05/15/2014 05:45 pm ET Updated Jul 15, 2014

The Legal System's Mistaken View of the Human Mind

Recent media accounts document the extent to which Supreme Court decisions are influenced by the pervasive ideological biases of individual justices. In a widely-noted study of thousands of free speeches cases, Epstein, Parker, and Segal report that the members of the Court regularly defend the constitutionality of speech they like and rule against speech they dislike. Thus, conservative Justices are more likely to support the rights of pro-life demonstrators to picket at abortion clinics and liberal Justices to support the rights of students to raise banners promoting marijuana use.

In an essay drawing heavily on a study by Geoffrey Stone, Thomas Edsall highlights a similar pattern with regard to this century's most highly significant Court decisions. For example, the horrors of judicial activism are cited by conservative Justices when they want to defer to legislation requiring strict voter ID but those fears go out the window when they want to strike down key elements of the Voting Rights Act. And of course, Bush v. Gore caused liberal Justices to become big fans of states' rights and conservative Justices to think nothing of the federal courts preventing a state from proceeding as it wished.

The existence of these hypocrisy-inducing ideological biases among Supreme Court Justices would not really be cause for comment -- after all, such predispositions shape the behavior of all humans -- except for the fact that the Justices typically deny the existence of any biases. For example, in an NPR interview that aired earlier this year, Sandra Sotomayor stated that Justices "decide cases based on the arguments parties raise" and went on to note the dire consequences of Justices coming "to their decision making with preconceived notions about an issue." Apparently it is just a wild coincidence that on divisive cases Justice Scalia is far more likely to vote with Justice Thomas than Justice Ginsberg. If Justices do not have "preconceived notions," parties in cases must make different arguments to Thomas and Scalia than they do to Ginsberg.

The fairy tale that it is possible for humans to make decisions without being influenced by their preconceived notions extends beyond the nine Supreme Court Justices. The entire legal system is constructed on the notion that, in making decisions, the matters people consider can be controlled by limiting the information they take in. Jurors are believed capable of unbiased decisions if they are forced to abide by the rules of the judicial process. Thus, jurors are eliminated if they already know anything about the case at hand, told to pretend they did not hear certain comments made during the proceedings, locked up to keep them from being exposed to information that has not been vetted by the system, and given specific instructions for their deliberations.

Recent advances in neuroscience and psychology consistently demonstrate the ridiculousness of the notion that unbiased decisions are possible. Apologies to Justice Sotomayor, "preconceived notions," many of them operating outside of conscious awareness, shape all human decisions -- even those made by Supreme Court Justices and carefully managed jurors. The arrogance of the legal system is at odds with what is now known of the human condition. Even if jurors did begin a case with no knowledge, they would quickly amass all kinds of irrelevant sentiments on the basis of the appearance, body language, and comportment of defendants, attorneys, and judges. They would not be able to ignore a comment that was ruled out of order. In fact, they might remember it more clearly if they are told to ignore it ("don't think of a white bear"). And they are quite likely to ignore the instructions of the judge if that is what it takes to reach the verdict they want. During testimony when I was a juror once, it came out that a certain individual had smoked marijuana. This point was completely irrelevant to the case and jurors were duly instructed to ignore the comment but when the jury began deliberations the instance of casual drug use was the first observation made and it clearly played heavily in the decisions of several jurors.

One example of the harm that results from the legal community's misunderstanding of human nature is its stubborn devotion to eyewitness testimony despite persistent findings that memories of personally experienced events often are badly flawed. Judges themselves also are influenced by factors they believe to be irrelevant. For example, a judge who has recently had a break is much more lenient to defendants than that same judge when there has been no break in proceedings for several hours. These results hold up under controls yet judges are convinced that such factors are irrelevant and that they are meting out impartial, unbiased justice.

The brain is less a rational processing unit for conscious thoughts than a mechanism for the construction of post hoc rationalizations of decisions that in actuality were shaped by forces operating outside of conscious awareness. Improvements in the legal process will be possible only when this updated understanding of human decision-making is accepted. Biases are an unavoidable aspect of the human condition. They push people to the political left or the political right and they incline people to support the accused or to support the state. Biases cannot be wiped out by the adoption of a few antiquated rules of evidence or by the wishful thinking of Supreme Court Justices. Instead of pretending these predispositions do not exist, the legal system needs to accept their existence and try to minimize them, or at least to work with them, in order to make it more likely that the truth will be ascertained and justice served.