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.

　　完美的微笑应该是什么样子的呢，是露出一口大白牙，还是抿起双唇并使嘴角上扬，对此我们都有自己的想法。一项新研究指出，确实是有正确的微笑方式的，而且这与面部表情密切相关。

　　When we think of the perfect smile, we often envision a wide, beaming 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 .

　　当我们想起完美的微笑的时候，我们往往想象的是喜气洋洋且露出所有牙齿的微笑。然而，明尼苏达大学的纳撒尼尔·赫尔维希和他的同事们发现，真正的微笑实际上并不在于露出几颗牙齿，而更多地在于面部表情的均衡和对称。

　　Researchers looked at 3D computer-animated facial models of more than 800 participants. The computer-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 symmetrical the smile was. Participants were then asked to rate the models’ smiles based on effectiveness, genuineness, pleasantness, and perceived emotional intent.

　　研究人员着眼于800多位参与者的3D电脑动画面部模型。他们为这些模型做了一系列的面部转换，改变了这些模型嘴角的弧度、露出的牙齿的数量、微笑的程度以及微笑的对称度。然后参与者被要求基于有效性、真诚度、愉悦感以及所领会到的情感意图来为这些模型的微笑评分。

　　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 a smile length that extended to what was dubbed the “sweet spot.” Smiles that demonstrated a quick sync of the left and right side of the face during smiling were also more highly related.

　　研究发现，最成功的微笑，也就是那个被评为最令人愉快、最真诚、最有效的微笑，它所展现的牙齿非常匀称，嘴角的弧度十分完美而且微笑的时间也被认为是“最合适的”。微笑的时候，脸部两边的快速同步也与此密切相关。

　　As Science Daily notes, smiling makes up a good portion of our nonverbal communication, making it important to have a grin that will draw people to you and also seem sincere. It’s also worth noting that perfect smile could help improve your health too.

　　《每日科学杂志》指出，微笑在我们的非语言交流中占据着很高的比例，面带微笑会吸引着人们来到你的身边，还会使你显得真诚，而这也使微笑变得尤为重要。值得注意的是，完美的微笑可能还有助于改善你的健康。