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Interview Techniques

Evasion vs. Deception

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

A common belief held by many investigative interviewers and most people in general is that when a person is being deceptive that their statements are literally saturated with deceit. Results of numerous studies of deception behavior does not support this conclusion.  In reality, people engage in evasion far more often than they do pure deception.

My colleague Dr. Martha Davis and I studied the video taped interrogations from 36 felony cases investigated by the New York Police Department.  Our study focused on identifying the verbal and nonverbal cues to deception by subjects in situations where there was significant jeopardy for the subject if their evasion and deception attempts failed.  One of the general observations we made that was very consistent with the results of previously published studies of deception was that people are far more evasive than deceptive.

Sustaining pure deception can be a difficult process for most people.  This is not to say that lying is “hard” but one’s ability to first create a deception and then sustain it under scrutiny is what is difficult.  Let’s face it.  The “deception” liar must remember the truth that they are attempting to hide and their first deception presentation.  Next when their previous lie is challenged they must create a new lie that dovetails with the first deception and most often it must be created on the fly.  At the same time they must leave the new lie open ended enough in case they are required to lie some more.  This a daunting task for anyone.

The most common technique the majority people including suspects use to avoid the truth is to practice evasion. Simple evasion does not require a great deal of creative thinking on the part of your deceitful suspect.  Evasion also does not require that one have a particularly acute memory just tell as much of the truth as possible.  Also consider the observations and reactions of the person who is the target of the lie because the lie teller is doing that very same thing.  Pure deception is more likely to raise the suspicions of the lie target that evasion.

The conclusion we can make is that subjects are far more likely to be evasive than deceptive.  The conclusion of our research drew an interesting parallel observation.  Investigative interviewers are more likely to diagnose the stress behaviors of evasion as markers of deception.  Deception behaviors generated by a subject are in fact rare.

Is It Really Deception Or Am I Being Deceived?

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

If a person moves their eyes to the right when they normally move them to the left, they are lying.  He crossed his legs – it must be a lie.  She was lying  – she couldn’t look me in the eye. You can tell he was lying because he was fidgeting the whole time.  We are exposed to so many urban legends about what are reliable signs of deception from so many supposedly informed or professional sources. How do we know which signs are really reliable deception cues or mere assumptions based on legend and folklore?  One way to be sure is to be sure that what you are being taught meets the “Daubert” challenge.

In a US Supreme Court ruling regarding Daubert vs. Merrell Dow, the court established guidelines for what qualifies as scientific evidence.  The court’s interest was to establish the rule that expert opinion based on a scientific technique is inadmissible unless the technique is “generally accepted” as reliable in the relevant scientific community.  Far too many of the claims made in some interview and interrogation courses about what are reliable human verbal and nonverbal signs of deception will not meet this standard.

The Daubert ruling requires that four main conditions be met as to what will be accepted as expert opinion on scientific evidence. These parallel principles accepted in the scientific community as empirical evidence.  These four court-based requirements in brief state:

Whether the proffered knowledge can be or has been tested empirically, i.e., whether it is ìfalsifiable;î (Has it undergone accepted scientific disciplined testing.)

Whether the theory or technique has been subjected to peer review and publication; (Has it been reviewed by the scientific community and  published in a scientific journal)

Whether, in the case of a particularly scientific technique, the method contains a high known or potential rate of error; (Does the technique used to test the theory have a high rate of accuracy.)

Whether the methodology is generally accepted. (Does the scientific community accept the testing method as reliable and objective)

What we should do as students of interview & interrogation and human behavior is to question claims made by instructors in our academies or classrooms that certain behaviors are signs of truth or deception.  As academy directors and instructors it is time we reviewed our course materials on the topic of interview & interrogation and make sure they meet the Daubert challenge. We should also question whether the claims made by quest or contract instructors meet these same stringent guidelines.  We can either deal with the issue now because in the future our course curriculum will be tested under Daubert’s strict guidelines.

For information about Daubert vs. Merrell Dow and its impact on what is considered expert testimony and scientific evidence, go to