What happens in your brain when you taste food | Camilla Arndal Andersen

Translator: Ivana Korom Reviewer: Krystian Aparta

譯者: Lilian Chiu 審譯者: SF Huang

So I had this very interesting experience

我有段非常有趣的經驗，

five years ago.

發生在五年前。

You know, me and my husband, we were out grocery shopping,

我和我先生出門買菜購物，

as we do every other day,

我們每兩天就會去一次，

but this time, we found this fancy,

但這次，我們發現一種昂貴的，

you know, I'm talking fair-trade, I'm talking organic,

我說的是符合公平貿易的、有機的，

I'm talking Kenyan, single-origin coffee

我在說的是肯亞的單品咖啡，

that we splurged and got.

我們捨得花大錢去買的咖啡。

And that was when the problem started already.

問題就是從那時開始的。

You know, my husband, he deemed this coffee blend superior

我先生認為這種調豆咖啡

比我們平常喝的便宜咖啡更優，

to our regular and much cheaper coffee,

which made me imagine a life based solely on fancy coffee

這讓我想像我們過著 只要高檔咖啡的生活

and I saw our household budget explode.

以及我們家庭預算的破表。

(Laughter)

（笑聲）

And worse ...

還更糟糕……

I also feared that this investment would be in vain.

我也擔心這項投資會白費。

That we wouldn't be able to notice this difference after all.

畢竟我們無法分辨出其中的差異。

Unfortunately, especially for my husband,

不幸的是，特別是對我先生而言，

he had momentarily forgotten that he's married to a neuroscientist

他時常忘了太太是一位神經科學家

with a specialty in food science.

且專長還是食品科學。

(Laughter)

（笑聲）

Alright?

是吧？

So without further ado,

所以，廢話不多說，

I mean, I just put him to the test.

我就把他抓來做測試。

I set up an experiment

我設計了一項實驗，

where I first blindfolded my husband.

先將我先生的眼睛矇住。

(Laughter)

（笑聲）

Then I brewed the two types of coffee

接著，我煮了兩種咖啡，

and I told him that I would serve them to him

告訴他我會一次拿一種咖啡給他喝。

one at a time.

Now, with clear certainty,

我先生非常肯定地描述

my husband, he described the first cup of coffee

第一杯咖啡比較生、比較苦。

as more raw and bitter.

You know, a coffee that would be ideal for the mornings

你知道的，這種咖啡很適合早晨，

with the sole purpose of terrorizing the body awake by its alarming taste.

唯一的目的就是用那嚇人的 口味把身體立刻喚醒。

(Laughter)

（笑聲）

The second cup of coffee, on the other hand,

而第二杯咖啡

was both fruity and delightful.

則帶有果香使讓人心情愉悅。

You know, coffee that one can enjoy in the evening and relax.

就是那種可在晚上享用， 使人放鬆的咖啡。

Little did my husband know, however,

然而，我先生並不知道，

that I hadn't actually given him the two types of coffee.

我其實沒讓他喝兩種咖啡。

I had given him the exact same cup of coffee twice.

他兩次喝到的都是同一種咖啡。

(Laughter)

（笑聲）

And obviously, it wasn't this one cup of coffee

很顯然，這一杯咖啡

that had suddenly gone from horrible to fantastic.

不會突然從難喝變好喝。

No, this taste difference was a product of my husband's own mind.

不，這種在口味上的差異 是我先生的心理作用造成的。

Of his bias in favor of the fancy coffee

他偏愛那款高價咖啡而產生的偏見，

that made him experience taste differences that just weren't there.

讓他嚐到了根本不存在的口味差別。

Alright, so, having saved our household budget,

好，所以，我們的家庭預算得救了，

and finishing on a very good laugh,

也以大笑作結，特別是我——

me especially --

(Laughter)

（笑聲）

I then started wondering just how we could have received

接著，我開始納悶，為什麼單一杯咖啡

會讓我們感受到兩種截然不同的反應？

two such different responses from a single cup of coffee.

Why would my husband make such a bold statement

為什麼我先生會冒著餘生 成為大眾笑柄的風險，

at the risk of being publicly mocked for the rest of his life?

做出如此大膽的陳述？

(Laughter)

（笑聲）

The striking answer is that I think you would have done the same.

驚人的答案是，我認為 換成你們也會做出一樣的結論。

And that's the biggest challenge in my field of science,

那是我的科學領域中最大的挑戰，

assessing what's reality behind these answers

評估我們接收到的這些答案 背後的真相是什麼。

that we receive.

