How your brain decides what is beautiful | Anjan Chatterjee

譯者: Lilian Chiu 審譯者: 易帆 余

It's 1878.

1878 年，

Sir Francis Galton gives a remarkable talk.

法蘭西斯高爾頓爵士 做了一場非凡的演說。

He's speaking to the anthropologic institute of Great Britain and Ireland.

演說的對象是英國 與愛爾蘭的人類學機構。

Known for his pioneering work in human intelligence,

高爾頓以他在人類 智慧領域的先驅工作聞名，

Galton is a brilliant polymath.

他是個博學的人。

He's an explorer,

他是個探險家、

an anthropologist,

是個人類學家、

a sociologist,

是個社會學家、

a psychologist

是個心理學家、

and a statistician.

也是個統計學家。

He's also a eugenist.

他還是個優生學家。

In this talk,

在那場演說中，

he presents a new technique by which he can combine photographs

他展示了一項新技術， 他可以把照片結合

and produce composite portraits.

產生出複合的肖像。

This technique could be used to characterize different types of people.

這項技術可以用來 描繪不同類型人的特色。

Galton thinks that if he combines photographs of violent criminals,

高爾頓認為，如果他可以把 暴力罪犯的照片結合起來，

he will discover the face of criminality.

他也許就能夠發現罪犯的面貌。

But to his surprise,

但，出乎他意料，

the composite portrait that he produces

他製作出的複合肖像竟然

is beautiful.

很美。

Galton's surprising finding raises deep questions:

高爾頓的意外發現， 帶出了更深的問題：

What is beauty?

美，到底是什麼？

Why do certain configurations of line and color and form excite us so?

為什麼將線條、顏色、形式 做某些配置之後就能感動我們？

For most of human history,

在大部份的人類史上，

these questions have been approached using logic and speculation.

人們都用邏輯和推測 來處理這些問題。

But in the last few decades,

但在最近幾十年，

scientists have addressed the question of beauty

科學家在處理關於美的問題時，

using ideas from evolutionary psychology and tools of neuroscience.

用的是來自演化心理學的想法 以及神經科學的工具。

We're beginning to glimpse the why and the how of beauty,

我們開始研究美的定義與成因，

at least in terms of what it means for the human face and form.

至少對臉部及外型 已經開始有了審美的概念。

And in the process,

在過程中，

we're stumbling upon some surprises.

我們偶然發現了一些驚喜。

When it comes to seeing beauty in each other,

談到互看順眼時，

while this decision is certainly subjective for the individual,

對個人而言，其審美標準 絕對是主觀的，

it's sculpted by factors that contribute to the survival of the group.

原因是因為這樣對 團體的生存有所貢獻。

Many experiments have shown

許多實驗都顯示，

that a few basic parameters contribute to what makes a face attractive.

有幾個基本參數 與臉孔的吸引力有關。

These include averaging, symmetry and the effects of hormones.

這些參數包括大眾臉、 對稱性、以及荷爾蒙的影響。

Let's take each one of these in turn.

我們一項一項來討論。

Galton's finding

高爾頓發現，

that composite or average faces are typically more attractive

混血兒或有大眾臉的人

than each individual face that contributes to the average

通常比一般單一血種的後代

has been replicated many times.

更具吸引力。

This laboratory finding fits with many people's intuitions.

這個實驗室的發現， 與許多人的直覺不謀而合。

Average faces represent the central tendencies of a group.

一般人的面孔代表了 一個團體的主要傾向。

People with mixed features represent different populations,

有混血特徵的人， 代表著不同的族群，

and presumably harbor greater genetic diversity

也被認定有著更高的 基因多樣性、

and adaptability to the environment.

以及對環境的適應力。

Many people find mixed-race individuals attractive

許多人覺得混血兒的臉孔 是較有吸引力的，

and inbred families less so.

而近親交配的家庭 就比較沒吸引力。

The second factor that contributes to beauty is symmetry.

與美有關的第二個因子是對稱性。

People generally find symmetric faces more attractive than asymmetric ones.

一般來說，人們覺得對稱的面孔 比不對稱的更有吸引力。

Developmental abnormalities are often associated with asymmetries.

不正常的成長通常都與不對稱有關。

And in plants, animals and humans,

植物、動物、及人類，

asymmetries often arise from parasitic infections.

造成不對稱的原因 通常是受到寄生蟲的感染。

Symmetry, it turns out,

因此，對稱性

is also an indicator of health.

