For centuries, juries have been hailed as a model of popular participation in government. Alexis de Tocqueville famously described the American jury as "both the most effective way of establishing the people’s rule and the most efficient way of teaching them how to rule." But even as he praised the jury’s role as a political institution, de Tocqueville worried that jurors might lack the knowledge needed to perform their judicial function properly. "The jury system," he wrote, "arose in the infancy of society, at a time when only simple questions of fact were submitted to the courts; and it is no easy task to adapt it to the needs of a highly civilized nation, where the relations between men have multiplied exceedingly." Today’s society is arguably even more "highly civilized" than that described by de Tocqueville in the 1830s, or at least more complex. It is therefore important to consider whether jurors have the knowledge and cognitive abilities needed to cope with the challenges of modern trials. Much evidence suggests that voters often fail to acquire the knowledge needed to cope with the enormous scope and complexity of modern government. Given the oft-made analogy between jury service and political participation, it is important to consider whether jurors are prone to similar pitfalls. Do they also often make poor decisions out of ignorance or illogical evaluation of evidence?
My tentative conclusion is that jurors are likely superior to voters in terms of both acquiring knowledge and utilizing it in a rational way. But ignorance and irrationality do sometimes compromise jury decision-making, especially in complex cases. They are even more likely to bedevil efforts to use jury-like institutions to make broad policy decisions, as opposed to merely decide discrete cases.
Part I summarizes the problem of political ignorance in the case of voters and explains some theoretical reasons why we would expect jurors to acquire greater relevant knowledge than voters do, and to use it more wisely. Part II discusses the relevant empirical evidence on jury knowledge and rationality. Much of that evidence shows juries performing fairly well. But it also suggests that ignorance and bias undermine the quality of jury decisions in unusually complex cases, such as ones involving scientific evidence, punitive damages, and complicated jury instructions. Overall, juries perform better than voters in large part because of the ways in which trials differ from elections. Unlike voters, jurors usually cast votes that have a high probability making a difference, and decide only a narrow specific case rather than a broad set of policy issues. They are also required to listen to extensive evidence from both sides before making a decision.
Finally, Part III expresses skepticism about the possibility of using jury-like mechanisms to help decide broad policy questions. Such proposals break down some of the key differences between jury service and voting that make the former function more effectively than the latter.