt retrieval strategies? Journal of Experimental Psychology: Learning, Memory and Cognition, 23, 1176-1189.

Kirschner, F., Paas F., & Kirschner P. A. (2010).  Task complexity as a driver for collaborative learning efficiency: The collective working-memory effect. Applied Cognitive Psychology. n/a-n/a - n/a-n/a.

Mesmer-Magnus, J. R., & DeChurch L. A. (2009).  Information Sharing and Team Performance: A Meta-Analysis. Journal of Applied Psychology. 94(2), 535 - 546.

Ormerod, T. 2005. The way we were: situational shifts in collaborative remembering. Research project funded by the Economic and Social Research Council (ESRC). http://www.esrcsocietytoday.ac.uk/ESRCInfoCentre/PO/releases/2005/march/...
http://www.eurekalert.org/pub_releases/2005-03/esr-wic032305.php

Weldon, M.S. & Bellinger, K.D. (1997). Collective and individual processes in remembering. Journal of Experimental Psychology: Learning, Memory and Cognition, 23, 1160-1175.

Woolley, A. W., Chabris C. F., Pentland A., Hashmi N., & Malone T. W. (2010).  Evidence for a Collective Intelligence Factor in the Performance of Human Groups. Science. science.1193147 - science.1193147.

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