Evolution of indirect reciprocity

In the paper

“After a couple of rounds the personal experience obtained with the given co-player becomes more decisive 62 .”

What the sources say

• Disputed

  The Design of the experiment section (page unavailable) says that no two subjects were paired more than once and that subjects knew this. Its design therefore rules out gaining experience with a given co-player over several rounds; the paper instead studies decisions based on information about a new partner’s past actions. (LLM, conf=0.89)

  Checked by a reasoning model — may be wrong.

  cites [62] Bolton, G. E., Katok, E. & Ockenfels, A. Cooperation among strangers with limited information about reputation. J. Public Econ. 89, 1457–1468 (2005) sourceExperimental — accuracy not yet measured

In the paper

“In this sense, the step from direct to indirect reciprocity corresponds simply to the step from personal enforcement to community enforcement 26-29 .”

What the sources say

• ?Not checked — no full text of the sourcecites [26] Binmore, K. Fun and Games: A Text on Game Theory (Heath, Lexington, Massachusetts, 1992)
• ?Not checked — no full text of the sourcecites [27] Rosenthal, R. W. Sequences of games with varying opponents. Econometrica 47, 1353–1366 (1979) source
• Supported

  The Introduction (page not provided) defines personal enforcement as retaliation by the victim and community enforcement as sanctions by other members after dishonesty toward a partner. That distinction supports the claimed correspondence between direct and indirect reciprocity. (LLM, conf=0.92)

  cites [28] Kandori, M. Social norms and community enforcement. Rev. Econ. Stud. 59, 63–80 (1992) source
• Supported

  The Introduction contrasts cooperation sustained by personal retaliation between the same two players with cooperation sustained by contagious punishments that spread through an anonymously matched population. This supports the claimed correspondence between direct versus indirect responses and personal versus community enforcement, although the paper uses different terminology. (LLM, conf=0.85)

  cites [29] Ellison, G. Cooperation in the prisoner's dilemma with anonymous random matching. Rev. Econ. Stud. 61, 567–588 (1994) source

In the paper

“The growth of e-auctions and other forms of e-commerce is based, to a considerable degree, on reputation and trust 5-10 .”

What the sources say

• Supported

  The Introduction says many online markets rely on electronic reputation systems to promote trust in transactions. It also describes feedback systems used by eBay and other platforms, supporting the claim's broad point about e-auctions and e-commerce. (LLM, conf=0.88)

  cites [5] Bolton, G. E., Katok, E. & Ockenfels, A. How effective are electronic reputation mechanisms? An experimental investigation. Manage. Sci. 50, 1587–1602 (2004) source
• Supported

  The Introduction says trust may play a critical role in developing the Internet as a marketplace. It also describes reputation systems used by online markets to increase trust between trading partners, including in e-auctions. This supports the claim's broad characterization without asserting a measured contribution to growth. (LLM, conf=0.90)

  cites [6] Keser, C. Trust and reputation building in e-commerce. IBM Watson Research Center, CIRANO working paper no. 2002s-75 http://www.cirano.qc.ca/en/publication_detail.php?id=2002s-75 (2002).
• ?Not checked — no full text of the sourcecites [7] Dellarocas, C. Sanctioning reputation mechanisms in online trading environments with moral hazard. MIT Sloan School of Management working paper no. 4297–03 http://ssrn.com/abstract=393043 (2003). source
• ?Not checked — no full text of the sourcecites [8] Bolton, G., Katok, E. & Ockenfels, A. in Applications of Supply Chain Management and e-Commerce Research (eds Geunes, J., Akcali, E., Pardalos, P. M., Romeijn, H. E. & Shen, Z.-J.) 195–216 (Springer, Dordrecht, 2005) source
• Supported

  In the section labeled “MARC MONGEAU” (page not provided), the paper says reputation systems help people decide whom to trust online and describes eBay’s high rate of successful transactions despite substantial risks. It also describes reputation systems used by online retailers beyond auction sites, supporting the broad claim that reputation and trust underpin these forms of e-commerce. (LLM, conf=0.84)

  cites [9] Resnick, P., Zeckhauser, R., Friedman, E. & Kuwabara, K. Reputation systems. Commun. ACM 43, 45–48 (2000) source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [10] Lucking-Reiley, D., Bryan, D., Prasad, N. & Reeves, D. Pennies from eBay: The Determinants of Price in Online Auctions. Vanderbilt Univ., Univ. Arizona working paper (1999).

