So I'm a dad now.

我現在當爸爸了。

And my wife got me these socks.

我老婆給我買來這雙襪子。

They're covered in my son's face.

上面滿滿是我兒子的臉。

Pretty much the cutest socks ever.

簡直是世界上最可愛的襪子！

Now that I'm a dad, I realize I'm basically only going to watch animated movies for the next decade.

當爸爸了嘛，我意識到接下來幾年我基本上都只會看動畫電影了。

And as I started thinking back about all the great Disney movies through the years, I noticed something weird has been happening to the princesses.

當我開始回想過去幾年的迪士尼賣座電影時，我從公主身上注意到一件奇怪的事。

In the earliest Disney films, the princesses more or less look like real, human women.

在最早期的迪士尼電影，公主長得比較貼近真實人類女性。

But through the years, something strange happens.

但在接下來幾年，奇怪的事情發生了。

Heads get bigger compared to their bodies, and their eyes get bigger compared to their heads.

相較於身體，頭部變大了。而眼睛在頭部的比例也越來越大。

By the time we get to Elsa, it's clear this 22-year old Frozen princess doesn't look like an adult female.

到了 Elsa，很明顯這位芳齡 22 歲的《冰雪奇緣》公主長得不像個成人女性。她的身體比例相當於一位八歲小孩。

She has the body ratios of an 8 year old.

Moana is supposedly 16 years old, but she has the body ratios of a 4 year old.

Moana 照理是 16 歲，但她的身體比例相當於一個四歲小孩。

Disney princesses have been looking more and more like children.

迪士尼公主看起來越來越像小孩了。

And this case of the Benjamin Buttons isn't just happening to princesses.

這種班傑明劇情般的返老還童奇幻旅程不只是發生在公主身上。

In fact, this is true all over Toon-Town.

事實上，這是卡通界的通則。

The designs of almost all cartoon characters have changed over time, and almost always in the same way.

幾乎所有卡通角色的設計都隨著時間演變，而且幾乎都朝同一個方向發展。

As they get older, they age in reverse.

當他們歲數增大，外表卻越顯年輕。

As we develop, we get a literal "head start." Our arms, legs, and bodies catch up as we get older.

當小胚胎發育時，我們真的是「從頭開始」。我們的手臂、雙腿和身體在我們年歲增加時才會慢慢追上。

That's why a newborn's eyes are already 75% of their adult diameter, and our brains hit 55% of their adult volume by 3 months of age.

這也是為什麼新生兒的眼睛已經佔了成人頭部直徑的 75%，大腦則在我們 3 個月大時達到成人大小的 55%。

Small bodies, big heads, big eyes.

身體小，頭大、眼睛大。

Biologist Konrad Lorenz speculated that these babyish features trigger an instinct in adult mammals to give love and attention.

生物學家 Konrad Lorenz 推測，這種「類嬰兒」的特徵觸發成年哺乳類關愛的本能。

When I show you this photo of a kitten, something happens in your brain that makes you want to cuddle and feed it--unless you're some kind of unfeeling monster.

當我給你看這張小貓照片時，對你的大腦造成了影響，讓你想要抱牠、餵牠，除非你是冷血的怪獸那就另當別論。

In other words, "cuteness" is nature's secret weapon to persuade adults into caring for babies.

換句話說，「可愛」是大自然的秘密武器，用來說服成年者照顧幼兒。

Disney is just using the same biological trick to encourage audiences to root for their characters.

迪士尼就是運用了這一個的生物學技巧，鼓勵觀眾支持他們的角色。

That's why cartoon protagonists tend to have juvenile characteristics, and the villains… not so much.

這也是為什麼卡通主角往往有年少的性格，而反派則是 ... 大大相反。

But this doesn't just happen in Fantasyland.

但這不僅止於幻想世界。

Which would you rather cuddle?

你比較想抱哪一個？

This cavalier king charles spaniel?

這隻騎士查理王小獵犬？

Or this wolf?

或是這隻狼？

This floppy-eared ball of snuggles has been selectively bred to be cute.

這隻毛茸茸的小肉球被特別培育要長得可愛。

It retains juvenile features into adulthood, or, what biologists call neoteny.

就算成年了，牠依然保有幼年特徵，也就是生物學家口中的「幼態持續」。

We see neoteny in many domesticated animals.

在許多受到人類豢養的動物身上我們都看得到幼態持續。

Although selecting for cuteness can explain the spaniel, animals like pigs show neoteny too.

雖然就小獵犬而言，可愛指數是經過特別培育的，但其他動物，比如豬，也會有幼態持續。

Why would ancient humans care about the cuddle-ability of something they were raising for bacon?

為什麼老祖宗人類會在乎可愛程度啊？畢竟牠們是被養來要做培根的。

Well, maybe cuteness is just a side-effect?

或許可愛只是一種副作用？

The most important trait in becoming a domesticated animal is… tameness.

