By Brittany Koziol
Eyebrow flashes may indicate veracity. Eyebrow flashes decrease when a threat is present. Getting caught in a lie presents a threat so, liars tend to eyebrow flash less when they dissemble. To accurately catalog eyebrow flash rates, a baseline must be established during a time a person has no reason to lie. Any changes from the baseline may signal a lack of sincerity.
The eyebrow flash is a quick up-and-down movement of the eyebrows that lasts for about one-sixth of a second. The eyebrow flash is a universal nonverbal friend signal. When you see someone from a distance, an eyebrow flash sends a nonverbal message that you are not a threat. A return eyebrow flash lets you know the other person is not a threat. When people are in comfortable situations, they tend to eyebrow flash more. Truthful people eyebrow flash more when they relive pleasurable experiences. When people share enjoyable stories, the facial expressions they displayed during the initial experience are reproduced when the story is retold. When people lie, they experience some level of discomfort. This uncomfortable feeling causes eyebrows to flash less because liars do not actually relive the activities or events they are talking about. Additionally, fear of discovery poses a threat. Therefore, the absence of eyebrow flashes or a reduction in eyebrow flash rate may indicate deception.
Eyebrow Flash Rate
Eyebrow flash rate determines the difference between a friendly eyebrow flash and a deceptive eyebrow flash. A friendly eyebrow flash is often accompanied by a sincere smile, which is another universal nonverbal friend signal. A deceptive eyebrow flash is slower and often followed by aggressive nonverbal displays or avoidance behavior. An exception to this phenomenon occurs when truthful people retell a traumatic event they experienced. If people relive a traumatic event, they will naturally eyebrow flash less because they are reliving an uncomfortable experience.
Eyebrow flashes tend to occur more when people feel comfortable. Conversely, eyebrow flashes tend to decrease when people feel uncomfortable, especially during the course of telling a lie. Therefore, eyebrow flashes may indicate veracity.
Caveat: No single nonverbal cue indicates deception. Clusters of nonverbal displays typically accompany deception. Each nonverbal cue must be judged against a baseline before concluding a person is lying. The best way to determine veracity is to compare what a person says against know facts.
Note: The author of this post is a student in my Spring 2017 Police Report Writing class at Western Illinois University. She submitted the winning entry in the in-class, best-written, end-of-semester paper competition. The blog post was edited for content and formatting.