Group decisions: From compromise to leadership in pig...( By studying how homing pigeons decide ...)

By studying how homing pigeons decide between two attractive options--following a habitual route home and flying in the company of another homing pigeon--researchers have deepened our understanding of the forces that underlie decision-making by social animals. The findings are reported by a research group led by Dora Biro of the University of Oxford and appear in the November 7th issue of Current Biology.

Social animals have to make decisions that affect not just themselves, but everyone in the group. For example, when embarking on a journey together, individuals must agree on the route--a difficult task if group members cannot assess who are the best navigators or who is best informed about possible routes. Is a "democratic" average of everyone's opinion best? Or is it better to trust a leader? And what circumstances influence how animals decide which of these strategies to follow?

In the new study, the researchers used miniature GPS tracking devices to follow the homing flights of pairs of pigeons, where both individuals had their own, previously established preferred routes leading back to the loft. When the birds were released as a pair, and when the two preferred routes were not very different, the conflict between birds' preferences was resolved by a mutual compromise in which both birds flew by an intermediate route. When preferred routes of the two birds differed greatly, however, the compromise position was replaced by a scenario in which the preferred route of one bird--who would emerge as the "leader"--was followed by both birds for the rest of the journey.

Using a mathematical model to better understand the basis of the paired birds' navigation choices, the researchers found that both forms of decision-making could emerge from just two simple forces acting simultaneously on the pigeons' behavior: "move toward your familiar route" and "move toward your partner." In cases of small disagreements about the route, these two fo
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Contact: Heidi Hardman
hhardman@cell.com
617-397-2879
Cell Press
6-Nov-2006