Lie Detection: A Changing of the Guard in the Quest for Truth in Court?

Article excerpt


Throughout history, human beings have sought to develop more effective methods of lie detection. (1) Lie detection remains a particularly important issue for members of the legal, criminal justice, and medical communities. (2) Courts, however, have been wary to allow recent methods of scientific lie detection into evidence. (3) Lately, scientists have started using more technologically sophisticated methods, such as functional magnetic resonance imaging (fMRI), to detect lies and deception. (4) In fact, some scientists believe it is at least possible that continued development of current techniques, such as fMRI, could result in methods accurate enough to be used in court. (5)

Interestingly, while scientists are working toward more accurate lie and deception detection technology, statisticians are beginning to research the accuracy of jury verdicts. (6) One study suggests that jury verdicts may be inaccurate more often than one would readily believe. (7) Given that lie detection technology is conceivably going to become more accurate, and also that jury verdicts may be inaccurate more often than once thought, some important questions are raised. What role should lie detection technology play in the courtroom as it reaches new levels of accuracy? Could advanced lie detection technology, like fMRI, replace the jury? What impact would highly accurate deception detection have on law and society? This note will directly address the developments in lie detection methods and recent research into jury verdict accuracy. It will then discuss the possible impacts of advanced, highly accurate lie detection on law and society.


A. Early Methods

Most early methods for discerning whether a subject was lying or telling the truth were hardly scientific at all. (8) Early techniques were based on magical and religious beliefs, and did not favor the individual accused. (9) For instance, one medieval method required the accused to walk across hot coals, and if he was burned, he was considered guilty of lying. (10)

A greater emphasis was placed on scientific reasoning during the Renaissance, and confronting and cross-examining witnesses became favored methods of lie detection. (11) Various other approaches developed over time as well, including phrenology in the 18th century. (12) Phrenology is the study of the shape of the skull and its relation to character traits. (13) However, phrenology was short-lived due to "its lack of scientific evidence." (14)

In 1991, an experiment was conducted where groups were asked to assess whether a subject was lying based on "facial, vocal and behavioral cues." (15) In most instances, the groups were not "significantly better than chance at accurately detecting liars." (16) Psychiatrists, however, have identified some methods of identifying deceptive behavior which analyze facial expressions, eagerness to discuss illness, and faked symptoms, but their methods are also limited in capacity. (17) Other methods that have been used include handwriting analysis (graphology), hypnosis, and "truth serums." (18) U.S. courts, however, generally do not admit graphology analysis into evidence, (19) and the Supreme Court has found confessions induced by drugs to be unconstitutional. (20) Hypnosis's value as a lie detector is also questionable because it is primarily designed to aid the subject's ability to recall information rather than discovering when the subject is deliberately concealing it. (21)

There are several other psychological and neuropsychological tests including the Minnesota Multiphasic Personality Inventory/-2, Structured Interview of Reported Symptoms, Test of Memory Malingering, and the Validity Indicator Profile that are used by forensic experts to evaluate when subjects are lying. (22) However, "[t]hey are in no way definitive, and on their own, are not admissible as proof of lying. …