Because how are we going to make food tastier

如果我們無法仰賴人們說的喜好口味，

if we cannot rely on what people actually say they like?

那我們要如何才能讓食物變得更可口？

To understand, let's first have a look at how we actually sense food.

為了了解這一點，咱們先來 談談我們如何感受食物。

When I drink a cup of coffee,

當我喝下一杯咖啡，

I detect this cup of coffee by receptors on my body,

我會用身體的接收器來偵測這杯咖啡，

information which is then turned into activated neurons in my brain.

資訊接著會被轉換成 我大腦中活化的神經元。

Wavelengths of light are converted to colors.

光的波長會被轉換為顏色。

Molecules in the liquid are detected by receptors in my mouth,

我口中的接收器 會偵測到液體的分子，

and categorized as one of five basic tastes.

將它歸為五種基本的味道。

That's salty, sour, bitter, sweet and umami.

分別為：鹹、酸、苦、甜、鮮。

Molecules in the air are detected by receptors in my nose

我鼻子中的接收器 會偵測空氣中的分子，

and converted to odors.

轉換為氣味。

And ditto for touch, for temperature, for sound and more.

對觸碰、溫度、聲音等等 都是同樣的道理。

All this information is detected by my receptors

我的接收器會偵測這些資訊，

and converted into signals between neurons in my brain.

將它們轉換為我大腦 神經元之間的訊號。

Information which is then woven together and integrated,

資訊接著會被交織、整合在一起，

so that my brain recognizes

於是，我的大腦會辨認出，

that yes, I just had a cup of coffee, and yes, I liked it.

是的，我剛喝了一杯咖啡，

是的，我喜歡它。

And only then,

要到那時，

after all this neuron heavy lifting,

在所有這些神經元的努力工作之後，

do we consciously experience this cup of coffee.

我們才會有意識地體驗喝到一杯咖啡。

And this is now where we have a very common misconception.

而這也是我們常誤解的地方。

People tend to think that what we experience consciously

大家通常會認為， 我們意識所體驗到的

must then be an absolute true reflection of reality.

就絕對是現實的真實反映。

But as you just heard,

但，各位剛剛都聽到了，

there are many stages of neural interpretation

在實體物件到意識體驗這中間，

in between the physical item and the conscious experience of it.

神經的詮釋會經歷許多階段。

Which means that sometimes,

那就表示，有時，

this conscious experience is not really reflecting that reality at all.

這種意識體驗可能 完全沒有反映出現實。

Like what happened to my husband.

就像我先生的例子。

That's because some physical stimuli may just be so weak

那是因為有些物理刺激太過微弱了，

that they just can't break that barrier to enter our conscious mind,

它們無法突破阻礙 進入我們的大腦意識中，

while the information that does

而能夠突破阻礙的資訊，

may get twisted on its way there by our hidden biases.

可能在到達大腦的路上 被我們的隱藏偏見給扭曲了。

And people, they have a lot of biases.

而人有很多偏見。

Yes, if you're sitting there right now, thinking ...

是的，如果你坐在那裡想著……

you could probably have done better than my husband,

你應該可以做得比我先生更好，

you could probably have assessed those coffees correctly,

你應該可以更正確地品評那些咖啡，

then you're actually suffering from a bias.

那你就是被偏見影響了。

A bias called the bias blind spot.

這種偏見叫做偏見盲點。

Our tendency to see ourselves as less biased than other people.

我們傾向認為自己的偏見 沒有別人那麼多。

(Laughter)

（笑聲）

And yeah, we can even be biased

是的，我們甚至會對我們 因偏見而認定的偏見而有所偏見。

about the biases that we're biased about.

(Laughter)

（笑聲）

Not trying to make this any easier.

沒有試著要把它給簡化。

A bias that we know in the food industry is the courtesy bias.

在食品產業中，我們知道 有一種偏見是禮貌性偏見。

This is a bias where we give an opinion

這種偏見就是，我們在給意見時，

which is considered socially acceptable,

會考量社會的接受度，

but it's certainly not our own opinion, right?

但那肯定不是我們自己的意見，對吧？

And I'm challenged by this as a food researcher,

身為食品研究者， 這對我來說是個挑戰，

because when people say they like my new sugar-reduced milkshake,

因為當大家說喜歡 我新發明的減糖奶昔時，

do they now?

他們真的喜歡嗎？（笑聲）

(Laughter)

Or are they saying they like it

或者，他們說喜歡它，

because they know I'm listening and they want to please me?

