game theory

The Quest for Meaning in Public Choice

One Sentence Summary:
Frameworks, composed of theories that are in turn composed of varying models need to be developed to study and make predictions about the complex behaviors that take place in social situations.
Disciplines:
Economics
Sociology
Psychology
Findings:
  • With incomplete information and information-processing capabilities, individuals competing for common-pool resources may make mistakes in choosing strategies designed to realize a set of goals.
  • Communication and sanctioning mechanisms among potentially competing members of a community competing for common-pool resources increases the efficiency and stability of resource exploitation.
  • A shared culture—generally accepted norms of behavior, common understanding, homogeneity of preferences and resources—improves the probability that a community will develop adequate rules and norms to govern the use of resources.
  • The transmission of culture, rules, and norms through information, knowledge, and skills across generations is a challenge for the stability of open, democratic, self-governing societies over time.
Keywords:
civil society
communication
competition
cooperation
game theory
group forming networks
property rights
public goods
sharing economy
Author(s) / Editor(s):
Published in:
American Journal of Economics and Sociology, vol. 63, issue 1, pages 105-147
Date:
January 2004
One Paragraph Summary:

A useful Institutional Analysis and Development (IAD) framework has evolved under the leadership of the Ostroms and their colleagues at Indiana University for over two decades. It has been applied with success in laboratory experiments on social behavior and in field studies and has enabled the creation of useful models with predictive value in diverse situations. Some results from the application of the IAD framework have lead to suggestions for effective use of common resources and norms for community decision making. The importance of effective communication and sanctioning mechanisms in effective community governance has become clear from the use of the framework.

One Page Summary:

The Institutional Analysis and Development (IAD) framework developed by the Ostroms and their colleagues at Indiana University provides a foundation for studying a multitude of theories, models, and predictions of public choice behaviors in different systems of governance and organization.

Frameworks define the action arena to which it would be applied; the resulting patterns of interactions and outcomes, and the means of evaluating those outcomes.

A framework is a general language about how varying rules, physical and material conditions, and attributes of a community affect the structure of action arenas, the incentives for actors, and resulting outcomes.

Action arenas include an action situation and the actors in that situation.

An action situation includes:

  • Participants
  • Positions
  • Outcomes
  • Action-outcome linkages
  • Control that participants exercise
  • Information
  • Cost and benefits of outcomes

Actors (individual or corporate) involve:

  • Resources brought to the situation
  • Values assigned to states of the world
  • Methods for dealing with knowledge and information
  • Selection processes for courses of action

Analysts can make strong predictions in tightly constrained situations of complete information: overuse of resources in an open commons where the actors do not share access to collective choice arenas.

Results are not as clear in situations where actors are embedded in communities with norms of fairness and conservation as well as the ability to communicate with each other.

Evaluation criteria can include a range of values for categories such as the following:

  • Economic efficiency
  • Fiscal equity among actors
  • Redistributional equity (e.g., policies to care for poorer individuals
  • Accountability
  • Conformance to a general morality
  • Adaptability to change

The IAD framework has been applied to various domains to make predictions of resulting behaviors in field settings. Examples of successful application include:

  • Police services
  • Urban public services in general
  • Common-pool resources: these were studied in laboratory as well as field settings. The IAD framework was used to create a theory of behavior. Communication of participants affects behavior: if no communication was permitted, the results approximated that of non-cooperative game theory. Communication led to different, more positive, results.
  • The IAD framework was used to develop extensive databases coding common-pool resources and diverse property regimes.

The Evolutionary Stability of Cooperation

One Sentence Summary:
Given a variety of strategies ranging from cooperative to combative, cooperative retaliatory strategies tend to be the most stable but remain vulnerable to invasion.
Disciplines:
Political Science
Sociology
Findings:
  • All strategies in iterative prisoner's dilemma games are vulnerable to invasion and therefore inherently unstable.
  • Tit-for-Tat (cooperative) strategies are the most stable. These strategies can withstand higher levels of invasion by competing strategies.
  • All strategies have a threshold of stability, if a certain percentage of the population adopts these strategies they can be self-maintaining.
Keywords:
cultural evolution
equilibrium
evolution
game theory
prisoners dilemma
reciprocity
tit-for-tat
Author(s) / Editor(s):
Published in:
Journal
Date:
June 1997
One Paragraph Summary:

Previous theorists had been divided regarding the stability of Tit-for-tat strategies in prisoners Dilemma gaming. Bendor and Swistak show, through seven theorems, that all strategies can be overwhelmed. There are, however, thresholds of stability where certain nice and retaliatory strategies can withstand large invasions of alternative strategies. At sufficient strength a strategy can either overwhelm the invader, support subcultures of strategy, or co-opt in the invader to a given level of invasion. Even nice and retaliatory strategies have a breakdown point, however. The authors conclude that the anything less than 100% cooperation would be inherently unstable.