In the paper

“A more sophisticated assessment rule should distinguish between justified and unjustified defection, and thus take into account the score of the receiver: someone withholding help from a 'bad' player should not pay with a reduced score 35,38,39,47 .”

What the sources say

• ?Not checked — no full text of the sourcecites [35] Nowak, M. A. & Sigmund, K. A strategy of win-stay, lose-shift that outperforms tit-for-tat in the prisoner's dilemma game. Nature 364, 56–58 (1993) source
• ?Not checked — no full text of the sourcecites [38] Ferrière, R. Help and you shall be helped. Nature 393, 517–519 (1998) source
• ?Not checked — no full text of the sourcecites [39] Leimar, O. & Hammerstein, P. Evolution of cooperation through indirect reciprocation. Proc. R. Soc. Lond. B 268, 745–753 (2001) source
• Partly supported

  In “Bifurcation Through Reputation” (page unavailable), the paper models cooperators defecting against known nonpunishers, so a coplayer’s reputation can affect the decision to help. It does not describe an assessment rule that distinguishes justified from unjustified defection or say that withholding help from a bad player leaves the donor’s score unchanged. (LLM, conf=0.78)

  cites [47] Sigmund, K., Hauert, C. & Nowak, M. A. Reward and punishment. Proc. Natl Acad. Sci. USA 98, 10757–10762 (2001) sourceExperimental — accuracy not yet measured

In the paper

“A stable mix of discriminating and undiscriminating altruists which cannot be invaded by defectors, is also obtained by assuming that as players grow older, their social network grows, and with it their information about their co-players' past 54,55 .”

What the sources say

• ?Could not verify

  Split into 2 atoms — 0 confirmed, 0 partially supported, 0 disputed, 0 misattributed, 2 unverifiable. Expand the claim to see per-atom verdicts.

  cites [54] Brandt, H. & Sigmund, K. The logic of reprobation: Assessment and action rules for indirect reciprocity. J. Theor. Biol. 231, 475–486 (2004) sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [55] Mohtashemi, M. & Mui, L. Evolution of indirect reciprocity by social information: The role of trust and reputation in evolution of altruism. J. Theor. Biol. 223, 523–531 (2003) source

In the paper

“But if players have different views about the reputation of others, then errors in perception can undermine cooperation 56 .”

What the sources say

• Supported

  In Results and Discussion (p. 4), the paper explains that incomplete information and misperception make reputation-based standing strategies difficult to use. It also reports that a standing strategy performed much less well under errors of perception, supporting the claim that differing information about reputations can undermine cooperation. (LLM, conf=0.87)

  cites [56] Brandt, H. & Sigmund, K. Indirect reciprocity, image scoring, and moral hazard. Proc. Natl Acad. Sci. USA 102, 2666–2670 (2005) source

In the paper

“Such a population structure, however, facilitates the evolution of altruism via group selection 56 .”

What the sources say

• ?Could not verify

  The Continuous-Entry Model for Indirect Reciprocity (pp. 2–3) analyzes reputation and information within a population, not group selection. Searches for separate groups, exchange, and migration found no passage addressing whether that population structure facilitates altruism. (LLM, conf=0.73)

  cites [56] Brandt, H. & Sigmund, K. Indirect reciprocity, image scoring, and moral hazard. Proc. Natl Acad. Sci. USA 102, 2666–2670 (2005) sourceExperimental — accuracy not yet measured

In the paper

“A good strategy for the latter is Observer Tit For Tat 35,68 .”

What the sources say

• ?Not checked — no full text of the sourcecites [35] Nowak, M. A. & Sigmund, K. A strategy of win-stay, lose-shift that outperforms tit-for-tat in the prisoner's dilemma game. Nature 364, 56–58 (1993) source
• ?Could not verify

  The Introduction describes a third person observing an investment and potentially rewarding the investor, while the Discussion compares indirect with direct reward. Neither passage evaluates a strategy for interested audiences. Searches for “Observer Tit For Tat” and an observing-and-reciprocating strategy found no passage addressing that claim. (LLM, conf=0.72)

  cites [68] Güth, W., Königstein, M., Marchand, N. & Nehring, K. Trust and reciprocity in the investment game with indirect reward. Homo Oecon. 18, 241–262 (2001) sourceExperimental — accuracy not yet measured

In the paper

“For example, donors are more generous if they learn that the recipient has recently made a donation to a charitable institution 72 .”

What the sources say

• ?Could not verify

  The Results and dictator-game passages report transfers and punishment, but do not say whether recipients had previously donated to charity or whether donors learned of such donations. Searches for “donation to a charitable institution” and “recipient donated charity” found no passage addressing the claimed effect. (LLM, conf=0.76)

  cites [72] Fehr, E. & Fischbacher, U. Third party punishment and social norms. Evol. Hum. Behav. 25, 63–87 (2004) sourceExperimental — accuracy not yet measured

In the paper

“Random fluctuations, however, make their frequencies drift up and down.”

In the paper

“In a remarkable calculation, Ohtsuki & Iwasa 41,48 analysed all 4096 strategies and proved that only 8 of them are evolutionarily stable under certain conditions, the so called 'leading eight'.”

What the sources say

• ?Not checked — no full text of the sourcecites [41] Nowak, M. A. & Sigmund, K. The dynamics of indirect reciprocity. J. Theor. Biol. 194, 561–574 (1998) source
• Not checked yetcites [48] Sugden, R. The Economics of Rights, Cooperation and Welfare (Blackwell, Oxford, 1986)

In the paper

“For stochastic population dynamics, the time average of the evolutionary oscillations can be centred on discriminators.”

In the paper

“In the absence of cooperators, defectors and discriminators form a bi-stable system: depending on the initial condition, either one or the other strategy wins.”

In the paper

“In the absence of defectors, discriminators and cooperators are in equilibrium.”

In the paper

“Game theory shows that cooperation can be sustained in the indirect reciprocity game if each player carries a label 27 .”

What the sources say

• ?Not checked — no full text of the sourcecites [27] Rosenthal, R. W. Sequences of games with varying opponents. Econometrica 47, 1353–1366 (1979) source

In the paper

“If the frequency is too low, defectors win.”

In the paper

“If the discriminators are sufficiently frequent, all three strategies coexist.”

In the paper

“The equilibria can be invaded by defectors if the frequency of discriminators is below a certain threshold.”

In the paper

“In the absence of discriminators, defectors win against cooperators.”

In the paper

“With all three strategies present, the dynamics lead either to defectors only or to a mixture of the two kinds of altruists.”

In the paper

“In each case, a long series of random fluctuations may eventually destroy the coexistence of the three strategies.”

In the paper

“If all three types are present in the population, the system displays two types of behaviour.”

In the paper

“If errors occur, or if an intended donation cannot be implemented through lack of resources, discriminating and undiscriminating altruists reach, in the absence of defectors, a stable coexistence with a well-defined frequency of discriminators.”

In the paper

“In the deterministic model, only the emergence of other conditional strategies can save cooperation in the long run 76 .”

What the sources say

• ?Not checked — no full text of the sourcecites [76] Fehr, E. Don't lose your reputation. Nature 432, 449–450 (2004) source

In the paper

“If the players meet randomly, however, or the social network is fluid, then upstream reciprocity is too diffuse to prevent defectors from taking over 2,55 .”

What the sources say

• Not checked yetcites [2] Alexander, R. D. The Biology of Moral Systems (Aldine de Gruyter, New York, 1987)
• ?Not checked — no full text of the sourcecites [55] Mohtashemi, M. & Mui, L. Evolution of indirect reciprocity by social information: The role of trust and reputation in evolution of altruism. J. Theor. Biol. 223, 523–531 (2003) source

In the paper

“Computer simulations and mathematical investigations of indirect reciprocity show that natural selection can favour strategies that help others based on their reputation.”

In the paper

“If players are arranged in closed loops, for instance: A gives B, who gives C, who gives D, who gives A again, cooperation can be stable, provided the loops are very short and the number of rounds sufficiently high 81,82 .”

What the sources say

• Not checked yetcites [81] Camerer, C. E. Behavioral Game Theory (Princeton Univ. Press, Princeton, 2003)
• ?Not checked — no full text of the sourcecites [82] Colman, A. M. Game Theory and its Applications in the Social and Biological Sciences (Butterworth-Heinemann, Oxford, 1995)

In the paper

“But first we note, in a wider context, that indirect reciprocity seems to require a 'theory of mind' 20 .”

