Friend-or-Foe Intentionality Priming in an Extensive Form Trust Game

In a laboratory experiment, we use an extensive form two person trust game to examine the hypothesis that human subjects have a preconscious friend-or-foe (FOF) mental mechanism for evaluating the intentions of another person. Instructions are used to weakly prime the FOF state: instead of the term "counterpart" for referring to the person that an individual is matched with, we substitute the word "partner" in one treatment, "opponent" in the other. This treatment produces a significant difference in trust and trustworthiness behavior in repeat interactions over time with distinct pairs on each trial. Trustworthiness with "partner" is over twice that for "opponent", and this reinforces trust, although both trust and trustworthiness erode over time. Keyword(s): Bargaining; Reciprocity; Trust and trustworthiness; Evolutionary psychology