Social and economie exchanges often occur between strangers who cannot rely on past behavior or the prospect of future interactions to establish mutual trust. Game theorists formalize this problem in several “one-shot” game – such as the trust game - predicting noncooperation – since the investor is not expecting trustee to reciprocate it is not rationally to invest. Bohnet and Zeckhauser (2004) suggest that, due to betrayal aversion, people seek to avoid situation in which one could be betrayed. We argue that this behavior could emerge also due to regret aversion.

In this article, we focus on two types of “aversion” which we deem essential aspects of the notion of trust: betrayal aversion (social) and ambiguity aversion (a special case of aversion to uncertainty). Based on trust-games studies in experimental economics and neuroeconomics, our main goal is to assess the conceptual, behavioral and neurobiological connections between betrayal and ambiguity aversions.

From a social and individual psychological point of view the bottom line of our trusting behavior could be our general aversion to ambiguous signals. We approach social trust in the terms of a phenomenon based on uncertainty aversion. Specifically, a reduction of the perceived uncertainty of a social interaction tends to build up a trusting climate conducive to trade by decreasing betrayal aversion. We hypothesize that betrayal aversion and ambiguity aversion bear such a negative correlation.

Focusing on this potential negative correlation our approach clearly differs from more positive accounts of trust centred on altruism.