When reconstructing plane and train announcements, teams outdo individuals
It pays to travel in a group. When people put their heads together, they can piece together the details of a train station or airport announcement that they heard better than even the most accurate group member can manage alone, a new study finds.
Teams’ advantage over individuals on this task depended on an exchange of opinions about what had been announced, enabling majority decisions to be reached, say evolutionary biologist Ralf Kurvers of the Leibniz-Institute of Freshwater Ecology and Inland Fisheries in Berlin and his colleagues.
This finding supports the idea that language evolved for sharing information and solving problems in groups, the researchers propose October 17 in PLOS ONE.
“The fact that groups beat their most accurate members at reconstructing sentences shows that even top performers have an incentive to join a group to solve certain complex problems,” Kurvers says.
Kurvers and his team studied the common experience of trying to figure out what was said in a publicly broadcast announcement. The researchers asked 167 German college students to listen to two arrival and departure messages that mimicked the sound quality of loudspeaker announcements in airports and train stations. The volunteers had to piece together details of what they’d just heard. One announcement stated, “The passengers on flight LG 327 to Stettin are requested to go to gate C31 immediately.”
Each volunteer heard one announcement individually and another while sitting in a group of seven or eight people. Starting when the announcement began to play, individuals had one minute to write down a sentence with its critical information and another four minutes to make any changes to their sentences. Teams had four minutes to discuss and write a sentence encapsulating what had been announced.
Groups made fewer errors and included more information than any individual did. Accuracy peaked at around 90 percent for group-constructed sentences containing pieces of information that matched what all or a majority of individual group members had reported.
An association between correct group and individual responses suggests that group members exchanged opinions to reach majority decisions, Kurvers says. In his view, group participants may have judged each other’s confidence levels as a check on whether to accept particular pieces of information (SN Online: 4/20/12).
Although confident group members may have provided the most accurate information about announcements, as Kurvers holds, reasons for groups outperforming individuals remain unclear, says psychologist Stefan Herzog of the Max Planck Institute for Human Development in Berlin. “Confidence is a two-sided cue,” he says, since some people have misplaced confidence in the correctness of their own opinions.
Kurver’s intriguing findings suggest that groups are especially good at solving problems that have concrete solutions, Herzog says.
R.J.G. Clément et al. Collective cognition in humans: groups outperform their best members in a sentence reconstruction task. PLOS ONE. Published October 17, 2013. doi:10.1371/journal.pone.0077943.
B. Bower. Two heads sometimes better than one. Science News online, April 20, 2012.