But why doesn't your gas seem half as smelly as those around you?

但為何我們放的屁不像其他人那麼臭？

Why do we like the smell of our own farts?

為什麼我們喜歡自己的臭屁呢？

Hilarious as it may seem, scientists have actually confirmed the fact that, in blind-smell tests, we truly do find our own smells much more appealing than others.

有趣的是，在一盲測試中，科學家已經證實，我們覺得自己的屁味比別人好聞。

Simply put, the more familiar you are with something, whether it be a song, picture, or even a smell, the more likely you are to prefer it.

簡而言之，不論是一首歌、一幅畫，甚至是味道，只要是你越熟悉的東西，你就會越喜歡。

And because the bacterial population in your body producing these smells is completely unique from every other individual, our farts truly have a one-of-a-kind brand that your nose can differentiate.

因為每個人體內導致放屁的菌體都不同，只有我們自己才能嗅出這獨一無二的臭屁。

But, from an evolutionary perspective, our reaction of disgust to other people's odor is likely our brains' attempt to prevent us from doing harm to our own bodies,

但從演化的觀點來看，我們會對他人的怪味感到反感，是大腦機制要保護我們受到傷害，

specifically interacting with sources of disease.

尤其是跟病原體接觸時，更會感到噁心。

When you think of it, most things that don't smell good, aren't good for you.

想想看，那些不好聞的東西，都對身體不好。

And the greater the risk of disease, the more intense your response will be.

染上疾病的風險越高，你身體的反應也會更激烈。

Surprising as it may seem, farts can spread disease.

令人驚訝的是，放屁也會傳播疾病。

In fact, there are many reported cases of farts spreading Streptococcus pyogenes, a pathogen that can cause tonsillitis, scarlet fever, heart disease, and even flesh eating disease.

許多已通報案例指出放屁會傳播化膿性鏈球菌，這種病原體會導致扁桃腺炎、猩紅熱、心臟病跟食肉细菌感染。

Seriously, the pathogen is expelled as fecal matter or poop particles in the air.

這種病原體以排泄物微粒的形式散播到空氣中。

Of course, this was a major concern for our ancestors who ran around naked, but for us underwear or pant[s] wearing folks, farts don't pose a real threat.

當然，對衣不蔽體、光溜溜跑來跑去的祖先來說，這點很值得擔心，但對有穿衣服的現代人來說，放屁不構成太大威脅。

And it's important that we've adapted to like our own odors, so that we can maintain proper hygiene.

習慣自己的味道很重要，這樣才能保持自己的衛生。

In the same way, mothers perceive their biological children's poop as less offensive than others, which allows them to take care of them without disgust.

同樣的道理，媽媽們不會覺得自己的小孩便便很臭，這樣才能好好的照顧他們，而不會感到反胃。

Of course, some of you may be thinking "I don't find farts disgusting at all!", and you're not alone.

你們可能會心想「我不覺得屁味很噁心啊！」，不過不是只有你們這麼想。

Perception of disgust is a combination of variables like age, gender, culture, and even personality.

大家對噁心的標準不太一樣，這些跟年齡、性別、文化甚至是個性有關。

So much so that people who are more anxious or socially conservative are often more sensitive to stink than their adventure seeking friends.

所以那些容易緊張或是不善交際的人，會比他們愛冒險的朋友們更在意自己的味道。

The anterior cingulate cortex, which processes surprise, also plays a big role.

腦中用來處理意外的前扣帶迴，也扮演了很重要的角色。

When we fart, we know it, and can anticipate the accompanying smell.

當我們要放屁時，我們會知道自己何時會放，也會預期有什麼樣的味道。

But when somebody rips a silent but deadly fart into a crowded room, the brains expectations of reality are smashed by the negative stimulus, making it all seem even more foul.

但若有人不小心在擠滿人的地方放了無聲的臭屁，大腦接受負面的刺激，會讓人有味道更臭的錯覺。

So next time you feel a silent stinker coming on, you might want to give everyone a heads up.

下次想要放這種無聲臭屁，可能要提醒大家要迴避一下。

Unless of course, you're alone; then you can bask in the glory of your own stench.

除非你自己一人，那就省下這些麻煩啦；你可以盡情享受臭味。

Don't forget, The AsapSCIENCE book just went on presale!

別忘了，AsapSCIENCE 書預售中！

Not only can you own a physical version of some of your favorite video episodes, which we've re-drawn and updated, but we wrote a whole bunch of new chapters answering questions that have never been answered here on AsapSCIENCE!

現在你可以看到你喜歡的影片都被轉成實體書籍，書中也為那些尚未解開的謎團編寫了新單元。

Check out asapscience.com/book to get your copy! We truly appreciate all of the support!

拜訪 asapscience.com/book 買一本吧！我們由衷感謝你的支持！

You can also watch our latest AsapTHOUGHT video "The Science of Beards" where we debate the scientific advantages of growing it out or staying clean shaven.

你也可以看看 AsapTHOUGHT 最新的影片「鬍子的科學」，以科學角度談論到底要不要留鬍子。

To beard or not to beard? Head over there with the link in the description, and let us know which side wins! And subscribe, for more weekly science videos!

要刮還是不刮？請點選下面的連結，我們想知道哪一個比較多人支持！記得訂閱以收看更多每週科學影片！