What is it about burgers and cakes that we crave?

是什麼讓我們對漢堡和蛋糕如此渴望？

And what is happening in our brains when we choose what to eat?

而當我們選擇吃什麼時，我們的大腦中發生了什麼？

If you hopped into an MRI machine and were offered a delicious chocolate milkshake, you would see your brain's reward system light up like a funfair.

如果你跳進核磁共振機，然後喝了杯美味的巧克力奶昔，你會看到你大腦的獎勵系統像遊樂場一樣閃閃發光。

Right above your eyes is your orbitofrontal cortex, a part of the brain which is especially developed in humans and primates.

在你眼睛的正上方是你的眼眶額葉皮質層，這個部位是在人類和靈長類動物中腦部特別發達的部分。

Here, bundles of neurons respond to different sensations and nutrients - taste, smell, how smooth and rich the milkshake feels - and the more your neurons light up, the more delicious the food seems.

在這裡，成束的神經元對不同的感覺和營養物質作出反應：味道、香氣，奶昔的滑順而豐富的口感，而越多的神經元被刺激，食物看起來就越美味。

Two things which particularly delight these reward neurons are fat and sugar.

有兩種食物會讓這些獎勵神經元特別高興，那就是脂肪和糖。

Combinations of fat and sugar can be even more delightful, such as in that delicious milkshake, or cakes, or doughnuts.

而脂肪和糖的組合就更讓它高興了，就像那杯美味的奶昔，或者蛋糕和甜甜圈那樣。

But your neurons don't just respond to these sensations, they also activate when you're planning what to eat in a contest with each other to get you to choose them.

但你的神經元不只是對這些感覺作出反應，當你思考著要吃些什麼時，它們也會被刺激，並彼此競爭雀屏中選的機會。

"Pick me." says silky smooth mouth feel.

「選我吧。」絲滑的口感如此說。

"No! Me!" shouts sugary sweetness.

「不對！選我啦！」甜蜜的滋味喊叫到。

"You never pick me." quietly mumbles the smell of broccoli.

「你每次都不選我。」花椰菜的味道小聲地嘟囔著。

And once you have chosen, the same neurons track your progress, and as you eat, they get less and less active as you approach fullness.

在你選擇之後，被選擇口味所屬的神經元便會在你將食物吃下肚時追蹤進度，並在你逐漸吃飽的同時變得越來越不活躍。

But we're not entirely at the mercy of the demands of our orbitofrontal cortex.

但我們並不是完全受制於我們的眼眶額葉皮質層。

Having information about the food can make a big difference.

瞭解關於食物的資訊可以帶來很大的不同。

Hop back into that MRI machine and slurp down some soup.

現在再次跳回核磁共振機中，並喝下一些熱湯吧。

There are two types - one is labelled "rich and delicious flavor", and the other is labelled "boiled vegetable water."

你面前有兩種熱湯：一個上面寫著「濃厚美味風味」，另一個則寫著「煮菜水」。

Your neurons light up at the taste of "rich and delicious", and less for "boiled vegetable water."

你的神經元在喝下「濃厚美味風味」的湯時亮起，而在喝下「煮菜水」時較少被刺激。

But wait a minute, you've been tricked! Those were both the same soup.

但等等，你被騙了！兩種其實是同一種湯。

The only difference was the name and that was enough to completely change your experience of it.

它們之間唯一的區別只有名字而已，但這卻足以完全改變你對它的感受。

This experiment was also done with wine - telling people that the wine cost more made their neuron activity increase and the wine tasted better.

也有人用紅酒做過一樣的實驗，告訴受試者紅酒的價格較貴能夠刺激它們的神經活動增加，讓紅酒喝起來更順口。

Another part of the brain involved in choosing food is the amygdala.

大腦中參與選擇吃什麼食物的另一個部位則是杏仁核。

The amygdala also has a role to play when you choose where to go out with another person.

杏仁核在你決定要和誰出去約會時，也具有一定的影響力。

If you've seen what they prefer in the past, your amygdala will have developed so-called simulation neurons.

如果你看過約會對象過去有著怎麼樣的偏好，你的杏仁核便會發展出模擬神經元。

These predict the choice you think they will make which you can then factor into your own suggestions of what to eat together.

它們會預測約會對象可能會做出怎麼樣的選擇，提供你做為要帶他們去吃什麼的參考。

Differences in our genes are also a factor in how susceptible we are to the siren call of our reward neurons, with some people being naturally more responsive to the reward we feel from eating sugar and fat than others.

