Compare methods

	Public Goods Game	Minimal Group Paradigm	Social Relations Model	Trust Game
Field	Social Psychology	Social Psychology	Social Psychology	Social Psychology
Family	Process / pipeline	Process / pipeline	Regression model	Process / pipeline
Year of origin	2000	1971	2006	1995
Originator	Experimental economics tradition; Fehr & Gachter (cooperation and punishment)	Henri Tajfel and colleagues	David A. Kenny and colleagues	Joyce Berg, John Dickhaut & Kevin McCabe
Type	Multi-player social-dilemma paradigm	Experimental paradigm for intergroup discrimination	Variance-decomposition model for dyadic data	Behavioral economic game as a social-psychology paradigm
Seminal source	Fehr, E., & Gachter, S. (2000). Cooperation and Punishment in Public Goods Experiments. American Economic Review, 90(4), 980-994.	Tajfel, H., Billig, M. G., Bundy, R. P., & Flament, C. (1971). Social categorization and intergroup behaviour. European Journal of Social Psychology, 1(2), 149-178.	Kenny, D. A., Kashy, D. A., & Cook, W. L. (2006). Dyadic Data Analysis. Guilford Press. ISBN: 9781572309869	Berg, J., Dickhaut, J., & McCabe, K. (1995). Trust, Reciprocity, and Social History. Games and Economic Behavior, 10(1), 122-142.
Aliases	Voluntary Contribution Mechanism, Common-Pool Contribution Game, Linear Public Goods Game	Minimal Group Experiment, Tajfel Matrices, Mere Categorization Paradigm	SRM, Kenny Social Relations Model, Round-Robin Variance Partition	Investment Game, Berg Game, Two-Player Trust Game
Related	3	3	3	3
Summary	The public goods game is the canonical multi-person social dilemma used to study cooperation. Each member of a group is endowed with money and simultaneously decides how much to keep privately and how much to contribute to a common pool; the pool is multiplied and split equally among all members regardless of contribution. Because the marginal per-capita return is less than one but the group return exceeds one, every individual is privately better off free-riding while the group is collectively better off if all contribute -- the defining tension of a social dilemma. Experiments consistently show people contribute well above the self-interested zero, but contributions decay over repeated rounds unless institutions intervene. Fehr and Gachter's influential demonstration that allowing players to pay to punish free-riders restores and sustains high cooperation made the paradigm central to research on norms, altruistic punishment, and collective action.	The minimal group paradigm is an experimental procedure, introduced by Henri Tajfel and colleagues in 1971, that strips intergroup conflict down to its barest possible cause: mere categorization. Participants are sorted into two groups on a trivial or random basis (for example, an alleged preference for one painter over another, or a coin toss), never meet other members, gain nothing personally, and then allocate points between anonymous in-group and out-group members using structured reward matrices. The striking and repeatedly replicated finding is that people favor their own group even when the category is meaningless and favoritism brings them no material gain. The paradigm became the empirical cornerstone of social identity theory, demonstrating that the cognitive act of dividing the social world into 'us' and 'them' is itself sufficient to produce discrimination.	The Social Relations Model (SRM), developed by David Kenny and colleagues, is a variance-decomposition framework for analyzing interpersonal perception and behavior in groups. When every member of a group rates (or behaves toward) every other member in a round-robin design, each rating reflects three distinct sources: the perceiver's general tendency to see others a certain way (actor effect), the target's general tendency to be seen that way by others (partner effect), and the unique adjustment a particular perceiver makes for a particular target (relationship effect), plus error. The SRM partitions the total variance into these components and estimates two kinds of reciprocity -- generalized (do people who like others tend to be liked?) and dyadic (do specific pairs uniquely reciprocate?). By separating the perceiver, the target, and their unique relationship, the SRM answers fundamental questions about whether interpersonal judgments lie in the eye of the beholder, the qualities of the person judged, or the chemistry of the dyad.	The trust game, introduced by Berg, Dickhaut, and McCabe in 1995 (and often called the investment game), is a two-player exchange that operationalizes interpersonal trust and reciprocity in money. An investor receives an endowment and may send any portion to an anonymous trustee; the experimenter multiplies the transfer (typically tripling it); the trustee then decides how much, if any, to return. Standard game theory with purely self-interested players predicts the investor should send nothing because a selfish trustee returns nothing -- yet investors reliably send substantial amounts and trustees reliably return some, contradicting the narrow self-interest prediction. Because the amount sent cleanly measures trust and the amount returned measures trustworthiness, the paradigm became a workhorse in social psychology, behavioral economics, and neuroscience for studying social preferences and cooperation between strangers.