What the sources say

• ?Not checked — no full text of the sourcecites [20] Whiten, A. & Byrne, R. W. (eds) Machiavellian Intelligence II: Extensions and Evaluations (Cambridge Univ. Press, Cambridge, UK, 1997) source

In the paper

“The simulations display occasional bursts of defection, which are based on a previous build-up of undiscriminating altruists.”

What the sources say

• ?Not checked — no full text of the sourcecites [35] Nowak, M. A. & Sigmund, K. A strategy of win-stay, lose-shift that outperforms tit-for-tat in the prisoner's dilemma game. Nature 364, 56–58 (1993) source
• ?Not checked — no full text of the sourcecites [38] Ferrière, R. Help and you shall be helped. Nature 393, 517–519 (1998) source
• ?Not checked — no full text of the sourcecites [39] Leimar, O. & Hammerstein, P. Evolution of cooperation through indirect reciprocation. Proc. R. Soc. Lond. B 268, 745–753 (2001) source

In the paper

“In the resulting population, help is channelled towards those who help 35-37 .”

What the sources say

• ?Not checked — no full text of the sourcecites [35] Nowak, M. A. & Sigmund, K. A strategy of win-stay, lose-shift that outperforms tit-for-tat in the prisoner's dilemma game. Nature 364, 56–58 (1993) source
• ?Not checked — no full text of the sourcecites [36] Nowak, M. A. & Sigmund, K. Evolution of indirect reciprocity by image scoring. Nature 393, 573–577 (1998) source
• ?Not checked — no full text of the sourcecites [37] Wedekind, C. Give and ye shall be recognized. Science 280, 2070–2071 (1998) source

In the paper

“Intriguingly, humans not only feel strongly about interactions which involve them directly, they also judge the actions between third parties, as evidenced by the contents of gossip 18 .”

What the sources say

• ?Not checked — no full text of the sourcecites [18] Dunbar, R. Grooming, Gossip and the Evolution of Language (Harvard Univ. Press, Cambridge, Massachusetts, 1996)

In the paper

“One is the paradoxical nature of the discriminating strategy.”

In the paper

“A considerable part of human cooperation is based on moralistic emotions - for instance, anger directed towards cheaters, or the proverbial 'warm inner glow' felt after performing an altruistic action.”

In the paper

“Individual-based simulations show that if the cost-to-benefit ratio is sufficiently low, and the amount of information about the co-player's past sufficiently high, cooperation based on discrimination can emerge.”

What the sources say

• ?Not checked — no full text of the sourcecites [35] Nowak, M. A. & Sigmund, K. A strategy of win-stay, lose-shift that outperforms tit-for-tat in the prisoner's dilemma game. Nature 364, 56–58 (1993) source
• ?Not checked — no full text of the sourcecites [36] Nowak, M. A. & Sigmund, K. Evolution of indirect reciprocity by image scoring. Nature 393, 573–577 (1998) source
• ?Not checked — no full text of the sourcecites [37] Wedekind, C. Give and ye shall be recognized. Science 280, 2070–2071 (1998) source

In the paper

“This yields the payoff structure of the familiar Prisoner's Dilemma game 21 .”

What the sources say

• Not checked yetcites [21] Axelrod, R. The Evolution of Cooperation (Reprinted by Penguin, Harmondsworth, 1989.) (Basic Books, New York, 1984)

In the paper

“Thus indirect reciprocity is likely to be connected with the origins of moral norms.”

In the paper

“A rational player would have to weigh the benefit of exploiting the co-player in one round against the cost of forfeiting collaboration in all future rounds, and thus would abstain from defection.”

In the paper

“The payoff-maximising move consists in defecting (Fig 1).”

In the paper

“Clearly, trigger strategies can still ensure a cooperative Nash equilibrium, such that if all players use them, no player would have an incentive to deviate.”

In the paper

“In a population of discriminators, unconditional cooperators can increase by random drift and eventually invite the invasion of defectors.”

