But even other species tend to have adorable infants.

但其它動物的寶寶似乎也很可愛。

So why has science conditioned us to find babies so precious?

為何大自然把我們設定成會呵護寶寶呢？

Is there something specific that triggers our urge to hold and squeeze them?

有沒有什麼特別原因引發我們想抱緊他們的衝動？

Interestingly, studies have found that macaque monkeys pay little attention to newborn faces, leading researchers to believe that the cute feeling may be an entirely human trait.

有趣的是，研究發現彌猴對新生兒並不會特別關注，使得研究人員相信可愛的心理反應可能是人類特有的天性。

Unlike many other species, once born, human babies are completely dependent on their parents for survival.

不像其他動物，人類寶寶一出生得完全依賴父母以求生存。

As a result, humans have adapted to find certain traits aesthetically pleasing and downright adorable in an effort to increase interaction, care and protection from parents.

因此人類發展出某些令人賞心悅目、楚楚可人的特徵，以增加與父母的互動，得到關愛與保護。

This, in turn, enhances offspring survival and perpetuates our species.

如此一來也提高後代存活率，讓我們的物種綿延不絕。

But what exactly makes something seem cute?

但究竟是哪些特徵讓我們覺得可愛呢？

Known as baby schema, scientists have come up with a set of tested traits that make something appear cute.

科學家發展出「寶寶基模」理論，他們列出一連串可愛特徵進行測驗。

These include a large rounded head, relative to the body, large eyes below the mid-line of the face, protruding cheeks, a big forehead, round body, and soft surfaces.

包括跟身體比起來，又大又圓的頭、大到佔據半張臉的眼睛、胖臉頰、寬額頭、圓身體、還有柔軟的肌膚。

Awwww!

哇嗚！

And, no doubt, our species is born with fully grown large eyes, almost full-sized brains, soft skin, big cheeks, and round bodies.

沒錯，人類出生時就擁有圓滾滾的眼睛、大大的頭、柔軟的肌膚、胖臉頰和圓身體。

In fact, in tests where baby photos are manipulated to have more baby schema traits, whether they're human babies or dogs and cats, for example, they're rated as cuter and participants felt a stronger motivation to take care of these babies.

是時尚，測驗中刻意把寶寶照片修成有更多基模特徵時，無論是人類寶寶或小貓小狗，相較下都被評為更可愛，受試者也有更強烈的欲望去保護這些寶寶。

Even when the front of cars were altered in accordance to the baby schema, like making the headlights become larger to mimic big eyes, participants experienced a more positive response.

即使把汽車車頭的外形依基模理論做調整，像是把車頭燈加大，呈現大眼睛的樣子，也得到受試者更正面的回應。

It turns out it's all in our head!

這一切全是大腦在做怪！

When viewing babies with enhanced baby schema proportions, the mesocorticolimbic system of our brain is activated.

當看到有寶寶基模比例的嬰兒時，大腦的中央皮質邊緣系統便啟動。

These parts of the brain enhance the anticipation of a reward and can lead to a sense of enjoyment and motivation to care for something and the urge to cuddle or hold an object.

此腦部區域會強化對獎酬的期待，產生愉悅感和保護他人的渴望，也有股衝動想把東西擁入懷中。

But what about things that aren't... so cute?

但是那些不那麼可愛的東西呢？

In fact, some creatures are downright ugly!

事實上，有些生物簡直醜斃了！

So what does science have to say about these?

這在科學上怎麼解釋？

Our friends at Earth Unplugged have answered this very question in our collaboration on animals,

我們和「地球不插電」節目一起合作動物相關研究，他們在節目中回答了這個問題。

so click on the screen or on the link in the description to find out.

請點擊螢幕或說明區的連結進入了解更多。

Huge thanks to the team at Earth Unplugged for providing us with all this footage.

大力感謝地球不插電團隊贊助我們這些影片。

Go watch their video and follow them for even more amazing content.

去看他們的影片，追蹤他們看更讚的內容。

And subscribe for AsapScience for more weekly science videos.

並訂閱 AsapScience 每週觀看科普影片。