Despite much research on the determinants of trust among strangers, its mechanisms are understood only rudimentarily. Recently, it has been proposed that people trust strangers because they believe they should, thus complying with an injunctive norm even if it conflicts with their preferences. However, given the boldness of this claim and in light of independent arguments and earlier findings that suggest otherwise, the hypothesis requires critical scrutiny. Thus, we tested whether the decision to trust (in the trust game) is indeed more strongly driven by what people think they should entrust rather than what they want to entrust in two studies. We consistently found a stronger influence of “want” than of “should” on trust decisions even when controlling for the fairness aspect inherent in the trust game. Thus, our findings speak against a predominant role of injunctive norms for trust behavior and confirm that the latter is mostly driven by preferences. Copyright © 2016 John Wiley & Sons, Ltd.