Compare methods

	Trust Game	Public Goods Game
Field	Social Psychology	Social Psychology
Family	Process / pipeline	Process / pipeline
Year of origin	1995	2000
Originator	Joyce Berg, John Dickhaut & Kevin McCabe	Experimental economics tradition; Fehr & Gachter (cooperation and punishment)
Type	Behavioral economic game as a social-psychology paradigm	Multi-player social-dilemma paradigm
Seminal source	Berg, J., Dickhaut, J., & McCabe, K. (1995). Trust, Reciprocity, and Social History. Games and Economic Behavior, 10(1), 122-142.	Fehr, E., & Gachter, S. (2000). Cooperation and Punishment in Public Goods Experiments. American Economic Review, 90(4), 980-994.
Aliases	Investment Game, Berg Game, Two-Player Trust Game	Voluntary Contribution Mechanism, Common-Pool Contribution Game, Linear Public Goods Game
Related	3	3
Summary	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.	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.