It's difficult to come up with a snappy intro to a story like this: Kim Jong-il is dead of a heart attack at age 69. It's also hard to deny that he was fascinating to watch, somewhat like a train-wreck writ large. But as interesting as Kim himself was as a world leader, it is the society that surrounded him that has always captured my attention. As a nation, it is reclusive, oppressive, and nearly self-supporting, with information only dribbling in and out; Kim's North Korean society, described as a "cult of personality" around the Supreme Leader, was (and is) characterized by a totalitarian leadership, a Communist economy, and restrictive social structures like the censored state-run media. Now, at the news of Kim's death the question that has always bugged me about North Korea comes up again: how do such societies evolve and maintain themselves?

Many scientific fields have something to say about this issue, including (but not limited to) sociology, psychology, media studies, political science, and economics. However, the topic has been a current event in behavioural ecology and evolutionary biology as well, and I think that recent work might offer some insights. In particular, there has been a push in behavioural biology to study both group dynamics in animals and the leadership of those groups. A recent paper by Andrew King, Dominic Johnson, and Mark Van Vugt reviews this topic in some detail and makes a great starting place for anyone looking to explore these themes. In their paper, King et al. pose the two questions that we might ask of Kim Jong-il: who leads groups, and how do they lead? There are many reasons why some individuals in a group may lead while others follow; in animals, these include:

* Motivation. For example, the hungriest fish take point position in a foraging shoal.

* Personality. Traits such as boldness can lead exploratory individuals to push forward and direct the movement of the group (a theme that I touched on in my own Ph.D. work on social foraging).

* Dominance. Many species, including primates and wolves, assort themselves by means of a dominance hierarchy. Individuals rank themselves in some way, such as intimidation or aggressive conflict, and the leader is the individual at the top of the hierarchy. Given that Kim suffered a heart attack it is worth noting that - as the brilliant nueroendocrinologist Robert Sapolsky has pointed out - being at the top of a dominance heirarchy in a despotic regime can bring with it a lot of stress and negative health consequences. Sapolsky argues persuasively that the trends seen in animal societies may apply quite well to human hierarchies as well, which is something that North Korea's new leader Kim Jong-Un might want to pay close attention to!

* Knowledge. Informed individuals in a group, such as those with information about predators or food sources, can emerge as natural leaders simply by virtue of having that information and acting on it.

King et al. also explore the way in which individuals actually lead groups once they have formed. In particular, they draw a distinction between passive leadership that is an emergent property of the group structure, and active leadership where leaders signal their intenta and give their fellows a chance to follow or not. Passive leaders lead simply by virtue of their actions, and as the authors point out, tend to be seen in homogenous groups where individuals have little conflict of interest. This is an exciting theme underlying the work of Iain Couzin's group, who do fascinating work on collective animal behaviour showing that a small minority of informed individuals can have powerful effects on the movement of groups; they've also managed to show the same effects occuring in humans. Active leaders, on the other hand, attempt to take control of the group's movement and provoke an active choice on the part of their followers; an example comes from bottlenose dolphins, who try to influence the travelling behaviour of their group by performing acrobatic signals.

Of course, explanations for Kim Jong-il's power over the North Korean people will be very complicated, and will hinge on the fact that Kim inherited the position from his father, Kim Il-sung. On the other hand, many primates show inheritance of social position, though my understanding of the relevant science is that this is more common for females and in spotted hyenas. But I believe that it is instructive to draw lessons from the evolution of animal groups when we study regimes like North Korea. If you discount the Great Man Theory of history, then the same processes that promote group formation and give rise to leaders within those groups may shed some light on how these leaders come to power in human societies.

The restriction of information and trade in North Korea is also an issue of some importance; research on information use in human and non-human animals is too huge a literature to cover here, but there is evidence that information acquired from and about others (social information) is important to primates, and both models and empirical research show that dominance can emerge from the information use and reputation, the so-called 'winner and loser effects' that are seen throughout the animal kingdom. Winner and loser effects, what we might call 'self-confidence' in humans, come from the information that animals gather while engaging in social interactions with others ("oops, I got my butt kicked that time, I guess I'm not that strong after all"). These effects not only help to predict the outcome of conflicts between animals, but can lead to the evolution of highly structured animal hierarchies. Even as a metaphor, it's interesting to draw parallels between winner effects and the personality cult that grew up around the Supreme Leader; I can't imagine a stronger winner effect than what Kim would have experienced every day (and taken to its logical conclusion, could help explain the oftentimes bizarre behaviour of the North Korean government).

Though many of the pieces of the puzzle have been gathered, the integration of our knowledge of animal aggregations and leadership into a cohesive whole is still in its infancy (as King et al. note in their introduction), but with exciting new advances in both theoretical and empirical work from recent years to draw on it has never been a better time to study these questions. I hate to make predictions, because there's no better way to be wrong than to predict the future, yet I will say that I believe I will see major impacts from these lines of research on our understanding of both animal and human societies during the span of my career. And if we can meld our understanding of the evolution of animal group behaviour with that of other social and cultural forces, perhaps our comprehension of, and ability to deal with, Kim Jong-Un's North Korea will be better than our understanding of Kim Jong-il's.

### References

Andrew J. King, Dominic D. P. Johnson, and Mark Van Vugt. The origins and evolution of leadership. Current Biology, 19:911–916, 2009.(

Jens Krause. The relationship between foraging and shoal position in a mixed shoal of roach (Rutilus rutilus) and chub (Leuciscus cephalus): a field study. Oecologia, 93(3):356-359, 1993.(

Robert M. Sapolsky. The influence of social hierarchy on primate health. Science, 308(5772):648-652, 2005.(

John R.G. Dyer, Christos C. Ioannou, Lesley J. Morrell, Darren P. Croft, Iain D. Couzin, Dean A. Waters, and Jens Krause. Consensus decision making in human crowds. Animal Behaviour, 75(2):461-470, 2008.(

David Lusseau and Larissa Conradt. The emergence of unshared consensus decisions in bottlenose dolphins. Behavioural Ecology and Sociobiology, 63:1067-1077, 2009.(

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Robert O. Deaner, Amit V. Khera, and Michael L. Platt. Monkeys Pay Per View: Adaptive Valuation of Social Images by Rhesus Macaques. Current Biology, 15(6):543-548, 2005.(

Claudia Rutte, Michael Taborsky, and Martin W.G. Brinkhof, What sets the odds of winning and losing? Trends in Ecology & Evolution, 21(1):16-21, 2006.(

G. Sander van Doorn, Geerten M. Hengeveld, and Franz J. Weissing. The evolution of social dominance II: multi-player models. Behaviour, 140:1333-1358, 2003.(