One Page Summary:

Theorists have posited that pure tit-for-tat strategies in iterative prisoners dilemma games were invulnerable. Is this correct? The authors seek to answer this question by examining the ability of various prisoners dilemma gaming strategies to withstand invasion by other competing strategies.

Bender and Swistak examine a gaming strategy universe that includes the strategies:

  • Tit for tat - a player will initially cooperate and then in future rounds mimic the behavior of their opponent.
  • Tit for 2 Tats - a player will cooperate for the first two rounds and then defect in rounds where their opponent defected in the previous two.
  • Suspicious Tit for Tat - a player will initially defect and then will mimic their opponent in future rounds.
  • Always Defect
  • Always Cooperate
  • Grim Trigger - Begin by cooperating, if opponent defects then always defect afterward.

These strategies were examined in pure conditions where only one existed, and then competing strategies were introduced. If a given strategy could withstand incursions by competing strategies it was deemed "stable".

Stability proved to be a continuum. All strategies proved to have points of equilibrium. At this point, a strategy can withstand its maximum level of incursion. That point is that strategy's maximum stability.

The Evolution of Strategies in the Iterated Prisoner's Dilemma

One Sentence Summary:
The genetic algorithm uses computer simulations to evolve different strategies for playing Prisoner's Dilemma games, and by observing the interactions of populations of agents over many runs, it is possible to make useful observations that could generalize to human behavior – such as the tendency of reciprocation to establish itself and spread if cooperating agents are able to encounter one another.
Disciplines:
Biology
Computer Science
Economics
Political Science
Information
Findings:
  • Genetic algorithms, developed for complexity and artificial life research, can be used to evolve strategies for playing Prisoner's Dilemma games that are well-adapted to different environments, and thus can be a probe of possible dynamics of human cooperation.
  • From a random start, populations of Prisoner's Dilemma strategies evolve away from cooperation to less cooperative rules, but after a number of runs, those players that reciprocate when encountering cooperation lock into mutually beneficial reciprocal cooperation: reciprocity, once established, can spread through a population that is originally dominated by non-cooperative strategies.
  • Genetic algorithms are highly effective method of searching for successful strategies in very large possibility spaces.
Keywords:
agent-based model
complexity
evolution
game theory
prisoners dilemma
reciprocity
tit-for-tat
Author(s) / Editor(s):
Date:
1987
One Paragraph Summary:

John Holland at University of Michigan developed a means of testing computer problem-solving methods by applying a method based on Darwinian evolution: agents (program) have a phenotype (the strategy the program uses for problem solving) and a genotype (the way strategies are represented in their programming code). Means of reproduction and mutation are specified. Agents interact with each other in a rigorously specified simulation, and the effectiveness of each agent is evaluated in a particular environment in relation to its interactions with other agents; successful strategies are reproduced at a higher rate than less successful strategies; pairs of successful offspring strategies are mated by combining genetic material; mutation is introduced. Simulations can be halted after specified numbers of runs and analyzed, then restarted. In about a quarter of simulation runs with sexual reproduction, better strategies than Tit-for-Tat evolved, and after a random start, populations tend to first evolve away from cooperation as less cooperative rules succeed more often, but can evolve back toward stable cooperation states if cooperative strategies encounter one another and reciprocate.

Social Science at 190 MPH on NASCAR's Biggest Speedways

One Sentence Summary:
NASCAR race draft line formations and dissolutions can serve as an example for cooperation and competition in other social domains.
Disciplines:
Economics
Sociology
Findings:
  • NASCAR drivers form and re-form into draft lines to take advantage of aerodynamic phenomena to gain an edge in competitions with other drivers who have basically equivalent automotive equipment. 'Draft partnerships' are necessary to get ahead; however, they must be abandoned strategically to win. Within a race, at high speeds, there is an ever-shifting pattern of cooperation and competition among rivals. This is a reflection of an important, desirable American trait: how to compete by doing a good job of cooperating.
  • If you don't cooperate (i.e., enter into draft lines) you will lose. However, if you don't 'defect' from deals at the right times (e.g., 'bump and run'), dissolving opportunistic partnerships, you will lose as well.
  • Reputations and trust are earned over time. Veterans rarely want to partner with rookies.
Keywords:
group forming networks
game theory
cooperation
complexity
competition
Author(s) / Editor(s):
Published in:
First Monday, Volume 5, Number 2
Date:
February 2000
One Paragraph Summary:

NASCAR drivers form and re-form into draft lines to take advantage of aerodynamic phenomena to gain an edge in competitions with other drivers who have basically equivalent automotive equipment. 'Draft partnerships' are necessary to get ahead; however, they must be abandoned strategically to win. Within a race, at high speeds, there is an ever-shifting pattern of cooperation and competition among rivals. This is a reflection of an important, desirable American trait: how to compete by doing a good job of cooperating. Essential to success in drafting are trust, acquired over time, and an effective communication support structure through networks of representatives (spotters). Complexity theory, social network analysis, and game theory are used to analyze the behaviors. The lessons are applied in other social domains.

