12.如果一個人眉頭沒有向內聚攏上抬，那么他可能沒有看上去那么悲傷

Psychologist Paul Ekman uses the term "reliable muscles" for the muscles in the face that you can't contract voluntarily.
心理學家保羅?艾克曼用“可靠的肌肉”來形容人們無法自如控制的面部肌肉。

If you observe a person expressing sadness both verbally and facially, but the inner corners of his eyebrows are not going up and in, he may not be experiecing sadness at all. He's unable to contract these muscles voluntarily despite his best efforts.
如果你發現有人用語言和面部表情表達悲傷，但是他的眉頭沒有上抬聚攏，那么他可能根本不難過。盡管他已經盡了最大努力，但是他還是無法自如地收縮這些肌肉。