(单词翻译:单击)
When you come home at the end of a long day, you might unwind with a lavender bubble bath.
晚上下班回到家后，你或许会用薰衣草泡沫浴放松一下自己。
Or maybe you light a zesty orange candle as part of your study ritual.
或是点燃一支清爽橘皮蜡烛作为学习仪式的一部分。
These habits fall under the umbrella of aromatherapy: the idea that smelling so-called "essential oils" can change your mood or even have healing effects.
这些习惯都属于芳香疗法范畴：所谓芳香疗法是指“香精油”能够改善你的心情，甚至有着治愈疗效。
It might all sound like pseudoscience, but there have been many studies showing that fragrant essential oils can make you feel more positive, relaxed, or even feel less pain.
这听起来有点像伪科学，但是很多研究表明芳香精油能让你感到积极、放松，甚至缓解疼痛。
But, and I'm sure you were waiting for me to say it, it might not only be the oils.
但是，我就知道大家在等我说这个，但是或许不仅仅是油在起作用。
There may also be other ways of explaining these effects, too.
还有很多其他方式能够解释这些效果。
Despite their name, essential oils aren't actually essential, at least, not for your body.
虽然名字如此，但精油并非必需品，至少你的身体并不需要精油。
Instead, they're found in the bodies of plants, where they're sometimes used for protection.
相反，它们被发现于植物中，有时起到保护作用。
These oils are complex mixtures of dozens of different compounds that are super small and light.
这些精油是几十种不同化合物质的复杂混合，这些物质超小且轻。
So unlike other smelly things, they can easily float up and into your nose.
所以和其他散发味道的物体不同，它们能够轻易地浮起来并进入你的鼻子。
Most of these compounds are either terpenes, which are made of chains of carbon and hydrogen atoms, or aromatic compounds,
这些化合物多数要么是萜烯—由碳和氢原子链组成，要么是芳香族化合物—
which are carbons and hydrogens arranged in a flat ring.
即排列在平面的环带的碳和氢。
Mixtures of these chemicals will form anything from peppermint oil to lavender oil.
这些化合物的混合将形成任何一种精油，比如薄荷油和薰衣草油。
Then, they're put in candles, lotions, and all sorts of products that can supposedly help you focus or relax.
然后，将它们放在蜡烛、洗剂以及各种用于帮助你放松的产品中。
Now, it is worth mentioning that some people claim aromatherapy can treat clinical anxiety, depression, or cancer.
值得一提的是，一些人认为芳香疗法能够治愈临床性焦虑症、抑郁症和癌症。
But there are few, if any, rigorous studies showing that the oils alone can do those things, no matter what the people selling them advertise.
但是证明仅靠这些油就能到达疗效的严格研究非常少，不论广告有多吹。
But, when it comes to relaxation or focus, those effects don't seem to just be marketing.
但说道放松和专注，那些效果似乎不是依靠市场营销出来的。
Tons of studies have shown that all those compounds reaching your nose really can change how you feel.
很多研究表明所有进入鼻子的化合物真的可以改善你的感受。
For example, a 2005 study published in the Journal of Physiology and Behaviour looked at how 220 patients waiting in a dentist's office responded to orange or lavender scents.
例如，2005年发表于《生理学与行为》期刊的一项研究对220名等待看牙医的病人他们对橘子或薰衣草香气的反应进行观察。
The patients either smelled those fragrances wafting around the waiting room, heard some cheerful music, or neither.
要么是给候诊室中的病人闻那些芳香，听欢快的音乐，要么什么都没有。
They were also handed questionnaires to fill in while they waited, which were surveys about things like pain, anxiety, and mood.
在等待时，还给他们分发问卷，对他们的疼痛、焦虑和心情进行调查。
Those who smelled either orange or lavender said they felt less anxious, more positive, and calmer compared to others who didn't get the scents or who listened to music.
相比那些没有闻到香气也没有听音乐的病人，那些闻着薰衣草或橘子味道的病人称他们没那么焦虑、更加积极且更加镇定。
And there are literally hundreds of other papers showing similar results from other experiments.
还有很多研究利用其他试验证明了类似的结果。
But even with all those studies, it's still not clear if the essential oils alone are really responsible for those changes -- or, if they are, how they work.
但即便有这些研究，我们还是不知道是否是这些精油单独起到了作用—如果是，那么它们是如何起到作用的。
There are some studies in rat brains that suggest essential oils could boost feel-good neurotransmitters in your brain, like dopamine and serotonin.
一些对老鼠大脑进行的研究表明精油能够促进让大脑感觉良好的神经递质，比如多巴胺和血清素。
Or they could dampen the autonomic nervous system, which controls your heart rate and breathing. But why they'd do this isn't as obvious.
