The Evolution of Cooperation

1. The Evolution of Cooperation Mike Ignatowski Dec 18, 2016

2. Topics • Evolution – how can cooperation evolve? • Computer simulation • Biology • Importance of cooperation at all levels • Society / Economics / Politics • Competition vs. Cooperation

3. Modern Developments • These new developments started with E.O. Wilson’s book Sociobiology in 1975 • Followed by The Selfish Gene by Richard Dawkins in 1976 • They entered a new phase with Axelrod’s book The Evolution of Cooperation in 1984 • Since then the field has taken off. We know much more than we did 2-3 decades ago.

4. The Big Problem: Explaining Altruism and Cooperationin light of Evolution • Even Darwin recognized this was a problem. It did not fit well into evolution by competition and natural selection • “…one special difficulty, which at first appeared to me insuperable, and actually fatal to my theory.” • Some people claimed this was a basic flaw in applying evolution to humans. • The existence of altruism and cooperation is a sign of divine creation of humans

5. Sociobiology Creates Some Controversy • Established a scientific argument for rejecting the common doctrine of “tabula rasa” (blank slate). • Offends some liberals and conservatives, who both favored the idea that human behavior is culturally based. • Offends some religious people who believe that moral rules are divine in origin. • Some people believe that sociobiology promotes racism, misogyny (prejudice against women) and eugenics. E.O. Wilson

6. Kin Selection • You can aid the survival of your genes by aiding the survival of genetically related individuals who have many of your genes. • Take risks to help your siblings and offspring • Take less risks to help more distant relatives

7. Social Insects(ants, bees, wasps) • Exploits kin selection to an extreme • All members of the social nest are (generally) descendents of one “queen” and thus very closely related. • All of the workers are sterile • The only way to pass on their genes is to make sure their queen is successful, and the colony is strong.

9. Reciprocal Altruism “I help you, in the anticipation that you will help me in the future” • Can extend beyond close relatives. • Generally viewed as “the next higher level of cooperation” • It has more complex ways of dealing with groups and “cheaters”.

10. The Evolution of Cooperation • 1984 book by Robert Axelrod • 1981 article by the same title • One of the most cited articles in the history of the journal Science The coolest computer experiment ever done - Mike Ignatowski

11. Prisoner’s Dilemma “Rational Strategy” (according to standard game theory) • You are always better off defecting no matter what the other person does. • Leads to each person serving 5 years in jail “Irrational Strategy” (according to standard game theory) • If both prisoners behave irrationally (cooperates with each other), then they each only serve 6 months in jail

12. A More Generalized Payoff Matrix We’ll use this version in the following discussions

13. Axelrod’s Computer Simulation of anIterated Prisoner’s Dilemma • Start with a large population of agents with different “strategies” • Repeatedly have each agent play each other many times • Sum up the total points scored by each agent • Remove the worst scoring agents (bottom 10%) from the population • Duplicate the best scoring agents (top 10%) and add those back to the population Repeat again from step one

14. Generation 1 Generation 3 Generation 6 D D C C D C C D C D D C D D D C D D D D D C D D D D D D D D Evolution of Population with Simple Strategies C = Always Cooperate D = Always Defect

15. Axelrod Asked Experts to Suggest More Complex Strategies • 14 people responded • Wide variety of different strategies • Axelrod added other strategies • Always cooperate • Always defect • Random choice

16. Early Generations • “Nice” agents (cooperate a lot) do poorly, • they are taken advantage of by “nasty” agents • “Nasty” agents (defect a lot) do well • take advantage of “nice” agents • Population ends with many “nasty” agents • Very few “nice” ones • Plus some mixed agents (do both C and D)

17. Middle Generations • Nasty agents spend most of their time defecting against other nasty agents • Each only gets 1 point • Mixed agents that can cooperate with other mixed agents do better • Provide they defect against other nasty agents • Long strings of 3 points from joint cooperation • Mixed agents grow and replace the nasty agents

18. Later Generations • Bad agents are all eliminated • Mixed agents dominate the population spending all their time cooperating with each other

19. Generation 1 Mid Generations D D M M D M C M M C M M D D M D C D M M M D D M M C D D M M Evolution of Population with More Complex Strategies Later Generations C = Nice agents D = Nasty agents M = Mixed C and D

20. Two Important Observation • There is no universal ideal strategy. • The best strategy for an agent always depends on the behavior characteristics of the rest of the population • Cooperation is hard to establish unless there are repeated interactions between agents • Implications to social policy and foreign policy

21. Real Life Example A real life example of spontaneous instances of cooperation during trench warfare in World War I • Troops of one side would shell the other side with mortars, but would often do so on a rigid schedule, and aim for a specific point in the other side's trenches, allowing the other side to minimize casualties. • The other side would reciprocate in kind. • The generals on both sides were satisfied that shelling was occurring and therefore the war was progressing satisfactorily, while the men in the trenches found a way to cooperatively protect themselves.

