Featured Research

from universities, journals, and other organizations

How Cooperation Can Evolve In A Cheater's World

Date:
June 29, 2006
Source:
Brown University
Summary:
Whether you're a free-loading virus or a meat-stealing monkey, selfishness pays. So how could cooperators survive in a cheater's world? Thomas Flatt, a postdoctoral research associate at Brown, was part of a group that created a theoretical model that neatly solves this dilemma, which has stumped evolutionary biologists and social scientists for decades. The trick: Keep the altruists in small groups, away from the swindling horde, where they multiply and migrate.

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, including a Brown University biologist, 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. The work appears in the Proceedings of the Royal Society B: Biological Sciences.

“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 typical public goods game, an experimenter gives four players a pot of money. Each player can invest all or some of the money into a common pool. The experimenter then collects money thrown into the pool, doubles it and divides it amongst the players. The outcome: If every player invests all the money, every player wins big. If every player cheats by investing a just few dollars, every player reaps a small dividend. But if a cooperator squares off against a cheater – with the altruist investing more than the swindler – the swindler always gets the bigger payoff. Cheating, in short, is a winning survival strategy.

Under the new model, the team introduced population dynamics into the public goods game.

Players were broken into groups and played with other members of their group. Each player then reproduced in proportion to the payoff they received from playing the game, passing their cooperator or cheater strategy on to their offspring. After reproduction, random mutations occurred, changing how much an individual invests. Finally, players randomly dispersed to other groups, bringing their investment strategies with them. The result was an ever-changing cast of characters creating groups of various sizes.

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.

The Swiss National Science Foundation and the Roche Research Foundation funded the work.


Story Source:

The above story is based on materials provided by Brown University. Note: Materials may be edited for content and length.


Cite This Page:

Brown University. "How Cooperation Can Evolve In A Cheater's World." ScienceDaily. ScienceDaily, 29 June 2006. <www.sciencedaily.com/releases/2006/06/060629230929.htm>.
Brown University. (2006, June 29). How Cooperation Can Evolve In A Cheater's World. ScienceDaily. Retrieved April 24, 2014 from www.sciencedaily.com/releases/2006/06/060629230929.htm
Brown University. "How Cooperation Can Evolve In A Cheater's World." ScienceDaily. www.sciencedaily.com/releases/2006/06/060629230929.htm (accessed April 24, 2014).

Share This



More Plants & Animals News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Fungus Killing Bats, Spreading in US

Deadly Fungus Killing Bats, Spreading in US

AP (Apr. 24, 2014) A disease that has killed more than six million cave-dwelling bats in the United States is on the move and wildlife biologists are worried. White Nose Syndrome, discovered in New York in 2006, has now spread to 25 states. (April 24) Video provided by AP
Powered by NewsLook.com
Blood From World's Oldest Woman Suggests Life Limit

Blood From World's Oldest Woman Suggests Life Limit

Newsy (Apr. 24, 2014) Scientists say for the extremely elderly, their stem cells might reach a state of exhaustion. This could limit one's life span. Video provided by Newsy
Powered by NewsLook.com
Raw: Kangaroo Rescued from Swimming Pool

Raw: Kangaroo Rescued from Swimming Pool

AP (Apr. 24, 2014) A kangaroo was saved from drowning in a backyard suburban swimming pool in Australia's Victoria state on Thursday. Australian broadcaster Channel 7 showed footage of the kangaroo struggling to get out of the pool. (April 24) Video provided by AP
Powered by NewsLook.com
Could Marijuana Use Lead To Serious Heart Problems?

Could Marijuana Use Lead To Serious Heart Problems?

Newsy (Apr. 24, 2014) A new study says marijuana use could lead to serious heart-related complications. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins