Slide 1:Evolution of Cooperation among Humans Rakesh Kumar Majhi School of Biological Sciences NISER, Bhubaneswar.


Slide 2:What is Science all about ???


Slide 3:Its all about asking The Right Question & ofcourse Trying to find an answer to it !!


Slide 4:HOW COULD COOPERATION EVOLVE AMONG HUMANS ?? Natural selection is conventionally assumed to favour the strong and selfish who maximize their own resources at the expense of others. But many biological systems, and especially human societies, are organized around altruistic, cooperative interactions.


WHAT IS THIS ALTRUISM ??? :WHAT IS THIS ALTRUISM ??? In the terminology based on Hamilton, Trivers and Wilson, an act is said to be altruistic if it is costly to perform but confers a benefit on another individual. WHY ARE WE BOTHERED ABOUT COSTS ??? In evolutionary biology, costs and benefits are measured in darwinian fitness, which means reproductive success.


How can Natural Selection promote Unselfish Behaviour ??? :How can Natural Selection promote Unselfish Behaviour ???


Slide 7:Cooperation is needed for evolution to construct new levels of organization. Genomes, cells, multicellular organisms, social insects, and human society are all based on cooperation. Cooperation means that selfish replicators forgo some of their reproductive potential to help one another. But Natural Selection implies competition and therefore opposes cooperation unless a specific mechanism is at work.


Why is this field under intensive study ???? :Why is this field under intensive study ????


Evolutionary Perspective: :Evolutionary Perspective: Evolutionary biologists are interested in the emergence of human societies, which constitutes the last (up to now) of the major transitions in evolution. Unlike other eusocial species, such as bees, ants or termites, humans display a large amount of cooperation between non-relatives.


Economic Perspective: :Economic Perspective: One-shot interactions between anonymous partners in a global market become increasingly frequent and tend to replace the traditional long-lasting associations and exchanges based on repeated give and take between relatives, neighours & members of same village. A substantial part of our life is spent in the company of strangers, and many transactions are no longer face-to-face. The growth of web-based auctions and other forms of e-commerce is built, to a considerable degree, on reputation and trust


Various mechanisms have been proposed, and a rich analysis of reciprocity has recently emerged: :Various mechanisms have been proposed, and a rich analysis of reciprocity has recently emerged: Direct reciprocity is captured in the principle: ‘You scratch my back, and I’ll scratch yours’ . But it is harder to make sense of the principle ‘You scratch my back and I’ll scratch someone else’s or ‘I scratch your back and someone else will scratch mine’ . Why should this work?


Slide 12:Presumably, I will not get my back scratched if it becomes known that I never scratch anybody else’s.


THERE ARE 5 RULES OF COOPERATION IN HUMANS : :THERE ARE 5 RULES OF COOPERATION IN HUMANS : Kin Selection Direct Reciprocity Indirect Reciprocity Network Reciprocity Group Selection


What is Kin Selection ??? :What is Kin Selection ??? J.B.S. Haldane had remarked, “I will jump into the river to save two brothers or eight cousins” . Hamilton formulated a rule basing on this that states : Natural Selection can favor cooperation if the donor and the recipient of an altruistic act are genetic relatives. Hamilton’s rule states that the coefficient of relatedness, r , must exceed the cost-to-benefit ratio of the altruistic act: r > c/b Relatedness is defined as the probability of sharing a gene. The probability that two brothers share the same gene by descent is 1/2; the same probability for cousins is 1/8. This introduces the concept of Selfish Genes .


What is Direct Reciprocity ??? :What is Direct Reciprocity ??? We also observe cooperation between unrelated individuals or even between members of different species. Trivers proposed another mechanism that led to formulation of repeated Prisoner’s Delimma. In every round, each player has a choice between cooperation and defection. If I cooperate now, you may cooperate later. Hence, it might pay off to cooperate. It assumes that there are repeated encounters between the same two individuals, and my behaviour depends on what you have done to me.


What is Indirect Reciprocity ??? :What is Indirect Reciprocity ??? Indirect reciprocity means that I help you & because of that Someone else helps me !!! Often the interactions among humans are asymmetric and fleeting. One person is in a position to help another, but there is no possibility for a direct reciprocation. We help strangers who are in need. We donate to charities that do not donate to us. Indirect reciprocity means there are repeated encounters within a group ; my behaviour also depends on what you have done to others.


What is Network Reciprocity ??? :What is Network Reciprocity ??? We have seen that Natural Selection favours Defectors in well mixed populations where everybody interacts equally likely with everybody else. But Real populations are not Well Mixed. Spatial structures or social networks imply that some individuals interact more often than others. A cooperator pays a cost, c, for each neighbor to receive a benefit, b. Defectors have no costs, and their neighbors receive no benefits. In this setting, cooperators can prevail by forming network clusters, where they help each other.


What is Group Selection ??? :What is Group Selection ??? Selection acts not only on individuals but also on groups. A group of cooperators might be more successful than a group of defectors. A population is subdivided into groups. Cooperators help others in their own group. Defectors do not help. Individuals reproduce proportional to their payoff. Offspring are added to the same group. If a group reaches a certain size, it can split into two. In this case, another group becomes extinct in order to constrain the total population size. There is competition between groups because some groups grow faster and split more often.


Conditions for the various types of Cooperation: :Conditions for the various types of Cooperation: Incase of Kin Selection, the coefficient of relatedness, r , must exceed the cost-to-benefit ratio of the altruistic act: r > c/b Direct reciprocity can lead to the evolution of cooperation only if the probability, w, of another encounter between the same two individuals exceeds the cost-to-benefit ratio of the altruistic act: w > c/b Indirect reciprocity can only promote cooperation if the probability, q, of knowing someone’s reputation exceeds the cost-to-benefit ratio of the altruistic act: q > c/b


Slide 20:For Network Reciprocity to favor cooperation, the benefit-to-cost ratio must exceed the average number of neighbors, k, per individual: b/c > k If n is the maximum group size and m is the number of groups, then group selection allows evolution of cooperation, provided that b/c > 1 + (n/m) SO ! THESE ARE THE MECHANISMS THAT FAVOUR EVOLUTION OF COOPERATION !!!


Slide 21:What makes Humans act Cooperatively , although Defecting would Provide them with immediate advantage ???? It is …………. Reputation !!!!! Reputation allows evolution of cooperation by indirect reciprocity. Natural selection favors strategies that base the decision to help on the reputation of the recipient.


Slide 22:What is the mechanism by which one gains reputation ????? It is through ……… Gossip !!!!!


Whats the Big Deal ??? :Whats the Big Deal ??? Although simple forms of indirect reciprocity can be found in animals, only humans seem to engage in the full complexity of the game. Language is needed to gain the information and spread the gossip associated with indirect reciprocity. Presumably, selection for indirect reciprocity and human language has played a decisive role in the evolution of human intelligence. Indirect reciprocity also leads to the evolution of morality and social norms.


Slide 24:Indirect reciprocity comes in two flavours: ‘Upstream reciprocity’ (left) is based on a recent positive experience. A person who has been at the receiving end of a donation may feel motivated to donate in turn. Individual B, who has just received help from A, goes on to help C. ‘Downstream reciprocity’ (right) is built on reputation. Individual A has helped B and therefore receives help from C.


Two Problems with Indirect Reciprocity: :Two Problems with Indirect Reciprocity: B has defected in previous rounds and therefore has a low reputation. a, If A does not help B, so as to punish B for previous defections, then why should the reputation of A be reduced? b, If A does help B, although B is a defector, then why should the reputation of A increase? Helping defectors destabilizes cooperation.


