看了美剧《Lie to me》吗？那里面的Lightman集团就是通过研究人的面部表情来判断他们是否在说谎，而这个判断过程中很重要的依据就是microexpression（微表情）。

A microexpression is a brief, involuntary facial expression shown on the face of humans when one is trying to conceal or repress an emotion. They usually occur in high stakes situations, where people have something to lose or gain.

微表情是人在试图隐藏或者控制某种情绪时不自觉地表现出来、且持续时间很短的一种面部表情。微表情通常会在人们经历得失、情势危急的时候出现。

Unlike regular facial expressions, few can fake a microexpression. They consist of and completely resemble the seven universal emotions: disgust, anger, fear, sadness, happiness, surprise, and contempt. Microexpressions can occur as fast as 1/25 of a second.

跟普通的面部表情不同的是，微表情很少能够装出来。微表情能够完全反映出人类共有的厌恶、愤怒、恐惧、悲伤、幸福、惊讶以及轻蔑这七种情绪特征。微表情能在1/25秒内一闪而过。