3. You need to be cautious!
- Investigation Guides
- An Employer's Guide to Conducting Internal Investigations
- 47 Quick Tips: Better Investigation Interviews
- Checklist for Sexual Harassment Investigations
- Black Book of Lie Detection
“A single lie destroys a whole reputation for integrity”- Baltasar Gracian
Because it is so difficult to read deception, it is very easy to make mistakes when trying to work out whether or not someone is lying. Although Polygraphs are only accurate in detecting lies 6o-8o% of the time (dependant on the skill of the operator), people are mostly only accurate 5o% of the time. And this statistic applies to many `experts' including law enforcement officials.
People often mistake physical manifestations of stress as being indicators of lies being told. This sometimes happens to innocent people standing trial in a criminal case for a crime they didn't commit. The irony is the guilty defendant will have had plenty of time, sometimes years, to rehearse their lie. The innocent person will not have rehearsed because they are telling the truth and are scared because they have a lot to lose.
No single behavior is a reliable indicator of deception. So don't assume that because the person looks away when you are talking to them, they are lying about something. You need to look for clusters or groupings of deception indicators.
Cultural context is particularly important. While there are some universal behaviors that cross culture, ethnicity and nationality, there are some gestures that have a positive meaning within one society and a negative meaning in another. Your chances of accurately determining whether or not someone is lying, increase if you are from the same cultural and social group
And then there is you. What biases and prejudices do you have? What preconceptions do you harbor and myths do you believe? There is much statistical evidence which demonstrates that police officers are more likely to question and arrest a person who has an ethnic minority background because of preconceptions and prejudices they have about the particular ethnic group.
Checklist
- What is the true basis for your suspicion?
- What biases, prejudices and preconceptions do you harbor towards the suspect?
- What motive might the suspect have for lying?
- Is the suspect an experienced liar?
- How skilled and experienced are you at detecting lies?
Table of Contents
- We all want to be lie detectors
- Types of liars and degrees of lying
- You need to be cautious
- Factors influencing detection accuracy
- Setting the scene
- Your body wants to confess
- Eye think you are lying to me
- Time to face the truth
- Listen like a lawyer
- Download the PDF