What the sources say

• ?Not checked — no full text of the sourcecites [35] Nowak, M. A. & Sigmund, K. A strategy of win-stay, lose-shift that outperforms tit-for-tat in the prisoner's dilemma game. Nature 364, 56–58 (1993) source
• ?Not checked — no full text of the sourcecites [38] Ferrière, R. Help and you shall be helped. Nature 393, 517–519 (1998) source
• ?Not checked — no full text of the sourcecites [39] Leimar, O. & Hammerstein, P. Evolution of cooperation through indirect reciprocation. Proc. R. Soc. Lond. B 268, 745–753 (2001) source

In the paper

“Experiments and everyday experience alike show that what Adam Smith called 'our instinct to trade, barter and truck' relies to a considerable part on the widespread tendency to return helpful or harmful acts in kind. We do so even if these acts have been directed not to us but to others.”

In the paper

“The second issue concerns the lack of stability of the cooperative outcome.”

What the sources say

• ?Not checked — no full text of the sourcecites [35] Nowak, M. A. & Sigmund, K. A strategy of win-stay, lose-shift that outperforms tit-for-tat in the prisoner's dilemma game. Nature 364, 56–58 (1993) source
• ?Not checked — no full text of the sourcecites [38] Ferrière, R. Help and you shall be helped. Nature 393, 517–519 (1998) source
• ?Not checked — no full text of the sourcecites [39] Leimar, O. & Hammerstein, P. Evolution of cooperation through indirect reciprocation. Proc. R. Soc. Lond. B 268, 745–753 (2001) source

In the paper

“All eight of these strategies distinguish justified from unjustified defections.”

What the sources say

• ?Not checked — no full text of the sourcecites [41] Nowak, M. A. & Sigmund, K. The dynamics of indirect reciprocity. J. Theor. Biol. 194, 561–574 (1998) source

In the paper

“In this case, the very fact that individuals are not perfect and sometimes defect involuntarily promotes the stability of cooperation 49 .”

What the sources say

• ?Not checked — no full text of the sourcecites [49] Ohtsuki, H. & Iwasa, Y. The leading eight: social norms that can maintain cooperation by indirect reciprocity. J. Theor. Biol.(in the press) source

In the paper

“If their frequency exceeds a certain threshold, defectors can invade and take over.”

What the sources say

• ?Not checked — no full text of the sourcecites [39] Leimar, O. & Hammerstein, P. Evolution of cooperation through indirect reciprocation. Proc. R. Soc. Lond. B 268, 745–753 (2001) source
• ?Not checked — no full text of the sourcecites [49] Ohtsuki, H. & Iwasa, Y. The leading eight: social norms that can maintain cooperation by indirect reciprocity. J. Theor. Biol.(in the press) source
• ?Not checked — no full text of the sourcecites [50] Lotem, A., Fishman, M. A. & Stone, L. Evolution of cooperation between individuals. Nature 400, 226–227 (1999) source
• ?Not checked — no full text of the sourcecites [51] Lotem, A., Fishman, M. A. & Stone, L. Evolution of unconditional altruism through signalling benefits. Proc. R. Soc. Lond. B 270, 199–205 (2002) source
• ?Not checked — no full text of the sourcecites [52] Fishman, M. A., Lotem, A. & Stone, L. Heterogeneity stabilises reciprocal altruism interaction. J. Theor. Biol. 209, 87–95 (2001) source

In the paper

“If such a consensual assessment can be achieved, the corresponding strategy is robust 38,39,41 .”

What the sources say

• ?Not checked — no full text of the sourcecites [38] Ferrière, R. Help and you shall be helped. Nature 393, 517–519 (1998) source
• ?Not checked — no full text of the sourcecites [39] Leimar, O. & Hammerstein, P. Evolution of cooperation through indirect reciprocation. Proc. R. Soc. Lond. B 268, 745–753 (2001) source
• ?Not checked — no full text of the sourcecites [41] Nowak, M. A. & Sigmund, K. The dynamics of indirect reciprocity. J. Theor. Biol. 194, 561–574 (1998) source

In the paper

“This property must hold for any strategy which maintains cooperation, eliminates cheaters and can overcome errors 48 .”

What the sources say

• Not checked yetcites [48] Sugden, R. The Economics of Rights, Cooperation and Welfare (Blackwell, Oxford, 1986)

In the paper

“Not if players have the same reputation in the eyes of all members of their population.”

In the paper

“This mixture can be vulnerable to the invasion of defectors 39,40 .”