或者它们会抑制自主神经系统，自主神经系统控制你的心率和呼吸。但是它们为何能够如此还不清楚。
As far as we can tell, there's no specific pathway that's triggered when these terpenes or aromatic molecules bind to the receptors in your nose.
据我们所知，当这些萜烯或稠环分子和鼻子中的受体进行捆绑时，并没有触发任何特殊通道。
Instead, it's more likely that essential oils work for psychological reasons.
相反，更有可能是精油只是心理原因的效用。
But, maybe unsurprisingly, figuring out what those reasons are isn't a walk in the park, either.
但是要弄清其中原因也不简单。
The research in this field hasn't exactly been bulletproof, and there are a ton of confounding variables most studies haven't been designed to account for.
对于该领域的研究并非无懈可击，多数研究并未对那些让人困惑的变量进行调查。
For example, it's possible that the situation or ritual around inhaling the scent could be more important than the smell itself.
例如，可能吸入香气时的场合或仪式比味道本身还重要。
One 2006 study showed that new mothers given lavender or citrus oil massages felt less anxious or tired after giving birth.
一项2006年的研究表明初产妇做过薰衣草或柑桔油按摩后，在生产完后，她们会感到没那么焦虑或疲劳。
But it may not have just been the smell of the oil. It could've also been that, well, massages are generally soothing.
但是这可能不仅仅是因为精油的香气，也可能是，嗯，按摩本是就很舒服。
Why these oils work could also just be a matter of preference or even the placebo effect.
这些精油的效用，可能就是个人偏好或者甚至是安慰剂效果。
That's where the effect comes from your beliefs and not from the properties or chemistry of the treatment.
这些效果来自于你的信仰而非治疗本身或其化学过程。
Or it could be a combination of these things.
又或者是这些事物的相互结合。
Right now, the reasons are really hard to pin down because there are some major scientific issues with how many of these studies were done.
现在其中原因很难确定，因为如何进行这些研究还涉及一些主要的科学问题。
The biggest, is that few of them are controlled and double blind.
最大的问题是其中一些是不可控的研究以及双盲研究。
A controlled study compares the test situation to something neutral basically to see if the experimental conditions have any effect.
一项可控研究对测试情况和一些中立因素进行基本对比以观察实验条件对其是否有影响。
And in a double blind study, neither the participants nor the experimenters know who's being tested with what. This helps prevent bias.
在一项双盲研究中，参与者和实验者都不知道会对哪组进行测试。这就帮助排除了偏见因素。
Another problem is that these studies also often ask people to rate their feelings using a questionnaire.
另一个问题是这些研究常利用问卷要求参与者评估自己的感受。
And the questions on these surveys can sometimes skew the results.
调查中的问题有时偏离了结果。
In that dentist study, for example, patients were asked to rate how calm they felt -- not how they felt in general.
例如在那个牙医实验中，病人们被要求评估自己有多镇定—而不是他们感觉如何。
By giving study subjects options for their feelings rather than leaving the question open,
给研究对象提供描述感受的研究主题选择而非开放性问题，
that could have made people seem calmer than they actually were.
这会使人们比真实感觉要更加镇定。
When it comes to scientific evidence, it's not always about the overall number of studies.
在提及科学证据时，其并非总是关于研究的总数量。
If those studies aren't well-designed, the results won't be conclusive.
如果那些研究设计不佳，其结果也不具总结性。
So to really understand how essential oils affect us and why they cause the feelings they do, it would help to have more rigorous research.
所以想真正了解精油如何影响我们以及为什么它们会触发这些感受，还需要进行更过严格的研究。
But while scientists are working on that, all of this doesn't mean that it's time to throw out your relaxing bath bombs or perfume diffusers.
但是虽然科学家还在研究阶段，所有这一切并不意味着你该扔掉自己的爆炸浴盐或香水扩散器。
There is plenty of evidence that using essential oils does something it's just not clear whether it's the oils or the experience of using them
有很多证据证明使用精油确有帮助，只是我们还不清楚是精油还是使用它们的过程
that's really responsible for the warm and fuzzy feelings.
起到了放松的作用。
Thanks for watching this episode of SciShow!
感谢收看本期《科学秀》！
If you liked exploring some of the psychology involved in essential oils, we've got the channel for you.
如果你喜欢探究精油的心理学世界，我们也有栏目推荐。
You can find even more videos about your mind and how it works over at youtube.com/scishowpsych.
你能在youtube.com/scishowpsych中看到更多相关视频。
