Recent advances in hierarchical or multilevel statistical models and causal inference using the potential outcomes framework hold tremendous promise for mock and real jury research. These advances enable researchers to explore how individual jurors can exert a bottom-up effect on the jury’s verdict and how case-level features can exert a top-down effect on a juror’s perception of the parties at trial. This dissertation explains and then applies these technical advances to a pre-existing mock jury dataset to provide worked examples in an effort to spur the adoption of these techniques. In particular, the paper introduces two new cross-level mediated effects and then describes how to conduct ecological validity tests with these mediated effects. The first cross-level mediated effect, the a1b1 mediated effect, is the juror level mediated effect for a jury level manipulation. The second cross-level mediated effect, the a2bc mediated effect, is the unique contextual effect that being in a jury has on the individual the juror. When a mock jury study includes a deliberation versus non-deliberation manipulation, the a1b1 can be compared for the two conditions, enabling a general test of ecological validity. If deliberating in a group generally influences the individual, then the two indirect effects should be significantly different. The a2bc can also be interpreted as a specific test of how much changes in jury level means of this specific mediator effect juror level decision-making.

Psychology of justice research has demonstrated that individuals are concerned with both the process and the outcomes of a decision-making event. While the literature has demonstrated the importance of formal and informal aspects of procedural justice and the relevancy of moral values, the present study focuses on introducing a new form of justice: Substantive justice. Substantive justice focuses on how the legal system uses laws to constrain and direct human behavior, specifically focusing on the function and the structure of a law. The psychology of justice literature is missing the vital distinction between laws whose function is to create social opportunities versus threats and between laws structured concretely versus abstractly. In the present experiment, we found that participant evaluations of the fairness of the law, the outcome, and the decision-maker all varied depending on the function and structure of the law used as well as the outcome produced. Specifically, when considering adverse outcomes, individuals perceived laws whose function is to create liability (threats) as being fairer when structured as standards (abstract guidelines) rather than rules (concrete guidelines); however, the opposite is true when considering laws whose function is to create eligibility (opportunities). In juxtaposition, when receiving a favorable outcome, individuals perceived laws whose function is to create liability (threats) as being fairer when defined as rules (concrete guidelines) rather than standards (abstract guidelines).