中国科技网4月15日报道（张微 编译）发表在心里学协会的期刊《心里科学》的一项最新研究表明，通过我们的汗味，人类可以传递比如快乐这样的积极情绪。这项研究表明，当我们愉悦的心情被接触到我们汗水人感受到的时候，我们产生了一种化学化合物或化学信号。

虽然以前的研究表明，恐惧和厌恶这类消极的情绪能够通过汗液中的化学成分进行传播，但是很少有研究探讨，积极的情绪是否具有相同的传播功能。“我们的研究显示，接触到心情愉快时产生的汗水时，能够诱发接收者一种幸福幻影，并引起情绪状态的蔓延，”荷兰乌得勒支大学心理学家，这项研究的高级研究员Gün Semin解释说。“这表明幸福快乐的人会将这种情绪传染给身边的人，让他们有福同享。在某种程度上，幸福的汗水有点像微笑——它是会传染的。”

为了确定这种情感化学信号是否会延伸成积极的情绪，Semin和同事们检验了人们快乐状态下的汗水是否会影响行为、感知和接触到汗水的人的情绪状态。

研究人员招募了12名白人男性，他们为这项研究提供汗水样本。参与者们不吸烟或服用任何药物，而且没有心理障碍。他们被禁止喝酒，性生活，食用有特殊味道的食物，以及在研究期间过度运动。参与者来到实验室，清洗并擦干了腋下，并在腋窝处粘上了吸水垫。他们穿上水洗布t恤坐下来完成研究任务。他们观看了一个试图诱发他们情感状态(恐惧、快乐、中性)的一个视频短片，还完成了隐性情绪的测量，在这个测量中他们被告知观察汉语符号并记录每个人愉快或不愉快。然后移除吸水垫并将其储存在瓶子里。

在第二部分研究中，研究人员招募了无心理障碍，呼吸系统疾病或其他疾病的36名白人女性。研究人员指出，这部分研究只有女性参与，女性拥有比男性更加敏锐的嗅觉和敏感的情绪表达。这是一样双盲研究，研究人员和实验参与者都不知道在实验中参与者会接触到哪一个汗水样本。

女性坐在椅子上，下巴置于腮托上。装有汗水样本的瓶子放置在一个与腮托连接的支架上，在目标任务之前立即打开瓶子。女性接触到每种类型(恐惧、快乐、中性)的汗水样本，不同样本之间有五分钟的间隔。

最初的数据分析证实，视频短片确实影响了男性参与者的情绪状态，观看恐怖视频之后男性显示出负面情绪，而且观看快乐视频的男性显示出积极情绪。

但这些情感状态会传递给女性参与者吗?行为学的研究结果表明，答案是肯定的。

面部表情数据分析显示，接触到“恐惧汗水”的女性显示出内侧额肌肉活动增加，这是恐惧表情的普遍特征。接触到“快乐汗水”下的女性显示出更多的面部肌肉活动，这是真诚笑容的体现，快乐表情的组成部分。在女性的面部反应和他们的界定愉快以及紧张的汗水之间没有显著的关联。

研究人员说这些发现表明，发送者(提供汗水样本的人)和接收者(接触到汗水的人)之间的一个“行为同步”。这些初步的研究成果表明，通过不同的化学信号，比如接收者所产生的发送者情感状态的模拟，我们就能够表达出积极和消极的情绪状态。

这项发现具有广泛的关联性——毕竟情感和汗水是人类经历的两个核心特征。快乐通过化学方式传播的事实，由于其潜在的商业应用价值，可能会引起“气味行业”的兴趣，Semin说。“我们人体汗液传播功能的一般模型还有另外一项任务，我们将继续完善它，了解人体汗液对接触到这些化合物的人神经系统的影响。”Semin总结道。

A sniff of happiness: Chemicals in sweat may convey positive emotion

Humans may be able to communicate positive emotions like happiness through the smell of our sweat, according to new research published in Psychological Science, a journal of the Association for Psychological Science. The research indicates that we produce chemical compounds, or chemosignals, when we experience happiness that are detectable by others who smell our sweat.

While previous research has shown that negative emotions related to fear and disgust are communicated via detectable regularities in the chemical composition of sweat, few studies have examined whether the same communicative function holds for positive emotions.

"Our study shows that being exposed to sweat produced under happiness induces a simulacrum of happiness in receivers, and induces a contagion of the emotional state," explains psychological scientist Gün Semin of Utrecht University in the Netherlands, senior researcher on the study. "This suggests that somebody who is happy will infuse others in their vicinity with happiness. In a way, happiness sweat is somewhat like smiling - it is infectious."

To determine whether this emotional chemosignaling extends to positive emotions, Semin and colleagues examined whether sweat taken from people in a happy state would influence the behavior, perception, and emotional state of people exposed to the sweat.

The researchers recruited 12 Caucasian males to provide the sweat samples for the study. The participants did not smoke or take any medications, and had no diagnosed psychological disorders. They were prohibited from engaging in alcohol use, sexual activity, consumption of smelly food, or excessive exercise during the study.

The sweat donors came to the lab, rinsed and dried their armpits, and had absorbent pads attached to each armpit. They donned a prewashed T-shirt and sat down to complete the study tasks. They watched a video clip intended to induce a particular emotional state (fear, happiness, neutral) and they also completed a measure of implicit emotion, in which they were asked to view Chinese symbols and rate how pleasant or unpleasant each one was. The sweat pads were then removed and stored in vials.

For the second part of the study, the researchers recruited 36 Caucasian females, with no psychological disorder, respiratory disease, or other illness. The researchers note that only females were included in this part of the study as women generally have both a better sense of smell and a greater sensitivity to emotional signals than men do. The study was double-blind, such that neither the researcher nor the participant knew which sweat sample the participant would be exposed to at the time of the experiment.

The women were seated in a chair and placed their chins on a chin rest. The vial containing the sweat sample was placed in a holder attached to the chin rest and was opened immediately prior to the target task. The women were exposed to a sweat sample of each type (fear, happiness, neutral), with a 5-minute break in between samples.

Initial data analyses confirmed that the videos did influence the emotional states of the male participants - men who watched the fear video showed predominantly negative emotion afterward and men who watched the happiness video showed predominantly positive emotion.

But were these emotions conveyed to the female participants? Some behavioral results suggest the answer is 'yes.'

Facial expression data revealed that women who were exposed to "fear sweat" showed greater activity in the medial frontalis muscle, a common feature of fear expressions. And women who were exposed to "happy sweat" showed more facial muscle activity indicative of a Duchenne smile, a common component of happiness expressions. There was no observable association, however, between the women's facial responses and their explicit ratings of how pleasant and intense the sweat was.

These findings, the researchers say, suggest a "behavioral synchronization" between the sender (the sweat donor) and receiver (the sweat smeller).

These findings, while preliminary, suggest that we communicate our positive and negative emotional states via distinct chemosignals, such that the receiver produces a simulacrum of the sender's emotional state.

The findings have broad relevance - emotion and sweat are two core features of the human experience, after all. But the fact that happiness may be communicated chemically could be of particular interest to the "odor industry," says Semin, due to its potential commercial applications.

"This is another step in our general model on the communicative function of human sweat, and we are continuing to refine it to understand the neurological effects that human sweat has on recipients of these chemical compounds," Semin concludes.