Alliance Friendship in the Social Networks of Bottlenose Dolphins
Resources:
http://rsbl.royalsocietypublishing.org/content/early/2010/11/01/rsbl.2010.0852
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0005802
The social networks of dolphins have long been studied, and a wealth of literature has been published on the subject. As dolphins, like humans, have relatively large brains, it is reasonable to presume that many of the complex phenomena that factor into the construction of dolphin social networks also apply to human social networks. In an article published in Scientific American, Jason Goldman suggests that the structure of dolphin social networks can inform our understanding of human friendships both at the level of groups of individual people as well as at the large-scale level of international relations. At the forefront is the concept of “social alliances.”
In a study conducted by Richard Connor, a professor of marine mammal biology at the University of Michigan, the social interactions of groups of bottlenose dolphins in Shark Bay, Australia were analyzed for patterns in behavior. In particular, the study focused on “friendships” or “alliances” between male dolphins. Prior to this study, it was well-known that dolphins exist in a “fission-fusion” society consisting of first-order and second-order alliances. In a first-order alliance, two or three male dolphins prevent one or more female dolphins from being “taken” by other males, and in a second-order alliance several groups of first-order-alligned dolphins form a larger group that works together to attack other second-order aligned dolphins to take their females. Thus, this two-level social hierarchy is entirely based on mating practices. What Connor’s group discovered was a tertiary level of alliance between dolphins. The University of Michigan group tracked the behavior of four groups of dolphins and found that when one group of males attempted to attack another group, a third group would often join to either help defend the attacked group or aid the antagonists. Evidently, groups of dolphins formed “alliances” with other groups.
What initially seemed strange about these alliances was that they were inconsistent based on previous “fights” between groups. For example, a group of dolphins labelled ‘PD’ in the study had frequent “fights” over females with a group labelled ‘KS,’ but when ‘KS’ was attacked by a group labelled ‘WC’, ‘PD’ aligned with ‘KS,’ despite previous fights. The alliances, then, are not based on conscientious altruism, but something else. What Connor’s group proposed is that dolphins form alliances based on a ranking of friendships that takes into account how other groups of dolphins rank them.
In terms of the topics discussed in class, this method of forming alliances is a game theoretic process. Dolphins must make decisions rationally based on the decisions they predict other dolphins will make. Something Goldman points out in his article is the way in which human international relations replicates this game theoretic formation of alliances. As in dolphin society, the strongest international ties are not based on altruistic reciprocity. For example, the US and China are strong economic partners in terms of international trade, yet the US and the UK have a stronger “friendship” despite significantly less financial reciprocity between the two nations. The US “ranks” the UK higher partially due to the perception that the UK ranks the US relatively high in its “list of friends.”
In fact, in a paper published by Peter DeScioli and Robert Kurzban, professors of psychology at the University of Pennsylvania, a theory of alliance-based human friendship is proposed. In this paper, DeScioli and Kurzban employ game theory explicitly to analyze the formation of human friendships. They propose that individuals form friendships primarily in order to maintain a support network in times of conflict. People establish a ranking system of their friends that takes into account the ranking they perceive their friends to have of them. This, of course, almost exactly resembles the alliance structure of bottlenose dolphins! Thus, the dolphin social network is predictive both of human society at a large scale as well as at the small scale of groups of individual friends. While it is natural to presume that humans form friendships based on altruism, this is a simplistic view. In reality, a game theoretic formation of alliances constitutes predictable machinery that underlies friendship formation both in human society as well as in dolphin society.