And The Pet Collective offers 24-hour coverage of puppies and kittens.

《Pet Collective》會 24 小時不間斷地播放有關狗狗和小貓的影片。

It's really cute.

真的超可愛！

But what is "cute", scientifically?

但以科學的角度來想，到底什麼是「可愛」？

I mean, why do we like soft, cuddly things, and why do cute things have a unique effect on us?

為什麼我們會喜歡柔軟、惹人憐愛的東西？為什麼可愛的東西對我們會有獨特影響？

Well, the word "cute" is a shortening of "acute", which originally meant "keen", "shrewd", "perceptive".

「可愛」這個字是 acute 的簡寫，原本意思是「渴望的」、「機靈的」以及「感知的」 。

About 180 years ago, the word "cute" began to be used as slang for a girl who was pretty.

約在 180 年前，「可愛」這個字就已經是用來形容漂亮女生的俚語。

And after that, it accrued a new meaning, and was used to describe cuddly, delicate, quaint, precious, youthful traits.

後來這個字獲得了新的意思，可以用來形容惹人憐愛的、嬌嫩的、有趣的、珍貴的以及年幼的特質 。

Konrad Lorenz studied cuteness in living things and put together a great specific list of what we consider cute.

Konrad Lorenz 研究生物的可愛性，並具體列出會讓我們認為可愛的物體清單 。

Small body size with a disproportionately large head, large eyes, and round and soft body features.

嬌小的身軀、搭配不合比例的大頭和大眼睛以及又圓又軟的身體特徵 。

But why exactly did these characteristics elicit an "awww" response from us humans?

但到底為什麼這些特徵會引起人們發出「哦～」的感嘆呢？

Well, Lorenz pointed that you can find all of those characteristics in the human baby, which makes sense.

Lorenz 指出這些特質全部都可以在人類寶寶身上看到，而且這說得通。

If merely looking at our offspring makes us instinctively feel protective and nurturing, well, that's great for all of us.

如果只看著我們的後代，就會使我們本能上地產生安全及呵護感；那對我們所有人都很好！

A fun consequence of this is that our experience of cuteness can be triggered by things that aren't human babies.

這個研究發現一個有趣的結果是，我們對於可愛的體驗也可以被嬰兒以外的事物引起。

For instance, shells, bunnies, owls, and even a hammer.

例如：貝殼、兔子、貓頭鷹或甚至是鐵鎚。

A hammer, how can that be?

一枝鐵鎚！這怎麼會可愛？

Take a look at this interactive tool from the Exploratorium.

看看這個來自科學探索館的互動式教學。

A hammer is boring.

一枝鐵鎚很乏味。

But if we apply Lorenz's traits and make it really round and really squat, it goes from a utilitarian tool to a cute, little, tiny hammer.

但如果我們運用 Lorenz 所列的可愛特徵，把這枝鐵鎚變得又圓又矮胖，它就會從一個實用的工具變成一個小巧可愛的鐵鎚。

Oh, he's just a little hammer; don't hurt him!

喔～他只是一枝小鐵鎚，不要傷害它！

It is a hammer that has become cute because we gave it qualities that we see in our own offspring.

這隻鐵鎚會變可愛是因為我們賦予它在我們後代身上會看到的可愛特質。

As Daniel Dennett puts it, "If human babies looked like this, instead of that, we would find this cute."

根據 Daniel Dennett 的說法：「如果嬰兒看起來像這樣 (右)，而不是那樣 (左)，我們就會覺得這個 (右) 可愛。」

And whenever we saw something that looked like it, we would wanna cuddle and snuggle with it.

而且我們不論何時看到像這樣的東西，都會想要撫摸、緊抱它不放。

All right, so we have a pretty good idea about the "how" and "what" of cute.

很好！所以我們現在已經知道可愛的「方法」及「程度」了。

But "where" is cute?

但是「什麼部位」使我們感覺到可愛？

Well, researchers have shown cute baby pictures to subjects while using functional MRI to track activity in the brain.

研究員拿出可愛寶寶們的圖片給正在做核磁共振的人看，並追蹤他們腦部的波動。

And sure enough, the cuter the baby in the picture, the more activation found right here, the nucleus accumbens, a pleasure center.

