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Interrogation Techniques

Voice Quality Changes – Truth or Deception
(A Deception Research Update)

by Stan B. Walters, CSP
“The Lie Guy®”

Among the multiple channels of communication that a person can use, the “voice channel” possesses three sub-channels: verbal content, thought line and voice quality. Voice quality is defined as the rate of speech, voice pitch and volume. The question for the interviewer is “Are any changes in voice quality characteristics broadcast by the subject reliable cues of deception?”

To answer this question, research studies have been testing the significance of voice changes exhibited by subjects in “live” interviews and interrogations. In the past, deception studies have used “staged” or “controlled” settings that allow for consistent interview conditions but don’t reflect real life reactions seen by interviewers. An extensive research study has been conducted using live interrogations in which a subject’s specific statements have been confirmed as truthful or deceptive. Voice quality changes where among the behavioral changes analyzed by the observers for their ability to isolate truthful from deceptive statements.

Results from this study have determined that when a subject is not experiencing elevated levels of stress and was at the same time being truthful, the subject did not show any significant voice quality changes. Obviously there is not much of a surprise in the results of this part of the study but we do have a critical baseline measurement. When the subject was under stress the voice quality cues did in fact show significant increase in the pitch of the voice, volume and the words per minute or at least in some of variation or combination of the characteristics. Interestingly, the subject was not being deceptive at the same time the voice quality changes occurred.

When false or deceptive statements where analyzed for the presence of voice quality changes, some interesting results were revealed. It was learned that as expected, subjects under significant stress and being deceptive did show changes in voice quality. However, it was also learned that deceptive subjects who are under stress might not show any significant changes in voice quality.

The conclusion about voice quality changes is that such changes can occur when subjects are being both truthful and deceptive and are therefore not reliable signs of deception. In addition, voice quality changes can be associated with an increase in stress in a subject but the lack of voice quality changes do not mean that your subject is not experiencing elevated levels of stress. He or she may in fact be able to exhibit their stress through other verbal or nonverbal channels.

Using Memory Context

by Stan B. Walters, CSP
“The Lie Guy®”

I was doing shopping recently at a department store in my town. I encountered a familiar face in the store. Being polite I smiled said “Hello” and “How’s it going?” I received a polite response but a rather puzzled look from the person. My wife asked how I knew this person to which I replied that I knew them but couldn’t remember why. After about three hours of searching my brain I remembered. I was responsible for helping to convict them almost 25 years ago for fraud and two counts of perjury. My problem was I couldn’t remember the person outside the context or the frame of reference in which I had encountered the person.

We all tend to remember people, things or events in terms of the context in which we were exposed to the stimulus which we have stored in our memory. When you find yourself interviewing your subject who appears to be genuinely having trouble remembering, try using that person’s frame of reference in which they may have exposed to the details.

Some examples would include having a waitress try to recall a customer’s order, a big tipper, noisy patrons or busing a very dirty table. A mechanic might remember body damage, engine repair, or a unique paint job. A patrol office remembers certain traffic stops based on location, violation, time of day, unusual passenger. Teachers will remember kids based on the class they were teaching, a student who excelled in a particular area or even by their parents or a sibling they had as student. Some people remember better when you mention smells, sounds, or specific colors.

All of us can have our memories jogged when we try to remember the emotional state in which we found ourselves before, during or after the encounter. Just listen to your friends telling about funny, exciting, thrilling or even traumatic experiences and you’ll hear frame of reference at work.

Human memory is quite complex in it’s function but once we understand the basics of how memories are acquired, stored and retrieve we can greatly improve the content quality of information we can gain from our exploratory, narrative interviews.