How may experimental jurisprudence contribute to legal questions or advance legal scholarship? This chapter provides a preliminary perspective from German criminal law with a focus on the specific legal practice of doctrinal reasoning (Rechtsdogmatik). It has not been in the focus of experimental jurisprudence, which is understood broadly as empirical studies with laypersons and experts about various legal questions. It overlaps with the classic field of psychology and law, but it is primarily interested in addressing normative aspects. German law is one of the main civil law systems, with firm roots in Roman law. German criminal law has noticeable influence on numerous legal systems throughout the world, from South America to Japan. The following thus hopes to promote the dialogue between these systems and between them and the common law jurisdictions.

In an 1870 essay, Oliver Wendell Holmes, Jr. made a series of penetrating observations about the common law that can still be profitably used by researchers in experimental jurisprudence today. First, Holmes observed that common law reasoning is a process in which judges decide the case before determining the principle on which that decision rests. Second, he suggested that this decision is typically fast, easy, and intuitive, while finding its rationale is often slow, difficult, and deliberate. Third, Holmes noted that this behavioral pattern applies not only to judges and lawyers, but to “other men,” that is, to human beings generally. Fourth, he observed that legal intuitions are often correct, whereas the reasons first offered to explain and justify them are often mistaken. Fifth, he suggested that common law reasoning can be modeled as a practical syllogism. Finally, Holmes implied that the common law is not a body of rules existing “outside the head” of those who discern and apply them, but a mental capacity or psychological entity of some sort. Each of these points anticipated key insights associated with strands of Legal Realism, and each offers valuable lessons for experimental jurisprudence.

We review experimental research on judicial decision-making with a focus on methodological issues. First, we argue that only experiments with relatively high realism, in particular real judges as study subjects, plausibly generalize to judicial decision-making in the real world. Most experimental evidence shows lay subjects to behave very differently from expert judges in specifically legal tasks. Second, we argue that studying the effects of non-law is not a substitute for studying the effects of law since large unexplained residuals could be attributed to either. Direct experimental studies of the law effect are few and find it to be puzzlingly weak. Third, we review the substantive findings of experiments with judges, distinguishing between studies investigating legal and nonlegal factors and paying close attention to the nature of the experimental task.

Settlement, not trial, is the predominant way in which most legal disputes are resolved. Despite this, very little research has examined how the public thinks about settlement. This chapter discusses the need for such research and describes the first few projects trying to fill that need. People hold complex and fairly accurate beliefs about the nature and prevalence of settlement. They also show remarkable willingness to draw inferences when parties settle, including inferences about a defendant’s responsibility. Some avenues for the future of this burgeoning field are also discussed.

Most of the contracts we sign are standard form consumer contracts. Also known as boilerplate or fine print agreements, these uniform “one-size-fits-all” agreements are the most common type of economic contract, used for billions of commercial transactions each year. As this chapter will highlight, experimental research has the potential to significantly inform the regulatory discourse about consumer contracts by providing evidence as to the problems that consumer contracts generate, as well as to the effectiveness of the regulatory tools currently implemented (or under consideration) in addressing these problems. This chapter reviews existing experimental scholarship on consumer contracting with the goal of elucidating its contributions to our knowledge, while at the same time highlighting what remains to be done. Its focus is on experimental studies involving three main issues: (1) consumers’ contracting realities – how consumers behave around form contracts; (2) consumer psychology – how consumers perceive form contracts and the law governing them; and (3) how different regulatory interventions could refashion these contracting realities.

Bias is a topic that has received intense academic study, but its importance within experimental jurisprudence has yet to be unpacked. To fill this lack, we make the following contributions in this chapter. First, we situate the topic within this newly named – but not necessarily new – academic movement: We present recent research on bias in the law and discuss whether it rightly fits within the remit of experimental jurisprudence. Second, continuing to draw on this recent research, we unpack issues that inhere to explorations of bias, ones that are important for understanding, in the experimental jurisprudence context, participants and the data they generate as well as researchers and the data they garner and interpret. Finally, we conclude by offering words of caution and guidance as bias research within experimental jurisprudence progresses.

People who live under a rule of law typically want their laws to work. At their strongest, laws cause people to refrain from doing what they otherwise would have done and act in favor of the law. This is “legal constraint.” If a law doesn’t do what is intended, there is a good chance that it is because of a failure of constraint. When people knowingly commit crimes, they have failed to be legally constrained. When judges reach results they favor because they did not pay due regard to the law that applies to their cases, they have failed to be constrained too. This is why political commentators frequently complain that a law “lacks teeth” or that judges are “activists.” But legal constraint is not just the stuff of political sniping. Legal philosophers, too, have a keen interest in it. In this chapter, I will first discuss how the insights of twentieth-century jurisprudence set the parameters for the empirical study of legal constraint. Thereafter, I will show how experimental methods are particularly well suited to this study. Finally, I will review the literature in experimental jurisprudence that bears upon legal constraint.

The complexity involved in developing and deploying artificial intelligence (AI) systems in high-stakes scenarios may result in a “liability gap,” under which it becomes unclear who is responsible when things go awry. Scholarly and policy debates about the gap and its potential solutions have largely been theoretical, with little effort put into understanding the general public’s views on the subject. In this chapter, we present two empirical studies exploring laypeople’s perceptions of responsibility for AI-caused harm. First, we study the proposal to grant legal personhood to AI systems and show that it may conflict with laypeople’s policy preferences. Second, we investigate how people divide legal responsibility between users and developers of machines in a variety of situations and find that, while both are expected to pay legal damages, laypeople anticipate developers to bear the largest share of the liability in most cases. Our examples demonstrate how empirical research can help inform future AI regulation and provide novel lines of research to ensure that this transformative technology is regulated and deployed in a more democratic manner.

Determining proximate causation is crucial for decisions about legal liability, but how judges select proximate causes is a notoriously disputed issue. Knobe and Shapiro (2020) recently argued that the perceived (ab)normality of causal factors explains both laypeople’s and legal experts’ causal selection patterns. While a large body of psychological research shows that people indeed often select abnormal factors as most important, this research has focused on a very narrow set of scenarios: two simultaneously occurring but independent causes that either conjunctively or disjunctively bring about some outcome. We here explore whether normality also guides causal selection in structures that may be more typical of many legal scenarios: successively occurring causes that are themselves causally connected (causal chains). Comparing effects of both statistical and prescriptive abnormality on causal selection in chains, we only find a tendency to select abnormal causes for manipulations of prescriptive but not statistical normality. Moreover, judgments about the counterfactual relevance of causes or about their suitability as targets of intervention were only moderately correlated with causal selection patterns. The interplay between causal structure and different kinds of (ab)normality in people’s reasoning about proximate causation may thus be more complex than is currently recognized.