How Many Wrongs Can Make A Right

Those of you sceptical of decision-making by committee may need to think again. Scientists have successfully demonstrated that groups of people can reach decisions more accurately than individuals.

Writing in the latest issue of the journal Animal Behaviour, the researchers report how groups of ten volunteers navigated closer to a target than singletons did, when given only limited information of where to go.

According to lead author, Jolyon Faria, from the University of Leeds, their experiment was designed to test ‘the many wrongs principle’ of animal navigation.

“First suggested in 1964 as a way to describe the movement of animal groups, the principle states that individual error can be overcome by staying within a group, so groups can navigate more precisely than singletons. As a result, the group as a whole stays on target, and does so more accurately than any given individual.

“When we provided only very low levels of information about the target, and hence uncertainty was high, large groups navigated the most accurately - as predicted by the principle.”

It did take groups longer to reach the target than singletons, however, suggesting that greater accuracy comes at the cost of slower decision-making.

The researchers recruited schoolchildren and colleagues to take part in their experiments, which involved them moving towards one of 16 numbered targets equally placed around the edge of a circular arena.

Members of a group were given a shortlist of targets, only one of which was the correct number. Each group member had a different list of targets, but all lists included the correct target’s number.

Group members – who were forbidden from communicating directly with one another - were then told to head toward whichever target they liked, as long as they stayed within arm’s reach of everyone else in their group.

“If the ‘many wrongs principle’ was operating, then groups of people, each of whom possessed approximate knowledge of the target location, should have converged on the correct target more accurately than a single person, because all their individual errors should cancel each other out via the mechanism of sticking together as a group,” explained Jolyon.

The sequences of target numbers ensured that each person in the group possessed the same amount of ‘directional uncertainty’ about where they should head, he added.

Jolyon and his colleagues varied group size from lone individuals up to 10 people, and the length of the shortlist between two and six possible targets. The results showed that the ‘many wrongs principle’ operated, but only when group size and uncertainty were at their greatest.

The researchers, who also came from the Universities of Essex and Bielefeld, hope their new findings might lead to a better understanding how many animals manage to navigate so well.

“The principle has been demonstrated using computer simulations, and has some support from studies on bird flocks, but before our experiments, no one had tested whether humans would show a similar kind of improved group-based accuracy. This may help explain how some animals can navigate so accurately, and why animals often navigate in groups,” said Jolyon.

Executive Editor of Animal Behaviour, Dr Louise Barrett commented: “These neat experimental results demonstrate both the value of using humans to test principles derived from animal research, as well as providing a novel demonstration of the power of the ‘vox populi’.”

The work is published online in the journal Animal Behaviour, and was funded by the Biotechnology and Biological Sciences Research Council (BBSRC). -- www.leeds.ac.uk