Let's Learn How to Keep Smile想當Social 達人？先學會保持微笑吧

We all have our own idea of what the perfect smile should look like, whether we show a mouthful of pearly whites or keep our lips closed and turned up at the corners just so. New research suggests that there really is a proper way to smile, and it has everything to do with facial expression.

When we think of the perfect smile, we often envision①envision 英 [?n?v??n] 美 [?n'v??n] vt. 想象；預想a wide, beaming②beaming 英 ['bi?m??] 美 ['bim??] adj. 喜氣洋洋的；愉快的；光亮的；耀眼的v. 照耀（beam的ing形式）grin, with all of our teeth showing. However, Nathaniel Helwig and his colleagues at the University of Minnesota discovered that a genuine smile actually rests less on showing teeth and more on facial balance and symmetry .

Researchers looked at 3D computer-animated facial models of more than 800 participants. Thecomputer-animated facial models underwent a series of facial transformations, with researchers changing the mouth angle, amount of teeth shown,the extent of the smile, and how symmetrical③symmetrical 英 [s?'metr?k(?)l] 美 [s?'m?tr?kl]adj. 勻稱的，對稱的the smile was. Participants were then asked to rate④rate 英 [re?t] 美 [ret] n. 比率，率；速度；價格；等級vt. 認為；估價；責罵vi. 責罵；被評價the models' smiles based on effectiveness, genuineness,pleasantness, and perceived emotional intent.

The results of the study found that the most successful smile—one that was rated most pleasant,genuine, and effective—had a perfect balance of teeth, an ideal mouth angle, and as mile length that extended to what was dubbed⑤dub 英 [d?b] 美 [d?b] vt. 配音；輕點；打擊；授予稱號n. 笨蛋；鼓聲the "sweet spot⑥sweet spot 甜蜜點；最有效點；最佳擊球位置."

完美的微笑應該是什么樣子的呢？是露出一口大白牙，還是抿起雙唇并使嘴角上揚？對此我們都有自己的想法。一項新研究指出，確實是有正確的微笑方式的，而且這與面部表情密切相關。

當我們想起完美的微笑的時候，我們往往想象的是喜氣洋洋且露出所有牙齒的微笑。然而，明尼蘇達大學的納撒尼爾·赫爾維希和他的同事們發現，真正的微笑實際上并不在于露出幾顆牙齒，而更多地在于面部表情的均衡和對稱。

研究人員著眼于800多位參與者的3D電腦動畫面部模型。他們為這些模型做了一系列的面部轉換，改變了這些模型嘴角的弧度、露出的牙齒的數量、微笑的程度以及微笑的對稱度。然后參與者被要求基于有效性、真誠度、愉悅感以及所領會到的情感意圖來為這些模型的微笑評分。

研究發現，最成功的微笑，也就是那個被評為最令人愉快、最真誠、最有效的微笑，它所展現的牙齒非常勻稱，嘴角的弧度十分完美，而且微笑的時間也被認為是“最合適的”。