yet somehow adds flavor to the plot of movies and inspiration for countless songs about heartbreak.

雖然會為電影增加一些有趣的情節或幫無數的心碎歌詞找到靈感

But why do people cheat in the first place? Is there a science behind it?

但究竟為什麼人們要劈腿呢？背後是否有科學依據？

Only about 3% of mammals are monogamous , meaning they stay with one partner their whole life

只有大約 3% 的哺乳動物是一夫一妻制，這意味它們一生都只與一個伴侶度過

and humans fall into this category.

人類也屬於這一類

From an evolutionary perspective, it creates an advantage

從進化的觀點來看，這創造了一個優勢，

where one partner can protect the younglings while the other searches for food and provides resources.

一方可以保護幼兒，而一方則去搜尋食物資源

But somehow, extra pair-mating or cheating is a fairly common human behavior.

但不知什麼緣故，出軌或背叛卻是一個人類相當普遍的行為

The gene coding for a dopamine receptor plays a key role in cheating for men and women.

多巴胺受體的基因排列在男女之間的偷吃行為中扮演一個關鍵的角色

Sometimes called the "happy hormone", it's released after pleasurable activities like

有時被稱作「快樂荷爾蒙」，它會在愉快的活動之後釋放

exercise, eating food, and orgasming.

像是運動、吃飯和性高潮

And one study found that

一項研究顯示，

50% of people who possess the long allele variant of this gene had cheated on their partner,

對偶基因中長體基因變異的人們中有 50% 會背叛他們的另一半，

compared to only 22% of people who have the short allele.

相較之下，擁有短等位基因的人們僅有 22% 會偷吃

The long allele participants also had a tendency to be risk-takers and succumb to addictive behaviors such as alcoholism.

而長等位基因變異的人們也有一種傾向，較喜歡冒險或是陷入成癮行為，例如酗酒

Perhaps the phrase once a cheater, always a cheater may have a basis in reality.

也許那句名言「一次不忠，就永遠都會不忠。」在現實中是有所根據的

Levels of the hormone vasopressin also play a role. Similar to oxytocin,

而抗利尿激素的多寡也扮演了重要的角色，類似催產素

which is sometimes called the "cuddle hormone" vasopressin can affect trust, empathy and social bonding.

被稱為「擁抱荷爾蒙」的抗利尿激素會影響人的誠信、同情和社交關係

In fact, injecting vasopressin directly into a polygamous montane vole's reward center

事實上，當一夫多妻制的山田鼠被注入抗利尿激素到他的中樞後

increases the likelihood of it becoming monogamous!

增加了牠們成為一夫一妻制的可能性！

People with autism also have lower vasopressin levels,

有自閉症者患者的抗利尿激素也是相對較低的，

affecting their ability to understand social cues.

影響了他們融入社會的能力

And in 2014 a study involving over 7000 Finnish twins

而在 2014 年的一項研究找了 7000 位芬蘭雙胞胎，

found that cheating women had a variant in the gene that codes for a vasopressin receptor

發現對另一半不忠的婦女在抗利尿激素受體的基因排編排上有些許變異

further suggesting that low levels of vasopressin have an influence on cheating.

進一步推論出抗利尿激素較少，可能會導致出軌與偷吃的行為

Money may also be a factor;

金錢可能也是一個因素，

males who earn significantly more than their female counterpart are more likely to cheat.

賺的錢比女人來得多的男人更容易背叛另一半

But they're also more likely to cheat on their wives if they are stay-at-home dads.

但如果他們是長期待在家的父親也較有可能背叛他們的妻子

Only when both partners have similar earning potential

只有當伴侶雙方有相似的經濟能力

do the chances of either cheating decrease significantly.

背判對方的機率才會顯著降低

Of course, many other life factors can lead to infidelity; from unresolved emotional issues,

當然，很多生活上的因素也都可能導致感情不忠；從難以解決的情緒問題、

baggage from past relationships and...excessive alcohol intoxication.

關係中的壓力與負擔，還有...過量的飲酒

Unfortunately same-sex partnerships have not been studied enough to gain any clear insights,

可惜的是，同性關係還沒有足夠的研究來取得明確的見解，

highlighting how scientific research continues to exclude specific minority groups.

這意味著科學研究一直在排除特定的少數群體在外

Either way, cheating is clearly based in biology and genetics for some of us, in spite of being a monogamous species.

無論哪種說法，儘管人類身為一夫一妻制的生物，大致來說對另一半不忠仍可歸究於生理學或遺傳學

Special thanks to Audible for supporting this episode and giving you a free audiobook at audible.com/asap.

特別感謝 Audible 支持這個影片，推薦給你們這個免費的有聲讀物：audible.com/asap.

This week we wanted to recommend the book "SuperBetter"

這週我們想推薦一本書「超好」，

where author and game designer Jane McGonigal explains

作者和遊戲設計師 Jane McGonigal 解釋了

how to cultivate greater resiliency in everyday life by using the mental strengths you apply to game-playing.

如何使用玩遊戲時的心理優勢來培養日常生活的彈性

You can get a free copy at audible.com/asap

你可以在 audible.com/asap 免費獲得一本

or any others of your choice from a massive selection!

或從大量的選擇中選擇任何你想要的！

We love them as they are great when you're on the go.

我們很喜歡，因為他們很棒，所以在你離開前我們想推薦給你

And subscribe for more weekly science videos!

訂閱頻道以獲得更多每週科學影片