One Page Summary:

NASCAR race draft line formations and dissolutions can serve as an example for cooperation and competition in other social domains.

NASCAR drivers form and re-form into draft lines to take advantage of aerodynamic phenomena to gain an edge in competitions with other drivers who have basically equivalent automotive equipment. 'Draft partnerships' are necessary to get ahead; however, they must be abandoned strategically to win. Within a race, at high speeds, there is an ever-shifting pattern of cooperation and competition among rivals. This is a reflection of an important, desirable American trait: how to compete by doing a good job of cooperating. Essential to success in drafting are trust, acquired over time, and an effective communication support structure through networks of representatives (spotters). Complexity theory, social network analysis, and game theory are used to analyze the behaviors. The lessons are applied in other social domains.

Communication via radio with intermediaries acting as agents (i.e., spotters) who negotiate with the intermediaries for other drivers is essential. Negotiations and deals need to be made rapidly. While deals may be cut before the race, most partnering emerges on the fly in consultation with spotters who have a larger picture of what's happening in the race. Interpersonal communication, dealmaking, and diplomatic skills may be as important as driving technique.

Partnerships are formed with trusted collaborators/competitors. Reputations are gained over time. Betrayals are remembered for years.

Veterans rarely want to partner with 'rookies'. Newcomers need to earn the confidence of the more experienced competitors.

Social science theories can be used to analyze the draft line behaviors:

  • Complexity theory: racers self-organize into structures that oscillate between order and chaos.
  • Social network analysis: draft lines are networks whose organization depends on drivers' social (interpersonal and relational properties) and human (personal properties) capital.
  • Game theory: drafting is a 'prisoner's dilemma' problem with incentives for cooperation and betrayal.

NASCAR drafting may be used as a metaphor in other domains. Examples cited include:

  • Career advancement in corporate circles: executives take along selected staff and lower-ranking executives as he or she advances, but defections from these draft lines are also common at strategic times.
  • International diplomatic and military alliances.
  • The Internet, in both its technical and social structures. Communication techniques allow the formation and re-formation of cooperating coalitions.

Six-Degrees: The Science of a Connected Age

One Sentence Summary:
Healthy social, technical, biological and professional networks are built on cooperative frameworks that enable them to quickly spread information and phenomena regardless of beneficial or malicious intent; this appears to be a deep structural characteristic of "small-world" or "scale-free" networks that have a relatively small number of hubs that enable extensive interconnectivity across large numbers of nodes.
Disciplines:
Biology
Business
Anthropology
History
Cultural Evolution
Computer Science
Technology
Physics
Economics
Political Science
Sociology
Psychology
Information
Mathematics
Findings:
  • 'Six-degrees' type separation spans social, physical, and mental distances.
  • Social networks have certain degrees of discord, but are recognized and utilized by people via group associations that make up our social identities.
  • For individuals, separations of more than two degrees nearly equate to being strangers.
  • For the transmission of ideas, fashion, or viruses, six degrees can nearly equate to being directly linked.
  • Throughout most networks, ideas promulgate via clusters who spread information or infection to other clusters through shared membership or proximity (or “shortcuts”).
  • Thoughts or ideas remain benign or contained until their natural growth reaches a critical threshold or phase transition; at this point they either die out or overwhelm the population.
  • Common networks can be simultaneously vulnerable and robust. This can be a strength, allowing the network to change and adapt to new information or threats. However these characteristics can also rapidly transmit contagions throughout the network and overwhelm it.
Keywords:
networks
interdependence
hierarchy
group forming networks
game theory
evolution
equilibrium
cultural evolution
cooperation
communication
Author(s) / Editor(s):
Published in:
Norton Press
Date:
2003
One Paragraph Summary:

Author Duncan Watts helped found the science of network theory. In Six Degrees he describes the evolution of the science. This narrative covers each step in the philosophical evolution to provide the reader with the context as well as the numbers behind the findings. Starting with Milgram's six-degrees studies from the 1950s as a base, they investigate the small-world problem and identify the mechanisms by which networks operate. They conclude that the solution to the small world problem reveals a series of balancing acts. Depending on context, people are either extremely connected or perceptually fragmented; networks are robust or fragile; and ambiguity can create opportunity or be a harbinger of a network's demise.

One Page Summary:

Six Degrees begins in the beginning. Stanley Milgram's initial small world studies are analyzed. His findings in seeing if a group of people in Nebraska can get a letter to someone in Massachusetts are scrutinized. Milgram left a puzzle. Mathematically, six degrees of separation can be shown and intuitively it is appealing. But do social networks actually work that way?

