Are body movements a valid lie detector?

By Greg Wright
Certified Fraud Examiner
Certified Financial Planner
National Speaker

“Kinesics,” is the study of human movement as culturally patterned visual communication. Anthropologist Ray Birdwhistell coined the term “kinesis,” as a positive alternative to "non-verbal communication" as the field was more usually known.  He did not like the term "body language."

According to Birdwell’s research, "Body movements are culturally patterned rather than universal." 

If body movements are cultural and not universal, as Birdwhistell maintains, how can it then be used by law enforcement and investigators to indicate if the subject is telling the truth or lying?

A good question.

How about Gaze Aversion?  Is it a valid indicator of someone not being truthful?

According to researchers, Black people who are entirely innocent are less likely to look police in the eye than Black people who are criminals.  White people suspected of a crime spend the most time out of all ethnic-racial groups, looking at the police officer in the eye. 

Most police officers believe the most critical physical demeanor cue is eye contact.  The Reid Technique's training manual is the most widely used guide for law enforcement officers, and almost all fraud investigator interview technique trainers have been trained using the Reid Technique training tools.

Because of this training - significantly - nearly all police officers (over 80%) believe that, when you are interviewing individuals, those who are lying look away – are gaze averse - and truthful people maintain eye contact. 

If you use "gaze aversion" as a cue to interpret an individual's credibility, you are going to be a lot more suspicious of Black folks than White folks.  And, you are going to be most suspicious of innocent Black Americans.  Wow!

How about “smiling” or “halting speech.”

A variation of expression may be smiling or halting speech.  Halting speech is someone speaking slowly and with a lot of hesitation.

A rule of thumb reinforced by training and relied upon by many law enforcement interviewers is that subjects who frequently smile is a sign of insincerity.  However, according to researchers, individuals that smile the most are innocent African-Americans, and those that smile the least are Hispanic suspects.  African-Americans speak fluidly, and Hispanics may stammer and nervously stop and start.  If you are a copy unfamiliar with Black or Hispanic individuals, you might “detain” Blacks for smiling too much and detain Hispanics for halting speech.

How about hand gestures?

Again, law enforcement officers are trained to believe that guilty suspects’ hand gestures, shrugs, grooming, protective movement, etc. are a pattern indicating guilt.  “Be sure to watch the hands,” we are told in law enforcement training manuals.

Below is a summary of the hand gestures research conducted by Prof. Richard Johnson, a noted criminologist.

Hand gestures per minute
Race-ethnicity	Average time in seconds
African-American - innocent	28.39
African American - suspect	23.98
White - innocent	07.89
White -suspect	17.43
Hispanic - innocent	22.14
Hispanic - suspect	31.41

A conclusion one can reach is that people vary greatly when or how long they look you in the eye, or if they smile, how fluidly they talk, or the kind and rate of their hand gestures.  None of these "behavior symptoms," in police interviewer parlance, or, to use the language of poker, are considered to be a "tell" and predict the truth or a lie. 

Where does this leave us? 

Is gaze aversion, smiling, halting speech, or hand gestures predictive of the truth or a lie?  Apparently, any of these may be judged by law enforcement officers as “probable cause” and the basis to detain someone.  Likewise, fraud investigators might label the interviewee as “not creditable.”

Have most law enforcement officers and fraud investigators been trained incorrectly about body language?

Mehrabian's 7% Rule

By Greg Wright
Certified Fraud Examiner
Certified Financial Planner
National Speaker

Sometimes, when searching for the truth, we jump at a promising shortcut.  The Mehrabian 7-33-55  rule was, for many, that shortcut.  But, the understanding of many is incorrect. 

The rule is not a lie detector.

When I ask an audience to yell out, "What do you think is more important, verbal or nonverbal behavior?", the audience will universally yell out "body language."

This important rule is that communication is only 7 percent verbal and 93 percent non-verbal.

Albert Mehrabian, Professor Emeritus of Psychology at the University of California is credited for this rule.  Although he originally trained as an engineer, he is best known for his research on the relative importance of verbal and nonverbal messages. 

His two research studies developed the 7-38-55 Rule of Personal Communication. In communication, according to the research, a speaker's words are only a fraction of his efforts. The pitch and tone of his voice, the speed and rhythm of the spoken word, and the pauses between those words express more than what is being communicated by words alone. 

Do words alone only account for 7% of communication?

Be careful. 

Mehrabian said, "Please note that this and other equations regarding (the) relative importance of verbal and nonverbal messages were derived from experiments dealing with communications of feelings and attitudes." "Unless a communicator is talking about their feelings or attitudes, these equations are not applicable."

Except for feelings & attitudes, the Mehrabian's 7% rule is not a lie detector.

The transcribed words of a witness or suspect are often more useful in determining the true facts of an event than a video recording of the statement.  Body language will often sidetrack you from the truth. You need to focus on the words. 

More on that later.  I have conducted hundreds of interviews of witnesses and fraud suspects.