What the sources say

• ?Not checked — no full text of the sourcecites [39] Leimar, O. & Hammerstein, P. Evolution of cooperation through indirect reciprocation. Proc. R. Soc. Lond. B 268, 745–753 (2001) source
• ?Not checked — no full text of the sourcecites [40] Panchanathan, K. & Boyd, R. A tale of two defectors: The importance of standing for evolution of indirect reciprocity. J. Theor. Biol. 224, 115–126 (2003) source

In the paper

“The problem with the concept of justified defection, however, is that it requires information, not only about the past of the co-player, but also the past of the co-player's co-players, and their co-players etc 35,39 .”

What the sources say

• ?Not checked — no full text of the sourcecites [35] Nowak, M. A. & Sigmund, K. A strategy of win-stay, lose-shift that outperforms tit-for-tat in the prisoner's dilemma game. Nature 364, 56–58 (1993) source
• ?Not checked — no full text of the sourcecites [39] Leimar, O. & Hammerstein, P. Evolution of cooperation through indirect reciprocation. Proc. R. Soc. Lond. B 268, 745–753 (2001) source

In the paper

“Such private lists of the scores of co-players are very plausible if individual interactions are only observed by a fraction of the population 35 .”

What the sources say

• ?Not checked — no full text of the sourcecites [35] Nowak, M. A. & Sigmund, K. A strategy of win-stay, lose-shift that outperforms tit-for-tat in the prisoner's dilemma game. Nature 364, 56–58 (1993) source

In the paper

“Again the stability of cooperation is threatened by unconditional altruists who merely wish to keep their own good score.”

In the paper

“The situation is altered in a significant way if players occasionally fail to cooperate although their strategy prescribes it 39,49-52 .”

What the sources say

• ?Not checked — no full text of the sourcecites [39] Leimar, O. & Hammerstein, P. Evolution of cooperation through indirect reciprocation. Proc. R. Soc. Lond. B 268, 745–753 (2001) source
• ?Not checked — no full text of the sourcecites [49] Ohtsuki, H. & Iwasa, Y. The leading eight: social norms that can maintain cooperation by indirect reciprocity. J. Theor. Biol.(in the press) source
• ?Not checked — no full text of the sourcecites [50] Lotem, A., Fishman, M. A. & Stone, L. Evolution of cooperation between individuals. Nature 400, 226–227 (1999) source
• ?Not checked — no full text of the sourcecites [51] Lotem, A., Fishman, M. A. & Stone, L. Evolution of unconditional altruism through signalling benefits. Proc. R. Soc. Lond. B 270, 199–205 (2002) source
• ?Not checked — no full text of the sourcecites [52] Fishman, M. A., Lotem, A. & Stone, L. Heterogeneity stabilises reciprocal altruism interaction. J. Theor. Biol. 209, 87–95 (2001) source

In the paper

“Effectively, discriminating players pay a cost for punishing bad coplayers.”

In the paper

“Nonetheless, the statistics of such games with full information look surprisingly similar to those obtained when players know only the score of the recipient.”

What the sources say

• ?Not checked — no full text of the sourcecites [64] Engelmann, D. & Fischbacher, U. Indirect reciprocity and strategic reputation building in an experimental helping game. Univ. Zürich working paper no. 132 http://www.iew.unizh.ch/wp/iewwp132.pdf (2002). source

In the paper

“People are nicer to others if third parties were nicer to them.”

What the sources say

• ?Not checked — no full text of the sourcecites [58] Wilson, D. S. A theory of group selection. Proc. Natl Acad. Sci. USA 72, 143–146 (1975) source
• ?Not checked — no full text of the sourcecites [63] Wedekind, C. & Braithwaite, V. A. The long-term benefits of human generosity in indirect reciprocity. Curr. Biol. 12, 1012–1015 (2002) source

In the paper

“The hypothesis that more information leads to more cooperation has been confirmed in experiments which compare three information conditions 61 .”

What the sources say

• ?Not checked — no full text of the sourcecites [61] Haley, K. J. & Kessler, D. M. T. Nobody is watching?: Subtle cues affect generosity in an anonymous economic game. Evol. Hum. Behav. 26, 245–256 (2005) source

In the paper

“For many players, however, the propensity to donate more than doubles, if they know that their action will be communicated, and thus affect their own score.”