Slide 26:A discriminating donor using this assessment rule refuses help to a ‘bad’ recipient, and therefore becomes ‘bad’, which reduces the chance of being helped in turn. Effectively, discriminating players pay a cost for punishing bad co-players. Such a form of altruistic punishment can promote cooperation in the community, but at a cost to the punisher, and thus can be viewed as a social dilemma. In the absence of discriminators, defectors win against cooperators. In the absence of cooperators, defectors and discriminators form a bistable system. In the absence of defectors, discriminators and cooperators are in equilibrium.


What Could make Individuals more Cooperative ???? :What Could make Individuals more Cooperative ????


The Eyes Have It !!! :The Eyes Have It !!!


Slide 29:People paid nearly three times as much for their drinks when eyes were displayed rather than a control image. Why does an image of a pair of eyes motivate cooperative behaviour ? It has been argued that images of eyes motivate cooperative behaviour because they induce a perception in participants of being watched. Although participants were not actually observed in the experimental conditions, the human perceptual system contains neurons that respond selectively stimuli involving faces and eyes.


What could be a Prerequisite for Cooperative Behaviour ???? :What could be a Prerequisite for Cooperative Behaviour ???? A Good MEMORY !!! It seems reciprocity is practiced only by organisms that can keep track of those who are helpful and those who are not. Humans have a great memory for faces and thus can maintain life long good—or hard—feelings toward people they don’t see for years. Most other species exhibit reciprocity only over very short time scale, if at all.


What else Could induce Cooperation ??? :What else Could induce Cooperation ??? Punishment !!!!


Slide 32:It has been suggested that costly punishment promotes cooperation even in non-repeated games and without any possibility of reputation effects. But most of our interactions are repeated and reputation is always at stake. Thus, if costly punishment is important in promoting cooperation, it must do so in a repeated setting. The option of costly punishment increases the amount of cooperation but not the average payoff of the group. Furthermore, there is a strong negative correlation between total payoff and use of costly punishment. Those people who gain the highest total payoff tend not to use costly punishment: winners don’t punish.


Slide 33:The results therefore support the hypothesis that reputational concerns may be extremely powerful in motivating cooperative behaviour . If this interpretation is correct, then the self-interested motive of reputation maintenance may be sufficient to explain cooperation in the absence of direct return. But then Why did Costly Punishment Evolve ?


Slide 34:Costly punishment might have evolved for reasons other than promoting cooperation, such as coercing individuals into submission and establishing dominance hierarchies. Punishment might enable a group to exert control over individual behaviour. Stronger individual could use punishment to dominate weaker ones. Costly punishment might force people to submit, but not to cooperate. The use of costly punishment in games of cooperation seems to be maladaptive. It has been shown that in the framework of direct reciprocity, winners do not use costly punishment, whereas losers punish and perish.


Why do People still Punish ?? :Why do People still Punish ?? High caudate activation seems to be responsible for a high willingness to punish, which suggests that caudate activation reflects the anticipated satisfaction from punishing defectors. Caudate activation is important because this brain region has been implicated in making decisions & taking actions that are motivated by anticipated rewards.


Has Simmilar studies been done to identify sites responsive to other actions? :Has Simmilar studies been done to identify sites responsive to other actions? Functional Magnetic Image Resonance of Ultimatum Game Players was done to examine neural substrates of cognitive and emotional processes involved in economic decision-making. Players were scanned as they responded to fair and unfair proposals. Unfair offers elicited activity in brain areas related to both emotion (anterior insula) and cognition (dorsolateral prefrontal cortex). Further, significantly heightened activity in anterior insula for rejected unfair offers suggests an important role for emotions in decision-making. (A) Map of the t statistic for the contrast [unfair human offer – fair human offer] showing activation of bilateral anterior insula and anterior cingulate cortex. Areas in orange showed greater activation following unfair as compared with fair offers . (B) Showing activation of right dorsolateral prefrontal cortex.


Slide 37:Ultimatum Game: In the Ultimatum Game, two players are given the opportunity to split a sum of money. One player is deemed the proposer and the other, the responder. The proposer makes an offer as to how this money should be split between the two. The second player can either accept or reject this offer. If it is accepted, the money is split as proposed, but if the responder rejects the offer, then neither player receives anything. In either event, the game is over.