Initially, Watts steps into the world of pure mathematic theory. Graph theory and random graphs are employed to build potential worlds in which connections can be made. These tools are detailed and their histories explained.

Watts and his colleagues then take the science to new levels, by introducing sociology, epidemiology, economics, and business models into this new multi-disciplinary science. Immediately, each new field of study brings with it new insights into network dynamics.

This convergence of disciplines reveals the social, transportation and technological networks that make up our world. These networks are, ultimately, made up of individuals. Individuals in turn relate back to the networks and define how they operate.

Socially, people relate to their network by clustering. Clusters are logical organizations of network elements. In a social context, we might cluster in terms of a religion, a favorite author, a school we are attending or an affinity for a type of food. Some of these have very close physical distance, while others have a social distance with members spread out over a large area.

Networks of this type are, to various extents, “scale-free” networks. If graphed these networks roughly follow a classic power law trend where the level of connectivity between two nodes in a network increases dramatically as more nodes are connected. Real-world scale-free networks tend to have highly connected hubs which rapidly, purposely, and efficiently transmit pertinent or pervasive content from one location to another. In social circles, these are networkers. In the airline network these are hub airports. In traffic they would be freeway interchanges.

Due to this architecture, the Internet and modern air transport have combined to greatly decrease the role of proximity in our social networks. This has had great impacts on commerce, tourism, cultural sensitivity and other social factors. However, it has also led to great risks in the transmission of diseases, sensitivity to distant economic fluctuations, and rapid spread of misinformation.

These dynamics create a type of network that Duncan calls simultaneously robust and vulnerable. Their strength and weakness is that, with rapid transmission from cluster to cluster, anything can move quickly from one location or group to another. He uses the example of Toyota, whose network of suppliers was organized in such a way as to quickly compensate for and recover from a potential economic catastrophe.

Stable scale-free networks do not rely on a rigid hierarchy to provide direction in times of crisis. Rather, the structure of the network itself can rapidly respond to an unforeseen situation.

Their network was arranged in such a way as to foster and reward communication. This communication helped cope with ambiguous or unplanned situations. Rather than paralyzing Toyota while people waited for a decision from a rigid hierarchy, the contractors in the network were able to analyze the calamity and provide a rapid response to it.

As mentioned above, this robustness also rapidly transmits malicious content as well. The Melissa Virus, SARS and Ebola are analyzed to show why the network did or did not transmit them and, when it did, how they eventually died out.

Watts ends this book by summarizing that the multidimensional nature of social distance is sometimes counterintuitive and subjective. People can feel close in a network sense to people they are physically distant from and, conversely, socially distant from people physically nearby.

He continues by warning that social and physical distances have shrunk. People can quickly travel from place to place and economies are highly interdependent. The sheer number of dependencies in the modern world may yield surprising results from seemingly insignificant actions.

He finishes by showing the stability of our networks with the example of how New York adapted to the 9-11 attacks. The City bounced back to semi-normal operations within a week. During the disaster, the best laid plans of emergency operations staff were scuttled by the utter unavailability of facilities and services designed to copy with disasters. The network will provide.

Nature's Magic: Synergy In Evolution And the Fate of Humankind

One Sentence Summary:
Synergies that convey advantages drive and accelerate biological and cultural evolution by providing a package of independent elements that confer benefits many times greater than those conferred by individual elements: in biology, synergies of independently evolved traits can lead to the development of the power of flight or the emergence of humans as the dominant species; in humans, complex, coordinated activity over sustained periods leverages the power of physical tools, cultural discoveries, and social organization.
Disciplines:
Biology
Economics
Findings:
  • Synergy, "the combined or cooperative effects produced by the relationships among various forces, particles, elements, parts, or individuals in a given context – effects that are not otherwise possible," is a key driver of biological and human cultural evolution by providing immediately useful packages of benefits.
  • Certain packages of different traits, strategies, tools, norms – such as those involved with the emergence of group foraging or, much later, agriculture convey such powerful immediate survival advantages on the human groups that use them that social-cultural change happens far more quickly than it would through Darwinian evolution.
  • Human cooperation leverages synergies of tools, knowledge about the environment, social and cultural practices, to economic advantage – the payoff for cooperation for a group is high enough to overcome the individual resistance and other barriers to bringing the elements together.
  • There are at least five, perhaps more, distinct paths to cooperation and complexity in biological evolution: altruism, reciprocity, functional interdependence, mutualism, and parasitism.
Keywords:
altruism
bioeconomy
cooperation
cultural evolution
ecology
evolution
game theory
Author(s) / Editor(s):
Published in:
Cambridge University Press
Date:
2003
One Paragraph Summary:

