Trust Games and Beyond

Abstract

Trust is fundamental for the stability of human society. A large part of the experimental literature relies on the Trust Game as the workhorse to measure individual differences in trust and trustworthiness. In this review we highlight the difficulties and limitations of this popular paradigm, as well as the relations to alternative instruments ranging from survey measures to neurochemical manipulations and neuroimaging.

Keywords: oxytocin; reciprocity; social neuroscience; social preferences; survey measures; theory of mind; trust; trustworthiness.

Figure 1

(A) The original Trust Game of Kreps (1990), where both trustor and trustee have just binary choices. (B) A qualitative depiction of the infinite game representing the continuous version of the Trust Game of Berg et al. (1995), as envisioned in experimental economics. The trustor is endowed with $X and can send any proportion p ∈ [0, 1]. The transfer pX is multiplied by a factor K > 1. The trustee receives K(pX) and can send back any proportion thereof, q ∈ [0, 1]. The trustee has a continuum of possible, alternative decision nodes, corresponding to all possible transfers by the trustor. (C) A discretized version of the Trust Game. The trustor is endowed with X = 2 and transfers are doubled (K = 2). Both trustor and trustee can only send integer amounts. (D) A heavily-discretized “mini-Trust Game,” as used, e.g., in Bohnet and Zeckhauser (2004). In all games, the upper payoff is the trustor's and the lower payoff is the trustee's.