How could one Ape among many ---Humans--- could become so radically different ???? :How could one Ape among many ---Humans--- could become so radically different ????


Bcoz of The Waiting Game ??? :Bcoz of The Waiting Game ??? To many researchers, our ability to trade immediate gratification for long-term rewards sets us apart from other, more impulsive animals. Without patience, activities from planting crops for later harvest to sending space probes to Mars would be impossible. Most studies suggest that animals have alow tolerance for delayed gratification. When offered a choice between two food pellets immediately or six pellets later, pigeons will wait only about 3.5 seconds for the larger reward. Rats are only slightly less impulsive in similar tests, and even monkeys seem to live largely in the present & can resist for only 14 sec.


Slide 40:In new studies, aimed at measuring how long our closest relatives, chimpanzees and bonobos, would play the waiting game : The apes were placed in an apparatus designed to give them a choice between two grape halves immediately or six grape halves later. Bonobos accepted a delay of about 74 seconds, whereas chimpanzees sweated out a full 2 minutes to get the larger reward — although they did a lot of fidgeting and head-scratching while they waited. The experiment shows that a capacity for delayed gratification was already present in the common ancestor of humans and apes!!!


Do Chimpanzees share a lot of characters with Humans??? :Do Chimpanzees share a lot of characters with Humans??? Although Chimpanzees may be quite Patient, yet they donot lend a helping hand to neighbours without expecting anything in return. However, the marmosets are about equally generous to genetically unrelated monkeys as they were to their kin.


Why do marmosets and humans engage in spontaneous altruism when other primates do not ? :Why do marmosets and humans engage in spontaneous altruism when other primates do not ? This may be attributed to the Role of Cooperative Breeding !!! Unlike other Primates, the children of marmosets & humans are taken care of not only by their parents, but also by other unrelated adults. Marmoset groups consist of a breeding pair plus an assortment of other helpers, whereas human parents often get help from grandparents, siblings, and friends. In humans, these altruistic tendencies, along with more advanced cognition, then nurtured the evolution of theory of mind.


Is there any field where Humans Stand Alone ??? :Is there any field where Humans Stand Alone ??? Its ………… Cultural innovations !!!! Although Chimps & other Primates show traits of Rudimentary Culture like the use of different tols for cracking nuts, the level of complexiy is unique to Humans !!!


What accounts for this cultural gap ? :What accounts for this cultural gap ? Other primates are poor at imitating others and learning from them. Humans, in contrast, are such good imitators that they accumulate culture and knowledge over generations, a “ratcheting” effect that bootstraps the slow pace of biological evolution with a powerful dose of cultural evolution.


Arent we underestimating Chimps capability to imitate??? :Arent we underestimating Chimps capability to imitate??? Whiten and his co-workers tied a length of fishing line to a lever so that they could surreptitiously pull it to deliver a grape. Yet when 12 chimps were exposed to this “ghost” apparatus, none learned to pull the lever themselves. The team concluded that chimps could only learn to use the machine if taught by another chimp or a human— through social learning or imitation.


So why aren’t humans always ‘generous, hopeful and forgiving’ ?? :So why aren’t humans always ‘generous, hopeful and forgiving’ ?? Part of the explanation is that cooperation is never a stable state. Mathematical studies show that cooperation is constantly challenged by defection. In a society of defectors, where no-one helps, a cluster of cooperation can emerge, if a few people switch to tit-for-tat . If I play tit-for-tat, I do whatever you have done to me. Tit-for-tat can’t persist for long, because its appetite for revenge is self-destructive. It is soon replaced by ‘generous tit-for-tat ’.


Slide 47:Here I cooperate whenever you have cooperated, but sometimes I cooperate even if you have defected. i.e. I am forgiving. For a while, cooperation thrives. But in a generous tit-for-tat population, the emergence of unconditional cooperators eventually invites the invasion of defectors. This process leads to cycles of cooperation and defection, which account, in part, for the mix of cooperators and defectors that persists in human societies.