The differential survival of packages of interdependent components, organisms, or people leads to the emergence of higher-level self-interests that transcend the interests of the parts and convey amplified benefits to the aggregation of components, from the symbiotic origins of mitochondria and chloroplasts to symbiotic microorganisms in the digestive systems of ruminants and humans, to social insects, to the evolutionary leap from tree-dwelling primates to savanna-dwelling humans. Cooperative synergies at the level of the cell, organism, species, and ecology have been central, not peripheral to the evolution of life. The evolution of human cultural traits such as social complexity, language, social foraging, the use of fire and cultural transmission of tool use and implement creation, settled agriculture, invention of technologies and symbolic communication of means for inventing technologies was both driven by synergies and necessitated new social arrangements that led to new synergies. Synergetic arrangements can be tested by removing any one element and observing whether the aggregate organism, ecology, or society can continue to exist without it.

One Page Summary:

Bacteria colonies that migrate and forage and form joint structures via chemical signaling, social insects that engage in joint problem solving behaviors via chemical signaling, symbiotic relationships between ruminants from termites to cattle with cellulose-digesting bacteria, Margulis' evidence for the symbiogenesis of mitochondria and hypthoses that flagella originated from the joining of free-swimming spirochetes with energy-producing but less-mobile microorganisms, the probably evolution of flight from a suite of synergistic functional changes, the emergence of protohumans are all cited by Corning as evidence that synergies play a central, not a peripheral role in evolution of complex life forms: "Synergy has played a key role in the progressive evolution of complex systems in nature. However, complexity is not an end in itself; it's a consequence of the innovations that produce more potent forms of synergy. Synergy is the 'driver.'"

William E. Hamilton's papers on "The Genetical Evolution of Social Behavior" in 1964 formalized the neo-Darwinian explanation of altruistic behavior as conferring benefits on close kin, but Robert Trivers' 1964 "Evolution of Reciprocal Altruism" decoupled kinship, cooperation, and altruism by offering evidence that the helping organism acts with the assumption that low-cost, low-risk assistance to another now will be repaid later – reciprocity.

Game theoretic models were driven to more realistically match human and biological behavior than Axelrod's and Hamilton's models when zoologist Martin Nowak and mathematician Karl Sigmund created "Pavlov," a Prisoner's Dilemma strategy based on "win-stay, lose-shift" that introduces punishment. Corning objects to inclusive fitness theory, reciprocal altruism, tit-for-tat as adequate explanatory frameworks because they exclude interactions that provide synergistic combined effects and are self-policing because they are interdependent – the way two oarsman are interdependent when trying to cross a river if they each have one oar. Corning claims "The intellectual fascination of the Prisoner's Dilemma game may have led us to overestimate its evolutionary importance."

Rejecting single-cause "prime mover" hypotheses for either biological or cultural evolution, Corning lists "five maybe six distinct paths to cooperation and complexity in evolution:" altruism, reciprocity, functional interdependence, mutualism, and parasitism.

In regard to humans, Corning points to specific probable synergistic packages that enabled proto-humans to evolve from tree-dwelling primates, for language to evolve as an adaptation on precursors, for hunting and gathering culture to dominate and spread, for fire use to be culturally maintained, and for settled agriculture to take root and replace nomadic foraging and hunting as the dominant human form of social organization. Asking how a small, lightweight primate that can't fly or run very fast, lacking natural defensive weapons, but having bipedal gait, manipulative hands, omnivorous digestive system and large brain managed to shift to an earthbound habitat, broaden its resource base, and expand its range, Corning proposes that "In a patchy but relatively abundant woodland environment that was also replete with predators, competitors , and sometimes hostile groups of conspecifics, group foraging and collective defense/offense was the most cost-effective strategy. There were immediate payoffs (synergies) for collective action that did not have to await the plodding pace of natural selection….There may well have been group selection, but it was not based on altruism. It involved what the economists call 'collective goods' or 'public goods.'"

Corning agrees with Jared Diamond that the emergence of agricultural civilization, empires, and wars of conquest in the fertile crescent 10,000 years ago was due to what Diamond himself called a "package" of ecological circumstances and cultural inventions that worked together synergistically: domesticated, genetically altered plants and animals, draft animals, technologies for plowing, cutting, threshing, grinding, food transport and storage, cooking, processing hides and fibers, sewing, manufacturing tools of stone, bone, and wood, as well as access to reliable fresh water sources, abundant fuel, long-distance trade, and defense against raiders. As a result, ten to one hundred times more people can be fed from one acre than from hunting-gathering, and a settled lifestyle permitted a reduction of the spacing of births from a four year separation among nomads to two years, leading to rapid population growth.

