Why Smiles Are Contagious

Smile! It makes everyone in the room feel better because they, consciously or unconsciously, are smiling with you. Growing evidence shows that an instinct for facial mimicry allows us to empathize with and even experience other people’s feelings. If we can’t mirror another person’s face, it limits our ability to read and properly react to their expressions. A review of this emotional mirroring appears February 11 in Trends in Cognitive Sciences.

[2] In their paper, Paula Niedenthal and Adrienne Wood, social psychologists at the University of Wisconsin, and colleagues describe how people in social situations simulate others’facial expressions to create emotional responses in themselves. For example, if you’re with a friend who looks sad, you might “try on” that sad face yourself—without realizing you’re doing so. In“trying on” your friend’s expression,it helps you to recognize what they’re feeling by associating it with times in the past when you made that expression.Humans extract this emotional meaning from facial expressions in a matter of only a few hundred milliseconds.

微笑吧！你的笑容令身邊的人如沐春風，因為他們會有意或無意地隨著你微笑。越來越多的證據表明，人類模仿面部表情的本能讓我們能夠與他人產生共鳴，甚至體悟他人的感受。如果我們不能模仿另一個人的面部表情，就很難理解對方的表情并做出恰當回應。《認知科學發展新動向》于2月11日刊登了一篇文章，對人類情感模仿本能進行評述。

[2]文章的作者——威斯康星大學的社會心理學家葆拉·尼丹瑟和阿德里安娜·伍德以及他們的同事們，在文章中描述了人在社交場合是如何模仿他人面部表情從而產生自身情感反應的。例如，如果你和一個滿面戚容的朋友在一起，可能也不由自主會“換上”那個悲傷的表情。“換上”朋友的表情，并把這個表情與自己過往的類似經歷聯系起來，可以幫助我們理解朋友的感受。人類能夠在短短幾百毫秒內從面部表情中提取出這種情感意義。

[3] “You reflect on your emotional feelings and then you generate some sort of recognition judgment, and the most important thing that results is that you take the appropriate action—you approach the person or you avoid the person,” Niedenthal says. “Your own emotional reaction to the face changes your perception of how you see the face, in such a way that provides you more information about what it means.”

[4] A person’s ability to recognize and“share” others’ emotions can be inhibited when they can’t mimic faces. This is a common complaint for people with central or peripheral motor diseases,like facial paralysis from a stroke or Bell’s palsy—or even due to nerve damage from plastic surgery. Niedenthal notes that the same would not be true for people with congenital paralysis,because if you’ve never had the ability to mimic facial expressions, you will have developed compensatory ways of interpreting emotions.

[5] People with social disorders associated with mimicry and/or emotion-recognition impairments,like autism, can experience similar challenges. “There are some symptoms in autism where lack of facial mimicry

[3]尼丹瑟說:“你先是回想自己的情緒感受，然后產生某種認知判斷；由此產生的最重要的結果是你采取了適當的行動——靠近或是遠離。人類對他人面部表情的情感反應會改變其對面部表情的認知，讓人類更加了解面部表情傳遞的含義。”

[4]當人們不能模仿他人面部表情時，他們識別情緒和“感同身受”的能力就會受到抑制。這在中樞或外周運動疾病的患者身上很常見，如中風或者貝爾氏麻痹癥導致的面癱，甚至由于整形手術造成的神經損傷導致的面癱。尼丹瑟指出，這對先天性麻痹的患者情況不適用，因為假如你從不具備模仿面部表情的能力，則會找到解讀情感的替代方法。

[5]自閉癥等與模仿或情緒認知缺陷相關的社交障礙患者可能面臨同樣的挑戰。“自閉癥患者的一些癥狀表現為面部模仿的缺失，其部分原因可能是抑制眼神交流。”尼丹瑟說道。尤其要注意的是，“在社交場合中的眼神交流對于自閉癥患者來說可能造成過度刺激，但是在某些情況下，如果鼓勵眼神交流，則有利于患者自發地或自動地進行面部表情模仿。”

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may in part be due to suppression of eye contact,” Niedenthal says. In particular,“it may be overstimulating socially to engage in eye contact, but under certain conditions, if you encourage eye contact, the benefit is spontaneous or automatic facial mimicry.”

[6] Niedenthal next wants to explore what mechanism in the brain is functioning to help with facial expression recognition. A better understanding of the mechanism behind sensorimotor simulation, she says, will give us a better idea of how to treat related disorders. ■

[6]下一步，尼丹瑟計劃探索大腦中何種機制在幫助人類進行面部表情識別。她說，人類只有更深刻地理解感覺運動模擬機制，才能找到治療相關疾病的更好辦法。 □