A SUBJECT'S POSTURE REFLECTS INTERNAL THOUGHTS
Dynamic vs. Static
An important assessment of a subject's posture is the extent of change within the posture over the period of a 30 or 40 minute interview. For a number of reasons, a truthful subject will exhibit a variety of different postures throughout the course of an interview. These postures will be appropriate given the content of conversation during the interview.
A deceptive subject, on the other hand, may assume an initial posture and never significantly deviate from that posture. It is theorized that the deceptive subject is exerting so much thought and energy to generate verbal responses to the interviewer's question, that nonverbal communication becomes frozen. A static posture clearly reflects a lack of confidence within the subject.
A forward vs. retracted posture
When a subject leans forward in the chair during a response, he is nonverbally reinforcing the verbal content of his response. This is frequently seen in truthful subjects during early portions of the interview, when key questions are asked. As the interview progresses, the truthful subject will assume a more relaxed and comfortable posture in the chair. Some deceptive subjects will lean forward in the chair throughout the entire interview. This is a challenging behavior, similar to the deceptive subject who stares at the investigator throughout the interview.
A retracted posture describes one in which the subject's feet or hands are restricted in some manner. This is most typical of the deceptive subject. The subject's feet may be pulled up under the chair, or tucked behind the front legs of the chair. In unusual cases, a subject may actually tuck a foot under his thigh, so as to partially sit on his foot. As can be visualized, when the subject's feet are retracted in this manner, it prevents the body from leaning forward to reinforce the strength of a verbal response. With respect to hands, the deceptive subject may sit on his hands or keep his hands wedged between the knees. This posture effectively prevents the hands from becoming involved during conversation to reinforce a verbal response.
A truthful subject exhibits high levels of interest and emotional involvement during an interview. To fully communicate with the interviewer he will align his body with that of the interviewer. The subject's entire body, the head, shoulders and hips, are all directly facing the interviewer. On the other hand, a deceptive subject may turn his legs and hips away from the interviewer. This posture reflects a lack of interest or emotional detachment.
Evaluation of Barriers
Within a posture, barriers represent crossed arms or legs. While crossed arms can be a comfortable posture while standing and talking to a friend, considering the high level of motivation associated with an investigative interview, it is inappropriate for a truthful subject to cross his arms. This behavior reflects either a challenge (generally feigned anger) or a protective gesture reflecting lack of confidence. In addition, of course, when the arms are crossed the subject's hands are restricted from movement which is also more typical of the deceptive subject.
Crossing of the legs is common in both truthful and deceptive postures. While seated, especially for an extended period of time, it is comfortable to occasionally cross, or re-cross the legs. However, there are some significant differences between the leg crossing behaviors of truthful and deceptive subjects. At the outset of an interview, when anxiety levels are highest and key questions are being asked, most truthful subjects will have their feet flat on the floor. As the interview progresses, and the subject realizes that the investigator is not accusatory in his questioning, it is common for the truthful subject to assume a more relaxed posture, including crossed legs. On the other hand, a subject who starts out the interview with crossed legs is more typical of the deceptive. This is a defensive posture, as though the subject wants to remain emotionally distant from the investigator.
A truthful subject's leg cross appears comfortable and relaxed. Whether it is an ankle-knee cross or knee-knee cross, the subject's muscles are non-contracted and loose. On the other hand, the deceptive subject's leg cross is often tight and restricted, where muscles are contracted. A good example of this is the leg cross in which the subject actually grabs the ankle to bring it up higher on the thigh.
.....Truthful relaxed posture ..............................Deceptive barriers
Changes in Posture
As previously mentioned, a truthful subject will display a number of different postures during the course of an interview. The timing of these posture changes will be natural. Conversely, it is highly indicative of deception when posture changes occur on cue to a question, such as the crossing or re-crossing of the legs, or a shift in the chair where a subject often uses his hands to momentarily lift or move his body within the chair. The investigator should look for these shifts during two significant time frames. The first is just before the subject answers a question:
Q: "Did you leave your house at all that night?"
S: (Shift in chair) "No, I really had nowhere to go so I stayed home."
The second significant timing is during the subject's verbal response:
Q: "Were you experiencing any financial difficulties last month?"
S: "Nothing out of the ordinary. (Shift in chair) That I can recall."
In conclusion, a subject's posture can offer meaningful information during an interview. As with all of the behavioral assessments that we teach at our course, there are factors other than truth or deception that may influence a subject's behavior and must be considered.