Just How Fast Are Leaked Micro-Expressions?
Christopher Philip
Much research has been presented about micro-expressions. Recent tv series “Lie to Me” has reinvigorated the public consciousness about these tiny units of emotion.
Micro-expressions are defined simply as expressions that flash across the face at a high speed which are leaked involuntarily.
Micro-expressions have wide implications specifically within the field of lie detection as it is believed that the expressions form so fast that a person is not able to stifle them, thus indicating an accurate, yet hidden emotion. Studies by Paul Ekman, considered to be the father of micro-expressions have claimed that well-trained inspectors reach 80% accuracy in lie detection based on these units of expression.
In fact, The Transportation Security Administration in the US has already employed a technique called Screening Passengers by Observation Techniques (SPOT) which is largely the result of findings from micro-expressions research. Though, it should be noted that in recent past, these techniques have suffered criticism on their effectiveness. Whether the programs continue or not as effective tools to detect lying is to be determined.
Whatever the case, Ekman believes that when a person tries to conceal his or her feelings, that true emotions tend to leak out more quickly and manifest themselves as micro-expressions.
Although there has been some mention of the precise duration of micro-expressions little research has been given to this exact phenomenon. For example, Ekman suggests that these expressions last 1/5 second – as the upper limit, as this boarders between conventional expressions and micro-expressions. In other cases, micro-expressions are said to be 1/3 second or even ¼.
In The Current Study
At team of researchers lead by Wen-Jing Yan Laboratory of Brain and Cognitive Science, Institute of Psychology, Beijing, China set out to study just how fast microexpressions lasted.
In all, 17 videos were selected as stimulus for the experiment and rated based on various intensity of emotion. Next, the participants, 22 in total, were told that they would be assessed on how well they were able to control their emotions as they watched the videos. To give the participants additional incentive to perform, they were told they would lose their 5 Chinese Yuan as punishment each time they leaked emotions. They were also told not to look away or turn their head.
Results Of The Study
Amazingly only 2 of the 22 participants were able to perfectly control their facial expressions. The results showed most micro-expressions occur on the order of about 500 ms. The fastest micro-expression observe was 166.67 ms. They also found that the theoretical lower limit is somewhere between 100 ms and 166 ms as skeletal muscle – for which all expressions require, can not function any faster.
Interestingly, they only found 15 micro-expressions which Ekman had defined. Other studies confirm this finding as 2% of over some nearly 700 genuine signals and faked signals.
Most micro-expressions appeared during the scenes of disgust whereas fear and happiness seldom appeared. Though smiling and laughter did appear often, they did not elicit micro-expressions according to the definition.
Image Credit: Andrew Imanaka
Resources
Wen-Jing Yan; Qi Wu; Jing Liang; Yu-Hsin Chen and Xiaolan Fu. How Fast Are The Leaked Facial Expressions: The Duration of Micro-Expressions. Journal Nonverbal Behavior. 2019; 37:217–230 DOI 10.1007/s10919-013-0159-8