Nothing But the Truth? Experiments on Adversarial Competition, Expert Testimony, and Decision Making

Many scholars debate whether a competition between experts in legal, political, or economic contexts elicits truthful information and, in turn, enables people to make informed decisions. Thus, we analyze experimentally the conditions under which competition between experts induces the experts to make truthful statements and enables jurors listening to these statements to improve their decisions. Our results demonstrate that, contrary to game theoretic predictions and contrary to critics of our adversarial legal system, competition induces enough truth telling to allow jurors to improve their decisions. Then, when we impose additional institutions (such as penalties for lying or the threat of verification) on the competing experts, we observe even larger improvements in the experts' propensity to tell the truth and in jurors' decisions. We find similar improvements when the competing experts are permitted to exchange reasons for why their statements may be correct.