我們的基因差異也會改變我們受獎勵神經元影響的程度，讓有些人天生就對將糖分與脂肪吃下肚的獎勵情緒比較敏感。

Scientific experiments give us clues about how our brains compute our choices of what to eat, but the way we experience these choices in our lives and in society is also complex.

科學實驗提供了我們的腦袋是如何計算要將什麼吃下肚的一些線索，但我們在生活以及社會中做出這類選擇的方式也十分複雜。

Dr. Emily Contois, Assistant Professor of Media Studies, gives her take.

媒體研究學助理教授 Emily Contois 博士給出了她的看法。

We choose the food we eat for a lot of different reasons:

我們選擇將什麼吃下肚有很多種不同的原因：

What's available at the grocery store? What's convenient?

超市裡有賣什麼？買什麼比較方便？

What's affordable? What do we have good memories about?

我們負擔得起哪些食物？我們對什麼食物有著美好的回憶？

What taste is good to us? What do we think is healthy?

什麼食物對我們來說比較美味？我們認為什麼食物才健康？

What is our current health status?

我們目前的健康狀況如何？

What defines our ideas about who we are?

是什麼定義了我們這個人？

So when we think about food in the digital age, one of the biggest things that has changed the way people eat and the kinds of foods that they are seeking out are social media platforms.

所以當我們在數位時代思考食物的本質時，人們的飲食習慣與找尋食物方式的最大改變便是社交媒體平台的出現。

Instagram, and the desire for people to be able to take beautiful food photos, has transformed the idea that you are what you eat into you are what you post.

Instagram，還有對於想要拍出漂亮實物照片的渴望，讓原本「人如其食」的思維，變成了社交媒體上的「人如其文」。

So we seek a lot of different things from the food that we eat.

我們從吃下肚的食物中尋求很多不同的東西。

We can seek comfort, we can seek a connection to history, to our families, to our heritage.

我們可以尋求安慰，我們可以尋求與歷史、家庭以及文化傳承的聯繫。

But we can also seek in it a sense of control.

但我們也可以在其中尋求一種控制感。

When we live in moments that are full of economic, political and social strife, sometimes we seek in food that sense of security and safety.

在這樣一個充滿經濟、政治與社會動亂的時代中，我們有時能在食物中尋求到某種安全感。

So in those moments, we sometimes see people get really interested in ideas about naturalness, health and purity, as a way to protect ourselves from contexts outside of our control.

在這樣的時代，我們有時會看到人們對於自然、健康與純淨飲食的追求，並藉此作為他們想從自己無法控制的環境下，保護自己的一種做法。

So food also tells stories about who we are. The full complexity of our identity.

因此我們也能藉由食物來訴說自己的身分認同，解釋自己身世的複雜性。

What we eat tells stories about our gender and our sexuality, our race and our ethnicity, our social class, or our aspirations about our social class, the region where we live, even whether we live in an urban or a rural area.

我們的食物選擇背後說明了我們的性別與性取向、種族與族裔、我們的社會階級，或是說我們對於自己社會階級的想像、我們所居住的區域，不論我們是住在城市或是鄉村地區皆然。

What we eat tells these contradictory, complex stories about who we are.

我們吃下肚的東西講述了這些矛盾而複雜，關於我們究竟是誰的故事。

In the future, we can use our knowledge of what is happening in our brains to design foods that are low in calories and are still attractive, but healthy.

在未來，我們可以利用我們對大腦中神經反應的知識，來設計卡路里低，卻仍具有吸引力的健康食品。

And we can help ourselves by understanding how our reward neurons plot to get what they want.

我們能藉由瞭解自己獎勵神經元是如何刺激我們將它們想要的東西吃下肚，來幫助自己。

We can be aware of times that we tend to make poor choices, like when we choose a food because of some label which appeals to us, rather than because of its taste.

我們可以在自己做出錯誤選擇時意識到問題所在，例如當我們因為一個食物的包裝，而不是因為味道而選擇它時。

So in the end, we are at least not fully at the mercy of our reward neurons.

這樣一來，我們至少不會完全受制於自己的獎勵神經元。

We can use our understanding to help design healthy foods and make healthy choices.

我們可以利用我們的理解以幫助設計出健康的食物，並做出健康的選擇。