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Detecting Deception: Calculating the Baseline

by | Jun 12, 2018

Written in collaboration with Janine Driver, author of You Can’t Lie to Me

In my previous blog post, I noted that when assessing whether someone is lying, you must first consider the person’s baseline – their typical behavior.


Body language helps us identify a person’s stress signals of deception. The key word here is “helps” – body language is far from foolproof. In fact, it can be quite misleading.

To begin with, not everyone feels stress about lying, and if they do, what does stress look like for them? It varies by individual.

A more effective approach to detecting deception is identifying “leakage,” or unintentional communication across multiple communication channels. These include:

  1. Facial expressions
  2. Gestures and body language
  3. Voice
  4. Communication style
  5. Verbal statements

Identifying leakage is only the beginning. Combined with your ability to identify the deviations from a person’s baseline behavior, you can create a powerful lie detector.


In fraud examination and other areas of lie detection, establishing a baseline of behavior, tone of voice and word choice can be challenging. Observing and noting nonverbal and verbal signals that are part of your subject’s general demeanor and social norms usually must be accomplished in a matter of a couple minutes.

Everyone has a “norm” – a basic pattern of behavior exhibited under normal amounts of stress – from how often or quick they blink to the words they tend to use.

Just as they have a norm, a person also has a “tic,” or a signal they are uncomfortable. You’ve seen these in your family and friends – the little smirk or quick scowl that washes over them when you have said something they disagree with.

However, even if you see a “tic,” keep looking – you won’t know what the person is “telling” you until you learn how to ask powerful questions.

Establishing the baseline will help you determine three key elements:

  1. Normal speech and gestures
  2. How does this change under stress?
  3. When and where are the most dramatic differences?


Establishing the baseline requires getting an unguarded assessment of your subject. Your best chance is to develop rapport with them. Being in rapport with someone – having them feel warm and trusting toward you – increases the likelihood they will be honest with you.

People tell more lies when they feel uncomfortable or less connected with others. Conversely, building rapport helps people to believe that you are trustworthy and makes them want to help you.

Below are a few ways to establish rapport:

     1. Set your intention to build rapport and your body language will follow suit.

  • Your body language should be open and welcoming.
  • Aim for steady, but not oppressive, eye contact.
  • Lean slightly forward toward them in a relaxed manner.

     2. Lead with empathy.

  • Thinking in someone else’s shoes without judgment is critical to detecting deception.

     3. Listen to their stories.

  • Having patience with an unguarded story goes a long way toward establishing rapport and the baseline.

     4. Mirror their movements – subtly.

  • Matched rhythms and movement helps put you in sync with one another.

     5. Use transparency to create trust.

     6. Ask open-ended questions to get them talking.

  • One or two simple and disarming open-ended questions go a long way. The key to crafting these questions is to share a bit about yourself. Then, pose an open-ended question about seemingly irrelevant personal information that they are likely to answer truthfully, as it is unrelated to the current situation.

Next, conduct a baseline checklist:


With limited time to establish a baseline, this 5-part mental baseline checklist can work wonders.  Keep in mind in that your observance of what you don’t see or hear can be as important as what you do see or hear.

Start with the top and work your way down the person:

     1. First check the face

  • How do they hold their head?
  • Do they touch their face? How often?
  • What about eye movement and eye contact?

     2. Then notice the voice 

  • Tone: are they a soft, medium or loud talker?
  • Pitch: low, medium, or high?
  • How fast or slow to they talk?

     3. Listen to the words

  • Do they use verbal fillers? How often?
  • Do they use full sentences?
  • How is their grammar?

     4. Notice their posture

  • How much space to they take up? Wide, average, or disappearing?

     5. Fidget factor

  • What do they do in a relaxed position?
  • Are they calm, slightly fidgety, or constantly moving?

Remember to keep your attention steady, your communication simple and your body language open, and you will be successful at getting an unguarded assessment in no time.

To learn more about our fraud examination work, contact us today.

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