Have you ever wondered how Santa Claus determined whether to leave you a present or a lump of coal on Christmas? How he knew if you’ve been naughty or nice? I don’t have any hard evidence to back me up, but I’m pretty sure that he must be a first-class lie detector.

If so, here are some of Santa’s secrets:

He began with a baseline

The first and most important step in Santa’s deception detection was learning your baseline behavior under relaxed or generally stress-free conditions so that he could compare it with the expressions, gestures, and other signals that are only apparent when you are under stress.

He watched you while you were chatting informally and he noticed how your body looked when you were relaxed. He saw your normal amount of eye contact and blink rate, the gestures you used most frequently, the posture do you assumed when you were comfortable, and your pace of speech and tone of voice.

Then, after he knew your behavioral baseline, he stayed alert for meaningful deviations that signaled a stress reaction (and possible deception) as you went through the days.

He noticed when you’re faking

There are seven basic emotions that are shared, recognized, and expressed the same way around the world. Discovered and categorized by Paul Ekman and his colleagues at the University of California in San Francisco, the universal emotional expressions are joy, surprise, sadness, anger, fear, disgust, and contempt.

When you don’t genuinely feel the emotion that you are trying to display, it often shows up in expressions that don’t use all the muscles in the face that are typically part of that emotion. For example, if your smile doesn’t include the eye muscles, it is not a felt smile. Real smiles crinkle the corners of your eyes and change your entire face. Faked smiles involve the mouth only and are often asymmetrical.

In monitoring your emotional reactions, Santa also looked for simulated emotions, where you tried to convince others that you felt a certain way by simulating the facial expression associated with that feeling. He noticed your “terribly sincere furrowed-brow” or your exaggerated display of anger that felt excessive. He knew, too, that any expression you displayed for more than five to ten seconds was almost certainly being faked.

He kept track of times when your verbal and nonverbal messages were not aligned

When your thoughts and words were in sync (when you believed what you were saying) it showed in your body language because your gestures, expressions and postures fell into natural alignment with your verbal message. But when Santa saw incongruence, where your nonverbal behavior contradicted your words – such as a side-to-side head shake while saying “yes” or a slight shoulder shrug (which is a sign of uncertainty) as you stated you were “absolutely positive.” he knew that verbal-nonverbal incongruence is often a sign of intentional deceit. At the very least, it showed an inner conflict of some sort between what you were thinking and what you were saying.

He looked for clusters

Clusters played a key role in Santa’s ability to spot lies. Your nonverbal cues occur in what is called a “gesture cluster” – a group of movements, postures and actions that reinforce a common point. A single gesture could have several meanings (or mean nothing at all), but when coupled with at least two other reinforcing nonverbal signals, the meaning became clearer.

According to research by David DeSterno of Northeastern University (research that he has surely shared with Santa Claus) there is one specific cluster of nonverbal cues that proved statistically to be a highly accurate indicator of deception. The “telltale four” body language signals that are associated with lying are hand touching, face touching, crossing arms, and leaning away.

He judged you as being truthful or deceptive only after considering the following . . .

For the vast majority of us, the act of lying triggers a heightened (and observable) stress response. But here’s what complicates matters:

  • Not all people demonstrate the same degree of emotion.
  • Not all liars (especially if polished or pathological) display readily detectable signs of stress or guilt.
  • Not all lies trigger a stress reaction. (Social lies, for example, are so much a part of daily life that they hardly ever distress the sender.)
  • Truthful (“nice”) people can exhibit signs of anxiety for a variety of perfectly innocent reasons, including the fear of not being believed or a discomfort when speaking about embarrassing or emotional topics.

Santa Clause took all this into consideration before vising your house – and that’s why on Christmas morning you received all those wonderful gifts.

Troy Media columnist Carol Kinsey Goman, PhD, is an executive coach, consultant, and international keynote speaker at corporate, government, and association events. She is also the author of The Silent Language of Leaders: How Body Language Can Help – or Hurt – How You Lead.

The views, opinions and positions expressed by columnists and contributors are the author’s alone. They do not inherently or expressly reflect the views, opinions and/or positions of our publication.