非常確定的是，越是可愛的寶寶，就越能激發腦部這個區域的活化——伏隔核，快樂中樞。

When activated, the nucleus accumbens releases dopamine.

伏隔核被活化時會釋放出多巴胺。

It's all part of our internal reward system.

這分布在我們體內的酬賞系統。

It's the same part of the brain targeted by cocaine and meth.

這也是吸食古柯鹼及甲基安非他命的腦部反應位置。

Cuteness is such a powerful force on the brain, in fact, that it can affect our behaviors ⏤ what we like, what we buy.

可愛在腦部有著很強大的影響力。事實上，它會影響我們的行為——我們所喜歡或購買的東西。

And, so, it's no coincidence that the creators of cartoon characters, like Mickey Mouse or Pikachu, have drawn them more and more cute over time.

所以，卡通人物的創作家將米老鼠或是皮卡丘畫得一次比一次地可愛並不是偶然。

The Japanese concept of "kawaii" is a great example of this, and it's one that's fun to quantify.

日本人所認為的「可愛」就是一個很好的例子，而且以數量表示起來會很有趣。

If you're an adult, how many of your own heads ⏤ stacked on top of each other ⏤ do you think it would take to equal your height?

如果你是個成年人，你們覺得要疊幾個你的頭，才會等於你的身高？

The answer for most of us is around seven and a half.

答案是：對我們大部分人來說，約是 7.5 個頭。

But illustrations of people that are meant to make them look heroic or noble tend to make the person around eight to eight-and-a-half heads high.

但是想畫一個英雄或高貴的角色時，會把人物畫到約 8 到 8.5 個頭高。

Cute goes the other way.

可愛則是相反的。

Manga characters tend to only be about five-and-a-half to six-and-a-half heads tall.

漫畫角色們通常只有 5.5 到 6.5 個頭高。

Back to babies.

回歸到嬰兒。

There are many other psychological factors at work that cause us to want to instinctively take care of our young.

有很多其他的心理因素促使著我們本能地想要呵護著小孩。

And to be sure, some of them are decidedly not cute.

可以知道的是，有些事情確定是不可愛的。

For instance, poopy diapers.

舉例來說，充滿便便的尿布。

Researchers have found that mothers, when exposed to soiled diapers, tend to consider the smell coming from their own child's diaper to be the least terrible, despite not knowing which diaper belonged to which kid.

研究者發現，當母親接觸到髒尿布時，她們會想著自己小孩的尿布臭味是最不難聞的，儘管不知道哪一個尿布是哪個小孩的。

When something retains juvenile traits all the way through adulthood, it is called "neoteny", and we love it, especially in animals that we keep as pets.

當某人直到成年都可以維持著年輕的特質，就稱為「幼態持續」。我們愛這種現象，特別是我們養的寵物。

Of course, us humans have selectively bred all kinds of animals to make each generation more and more useful to us.

當然，我們人類選擇性地培育各種動物，讓每一代的動物能更符合我們的需求。

But the dog may be the animal that we have spent the most time designing, making each generation better at hunting or better at staying cuter for longer.

但狗應該是人類花最久的時間來培育的動物，讓每一代越來越會打獵或越能維持可愛。

Dogs like this have been designed by us to look, grow, and behave in ways that we want.

這些狗的外貌、成長以及行為已經被培育成我們喜愛的形式。

Not that dissimilar from how we would design, say, a DVD player and its features.

就如同我們會設計 DVD 播放器及它的功能一樣。

So, whether it's staying cute forever or just being a really great hunting companion, the modern dog, more than any other animal, could be considered not so much a consequence of nature as much as it is a piece of human technology.

所以，不論是永遠地可愛下去或是單單成為一個非常好的打獵夥伴，相對於其他任何動物，現代的狗可以被認為不再是大自然演化的結果，而是人類科技的作品。

As "Science Friday" puts it, "The dog is man's best friend because it may be man's best invention."

如同《Science Friday》所指出：「狗是人類的最要好的朋友，可能是因為牠是人類的最好發明。」

So, go pet a cute dog today.

所以，去養一隻可愛的狗狗吧！

And, as always, thanks for watching.

一如往常地，謝謝您們的觀看。