動物成為家畜最主要的一點是馴養程度。

Whether it's a companion, a worker, or a food source, you can't have a productive relationship with fearful or aggressive animals.

不論是當做伴侶、工作夥伴或是食物來源，你都無法和恐怖、有攻擊性的動物發展關係。

That fight or flight response is something that most animals only acquire as they get older--baby animals are pretty chill with humans.

「戰或逃反應」是大多數動物到了成年才會有的，動物寶寶基本上和人類相安無事。

So an animal that somehow never "grows up" in that sense might make the best candidate for domestication.

所以「永遠不會長大」的動物，在某方面上，或許就成了最適合豢養的對象。

Beginning in the 1950s, Soviet scientist Dmitry Belyaev began a breeding experiment to study this idea, using wild silver foxes.

最早在 1950 年代，蘇聯科學家 Dmitry Belyaev 開始了一項野生銀狐的育種實驗，試圖探討這個理論。

The foxes were tested for their reaction to human contact, and only the foxes that were friendly toward experimenters were allowed to breed.

實驗測試狐狸對人類接觸的反應，只有那些能夠親近的才會被繁殖。

After just 20 generations, his foxes had not only changed in behavior, but also in appearance.

過了僅僅 20 代，他的狐狸不僅在行為方面改變，外貌也有轉變。

Floppy ears, smaller jaws, and shorter tails that now wagged whenever humans were around.

鬆軟的塌耳朵、小巧的下巴、短短的尾巴，牠們看到人類靠近就會摇尾巴。

Belyaev noted changes in hormones and brain chemistry that he suspected were capable of reshaping the foxes' external features.

Belyaev 注意到他預期的荷爾蒙和腦部化學物質改變，這些都會重塑狐狸的外觀特徵。

What does this tell us?

這意味著什麼？

If you select for one childish trait, a bunch of others tend to come along with it.

當你選擇了一項幼兒特質，就會附贈其他一大堆。

Evolutionary biologist Stephen J. Gould noticed that the same was true of the world's most famous cartoon character: Mickey Mouse.

演化生物學家 Stephen J. Gould 發現，這演變也發生在全世界最有名的卡通角色身上，那就是米奇。

OG Mickey was... kind of a jerk.

初代的米奇其實 ... 挺混賬的。

But as his personality got softer and sweeter, so did his appearance.

但隨著他的個性變得更圓滑、甜美，他的外貌也跟著轉變。

By the 1950s, Mickey had not only become the child-like mouse we know today, he'd become a nice guy.

到了 1950 年代，米奇不僅成為了我們今日熟知、小孩般的老鼠，他也變成了一個好好先生。

But beyond pets or cartoons, you can also see neoteny in yourself.

但不只是寵物和卡通，你在自己身上也看得到幼態持續。

Most biologists agree that humans are, in many ways, big babies.

多數生物學家同意，人類其實在很多方面就是個大寶寶。

Compared to other adult primates, we grow less body hair, have shorter limbs, and flatter faces.

相較於其他成年靈長類，我們比較少體毛、四肢比較短、臉也比較扁平。

And if you compare how much a chimp's skull morphs as it matures, you can see that our skull shape changes much less.

而當你比較猩猩在發育時的頭骨演變，就會發現我們的頭骨不怎麼會改變。

Our neoteny offered us lots of evolutionary advantages.

幼態持續給了我們許多演化優勢。

Less body hair meant we could run farther in that African heat, and our faces were more visible to each other as social interaction became more important.

較少體毛意味著我們在非洲艷陽下能夠跑更遠，而當社會互動越來越重要時，我們的臉也顯得比較好互相辨識。

Also, suppressing our own fight or flight response meant we could cooperate and organize in larger numbers.

還有，幼態持續抑制了我們的戰或逃反應，讓我們更能夠以大群體合作。

And most importantly, these big brains need a lot of room and time to develop, which is why we rely on our parents for much longer than most mammals.

最重要的是，這些大腦袋需要大空間還有時間發育，這也是為什麼我們比其他哺乳類花更多時間仰賴父母。

It might not be a coincidence that the more complex our society gets, the more time humans need to become independent.

這或許不是巧合，我們的社會結構越複雜，我們就的確需要更多時間才能獨立。

Childhood is a time for experimentation and learning--most animals get locked into pretty rigid programs by the time they're adults.

童年是拓展和學習的階段，多數動物到了成年期就已經完全脫離幼年。

By extending our childhood into adulthood, we can learn and change as long as we live.

透過將我們的童年延長至成年，我們就能持續學習、演變。

Maybe that's why so many of us still love cartoons.

或許這也是為什麼我們許多人依然熱愛卡通。

Because we may get old, but we never grow up. That's what makes us human.

因為我們或許是會變老，但我們不會「長大」。人類就是如此。

Stay curious.

永保你的好奇心！