22. General Characteristics of Successful Cooperating Strategies • Nice • The most important condition is that the strategy must be "nice", that is, it will not defect before its opponent does. Almost all of the top-scoring strategies were nice. • Retaliating • A successful strategy must not be a blind optimist. It must always retaliate. An example of a non-retaliating strategy is Always Cooperate. This is a very bad choice, as “bad" strategies will ruthlessly exploit such softies. • Forgiving • Another quality of successful strategies is that they must be forgiving. Though they will retaliate, they will once again fall back to cooperating if the opponent does not continue to play defects. This stops long runs of revenge and counter-revenge, maximizing points. • Non-envious • The last quality is being non-envious, that is not striving to score more than the opponent (impossible for a ‘nice’ strategy, i.e., a 'nice' strategy can never score more than the opponent). In other words, be a “Provokable Nice Guy” – with forgiveness

23. Group Insiders and Outsiders Consider the following new situation • Most interactions are with a small group of other agents • Occasional interaction (non-repeating) with an agent outside the group Dominant strategy becomes: • Cooperate with group members • Defect against outsiders Social Cohesion

24. ReputationIndirect Reciprocal Altruism Consider a very large population • each agent only interacts with another given agent once or twice. • Leads to a un-cooperative (nasty) population But what if other agents can observe your past interactions with all other agents? • Leads to cooperating Tit-for-Tat populations again • Establishing a good “reputation” is key to an agent’s success • i.e. nice, retaliating, forgiving, non-envious • Note: Much of our casual conversation is about how other people behaved – about monitoring their reputation.

25. Ultimatum Game $1,000 Split between two people Person A: decides on the distribution • 50/50, 60/40, 80/20 etc… Person B: Accepts or rejects the offer • If rejected, neither person gets any money (One time single play in private, no iterations, no public observation of your behavior)

26. Ultimatum Game – cont. “Rational” game theory suggests that: Person A: Keeps $999, offers B $1 Person B: Accepts the offer • $1 is better than nothing • In reality, most people will offer 50% to 30% to person B • Most people acting as “person B” will reject any offer below ~20%-30% • There is a strong impulse to “punish” people if they decide on an unfair distribution. • Most people don’t really understand the implications of this being a single non-iterated event, or that it does not effect their reputation since it is done in private. • Punishing has become a very strong impulse for preserving cooperation, even at a cost to the punisher.

27. Have we been characterizing evolution wrong all these years? • Mutations • Natural Selection -> survival of the fittest • Development of Increased Cooperation The story of evolution has been a story of increasing levels of cooperation across all levels of biology.

28. Genes / DNA • Why don’t we have thousands of lose genes (DNA snippets) floating around in the cell nucleus? • Maybe early organisms did • And such DNA snippets tried to out reproduce each other, using up much of the cell’s resources • Putting them on a single DNA strand prevented this competition to independently reproduce. • A gene would only reproduce if the entire cell reproduced.

29. Eukaryotes • The transition to complex cells with internal structures • Incorporated mitochondria and chloroplasts into the internal cell structure • Both have their own DNA, and were probably separate creatures at one time

30. Multi-cell Organisms • Lichen is as far as this got with cells having different genetic material • More complex organisms have cells with identical genetic material • Most of these cells are “sterile” – they don’t reproduce • Only specialized stem cells reproduce. • This helps avoid competition between mutations.

31. Multi-cellular Organisms - cont. • And of course only a very small set of cells within a large organism can produce another organism. • For the vast majority of cells, they can only successfully reproduce if the entire organism reproduces. • This results in a complex division of labor with all the cells working together for the success of the organism

32. Large organisms have really become “colonies” of organisms in a cooperating relationship • There are 10x more bacteria cells that make up a functioning human body than there are “human cells”. • Mainly in your digestive system

33. Cooperation across the full spectrum of levelsEvery major advance in evolution of life has been an advance in cooperation at larger scales • Genetic level • Cellular level • Multi-cellular Organisms • Social: multiple multi-cellular organisms

34. Cooperation is very common among most animals and insects.

35. A picture of monkeys reminding us of the incredible benefits of cooperation….

37. The development of human levels of cooperation is a rare event. • It leads to increased communication, language, culture, shared knowledge…. • It only happened once in the history of life on Earth • It lead to a domination of the ecosystem

38. Most social evolution = cooperation at larger scales

39. Rethinking Market Economies • Competition is their fundamental element • Enabling cooperation between large groups is their fundamental element • Buyers / Sellers / Producers / Middle-men • The Modern Corporation

40. “Competition has been shown to be useful up to a certain point and no further, but cooperation, which is the thing we must strive for today, begins where competition leaves off.” –Franklin D. Roosevelt

41. Competition must always happen within a constraining cooperative effort. Unrestrained competition unsustainable

42. Competition can lead to poor results Race to the bottom: safety & environmental laws Wasteful consumption from status competition Overuse of common resources Competition within teams is generally bad Hiding information: Cancer research… Congress – government shutdown

43. Growing Cooperation

44. Cooperative open source revolution

45. Cooperation at greater levels International Trade International Treaties Scientific

46. Facebook 1.7B users ( larger than any nation )

47. Rethinking Market Economies Competition is the most important thing Competition and cooperation are both fundamentally important Actually, cooperation is becoming the most important thing