Featured Research

from universities, journals, and other organizations

How Cooperation Can Evolve In A Cheater's World

June 29, 2006
Brown University
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.

Related Articles

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 March 29, 2015 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 March 29, 2015).

Share This

More From ScienceDaily

More Plants & Animals News

Sunday, March 29, 2015

Featured Research

from universities, journals, and other organizations

Featured Videos

from AP, Reuters, AFP, and other news services

Vietnam Rice Boom Piles Pressure on Farmers and the Environment

Vietnam Rice Boom Piles Pressure on Farmers and the Environment

AFP (Mar. 29, 2015) — Vietnam&apos;s drive to become the world&apos;s leading rice exporter is pushing farmers in the fertile Mekong Delta to the brink, say experts, with mounting costs to the environment. Duration: 02:35 Video provided by AFP
Powered by NewsLook.com
Raw: Lioness Has Rare Five-Cub Litter

Raw: Lioness Has Rare Five-Cub Litter

AP (Mar. 27, 2015) — A lioness in Pakistan has given birth to five cubs, twice the usual size of a litter. Queen gave birth to two other cubs just nine months ago. (March 27) Video provided by AP
Powered by NewsLook.com
Jockey Motion Tracking Reveals Racing Prowess

Jockey Motion Tracking Reveals Racing Prowess

Reuters - Innovations Video Online (Mar. 26, 2015) — Using motion tracking technology, researchers from the Royal Veterinary College (RVC) are trying to establish an optimum horse riding style to train junior jockeys, as well as enhance safety, health and well-being of both racehorses and jockeys. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Bear Cubs Tumble for the Media

Bear Cubs Tumble for the Media

Reuters - Light News Video Online (Mar. 26, 2015) — Two Andean bear cubs are unveiled at the U.S. National Zoo in Washington, D.C. Alicia Powell reports. Video provided by Reuters
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.


Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News


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