Feigned unconcern. Deceptive persons will often appear casual and unconcerned and may adopt an unnatural slouching posture. They may also react to serious questions with nervous or false laughter or feeble attempts at humor. Honest persons tend to be very concerned about being suspected of wrongdoing, and will treat serious questions seriously. Nonverbal cues, which include the eyes and all other body language, account for about 40% of the communication taking place between the interviewer and the subject (Thornhill, 1995). The Fraud Examiners Manual (1999) lists some of these nonverbal cues of deception as follows: Breaking eye contact. It is very difficult for most people to lie while maintaining eye contact. Full body motions. When asked sensitive, possibly incriminating questions, deceptive persons tend to change their posture completely--as if moving away from the interviewer-
in an effort to relieve the mounting anxiety they are experiencing. Honest persons tend
to lean forward toward the interviewer when questions are serious. Crossing the arms and/or legs. Is a classic defensive reaction to difficult or uncomfortable questions. A variation is crossing the feet under the chair and locking them. The purpose of crossing is again to relieve the mounting anxiety the deceptive person is experiencing. Change in the use of illustrators. Illustrators are the gestures made primarily with the hands to enhance communication. During non-sensitive questions, illustrators may be used at one rate while during threatening questions deceptive persons may either increase or decrease their use of illustrators. Reaction to evidence. Deceptive persons tend to be casual about observing possibly incriminating documents presented to them during an interview, and then shove them away, as if wanting nothing to do with the evidence. Honest persons, on the other hand, tend to take a keen interest in the documents as if searching for information which might exonerate them.