Corning cites contemporary examples of synergistic cultural evolution involving the creation of new forms of collective action, together with new toolsets. The Igorot people of the remote mountains of Luzon, in the Philippines, use a vast, elaborate, intricately constructed combination of terraces, dams, canals, and ponds to grow rice sustainably and with remarkable efficiency. It was originally thought that the system was thousands of years old, but anthropologist Charles Drucker turned up evidence indicating that lowlanders who had practiced slash-and-burn agriculture for millennia were forced to migrate to the highlands when Spanish invaders seized choice lowlands. The sustainable high yields of Igorot rice farming depends on constant replenishment of soil nitrogen in places where there is not a natural abundant supply. The Igorot use ponds of blue-green algae that live in symbiosis with the rice plants, receiving carbon dioxide from the rice in exchange for fixing nitrogen. In order to use and maintain this new, complex technological and ecological system the former slash-and-burn lowlanders had to invent a new social and political system involving the disciplined coordination of many family groups.

The Great Basin Shoshone of North America, studied by Julian Steward in the 1930s, forage in very small family groups, with plants providing 80% of their calories. In winter, however, several families gather in larger camps near an abundant resource and trade information, teach each other skills, and find mates. During rabbit drives, groups of 75 or more coordinate efforts deploying nets hundreds of feet long. A division of labor is temporarily established between net holders and beaters, under the supervision of a temporary rabbit boss.

Work by Gintis, Bowles, Fehr and Gächter indicate that strong reciprocity among humans is egoistic, not altruistic or cooperative, and depends on aggressive punishment of cheaters. This is related to work by Boyd and Richerson on group-serving norms of "fairness." Corning notes: "…the principle of fairness came to play a central role in reconciling conflicting claims of self-interest within the groups/bands/tribes that were indisipensable to our ancestors' survival and reproductive success over many thousands of generations."

How To Cope With Noise in the Iterated Prisoner's Dilemma

One Sentence Summary:
The Tit-for-Tat strategy is vulnerable to noise – errors in implementing choices – that can lead to echoing defections, but can be made less sensitive by adding generosity (occasionally refraining from punishing defection by opponent) and contrition (refraining from punishing a reaction to accidental defection.)"
Disciplines:
Biology
Computer Science
Economics
Political Science
Findings:
  • Random errors in implementing strategies is common in the real world ("noise"), and Tit-for-Tat is sensitive to noise because echoes of a mistake (a defection that was meant to be a cooperation) can continue indefinitely.
  • An article in Nature, 1993 (Nowak& Sigmund, "Strategy of Win-Stay, Lose Shift That Outperforms Tit-for-Tat," 364: 56-58) highlighted a strategy that also applies to real-world situations – defectors can shift partners until they find those that are exploitable, and cooperators can shift partners until they find co-cooperators.
Keywords:
agent-based model
complexity
cooperation
game theory
reciprocity
tit-for-tat
prisoners dilemma
Author(s) / Editor(s):
Published in:
Journal of Conflict Resolution 39, No. 1: 183-189
Date:
March 1995
One Paragraph Summary:

Axelrod became concerned with the problem of noise – mistaken defections in Prisoner's Dilemma games that can lead to echoing repetitions – during the Cuban Missile crisis. Adding generosity and contrition to Tit-for-Tat and reimplementing the 63 rules of the original iterated Prisoner's Dilemma tournament proved to be an effective way of coping with noise; Win-Stay, Lose-Shift did not do as well in such an environment. Axelrod was able to put Soviet and US nuclear strategists together to play Prisoner's Dilemma in 1988 for an audience of social scientists -- with noise deliberately introduced. This tournament was the basis for Axelrod's statement that "Noise calls for forgiveness, but too much forgiveness invites exploitation." The authors also noted: "Generosity can correct an error by either player, but contrition can only correct one's own error. Thus, when the population of strategies one is likely to meet has not adapted to the presence of noise, a strategy like Generous Tit-for-Tat is likely to be effective. On the other hand, if the strategies of the other players one is likely to meet have already adapted to noise, then a strategy like Contrite Tit-for-Tat is likely to be even more effective because it can correct its own errors and restore mutual cooperation almost immediately."

Foundations of Human Sociality (Introduction and Overview)

One Sentence Summary:
Experiments like the Ultimatum Game and the Public Goods Game (one shot games for real money divided among strangers) that have been conducted in different countries all over the world have shown that group behavior frequently does not fit the traditional model of self-interested actors, that it is too richly varied between cultures to support a universal sense of fairness, and that a higher degree of market integration and higher payoffs to cooperation can be linked to greater levels of prosocial behavior.
Disciplines:
Economics
Sociology
Psychology
Findings:
  • People are willing to reward fairness and reciprocity and punish those who do not act pro-socially, even at cost to themselves.
  • Group-level differences in behavior proved to be greater than individual-level differences, indicating cooperative behavior might be more embedded in cultural conditions than was previously thought. While one culture might take advantage of a person who is too altruistic, another might exclude a person for being too self-interested.
Keywords:
trust
reputation
reciprocity
public goods
prisoners dilemma
game theory
equilibrium
cultural evolution
cooperation
communication
assurance game
altruism
Published in:
Oxford University Press
Date:
2004
One Paragraph Summary:

