Psychologists need to educate judges and juries about psychological methods, found speakers at APA's convention.

Psychologists' testimony for the defense in capital punishment cases often works as well as no testimony at all, reported Nova Southeastern University (NSU) psychologist David Shapiro, PhD, at APA's 2007 Annual Convention.

With the help of his students, Sharpiro examined the effect of psychologists' testimony in capital punishment cases in a sample of U.S. states. He found that judges and juries were just as likely to impose the death penalty when a psychologist testified that the defendant is mentally ill as when no psychologist testified.

"The judges and juries tend to interpret [psychologists' testimony] as, 'Oh, this is person is mentally ill. They must be dangerous. Let's put them to death,'" Shapiro said.

The one exception to this rule seemed to be when the defendant had a history of abuse, Shapiro said. But when psychologists diagnose something such as depression, judges and juries seem to dismiss psychologists' testimony altogether. For example, in one death penalty case, the judges' written court decisions made no reference to the psychologist's testimony on the defendant's severe depression, noted Shapiro.

Fellow panelist and NSU professor Lenore Walker, EdD, reported a similar trend in child custody cases, where judges virtually ignored psychologists' testimony. Walker said that there are presumptions in the law that psychologists have to fight-such as, custody should go to the parent who offers more shared custody rights to the other parent, even if domestic violence was present. Psychologists who make recommendations in a child's best interest based on careful evaluation can have their testimonies overridden because some judges rely too much on these presumptions, she said.

Shapiro and Walker posit that such oversights and misinterpretations stem from widespread biases against people with mental illness and the field of psychology. Judges and juries tend to trust their guts over psychologists' testimony, they explained, especially when psychologists on different sides of the aisle present competing evidence. When that happens, juries have trouble evaluating both testimonies, so they disregard them.

To reverse such alarming trends, psychology needs to educate judges and juries about which psychological methods are reliable and which aren't, Shapiro said. To that end, Walker recommends psychologists visit judicial colleges and offer to explain psychological methodology to judges. And psychologists should address potential prejudices against their testimony in court, Walker said. Raising awareness of those biases helps judges and juries resist them, she said. "We need to counter those biases by having a more active expert testimony," Shapiro says.