Psychology research is not generally very good at capturing change. Measurements tend to be fairly static, either looking at one slice of time or asking participants to average over a period. Which is why this research on smiling is so unusual. Some of the best known research on smiling is about how people judge an authentic smile - the so-called 'Duchenne smile' or the 'crinkly-eyed smile'. What this research asks, though, is how does a smile's speed in combination with head-tilt and gender affect its perception.

    In this experiment, one hundred participants, half men half women, were sat in front of a monitor to judge the smiles of synthetic faces (Krumhuber, Manstead & Kappas, 2007). They watched the faces smiling - some whose smile appeared in just over 0.1 of a second, and some whose smile appeared in just over 0.5 of a second. At the same time, some of the heads were tilted to the left and some to the right. Participants then had to judge the smiles on how trustworthy, attractive, dominant, fake and flirtatious they made the faces seem.

    Results

    The study replicated a previous finding that a long-onset smile (0.5s onset) is seen as more authentic and flirtatious. On top of this, the researchers found long-onset smiles were perceived as more attractive, more trustworthy and less dominant. Head tilting also increased attractiveness and trustworthiness but only if the head was tilted in the right direction. In this case, the right direction was the same way as eye orientation or towards a partner.

    Gender

    There was also evidence that smiles are perceived in different ways depending on the gender of both the target and the observer. Previous research has found that smiling is associated with attractiveness in women, but dominance in men. These are probably a result of gender stereotypes. One finding in the present study was that women's smiles were judged less authentic than men's. Krumhuber et al. (2007) speculate that this is because women tend to smile more than men, so their behaviour is seen as more usual and therefore less informative. The reverse may be true for men.

    While women's smile were more likely to be discounted, it seemed women were generally better at detecting the difference between short- and long-onset smiles. The differences found in this study, therefore, were mostly due to female participants rather than the men. Krumhuber et al. (2007) suggest this ties in with findings men are more likely to interpret ambiguous or inauthentic signals (short-onset smiles) as flirtatious behaviour. They can't (or won't) tell the difference.

    心理學研究在與時俱進上做得不太好，測量變得一成不變，要么隨便瞄一眼（結果）要么問問被試（結果）平均一下啊整合成一個模型。這也是為什么這項對微笑的研究如此不同尋常。一些最知名的對微笑的研究都是關于人們怎么辨認一個真誠的微笑-又稱杜鄉的微笑①或魚尾紋微笑。而這項研究是一個微笑的速度、頭部傾斜還有性別是怎樣綜合影響微笑的效果的。

    在實驗中，一百名被試男女各占一半，坐在一個顯示器前來辨認一些人工合成的笑臉 (Krumhuber, Manstead & Kappas, 2007)。他們觀看的臉上出現的微笑有的只持續0.1秒，有的持續0.5秒。與此同時，一些頭部在微笑時左傾，一些右傾。然后被試將判斷他們看過的笑臉有多大程度的真實、有吸引力、張揚、虛偽和調情。

    結論

    研究驗證了之前的發現，一個長時間的微笑（持續0.5秒）看起來更真誠和引人遐想。研究人員進一步發現了長時間微笑顯得更有吸引力、更真誠而不那么張揚。頭部微傾同樣會增加吸引力和可信度但只限于右傾。在這里右傾指的是你面向對方時的右邊。

    性別

    也有證據顯示觀看者和微笑者的性別對結果都有影響。以往的研究發現在女人看來微笑是和吸引力聯系在一起的，但對男人這種聯系更明顯。這可能與成見有關。最近的一項發現是女人比男人更常微笑，所以她們的這一行為就更普通而因此削弱了信息性。反過來對男人也適用。

    雖然女人的微笑更容易被忽略，但女人在辨別長、短微笑的區別上做的要比男人好。這項發現的原因可能是由于女性被試在測試中更專注。Krumhuber et al. (2007)認為這項發現意味著男人更容易把模棱兩可或者不真實的信號（短持續微笑）當成調情行為。他們不能（或不愿）發現區別。