In the paper

“Moreover, players who justifiably refuse to donate to a defector display in the following round an increased tendency to provide donations, as if to make up for that refusal.”

What the sources say

• ?Not checked — no full text of the sourcecites [64] Engelmann, D. & Fischbacher, U. Indirect reciprocity and strategic reputation building in an experimental helping game. Univ. Zürich working paper no. 132 http://www.iew.unizh.ch/wp/iewwp132.pdf (2002). source

In the paper

“From the first experiments onwards, it was clear that a substantial part of the players frequently decide to donate.”

In the paper

“In particular, the image score of potential recipients correlates well with their expectation to actually receive money 58 .”

What the sources say

• ?Not checked — no full text of the sourcecites [58] Wilson, D. S. A theory of group selection. Proc. Natl Acad. Sci. USA 72, 143–146 (1975) source

In the paper

“But several experiments show that even players who know that their score will not be communicated show generous behaviour 61,63 .”

What the sources say

• ?Not checked — no full text of the sourcecites [61] Haley, K. J. & Kessler, D. M. T. Nobody is watching?: Subtle cues affect generosity in an anonymous economic game. Evol. Hum. Behav. 26, 245–256 (2005) source
• ?Not checked — no full text of the sourcecites [63] Wedekind, C. & Braithwaite, V. A. The long-term benefits of human generosity in indirect reciprocity. Curr. Biol. 12, 1012–1015 (2002) source

In the paper

“The return rates turn out to be no lower than if they were addressed to the own donor 66,67 .”

What the sources say

• ?Not checked — no full text of the sourcecites [66] Greiner, B. & Levati, M. V. Indirect reciprocity in cyclical networks: An experimental study. Max Planck Institute, Jena, working paper no. 2003-15 ftp://papers.mpiew-jena.mpg.de/esi/discussionpapers/2003-15.pdf (2003).
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [67] Dufwenberg, M., Gneezy, U., Güth, W. & van Damme, E. Direct vs indirect reciprocity: An experiment. Homo Oecon. 18, 19–30 (2001)

In the paper

“Reputation has a considerable influence on the decisions.”

In the paper

“In experimental situations which are not based on rigid networks, the decisions of donors also tend to mirror their own recent experience 58,63 .”

What the sources say

• ?Not checked — no full text of the sourcecites [58] Wilson, D. S. A theory of group selection. Proc. Natl Acad. Sci. USA 72, 143–146 (1975) source
• ?Not checked — no full text of the sourcecites [63] Wedekind, C. & Braithwaite, V. A. The long-term benefits of human generosity in indirect reciprocity. Curr. Biol. 12, 1012–1015 (2002) source

In the paper

“In extreme cases, this leads to cooperation even in the absence of indirect reciprocity.”

In the paper

“The propensity for indirect reciprocation is apparently widespread.”

In the paper

“Defectors are often punished although this reduces the endowment of the punisher.”

What the sources say

• ?Not checked — no full text of the sourcecites [70] Gintis, H. Game Theory Evolving: A Problem-Centered Introduction to Modeling Stategic Interaction (Princeton Univ. Press, Princeton, 2000)
• ?Not checked — no full text of the sourcecites [71] Fehr, E. & Fischbacher, U. Social norms and human cooperation. Trends Cogn. Sci. 8, 185–190 (2004) source

In the paper

“Indirect reciprocity and public goods games are also closely connected.”

In the paper

“Conversely, if players know that their own score is passed on, they are much more likely to donate than otherwise 59,60 .”

What the sources say

• ?Not checked — no full text of the sourcecites [59] Wedekind, C. & Milinski, M. Cooperation through image scoring in humans. Science 288, 850–852 (2000) source
• ?Not checked — no full text of the sourcecites [60] Seinen, I. & Schram, A. Social status and group norms: Indirect reciprocity in a repeated helping experiment. Eur. Econ. Rev. (in the press) source

In the paper

“Experiments investigating whether a player's justified defections lowers his or her chance to receive subsequent donations indicate that cognitive problems challenge the donor 64 .”

What the sources say

• ?Not checked — no full text of the sourcecites [64] Engelmann, D. & Fischbacher, U. Indirect reciprocity and strategic reputation building in an experimental helping game. Univ. Zürich working paper no. 132 http://www.iew.unizh.ch/wp/iewwp132.pdf (2002). source

In the paper

“Evidence for strategic reputation building is found in many experiments.”