是因為他們知道我在聽， 而他們想要取悅我？

Or maybe they just to seem fit and healthy in my ears.

又或許他們只是想讓我覺得 他們蠻健康的。

I wouldn't know.

我不會知道。

But worse, they wouldn't even know themselves.

但，更糟的是，

他們自己也不知道。

Even trained food assessors,

即使受過訓練的 食物評估者被明確教導

and that's people who have been explicitly taught

to disentangle the sense of smell and the sense of taste,

如何區別嗅覺和味覺，

may still be biased to evaluate products sweeter

可能仍然會有偏見地將 含有香草的產品評估為比較甜。

if they contain vanilla.

Why?

為什麼？

Well, it's certainly not because vanilla actually tastes sweet.

肯定不是因為香草 真的嚐起來比較甜。

It's because even these professionals are human,

是因為這些專家畢竟是人，

and have eaten lot of desserts, like us,

也和我們一樣吃過許多甜點，

and have therefore learned to associate sweetness and vanilla.

因此會把甜味和香草連結在一起。

So taste and smell and other sensory information

所以，味覺、嗅覺和其他感知訊息

is inextricably entangled in our conscious mind.

在我們的大腦意識中緊緊糾纏在一起。

So on one hand, we can actually use this.

一方面，我們能善加利用。

We can use these conscious experiences,

我們可以用這些意識體驗，

use this data, exploit it by adding vanilla instead of sugar

利用這些資料，研究以香草而非糖

to sweeten our products.

來增加產品的甜度。

But on the other hand,

但另一方面，

with these conscious evaluations,

就算有這些意識的評估，

I still wouldn't know

我仍然不知道，

whether people actually liked that sugar-reduced milkshake.

大家是否真的喜歡減糖奶昔。

所以，要如何處理這個問題？

So how do we get around this problem?

How do we actually assess what's reality

要如何真的評斷

這些有意識的食物評估背後的真相？

behind these conscious food evaluations?

The key is to remove the barrier of the conscious mind

關鍵在於移除意識大腦的阻礙，

and instead target the information in the brain directly.

直接針對大腦中的資訊來解讀。

And it turns out

結果發現，

our brain holds a lot of fascinating secrets.

我們的大腦中有許多迷人的秘密。

Our brain constantly receives sensory information from our entire body,

我們的大腦持續地從全身接收感官資訊，

most of which we don't even become aware of,

我們大部份根本不會意識到，

like the taste information that I constantly receive

比如從我的消化道

所接受到的味道資訊。

from my gastrointestinal tract.

And my brain will also act on all this sensory information.

我的大腦會根據所有的 感官資訊來對應運作，

It will alter my behavior without my knowledge,

它會在我沒意識到的情況下 改變我的行為，

and it can increase the diameter of my pupils

當我體驗到我真的 很喜歡的事物時，

我的瞳孔會放大。

if I experience something I really like.

And increase my sweat production ever so slightly

如果那樣的情緒很強烈，

它還會稍稍增加我的流汗量。

if that emotion was intense.

And with brain scans,

掃瞄我們的大腦後，

we can now assess this information in the brain.

我們就能評估大腦中的這些資訊。

Specifically, I have used a brain-scanning technique

明確來說，我曾經 用一種大腦掃瞄技術

called electroencephalography,

叫做腦電 (波) 圖，

or "EEG" in short,

簡稱 EEG，

which involves wearing a cap studded with electrodes,

頭上要戴著鑲有電極的帽子，

128 in my case.

我用的有 128 個電極。

Each electrode then measures the electrical activity of the brain

每個電極都會測量大腦的電活動，

with precision down to the millisecond.

精準度到毫秒。

The problem is, however,

然而，問題是，

it's not just the brain that's electrically active,

有電活動的不只是大腦，

it's also the rest of the body as well as the environment

身體其他部位以及環境

that contains a lot of electrical activity all the time.

都時時刻刻有大量的電活動。

To do my research,

為了我的研究，

I therefore need to minimize all this noise.

我必須要將這些干擾降到最低。

So I ask my participants to do a number of things here.

所以，我請我的受試者做幾件事。

First off,

第一，

I ask them to rest their head in a chin rest,

我請他們把頭枕在下巴架上，

to avoid too much muscle movement.

避免過多肌肉運動。

I also ask them to, meanwhile, stare at the center of a computer monitor

同時，我也請他們 盯著電腦螢幕的中心，

to avoid too much eye movements and eye blinks.

