Abstract

The reasonable person standard is of great importance to US criminal and tort law. According to the law, whether or not an agent acted reasonably does not depend on features of the outcome which are not under her control. Mock juror attributions of reasonableness, however, are shown to be outcome-dependent. A series of experiments reveals that this outcome-dependence does not constitute a bias, since the very folk concept of reasonableness is outcome-sensitive. Consequently, the law makes a mistaken assumption as to what kind of concept of reasonableness lay jurors will apply in court. This conceptual misalignment, it is argued, could lead to serious injustice in US trials. This paper presents a series of studies (total N=579) which demonstrate that folk judgments concerning the reasonableness of decisions and actions depend strongly on whether they engender positive or negative consequences. A particular decision is deemed more reasonable in retrospect when it produces beneficial consequences than when it produces harmful consequences, even if the situation in which the decision was taken and the epistemic circumstances of the agent are held fixed across conditions. This finding is worrisome for the law, where the reasonable person standard plays a prominent role. The legal concept of reasonableness is outcome-insensitive: whether the defendant acted in a reasonable fashion or not depends exclusively on her context of action, no matter how things play out. Folk judgments of reasonableness are thus inconsistent with the legal concept of reasonableness. Problematically, in common law jurisdictions, the decision whether a defendant’s behavior was reasonable or not is frequently (though not necessarily) delegated to a lay jury.