Excerpted from Complexity Digest 2010.15 by Bruce Hannon
Does diversity always grow?, Nature
Excerpt: McShea and Brandon do not claim that their law represents a wholly new evolutionary principle, rather that it is a unifying one. The tendency for increasing diversity has been recognized previously in specific situations. For example, molecular geneticists know that, in the absence of selection, populations will diverge genetically as neutral mutations accumulate. And evolutionary biologists have noticed that tissues and organs that are not subject to selection, such as the eyes of cave-dwelling fish, often show more variation between individuals. The authors aim to encompass these various findings in a single theory that covers all of the fields in which the principle has been seen (...)
- Source: Does diversity always grow?, Samir Okasha, DOI: 10.1038/466318a, Nature 466, 318, 2010/07/15
Who should pay for the police?, Nature
Excerpt: If players are allowed to fine free-riders, but at a cost to themselves, they will generally do so: they care more about fairness than profit. This, however, can introduce another problem, a second-order temptation to free-ride: you contribute to the pot but leave others to shoulder the cost of sanctioning the cheaters who don't. So there's an infinite regress of opportunities to free-ride, which can eventually undermine cooperation.
- Source: Who should pay for the police?, Philip Ball, DOI: 10.1038/news.2010.351, Nature, 2010/07/14
Punish, but not too hard: How costly punishment spreads in the spatial public goods game, arXiv
Excerpt: We study the evolution of cooperation in spatial public goods games where, besides the classical strategies of cooperation (C) and defection (D), we consider punishing cooperators (PC) or punishing defectors (PD) as an additional strategy. Using a minimalist modeling approach, our goal is to separately clarify and identify the consequences of the two punishing strategies. Since punishment is costly, punishing strategies loose the evolutionary competition in case of well-mixed interactions. When spatial interactions are taken into account, however, the outcome can be strikingly different, and cooperation may spread. (...)
- Source: Punish, but not too hard: How costly punishment spreads in the spatial public goods game, Dirk Helbing, Attila Szolnoki, Matjaz Perc, Gyorgy Szabo, arXiv:1007.0431, 2010/07/03
Probing Culture's Secrets, From Capuchins to Children, Science
Excerpt: Scientists once designated culture as the exclusive province of humans. But that elitist attitude is long gone, as evidenced by a recent meeting (...) on how culture, usually defined as the passing on of traditions by learning from others, arises and changes. The 700 attendees, a mixture of researchers and members of the public, heard talks on cultural transmission in fish, meerkats, birds, and monkeys, as well as in extinct and living humans. Researchers probed questions such as what sparks cultural trends and how complex traditions are transmitted, and most agreed that studies of both animals and children will provide important clues.
- Source: Probing Culture's Secrets, From Capuchins to Children, Michael Balter, DOI: 10.1126/science.329.5989.266, Science Vol. 329. no. 5989, pp. 266 - 267, 2010/07/16
Particle Swarm Optimization, Swarm Intelligence
Abstract Excerpt: The Particle Swarm Optimizer (PSO), one of the pillars of Swarm Intelligence, is a remarkable algorithm for at least two reasons: (a) it has a very simple formulation which makes it easy to implement, apply, extend and hybridize, and (b) it is a constant source of complex and emergent phenomena, which are at the essence of swarm intelligence. Many people around the world are exploring PSOs and their applications.
- Source: Editorial for the special issue on Particle Swarm Optimization, Riccardo Poli, Andries Engelbrecht, Jim Kennedy, DOI: 10.1007/s11721-009-0033-9, Swarm Intelligence Volume 3, Number 4, Pages 243-244, 2009/12
Frontiers of Collaboration: The Evolution of Social Networking, Knowledge@Wharton
Summary: Social networking tools such as Twitter and the emerging Google Wave web application are taking businesses to the frontiers of real-time communication and collaboration. The technology has the potential to make it easier to discover and share information and interact with others. But the key word is "potential." During a panel at the last Supernova technology strategy conference, experts talked about what makes the current crop of services more promising than those that came before, and the obstacles to further progress.
- Source: Frontiers of Collaboration: The Evolution of Social Networking, Knowledge@Wharton, 2010/07/07
Firefly Synchrony: A Behavioral Strategy to Minimize Visual Clutter, Science
Abstract: Most firefly species (Coleoptera: Lampyridae) use bioluminescent flashes for signaling. In some species, the flashing between males occurs rhythmically and repeatedly (synchronically) with millisecond precision. We studied synchrony’s behavioral role in the North American firefly, Photinus carolinus. We placed a female in a virtual environment containing artificial males that flashed at varying degrees of synchrony. Females responded to an average of 82% of synchronous flashes compared with as few as 3% of asynchronous flashes. We conclude that one function of flash synchrony is to facilitate a female’s ability to recognize her conspecific male’s flashing by eliminating potential visual clutter from other flashing males.
- Source: Firefly Synchrony: A Behavioral Strategy to Minimize Visual Clutter, Andrew Moiseff, Jonathan Copeland, DOI: 10.1126/science.1190421, Science Vol. 329. no. 5988, p. 181, 2010/07/09