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Paolo Massa

Contact me at or via email at paolo AT gnuband DOT org

Paolo massa.png

Researcher at Institute for scientific and technological research in Trento (Italy) and one of the founders of this wiki.

Interests: trust (trust networks, trust metrics), reputation (reputation systems), recommender systems, carpooling, couchsurfing, free software, gift economy, reputation economy, sharing as a modality of economic production, and some more.

Blog (with list of publications) at

Author of:

Personal todo / not updated actually

(We observe that women exhibit a higher degree of altruism than men for both trust and trustworthiness)
  • read Liberman, V., Samuels, S.M. & Ross, L. (2004) The name of the game: Predictive power of reputations versus situational labels in determining prisoner's dilemma game moves. Personality and Social Psychology Bulletin 30:1175-1185.
Liberman et al. (2004), for example, found a swing from 1/3 to 2/3 cooperation in the prisoner's dilemma when it was described as the "Community Game" instead of as the "Wall Street Game".
Researchers from across the social sciences have found consistent deviations from the predictions of the canonical model of self-interest in hundreds of experiments from around the world. That research, however, cannot determine whether the uniformity results from universal patterns of human behavior or from the limited cultural variation available among the university students used in virtually all prior experimental work. To address this, we undertook a cross-cultural study of behavior in Ultimatum, Public Goods, and Dictator Games in a range of small-scale societies exhibiting a wide variety of economic and cultural conditions. We found, first, that the canonical model – based on pure self-interest – fails in all of the societies studied. Second, our data reveal substantially more behavioral variability across social groups than has been found in previous research. Third, group-level differences in economic organization and the structure of social interactions explain a substantial portion of the behavioral variation across societies: the higher the degree of market integration and the higher the payoffs to cooperation in everyday life, the greater the level of prosociality expressed in experimental games. Fourth, the available individual-level economic and demographic variables do not consistently explain game behavior, either within or across groups. Fifth, in many cases experimental play appears to reflect the common interactional patterns of everyday life.

Recent investigations have uncovered large, consistent deviations from the predictions of the textbook representation of Homo economicus (Roth et al, 1992, Fehr and Gächter, 2000, Camerer 2001). One problem appears to lie in economists’ canonical assumption that individuals are entirely self-interested: in addition to their own material payoffs, many experimental subjects appear to care about fairness and reciprocity, are willing to change the distribution of material outcomes at personal cost, and reward those who act in a cooperative manner while punishing those who do not even when these actions are costly to the individual. These deviations from what we will term the canonical model have important consequences for a wide range of economic phenomena, including the optimal design of institutions and contracts, the allocation of property rights, the conditions for successful collective action, the analysis of incomplete contracts, and the persistence of noncompetitive wage premia. Fundamental questions remain unanswered. Are the deviations from the canonical model evidence of universal patterns of behavior, or do the individual’s economic and social environments shape behavior? If the latter, which economic and social conditions are involved? Is reciprocal behavior better explained statistically by individuals’ attributes such as their sex, age, or relative wealth, or by the attributes of the group to which the individuals belong? Are there cultures that approximate the canonical account of self-regarding behavior? Existing research cannot answer such questions because virtually all subjects have been university students, and while there are cultural differences among student populations throughout the world, these differences are small compared to the range of all social and cultural environments. To address the above questions, we and our collaborators undertook a large cross-cultural study of behavior in ultimatum, public good, and dictator games. Twelve experienced field researchers, working in twelve countries on four continents, recruited subjects from fifteen small-scale societies exhibiting a wide variety of economic and cultural conditions. Our sample consists of three foraging societies, six who practice slash-and-burn horticultural, four nomadic herding groups and three sedentary, small-scale agriculturalists. Our results are described in detail, with extensive ethnographic accounts of the cultures we studied, and citations to the relevant literature in Henrich, et al, 2001. The societies were: Machiguenga Peru, Hadza (Small Camp) Tanzania, Tsimané Bolivia, Quichua Ecuador, Hadza (all camps) Tanzania, Torguud Mongolia, Khazax Mongolia, Mapuche Chile, Au PNG, Gnau PNG, Hadza (Big Camp) Tanzania, Sangu (farmers) Tanzania, Unresettled Zimbabwe, Achuar Ecuador, Sangu (herders) Tanzania, Orma Kenya, Resettled Zimbabwe, Ache Paraguay, Lamelara Indonesia
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