What’s the Winning Stratergy ?? :What’s the Winning Stratergy ?? Mathematical analysis shows that winning strategies tend to be generous, hopeful and forgiving. Generous here means not seeking to get more than one’s opponent; Hopeful, means cooperating in the first move or in the absence of information; and Forgiving, means attempting to reestablish cooperation after an accidental defection. If I am willing to let others have a slightly bigger share of the pie, then people will want to share pies with me !!!


Conclusions : :Conclusions : We know that The Two Fundamental Principles involved in Evolution are Mutation & Natural Selection. But Evolution is Constructive because of Cooperation. New levels of Cooperation evolve when competeting units in the lower levels begin to cooperate. Cooperation allows specialization and thereby promotes biological diversity.


Conclusions (Cont.)‏ :Conclusions (Cont.)‏ Perhaps the most remarkable aspect of evolution is its ability to generate cooperation in a competitive world. Thus, we might add “ natural cooperation” as a third fundamental principle of evolution beside mutation and natural selection.


My Views : :My Views : The Desire to Punish (like Millitancy & Naxalism) is harming the Cooperator, Defector & the Punisher alike. Humans create their own environment whereas animals adapt to their environment. The level of Cooperation that exists among humans has placed Humans at an advantage over other Species. However major defections like Corruption, Frauds are threatening the stability of Cooperative institutions.


Slide 52:Working together in a institution like NISER, we should maximize Cooperation through Group Selection. Hope this presentation will motivate you in that direction!! However there is a need to have better interpersonal relations not just through Direct Reciprocity but also through Indirect Reciprocity. Cooperation among NISERites & that between NISER & other Research institutions will maximize benefits.


References: :References: Nowak Martin A, Sigmund Karl, Evolution of indirect reciprocity, Nature 437, 1291 (2005). Dreber Anna, Rand David G., Fudenberg Drew & Nowak Martin A, Winners don’t punish, Nature 452, 348 (2008). Nowak Martin A, Five Rules for the Evolution of Cooperation , Science 314, 1560 (2006). Dominique J.-F. de Quervain, et al., The Neural Basis of Altruistic Punishment , Science 305, 1254 (2004). Alan G. Sanfey, et al., The Neural Basis of Economic Decision-Making in the Ultimatum Game, Science 300, 1755 (2003).


Slide 54:Henrich Joseph, Cooperation, Punishment, and the Evolution of Human Institutions, Science 312, 60 (2006). Pennici Elizabeth, How did Cooperative Behaviour evolve?, Science 309, 93 (2005). Nowak, M. A. & Sigmund, K., Evolution of indirect reciprocity by image scoring, Nature 393, 573 (1998). Bshary, R. & Grutter, A. S., Image scoring and cooperation in a cleaner fish mutualism, Nature 441, 975–978 (2006). Bateson, M., Nettle, D. & Roberts, G., Cues of being watched enhance cooperation in a real-world setting. Biol. Lett. 2, 412–414 (2006).


Slide 55:Nowak Martin A., Generosity: A winner’s advice, Nature 456, 7222 (2008). Vogel Gretchen, Evolution of the Golden Rule, Science 303, 1128 (2004). Fowler James H., Schreiber Darren, Biology, Politics, and the Emerging Science of Human Nature, Science 322, 912 (2008). Boyd Robert, The Puzzle of Human Sociality, Science 314, 1555 (2006). Balter Michael, Why We’re Different: Probing the Gap Between Apes and Humans, Science 319, 404 (2008).


Aknowledgements : :Aknowledgements : My Sincere thanks to: Dr. Anita Roy Dr. Palok Aich Mr. Arnab Saha Mr. Swagat Sanket Priyadarshan


: Please send u'r feedbacks to: rakesh@niser.ac.in Thank You All !!