In this BBC documentary Richard Dawkins explores the evolution of cooperation. The problem has been discussed intensely since Darwin’s time and is still being investigated scientifically. Cooperative species are quite successful but rare. Social insects (ants, wasps, bees and termites) make up only 3 percent of animal diversity yet they may constitute up to 50 percent of the total animal biomass in land habitats. Among 43,678 known species of spiders cooperative behavior evolved in only a few.
How could a worker ant give up reproduction and devote herself completely for the survival of the queen? What are the conditions necessary to reinforce cooperation? Is it possible to punish cheaters? If so, how? When does cooperation fail? Before searching for answers to these questions we must understand a very important concept called Game Theory. The concept is so influential in our understanding of social phenomena that it generated 12 Nobel prizes until 2012. An excerpt from a popular British tv show may help understand the basics of a hypothetical game theory scenario called Prisoner’s dilemma:
As we can see, both players are under pressure to decide whether to cooperate or to defect. What does this have to do with anything in the real world? Game Theory principles can be used to understand larger population level outcomes from analysis of walking patterns to prevent stampedes during Haj in Saudi Arabia to consequences of China’s one child policy known as the Little Emperor Effect.
Dawkins illustrates a game theoretical situation by an example of tragedy of the commons a concept popularized in 1968 by ecologist Garrett Hardin. In his example, the selfish behavior of cattle owners lead to overgrazing and thus the fields get degraded and become dominated by undesirable species such as ragworts and thistles. The field is shared by many. Each farmer knows that he is better off to send as much cattle as possible, since the next farmer may do likewise, even if he showed restraint (or choose to cooperate).
Dawkins then goes on to explain how altruism can be a handicap if it is not repayed. Parasites pose a huge burden on organisms. Surely, we’ve all had a tick we could not reach, and having an extra pair of hands is always handy. Take a look at the short video of a skink infested with ticks below. The way ticks attached themselves under the armpits is a clear indication that this individual is alone in its fight against parasites. Dawkins’ story involves birds removing ticks. When all the birds groom one another, there is a net benefit. However, when one bird grooms another, but is not groomed back, then the “cheating” bird has gained an unfair advantage. Check out the parasite load on this poor skink. The reciprocal grooming behavior never evolved and the individuals have to deal with ticks alone:
Southestern Five-lined Skink (Plestiodon inexpectatus) with Ticks from Uzay Sezen on Vimeo.
Punishment can be a very influential way to enforce cooperation. However, it can be rather costly because there is a threat of retaliation. A rather elaborate example of this kind of behavior is observed in cleaner fish of the tropical reefs. These fish collectively clean “client” fish that come to cleaning stations. Dawkins emphasizes cooperation among different species. We now know that there’s also a quite remarkable level of cooperation among the fish of the same species as well. If a client fish leaves early this is a sign of cheating: One or a few of the cleaners must have taken a bite out of the client (usually from the yummy soft gills which incites pain) instead of eating dead skin and/or parasites. In these situations, male fish chases around all females in the group as a punishment. This is known as third party punishment since the male fish is not hurt directly.
Dawkins then describes a competitive tournament of computer simulations organized by a professor of political science Robert Axelrod. The different simulations were meant to demonstrate what strategy could be most effective along a cooperative vs selfish continuum. Examples are starting cooperative and switching to less cooperative, starting not cooperative and becoming more cooperative based on the opponent, being mostly cooperative but occasionally sneaking in a selfish move (exactly what the cleaner fish is trying to avoid), etc. Surprisingly, the best strategy was “tit for tat”. In other words, opening cooperatively and then simply copying the other’s strategy at each turn thereafter. Neither being recklessly selfish nor naively cooperative worked as well. However, the strategy only works when a sufficient number of other players engage the same strategy. In other words, when tit for tatters play each other the result is that everyone wins. Dawkins explains that for the strategy to work there must be a critical mass of tit for taters at the onset. In this way, tit for tatters don’t go extinct in a population embedded with cheaters.
Are there any real world examples of tit for tat communities? Dawkins explains that vampire bats use this strategy. On any given night a certain percentage of vampire bats will fail to find a host. Other bats will share with unsuccessful bats that evening, but only if the favor was repayed earlier. In evolutionary biology this is know as reciprocal altruism where an organism behaves in a manner that temporarily reduces its chance for survival while increasing survival chance of others, with the expectation that the others will act in a similar manner at a later time.
Cooperative food sharing in vampire bats from Gerald Carter on Vimeo.
Finally, signalling for cooperation is very important. Like the football game example at the beginning of the documentary, the stable strategy could be to reduce competition especially when a win-win situation is straightforward. Snipers firing deliberately off target in trenches of the First World War was a well recorded way of signalling for cooperation. As a contemporary example, there was one particularly interesting verbal exchange between the protesters and the riot police recorded during weeks long heavy street clashes in Gezi Park resistance in Istanbul. Protesters were signalling for peace by inviting the riot police for a call-and-response style chanting of Turkish flag colors. In the video below when protesters chant “red” (kırmızı) riot police responds with “white” (beyaz) signalling for conflict resolution. Signalling for peace requires an honest first move. The video was recorded in Beşiktaş district whose team colors are black and white. Inviting riot police to say “white” is therefore quite tricky since protesters may answer with “black” instead of “red” and could easily fan the anger of the police which notoriously have been known to react brutally. Making the first move positive (chanting “red”) eliminates this kind of escalation from the beginning:
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