Increased blink rate and the eye flutter- clues to deception.

Increased blinking rate from the average, which is about 6-8 blinks per minute is a sign of increased anxiety.  The eye flutter, a series of rapid blinks, indicates a sudden and significant increase in anxiety.  Herman Cain (see video below) displays a great deal of this in his interview with Wolf Blitzer on CNN.


Herman Cain displaying increased blink rate (and “duping delight”) while being interviewed by Wolf Blitzer on CNN.

How are these indicators of deception?  When telling the truth, the brain does not need to work as hard due to the fact that the memories are stored and easily retrieved if the incident in question happened fairly recently or was something that was significant (typically a crime or deception will be something that is significant to the perpetrator and easily recalled). This is not a stressful situation.  When being deceptive, the anxiety increases and can manifest itself through increased blink rate.  Keep in mind, not all people have the same blink rate.  What you need to observe is an obvious or sudden increase or decrease.  A decrease in blink rate is an indicator of deep thought or increased cognitive load, but this is a different kind of thinking.

Increased blink rate has been associated with increased anxiety. Decreased blink rate has been associated with high cognitive load. These both may be right, but there is more to the story. Recent research , Soghra Akbari Chermahini and Bernhard Hommel in the Netherlands recently assessed the relation between creativity and dopaminergic functioning by assessing participant’s spontaneous eye blink rate (EBR), a well-established clinical measure of striatal dopamine production. (Kaufman, 2010) These researchers found that increased blink rate indicates higher creativity levels. They studied groups of people given two separate tasks. One that requires divergent thinking (creativity) and one that requires convergent thinking (fluid intelligence or logic). The researchers found those who engaged in the divergent or creative thinking test exhibited higher blink rates than those who were in the convergent or logical task. How does this apply to deception detection? Context, as always, is key, but the research would seem to suggest that increase in blink rate is an indicator of increase in creative thought. Yes, anxiety can increase blink rate, but for different reasons. Stress dries out the eyes and blinking lubricates them. Decreased blink rate is more an indicator of deeper, problem solving cognitive load. This research appears to support the belief that a person making up a story on the fly, or creating a false answer, will have an increase in blink rate.

So if, in response to a question or other stimulus, you observe an eye flutter, what does that mean?  Generally speaking, it means one of two things:

1. the person will withhold information ( a form of lying).  They are experiencing sudden, elevated anxiety levels and must quickly figure out how to phrase their response appropriately without divulging some sensitive information.  The increase in blink rate while speaking or listening is an indicator of the same thing, they are experiencing anxiety.

2. The issue or topic is sensitive to them.  They might have a good reason for the eye flutter in this case, such as if you asked them a highly personal or rude question.  In these scenarios, the increased anxiety is likely coming from the attempt to process your questions intent rather than hide truth.  It is important to think about how you ask your questions in order to allow your reads of the subject to be more accurate.

Here is the Herman Cain example of increased blink rate:

The increase in blink rate and the eye flutter happen unconsciously and the person will be unaware they are even doing it.  These are not to be confused with eye blocking (either with the hands or by closing the eyes), which indicate a different thought process.

Your strategy?  If you see an eye flutter, or significant increase in blink rate in response to a question, the response is likely not well thought out.  After all, it is likely the subject withheld information or created a response on the fly.You can use this shallow response to your advantage by probing the response with open, dialogue inducing questions.  The liar’s story will fall apart.


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