Coherence and credibility in the story-model of jurors’ decision-making: Does mental simulation really drive the evaluation of the evidence?

Abstract

According to the “story-model” of jurors’ decision-making, as advocated by Pennington and Hastie (1986, 1988, 1992, 1993), jurors in criminal trials make sense of the evidence through the construction of a mental representation of the events, rather than through the estimation and combination of probabilities. This ‘story’ consists in a causal explanatory scenario of the crime, and is supposed to drive the jurors’ choice of a verdict. As suggested by Heller (2006), the story-model can be described as a legal application of the simulation heuristic (Kahneman and Tversky 1982), according to which people determine the likelihood of an event based on how easy it is to picture the event mentally: the easier to mentally simulate the prosecution scenario, the higher the conviction rate. The primary goal of this paper is to present the main tenets of Pennington and Hastie’s (1986, 1988, 1992, 1993) “story-model” of jurors’ decision-making, and to draw a few criticisms thereof, in the light of an analysis of evidential reasoning. While acknowledging that some fundamental reasons for adopting this model are well-grounded, and make it a plausible account of jurors’ reasoning, we raise some issues concerning its core theses. In particular, we show that the claim that the evaluation of the credibility of the evidence is mediated by story construction, and determined by the coherence of the story, is not tenable as such, and needs to be complemented by a more probabilistically centered approach.