也是健康的指標。

In the 1930s,

在 1930 年代，

a man named Maksymilian Faktorowicz

有個叫蜜斯米蘭佛陀維茲的人，

recognized the importance of symmetry for beauty

當時他在設計美容校準儀時，

when he designed the beauty micrometer.

體認到對稱性對於美的重要性，

With this device,

有了這個儀器，

he could measure minor asymmetric flaws

他可以測量出微小的對稱瑕疵，

which he could then make up for with products he sold from his company,

接著他就可以用他公司 所販售的產品來補救，

named brilliantly after himself, Max Factor,

並很聰明地把他的名字取其諧音 作為公司的名稱，蜜絲佛陀，

which, as you know, is one of the world's most famous brands

各位應該知道，它是世界知名的

for "make up."

化妝品公司之一。

The third factor that contributes to facial attractiveness

與臉部吸引力有關的第三個因子是

is the effect of hormones.

荷爾蒙的影響力。

And here, I need to apologize for confining my comments

在此我得道個歉，因為我的意見

to heterosexual norms.

僅限於異性戀的標準上。

But estrogen and testosterone play important roles

但在形成被我們認為 有吸引力的那些特徵上，

in shaping features that we find attractive.

雌激素和睪丸素 扮演了重要的角色。

Estrogen produces features that signal fertility.

雌激素產生的特徵 會傳達出生育力。

Men typically find women attractive

男人通常會覺得，同時俱有

who have elements of both youth and maturity.

年輕和成熟元素的女人 很有吸引力。

A face that's too baby-like might mean that the girl is not yet fertile,

太幼齒的面孔可能代表著 這個女孩還沒有生育能力，

so men find women attractive

所以能吸引男人的女人

who have large eyes, full lips and narrow chins

通常有大眼睛、豐脣、窄下巴，

as indicators of youth,

這些都是年輕的指標；

and high cheekbones as an indicator of maturity.

而高顴骨則是成熟的指標。

Testosterone produces features that we regard as typically masculine.

睪丸素產生的特徵，通常會被我們 認定為很有男子氣概。

These include heavier brows,

這些特徵包括濃眉、

thinner cheeks

瘦臉頰、

and bigger, squared-off jaws.

較大且方形的下頜。

But here's a fascinating irony.

但這裡有個很迷人的諷刺。

In many species,

在許多物種中，

if anything,

睪丸素的增加

testosterone suppresses the immune system.

反而會抑制免疫系統。

So the idea that testosterone-infused features are a fitness indicator

所以認為睪丸素 所賦予的特徵是強健的指標，

doesn't really make a whole lot of sense.

其實不是很有道理。

Here, the logic is turned on its head.

在這裡，邏輯被顛覆了。

Instead of a fitness indicator,

科學家提出了一條 生理缺陷原則，

scientists invoke a handicap principle.

指出睪丸素並非強健的指標。

The most commonly cited example of a handicap

最常被引用的生理缺陷例子，

is the peacock's tail.

就是孔雀的尾巴。

This beautiful but cumbersome tail doesn't exactly help the peacock

這美麗但累贅的尾巴 並不能幫助雄孔雀

avoid predators

避開獵食者，

and approach peahens.

也不方便接近雌孔雀。

Why should such an extravagant appendage evolve?

為什麼這種奢華的 附屬品會被演化出來？

Even Charles Darwin,

即使達爾文，

in an 1860 letter to Asa Gray wrote

在 1860 年寫給 阿薩格雷的信上也提到，

that the sight of the peacock's tail made him physically ill.

看見孔雀尾巴會讓他 感到身理上的不舒服。

He couldn't explain it with his theory of natural selection,

他無法用他的天擇說 來解釋原因，

and out of this frustration,

出於這挫折，

he developed the theory of sexual selection.

他發展出了性擇說。

On this account,

由於這個原因，

the display of the peacock's tail is about sexual enticement,

孔雀展示尾巴的目的是性誘惑，

and this enticement means it's more likely the peacock will mate

這種誘惑意味著這孔雀 很可能想交配、

and have offspring.

想生育後代。

Now, the modern twist on this display argument

換個現代的角度想，

is that the peacock is also advertising its health to the peahen.

雄孔雀是在向雌孔雀展現牠的健康。

Only especially fit organisms can afford to divert resources

只有特別強健的有機體 才有資格傳宗接代，

to maintaining such an extravagant appendage.

並保有這奢華的附屬物。

Only especially fit men can afford the price that testosterone levies

只有特別健康的人，

才承擔得起睪丸素 抑制免疫系統的風險。

on their immune system.

And by analogy, think of the fact

舉個類似的現實例子，

that only very rich men can afford to pay more than $10,000 for a watch

只有超級富翁才有能力買支 超過一萬美金的手錶，

as a display of their financial fitness.

