Story of Psychology - Morton Hunt [422]
Leonard Saxe, formerly at Boston University and now at Brandeis, has offered a convincing explanation of the weakness of polygraph evidence. The polygraph, he says, is not a lie detector but a fear detector. If people are afraid the machine will expose their lying, they develop a fear reaction that the machine reports—but if they do not believe the machine can do so, they lie without being afraid, and the machine reports that they have told the truth.84
Because of the unreliability and doubtful validity of polygraph testing, most courts do not usually admit the results as evidence and psychologists rarely do polygraph testing. (It is generally done by technicians who call themselves “polygraphers.”) But polygraph results are not entirely barred from the courtroom; the Supreme Court has left it to the courts of each jurisdiction to determine how and when to allow them, or to exclude them altogether (United States v. Scheffer, 523 U.S. 303 [1998]). A number of jurisdictions that otherwise exclude polygraph evidence nonetheless allow the parties to stipulate to the admissibility of the evidence before the test is administered. These courts typically set requirements on matters such as the qualifications of the polygraph examiners and the conditions under which the tests are to be given.85
Plaintiffs and defendants sometimes take a polygraph test before the trial and, if the results favor them, release the news to the press. The results do not become evidence, but the public and, unfortunately, some jurors in the case may form an opinion on the basis of the so-called evidence.
Scientific jury selection: The courtroom application of psychology in jury selection is of very questionable social value. Its proponents claim that it makes jury trials fairer, but its aim is to select jurors predictably biased in favor of the psychologist’s client.
Scientific jury selection, which has existed for over three decades, is a specialized service that can cost a plaintiff or defendant anywhere from fifty thousand to hundreds of thousands of dollars; accordingly, it is used chiefly in major damage suits and key civil rights cases, although some low-cost services have recently become available for smaller, low-budget cases.86 The service is provided mostly by market research and management consultant firms that have on their staffs, or hire for the purpose, sociologists and psychologists whose research furnishes the client’s lawyers with information about what kinds of jurors to avoid and what kinds to select.
Lawyers, of course, have a number of their own rules of thumb as to what kinds of jurors are desirable or undesirable in different cases, and they try in the voir dire (the questioning of potential jurors) to select those they think are not biased against—or, even better, are biased in favor of—their client. The system is reasonably fair only because both sides question each candidate in order to select or reject him or her. Scientific jury selection adds to this process covertly gathered significant information about the personality traits and background characteristics of potential jurors from which the expert predicts, with considerably greater accuracy than the lawyer, how they will react to the two sides in the case.
An early, but still archetypal, example of the genre is the scientific jury selection conducted in 1975 by the defense in the murder trial of Joan Little, a black prisoner who had allegedly been raped by a prison guard and then killed him with an icepick. A team of sociologists and psychologists working for the defense began with demographics. They ascertained that Beaufort County, North Carolina, where the crime occurred, was 30 percent black but that the jury pool was only 13.5 percent black, and so advised the defense lawyers. For that reason and others the judge granted the defense motion for a change of venue.
In the new venue the research team