What is the key to identifying deceptive nonverbal behaviors? originally appeared on Quora, the place to gain and share knowledge, empowering people to learn from others and better understand the world.

This is a great question and based on the plethora of research that has been carried out by researchers across the globe, including my own, I can say with conviction that there are no nonverbal behaviors indicative of deception. Put another way, there are no nonverbal behaviors that when observed always indicate deception. However, observing an individual’s nonverbal behaviors can help you to identify when they are hiding something, just not in the way that one might assume.

When an individual is being deceptive there are two main reasons why you may see some changes in their nonverbal behaviors, let’s discuss why these are often misunderstood as indicating deception.

1. Attempting to deceive someone can be highly distressing.

When attempting to deceive someone, you are likely to experience feelings of distress associated with guilt and the fear of getting caught, as well as stress associated with constructing a plausible story. In turn, stress and distress are unconsciously expressed through our nonverbal behaviors. But a nonverbal cue of distress is just that, a cue of distress, not deception. Although the two are related they are not synonymous. Someone who is innocent may also show cues of distress, whilst someone who is lying may feel no distress at all.

2. Attempting to deceive someone is more cognitively demanding than telling the truth.

When you are constructing a lie, not only are you attempting to manufacture a new version of events, but you are also trying to ensure the story is plausible and that you able to remember it, whilst also trying to remember details of what you have previously said and navigate the social interaction. This is extremely cognitively demanding and means that you have less cognitive resources available to control and regulate your nonverbal expressions of emotion. As such, your true emotions may ‘leak’ out through your nonverbal behaviors. But once again, this is simply the expressions of emotion and not deception.

However, you do not need to look far to find yet another self-proclaimed expert promoting themselves as a ‘human lie detector’ based on their ability to accurately decode deception from nonverbal behaviors alone. This is usually followed by the proposition that if you buy access to their courses you can learn to accurately detect nonverbal cues to deception too. Please exercise caution before buying into such promises.

Nonverbal cues associated with changes in emotion and inappropriate affect are important indicators that something may not be quite right, but to suggest that they indicate deception is dangerous and does not stand up to scientific scrutiny. If you are interested in detecting deception, approaches such as forensic linguistics and statement analysis will have a lot more to offer you.

This question originally appeared on Quora.

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