Study examines judges' decision-making patterns. (News & Trends).

"Judges, it seems, are human." So concluded the authors of a recent study on decision-maker thinking. "Like the rest of us, their judgment is affected by cognitive illusions that can produce systematic errors in judgment."

The researchers' hypothesis was that like all people, judges rely on mental shortcuts called heuristics to make complex decisions. Relying on these shortcuts usually leads to good judgment, but it can also produce poor results. "The very nature of human thought can induce judges to make consistent and predictable mistakes in particular situations," wrote the authors.

Juries provide a healthy counterbalancing effect in the courtroom, they concluded. "On balance, ... our results suggest that those clamoring for judges to replace juries should proceed with caution. Judges are likely to make better decisions in certain circumstances because their training and experience will enable them to avoid the more pernicious effects" of certain cognitive illusions, the authors wrote.

"On the other hand, group decision-making or the insulation afforded by a judicial gatekeeper may enable juries to make better decisions than judges in other circumstances."

Chris Guthrie, acting associate dean and associate professor at the University of Missouri School of Law; Jeffrey Rachlinski, a law professor at Cornell Law School; and Andrew Wistrich, a U.S. magistrate judge in California, surveyed 167 U.S. magistrate judges using a brief questionnaire designed to identify the influence of five common cognitive illusions:

* "anchoring"--using a potentially irrelevant or biased starting point on which to base an estimate

* "framing"--treating economically equivalent gains and losses differently

* "hindsight bias"--believing that past events could have been predicted better than they actually were predicted

* "representiveness heuristic"--ignoring important background statistical information in favor of distinguishable information, such as appearance

* "egocentric bias"--overestimating one's own abilities.

The study looked at instances when judges were more likely than juries to make unbiased decisions and vice versa. Judges with decision-making experience can blunt the effects of cognitive illusions--for example, they might avoid the unwanted effects of anchoring when determining or reviewing damages awards if they are aware of awards in comparable cases and use this information as an anchor.

Juries, however, engage in group deliberation, which might reduce some cognitive illusions. For example, while an individual's memories of events may be altered by hindsight bias, groups working together usually remember more of the relevant facts, which can counteract the bias. And, according to the study, "a jury trial has a substantial advantage over a bench trial" if the only way to avoid a cognitive illusion is to restrict the potentially misleading information from the fact finder--for example, by withholding immaterial information from jurors.

Changes to procedural, evidentiary, and substantive rules could minimize the effects of cognitive illusions on judicial decision-making, the authors suggested. They cited some such rules that already exist: For example, in medical malpractice cases courts aren't asked to determine whether the defendant behaved "reasonably" but whether he or she behaved in a manner consistent with customary practices established by the profession.

However, adopting reforms to reduce the effects of one type of illusion "will skew the litigation process because any single reform will fail to reduce the effects of other illusions" and might adversely affect a category of litigants. The authors found, for example, that the hindsight bias "generally benefits tort plaintiffs because it makes it seem as if the defendant had a greater ability to predict the adverse outcome than was actually true. Similarly, anchoring makes it easier for plaintiffs to obtain higher damage awards, because defendants typically cannot provide an anchor without implicitly admitting that they should be held liable."

Therefore, said the authors, if the legal system were to enact rules that address only these illusions without considering the effects of other cognitive illusions, the reform could "skew the system against plaintiffs."

The authors suggested that judges educate themselves about cognitive illusions and try to avoid the errors they produce. Also, "greater experience, training, and specialization should enable judges to make better decisions," the authors said. For example, full-time trial judges might develop a better sense of when a cognitive illusion is interfering with their decisions than judges who conduct trials only on a part-time basis.

The study, Inside the Judicial Mind, was published in the May 2001 issue of the Cornell Law Review.