來彰顯他們的經濟實力。

Now, many people hear these kinds of evolutionary claims

許多人聽到這類的演化主張，

and think they mean that we somehow are unconsciously seeking mates

就會想，是不是這個原因，

我們人類會下意識地 去尋找健康的配偶。

who are healthy.

And I think this idea is probably not right.

我認為這個想法可能不太對。

Teenagers and young adults are not exactly known for making decisions

青少年和年輕人容易被看上的原因，

並不完全是他們健康條件上的優勢。

that are predicated on health concerns.

But they don't have to be,

他們也不想這樣，

and let me explain why.

讓我來解釋原因。

Imagine a population

想像有一個族群，

in which people have three different kinds of preferences:

族群中的人有三種偏好：

for green, for orange and for red.

有人偏好綠色、有人偏好橘色、 有人偏好紅色。

From their point of view,

從他們的觀點，

these preferences have nothing to do with health;

這些偏好與健康無關；

they just like what they like.

他們就是喜歡這顏色。

But if it were also the case that these preferences are associated

但如果我們人類對這些 顏色偏好的比率

with the different likelihood of producing offspring --

也剛好與產生後代的有關…...

let's say in a ratio of 3:2:1 --

假設原來的比率是 3:2:1…...

then in the first generation,

那麼，在第一代中，

there would be 3 greens to 2 oranges to 1 red,

會有三個綠色、 兩個橘色、一個紅色。

and in each subsequent generation,

在後續的每個世代中，

the proportion of greens increase,

喜歡綠色的比例會增加，

so that in 10 generations,

在十代之後，

98 percent of this population has a green preference.

這個族群中就有 98% 的人都偏好綠色。

Now, a scientist coming in and sampling this population

現在來了一個科學家， 對這個族群進行抽樣，

discovers that green preferences are universal.

發現對綠色的偏好是很普遍的。

So the point about this little abstract example

這個小小的純理論例子的重點是，

is that while preferences for specific physical features

雖然對於特定身體特徵的偏好

can be arbitrary for the individual,

可能是因人而異的，

if those features are heritable

但如果那些特徵是有遺傳性的，

and they are associated with a reproductive advantage,

而且與繁殖優勢有關聯的話，

over time,

隨時間過去，

they become universal for the group.

這些特徵就會變成團體的普遍現象。

So what happens in the brain when we see beautiful people?

所以，當我們看見美麗的人時， 頭腦中會發生什麼變化？

Attractive faces activate parts of our visual cortex

有吸引力的臉孔會觸發 我們的部份視覺皮層，

in the back of the brain,

它位在大腦的後方，

an area called the fusiform gyrus,

這個區域叫做梭狀回，

that is especially tuned to processing faces,

專門用來處理臉孔資訊，

and an adjacent area called the lateral occipital complex,

還有一個相鄰的區域， 叫側枕葉複合體，

that is especially attuned to processing objects.

它是特別用來處理物件資訊的。

In addition,

此外，

attractive faces activate parts of our reward and pleasure centers

具吸引力的臉孔會觸發

位在我們大腦前方深處的 獎賞與快感中樞，

in the front and deep in the brain,

and these include areas that have complicated names,

包括一些名稱複雜的區域，

like the ventral striatum,

比如腹側紋狀體、

the orbitofrontal cortex

眼眶額葉皮質、

and the ventromedial prefrontal cortex.

及腹內側額葉。

Our visual brain that is tuned to processing faces

我們用來處理臉孔的視覺大腦

interacts with our pleasure centers

會和我們的快感中樞互動，

to underpin the experience of beauty.

強化對美感的體驗。

Amazingly, while we all engage with beauty,

但驚人的是， 當我們「遇見」美麗時，

without our knowledge,

卻不知道，

beauty also engages us.

美麗同時也「遇見」了我們。

Our brains respond to attractive faces

即使我們沒有想著美，

even when we're not thinking about beauty.

我們的大腦卻會對 有吸引力的臉孔做出反應。

We conducted an experiment in which people saw a series of faces,

我們做了一個實驗， 讓人們看一系列的臉孔，

and in one condition,

在一個條件下，

they had to decide if a pair of faces were the same or a different person.

他們得要判定一對臉孔 是否屬於同一個人。

Even in this condition,

即使在這個情況中，

attractive faces drove neural activity robustly in their visual cortex,

有吸引力的臉孔會明顯地驅動 受測者視覺皮層的神經活動，

despite the fact that they were thinking about a person's identity

儘管當時他們在想的是人的身份，

and not their beauty.

