Popular detective novels, murder mysteries, and prime time investigation programs would like the public to believe that only systematic sleuthing and the latest forensic techniques resolve the criminal investigations. The current best selling books about body language would also lead readers to believe one can automatically recognize deceptive behavior by the crossing of the legs, the overuse of hand gestures, or the scratching of the nose.

According to Columbia Dr. Frank Horvath, a retired professor from the School of Criminal Justice at Michigan State University in East Lansing, Michigan, research indicates it is the interpersonal communication between the investigator and the suspect that most typically leads to the identification of an offender. The BAI (Behavior Analysis Interview), confessions and factual analysis are the most practical and dependable criteria, and their limitations must be carefully considered.

Dr. Horvath’s research shows there are observable body language clusters of differences between those who tell the truth and those who lie but cannot be taken out of context and generalized to apply to all human behavior. According to Dr. Horvath, detectives “solve” cases by talking with victims, witnesses, and suspects. Next, the investigators establish a non–accusatory pattern of verbal and body language. After the pattern is established of what is normal body behavior for that suspect in a controlled environment, then and only then, can changes in body language mechanics be of significant value.

“It is a myth to assume that any individual can spot a thief or killer at first sight because of his shifting eyes, silent pause, or nervousness,” said Dr. Horvath. “But after the establishment of the ground truth, our research shows that liars tend to show more foot movement than truth–tellers. Pupillary changes are also more observable in deceptive behavior. Liars also tend to stay cognitively busy, are more apt to show a closed posture, have noted pitch changes, sentence changes, neutral descriptions, and more pronoun and tense deletion.”

Dr. Horvath’s research also showed that deceptive suspects were less likely to offer helpful investigative information. Liars tended to show less genuine smiles, less repetition of story elements, less spontaneity and less sincerity in their responses.

On the other hand, truthful suspects are helpful to the interviewer and show an expectancy to be exonerated. Truthful subjects often exhibit resentment toward the guilty person and demonstrate a more open, forward–leaning and comfortable posture during interpersonal communication.

“Beware of the body language books that offer quick assessments of body talk,” adds Dr. Horvath. “They can be very misleading. There is no single body behavior mannerism that determines whether someone is lying or not. Snap judgements on personal characteristics can be extremely misleading.”

Dr. Frank Horvath supervises a project for the U.S. Department of Justice at Fort Jackson. He is a licensed polygraph examiner and a charter member of the America Polygraph Association. When asked about living in the south, Horvath grinned spontaneously, relaxed his posture, and gestured with his hands. “I love the weather, and that’s no lie!”