It’s a truth borne out in biology and economics: Selfishness pays. Viruses can steal enzymes to reproduce. Tax evaders can take advantage of public services to survive and thrive. And, according to game theory, the cheats win out over the altruists every time.

Yet cooperation is a hallmark of human society, allowing for the creation of everything from the local grange to the United Nations. Cooperation can also be found in the animal world. Lions hunt in packs. Ants and bees create colonies. So how could cooperation evolve in a cheater’s world?

It’s a paradox called the 'tragedy of the commons,' a conflict between individual interests and the common good that has stumped scientists for generations. Now a trio of researchers has created a unique theoretical model that can explain the rise of cooperation. Under their model, altruists not only survive, they thrive and maintain their numbers over time.

“What’s exciting about our approach is that is so simple and so general – in principle it can be applied to explain cooperation at all levels of biological complexity, from bugs to humans,” said Thomas Flatt, a postdoctoral research associate in Brown’s Department of Ecology and Evolutionary Biology. “It’s also exciting because cooperation is a critical notion in so many disciplines, from biology to sociology. Yet its existence and persistence doesn’t always make sense. Now we have a new mechanism that explains when cooperation can work.”

Timothy Killingback, a mathematician at the College of William & Mary, led work on the model. It’s based on public goods games, a staple of game theory and a simple model of social dilemmas. Under the new model, the team introduced population dynamics into the public goods game. After running the model through 100,000 generations, the results were striking. Cooperators not only survived, they thrived and maintained their numbers over time. The key is group size.

“In our model, you can get groups of different sizes – and cooperators seem to flourish in smaller groups,” Flatt said. “In these smaller groups, the high investments of cooperators begin to pay off. Cooperators have a higher level of fitness, so they reproduce at higher rates. This allows them to get a toehold within a group, then dominate it, then send their offspring to spread their altruism elsewhere.”

The model created by Killingback, Flatt, and Jonas Bieri, a Swiss population biologist and computer programmer, is unlike any other. It relies solely on population dynamics to explain the evolution of cooperation. Most other models assume more complicated mechanisms such as kin selection, punishment and reciprocity. Some of those mechanisms require cognition, so those models can only be applied to humans and higher-order animals. >from *How Cooperation Can Evolve in a Cheater’s World*. June 29, 2006

related context
> the spatial scale of competition influences cooperative behavior. 'humans behave less cooperatively when they think they are in direct 'local' competition with each other, and more cooperatively under circumstances of 'global'-scale competition.' june 5, 2006
> evolution: cheats don't always prosper. 'cheaters produce energy rapidly by quickly taking in all the sugar they can and only partially converting it into energy. while this ensures swift energy production for the individual, it is a wasteful method that reduces resources available for the group as a whole.' may 26, 2006
> why we give. 'reciprocity is arguably the foundational basis of cooperation in humans. without some kind of payback, altruism can be a very costly endeavor in small-scale societies subsisting on wild foods.' december 30, 2005
> revenge: neural basis of altruistic punishment. september 10, 2004
> cooperation evolution. october 8, 2003
> social cooperation is intrinsically rewarding to the human brain. 'during the mutually cooperative social interactions, activation was noted in those areas of the brain that are linked to reward processing.' july 19, 2002

imago
> keep to the footpaths the tragicall trashing machine cheater

sonic flow
> the swindling horde [stream]
the swindling horde [download]

openfriday@straddle3
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plea for can ricart
nau21 plea
what's hapening with creative spaces in barcelona? by jeffrey swartz
creativity concept and ideology by matteo pasquinelli
wednesday, july 19, 2006. 20 h
straddle3. c/ riereta, 32 1-3
barcelona