In the paper

“Donations are more frequent in earlier rounds, when the own reputation has a higher impact on the future income.”

In the paper

“But the additional knowledge did enhance cooperation 61 .”

What the sources say

• ?Not checked — no full text of the sourcecites [61] Haley, K. J. & Kessler, D. M. T. Nobody is watching?: Subtle cues affect generosity in an anonymous economic game. Evol. Hum. Behav. 26, 245–256 (2005) source

In the paper

“Such donors cannot be motivated by selfish interests.”

In the paper

“Since this discriminating strategy distinguishes between justified and unjustified defection, it is effectively a non-costly form of punishing free riders in the public goods game.”

In the paper

“If players are informed about their recipient's action in the public goods game, they tend to be more generous towards recipients who contributed much.”

What the sources say

• ?Not checked — no full text of the sourcecites [73] Milinski, M., Semmann, D. & Krambeck, H. J. Donors in charity gain in both indirect reciprocity and political reputation. Proc. R. Soc. Lond. B 269, 881–883 (2002) source

In the paper

“A discriminating strategy, which defects in all rounds of the indirect reciprocity game if the recipient is known to have defected in the public goods game, can guarantee stable cooperation.”

What the sources say

• ?Not checked — no full text of the sourcecites [74] Milinski, M., Semmann, D. & Krambeck, H. J. Reputation helps solve the ‘tragedy of the commons’. Nature 415, 424–426 (2002) source
• ?Not checked — no full text of the sourcecites [75] Panchanathen, K. & Boyd, R. Indirect reciprocity can stabilize cooperation without the second-order free-rider problem. Nature 432, 499–502 (2004) source

In the paper

“Finally, indirect reciprocity has coevolved with human language.”

In the paper

“Conversely, players are more willing to contribute to the public goods if they know that this will be communicated before the start of the indirect reciprocity game.”

What the sources say

• ?Not checked — no full text of the sourcecites [73] Milinski, M., Semmann, D. & Krambeck, H. J. Donors in charity gain in both indirect reciprocity and political reputation. Proc. R. Soc. Lond. B 269, 881–883 (2002) source

In the paper

“The contributions to the public good do not deteriorate from one round to the next.”

What the sources say

• ?Not checked — no full text of the sourcecites [73] Milinski, M., Semmann, D. & Krambeck, H. J. Donors in charity gain in both indirect reciprocity and political reputation. Proc. R. Soc. Lond. B 269, 881–883 (2002) source

In the paper

“This is not the case if indirect reciprocity games are sandwiched between the rounds of the public goods game.”

What the sources say

• ?Not checked — no full text of the sourcecites [73] Milinski, M., Semmann, D. & Krambeck, H. J. Donors in charity gain in both indirect reciprocity and political reputation. Proc. R. Soc. Lond. B 269, 881–883 (2002) source

In the paper

“An even more remarkable effect was found in an experiment alternating rounds of the public goods game with rounds of the indirect reciprocity game 73 .”

What the sources say

• ?Not checked — no full text of the sourcecites [73] Milinski, M., Semmann, D. & Krambeck, H. J. Donors in charity gain in both indirect reciprocity and political reputation. Proc. R. Soc. Lond. B 269, 881–883 (2002) source

In the paper

“Since this discriminating strategy distinguishes between justified and unjustified defection, it is effectively a non-costly form of punishing free riders in the public goods game.”

In the paper

“In a fluid population, where most interactions are anonymous and people have no possibility of monitoring the social score of others, indirect reciprocity has no chance.”

In the paper

“For indirect reciprocity a similar rule holds 35 : the probability, q , to know the social score of another person must exceed the cost to benefit ratio”

What the sources say

• ?Not checked — no full text of the sourcecites [35] Nowak, M. A. & Sigmund, K. A strategy of win-stay, lose-shift that outperforms tit-for-tat in the prisoner's dilemma game. Nature 364, 56–58 (1993) source

In the paper

“In a socially viscous population, where people know each others reputation, cooperation by indirect reciprocity can thrive.”

In the paper

“Upstream reciprocity seems more liable to exploitation, since the support is not directed towards those who gave support.”

In the paper

“The role of genetic relatedness that is crucial for kin selection is replaced by social acquaintanceship.”