The self-regarding and outcome oriented picture of human behavior presented in traditional economics does not explain why humans care so much about each other and about how social interaction is carried out, not just the end goals. The Ultimatum Game, designed by Werner Guth, is just one illustration of how real people will not always follow the dictates of self-interested rationality. Two subjects are given a sum of money, one is given the power to divide the sum, and the other can either accept or reject (in which case neither get any money). Research from conducting hundreds of trials of the game with thousands of students in Europe, Japan and the USA has shown that the responders frequently reject low offers and proposers frequently propose near equal divisions, even though it is to their monetary disadvantage. While early experiments on undergraduates seemed to suggest that there was a universal sense of fairness, extended research in different cultures (hunter-gatherers, slash-and-burn agriculturists, nomadic pastoralists) has exposed much cultural variation in responses, indicating that local cultural conditions play an important role in how people approach cooperation.

One Page Summary:

The self-regarding and outcome oriented picture of human behavior presented in traditional economics does not explain why humans care so much about each other and about how social interaction is carried out, not just the end goals. The Ultimatum Game, designed by Werner Guth, is just one illustration of how real people will not always follow the dictates of self-interested rationality. Two subjects are given a sum of money, one is given the power to divide the sum, and the other can either accept or reject (in which case neither get any money). Research from conducting hundreds of trials of the game with thousands of students in Europe, Japan and the USA has shown that the responders frequently reject low offers and proposers frequently propose near equal divisions, even though it is to their monetary disadvantage. While early experiments on undergraduates seemed to suggest that there was a universal sense of fairness, extended research in different cultures (hunter-gatherers, slash-and-burn agriculturists, nomadic pastoralists) has exposed much cultural variation in responses, indicating that local cultural conditions play an important role in how people approach cooperation.

While mean proposals for university students from all over the world was usually between 42 and 48 percent, mean proposals from this cross-cultural study varied from 25 to 57 percent. Rejection rates, the action of the responders, also varied considerable between groups. Individual-level economic and demographic variables did not explain behavior as well as group-level behavior, and game play often could be connected to the people's common patterns of interaction. For example, the Orma recognized that one of the experiment's games was similar to the harambee, a local institution of giving to public goods like roads and schools. They began calling it 'the harambee game' and displayed highly prosocial behavior. In other groups, like the Au and Gnau, frequent rejection of generous offers can be explained by a cultural association with gift-giving: accumulating gifts, even if unsolicited, can imply a lowered status and force the receiver into future obligations or political alliance. The cross-cultural study showed that, in the case of groups at the extremes of behavior, "contrasting behaviors seem to reflect their differing patterns of everyday life, not any underlying logic of hunter-gatherer life ways."

The effect of market integration on cooperation to obtain a monetary reward can be explained easily: individuals from market-oriented societies when put in the context of one of the games are able to seek analogues in their daily activities of using and trading money with strangers. "Those who do not customarily deal with strangers in mutually advantageous ways may be more likely to treat anonymous interactions as hostile or threatening, or as occasions for the opportunistic pursuit of self-interest."

Evolution of Indirect Reciprocity

One Sentence Summary:
Cooperation through indirect reciprocity, captured by the phrase "I help you, someone else helps me", requires the evolution of reputations and communication of those reputations among the larger group (as in the human instinct to gossip), cognitive abilities beyond being able to identify relatives (required for kin selection) or the individuals who have cooperated with you in the past (required for direct reciprocity).
Disciplines:
Economics
Sociology
Psychology
Findings:
  • "The hypothesis that more information leads to more cooperation has been confirmed in experiments, which compare three information conditions. In one condition, players have no information about their co-players; in the second they are told about what their co-players have decided when last in the role of a donor; and in the third they also know about the score of the recipient of the co-player. We note that this is not always enough to decide whether a previous defection was justified or not. However, the additional knowledge did enhance cooperation."
  • "Indirect reciprocity is situated somewhere between direct reciprocity and public goods. On the one hand it is a game between two players only, the donor and the recipient, but on the other hand it has to be played within a larger group. Richard Alexander claimed that indirect reciprocity originates from direct reciprocity in the presence of interested audiences."
  • "It is easy to conceive that an organism experiences as 'good' or 'bad' anything that affects the organism's own reproductive fitness in a positive or negative sense. The step from there to judging, as 'good' or 'bad', actions between third parties, is not obvious. The same terms 'good' and 'bad' that are applied to pleasure and pain are also used for moral judgements: this linguistic quirk reveals an astonishing degree of empathy, and reflects highly developed faculties for cognition and abstraction."
  • Even a group of players with discriminating strategies can be sidetracked by imperfect transfer of reputation information, as in unfounded rumors or exaggeration: "if players have different views about the reputation of others, then errors in perception can undermine cooperation."
  • In empirical studies, discriminating players are sensitive to their own score: "players who justifiably refuse to donate to a defector show an increased tendency to provide donations in the following round, as if to make up for that refusal. This indicates that they expect their refusal to lower their score in the co-players' eyes and that they do not rely on the community's understanding."
Keywords:
agent-based model
altruism
assurance game
communication
cooperation
equilibrium
game theory
language
norms
prisoners dilemma
public goods
punishment
reciprocity
reputation
tit-for-tat
trust
Author(s) / Editor(s):
Published in:
Nature 437, 1291-1298
Date:
October 27, 2005
One Paragraph Summary:

Cooperation through indirect reciprocity, can be captured by the phrase "I help you, someone else helps me". Indirect reciprocity helps explain how cooperation is possible at all when economic transactions move beyond small villages where one can easily keep track of one's interactions with everyone else. The success of strategies of indirect reciprocity in empirical studies might be attributable to the fact that humans care so deeply not only about how they are treated, but about the results of interactions between third parties. This concern and the desire to communicate concerns, or gossip, might in turn be explained by evolutionary psychology and the benefits of cooperation in large groups, surpluses resulting from division of labor. To test strategies of indirect reciprocity no two players can interact more than once and the scores of players (the portion of times they have cooperated with others) must be visible. A player choosing a simple version of indirect reciprocity will only cooperate with those whose score is above a certain threshold. However, this player might be punishing another player using indirect reciprocity who has only interacted with defectors. "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." A more sophisticated strategy would have a player discriminate between justified defection (defecting to punish someone who always defects) and unjustified defection (defecting regardless of the recipients reputation). This strategy avoids the case where a group of players who always cooperate is invaded by a group of players who always defect, but it requires the cognitive abilities to keep track of interactions that are far removed from one's own.

Coalitional Effects on Reciprical Fairness in the Ultimatum Game: A Case from the Ecuadorian Amazon

One Sentence Summary:
Patton attributes differences between two Ecuadorian ethnic/political groups in their willingness to cooperate in the Ultimatum Game to the groups' "differences in coalitional stability, perceptions of trust, and needs to maintain reputation," and emphasizes properties of the groups' political environment over individual differences.
Disciplines:
Anthropology
Political Science
Findings:
  • Market integration in nonwesternized cultures might have had a negative impact on cooperation by introducing unequal access to goods and conflict between western institutions and local nonhierarchical structures. The more market-integrated group (and the one described as more cooperative), the Quichua, proposed significantly smaller divisions compared to the Achuar. This poses a counterexample to a hypothesis presented in the Overview to this book, that market integration means frequent interactions and a familiarization with the process of cooperating with strangers, which translates into cooperation in the Ultimatum Game.
  • The most important factor in cooperation during the game was group coalition strength, over the much less significant or near significant factors of sex, age, and social status. Alarmingly high homicide rates among males in the area magnify the importance of coalition strength. "Coalitional instability undermines one's ability to condition future play, and discounts the benefits derived from investing in the creation and maintenance of a reputation as a fair player."
  • Longstanding habits of reciprocal fairness that flourish in politically stable environments overrode factors that would otherwise tempt self-interested behavior, such as the anonymous and one-shot properties of this Ultimatum Game.
Keywords:
reciprocity
game theory
cooperation
capitalism
assurance game
altruism
reputation
social capital
trust
Author(s) / Editor(s):
Published in:
Oxford University Press
Date:
2004
One Paragraph Summary:

This study examined patterns of cooperative behavior of two ethnic/political groups in Conambo of the Ecuadorian Amazon, the Achuar and the Quichua, with the Ultimatum Game. The participants were randomly divided into proposers and responders. Proposers were told to divide 20 coins worth a total of a days labor (approximately $3.85) into two piles, one for them and one for the responders. The proposer then left the room and a responder was brought in, not knowing the identity of their proposer, and asked to accept or reject the division (rejection of the division entailed no money for either participant, aside from the 5 coins given to all at the start for their time). A successive pile technique was used to determine the alliance strength of all participants. Informants were asked to divide photographs of the participants according to who would be most reliable in maintaining a coalition during a conflict. The researchers found that proposers with higher average alliance strength gave more generous offers and that the Achuar, with higher average alliance strength, had an average proposal of 42.9 percent, while the Quichua, with lower average alliance strength, had an average proposal of 24.6 percent. "The relationship between average alliance strength and amounts offered appears to be a group effect rather than an individual effect."

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