而不是他們美不美。

Another group similarly found automatic responses to beauty

另一群人也有類似發現，

在我們的快感中樞裡， 我們對美會有自動的反應。

within our pleasure centers.

Taken together, these studies suggest

整體來看，這些研究指出，

that our brain automatically responds to beauty

我們的大腦會藉由視覺和快感的連結

by linking vision and pleasure.

對美會自動的反應，

These beauty detectors, it seems,

似乎，每回當我們看到美時，

ping every time we see beauty,

這些對美有反應的偵測器就會響起，

regardless of whatever else we might be thinking.

不論我們當時在想什麼其它的事。

We also have a "beauty is good" stereotype embedded in the brain.

我們腦中也內建了一個 「美等於好」的刻板印象。

Within the orbitofrontal cortex,

在眼眶額葉皮質中，

there's overlapping neural activity

對於「美」及「好」

in response to beauty and to goodness,

所造成的神經活動反應 是有重疊性的，

and this happens even when people aren't explicitly thinking

即使人們沒有特別去想著美或好，

about beauty or goodness.

也會發生。

Our brains seem to reflexively associate beauty and good.

我們的大腦似乎會反射性地 把美與好連結在一起。

And this reflexive association may be the biologic trigger

社會上因「美」而產生的回饋，

其背後的關聯性可能就是 這些生物觸發器在驅動。

for the many social effects of beauty.

Attractive people receive all kinds of advantages in life.

有吸引力的人， 在人生中有各種優勢。

They're regarded as more intelligent,

他們會被視為比較聰明，

more trustworthy,

比較值得信賴，

they're given higher pay and lesser punishments,

他們會比較高薪、比較少受懲罰，

even when such judgments are not warranted.

即使這類的判斷是沒根據的。

These kinds of observations reveal beauty's ugly side.

觀察到這種現象 也揭露出美的醜陋面。

In my lab, we recently found

在我的實驗室中，我們最近發現

that people with minor facial anomalies and disfigurements

有輕微面部異常及缺損的人，

are regarded as less good, less kind,

會被認為比較不好、比較不仁慈、

less intelligent, less competent and less hardworking.

比較不聰明、比較沒能力、 且比較不努力。

Unfortunately, we also have a "disfigured is bad" stereotype.

不幸的是，我們也有 「缺損等於不好」的刻板印象。

This stereotype is probably exploited and magnified

大眾媒體的影像可能會利用和放大

by images in popular media,

這種刻板印象，

in which facial disfigurement is often used as a shorthand

他們常用「面部缺損」 這種簡單的描繪方式

to depict someone of villainous character.

來形容反派人物。

We need to understand these kinds of implicit biases

我們需要了解這類的暗示性偏見，

if we are to overcome them

才有可能克服它們，

and aim for a society in which we treat people fairly,

並朝向一個能平等待人的社會邁進，

based on their behavior and not on the happenstance of their looks.

不要只是看一個人的外表 就斷定人的好壞。

Let me leave you with one final thought.

讓我留給各位一個最後的思考。

Beauty is a work in progress.

美的定義還在改變。

The so-called universal attributes of beauty

所謂放諸四海皆準的美的特徵

were selected for during the almost two million years of the Pleistocene.

是從幾乎兩百萬年的 「更新世」所挑選出來的。

Life was nasty, brutish and a very long time ago.

那時生命很糟糕、很粗野、很古早。

The selection criteria for reproductive success from that time

當時能繁衍成功的選擇標準

doesn't really apply today.

在現今並不適用。

For example,

比如，

death by parasite is not one of the top ways that people die,

因寄生蟲而造成死亡 並不是人類前幾名的死因，

at least not in the technologically developed world.

至少在技術發達的世界中不是。

From antibiotics to surgery,

從抗生素到手術，

birth control to in vitro fertilization,

從生育控制到試管授精，

the filters for reproductive success are being relaxed.

繁殖成功的過濾器已經被放寬了。

And under these relaxed conditions,

在這些放寬的條件下，

preference and trait combinations are free to drift

偏好與特性的組合可以自由搭配，

and become more variable.

也變得更多樣性。

Even as we are profoundly affecting our environment,

即使我們會深深影響我們的環境，

modern medicine and technological innovation

現代醫學及技術創新

is profoundly affecting

會深深影響著

the very essence of what it means to look beautiful.

我們對美的定義。

The universal nature of beauty is changing

即使我們正在改變全世界，

even as we're changing the universe.

普世價值對美的定義也在改變。

Thank you.

謝謝大家。

(Applause)

（掌聲）