避免太多眼球轉動和眨眼。

And I can't even have swallowing,

甚至不能有吞嚥，

so I ask my participants to stick the tongue out of their mouth

所以我請我的受試者把舌頭伸出來，

over a glass bowl,

下面有個玻璃碗接著，

and then I constantly let taste stimuli onto the tongue,

然後，我不斷地把 味道刺激物放到舌頭上，

which then drip off into this bowl.

刺激物接著會落入這個碗中。

(Laughter)

（笑聲）

And then, just to complete this wonderful picture,

接著，為了完成這美好的畫面，

I also provide my participants with a bib,

我提供我的受試者一條圍兜，

available in either pink or blue, as they please.

有粉紅色和藍色可以選擇。

(Laughter)

（笑聲）

Looks like a normal eating experience, right?

看起來像是個正常的 進食體驗，對吧？

(Laughter)

（笑聲）

No, obviously not.

不，顯然不像。

And worse,

更糟的是，

I can't even control what my participants are thinking about,

我甚至無法控制受試者在想什麼，

so I need to repeat this taste procedure

所以我得要重覆 這個嚐味道的程序很多次。

multiple times.

Maybe the first time, they're thinking about the free lunch

也許第一次時，他們在想著 我提供的免費午餐，

that I provide for participating,

or maybe the second time, they're thinking about Christmas coming up

或許第二次時， 他們在想著聖誕節快到了，

and what to get for Mom this year, you know.

今年要買什麼給老媽。

But common for each response is the response to the taste.

但每次共有的反應 都是對味道的反應。

So I repeat this taste procedure multiple times.

所以我把這個味道程序 重覆了許多次。

Sixty, in fact.

事實上，是六十次。

And then I average the responses,

接著，我從實驗結果算出平均值，

because responses unrelated to taste will average out.

因為和味道無關的反應會被平均掉。

And using this method,

用這個方法，

we and other labs,

我們和其他實驗室

have investigated how long a time it takes from "food lands on our tongue"

研究出從「食物落到舌頭上」

到大腦搞懂它是什麼味道 需花費多少時間。

until our brain has figured out which taste it's experiencing.

Turns out this occurs within the first already 100 milliseconds,

結果發現，這個過程 會在前一百毫秒發生，

that's about half a second before we even become aware of it.

也就是我們意識到 是什麼味道之前的半秒鐘。

And next up, we also investigated

接著，我們去研究

the taste difference between sugar and artificial sweeteners

味道極相近的糖和人工甜味劑之間的

that in our setup taste extremely similar.

味道差別。

In fact, they tasted so similar

事實上，它們嚐起來非常相似，

that half my participants could only barely tell the taste apart,

有一半的受試者幾乎 無法分別兩種味道，

while the other half simply couldn't.

另一半根本分辨不出來。

But amazingly,

但，驚人的是，

if we looked across the entire group of participants,

如果觀察所有的受試者，

we saw that their brains definitely could tell the taste apart.

我們會發現他們的大腦 絕對可以分得出兩種味道。

So with EEG and other brain-scanning devices

所以，靠著 EEG 及其他掃瞄大腦的裝置，

and other physiological measures --

及其他生理測量值—— 汗水和瞳孔大小——

sweat and pupil size --

we have new gateways to our brain.

我們有了通往大腦的新門徑。

Gateways that will help us remove the barrier of the conscious mind

這門徑能協助我們 移除意識大腦的阻礙，

to see through the biases of people

看穿人的偏見，

and possibly even capture subconscious taste differences.

甚至可能可以捕捉到 潛意識的味道差異。

And that's because we can now measure people's very first response to food

那是因為，我們現在可以測量 人對於食物的第一反應，

before they've become conscious of it,

在他們意識到自己的反應之前，

and before they've started rationalizing why they like it or not.

在他們開始合理化 喜歡與否之前的反應。

We can measure people's facial expressions,

我們能測量人的面部表情，

we can measure where they're looking,

我們能測量他們在看哪裡，

we can measure their sweat response,

我們能測量他們的流汗反應，

we can measure their brain response.

我們能測量他們的大腦反應。

And with all these measures,

有了這些測量值，

we are going to be able to create tastier foods,

我們將能夠創造出更美味的食物，

because we can measure whether people actually like

因為我們能測量大家是否 真的喜歡那減糖奶昔。

that sugar-reduced milkshake.

And we can create healthier foods without compromising taste,

我們能創造出更健康的食物， 且不用在味道上做妥協，

because we can measure the response to different sweeteners

因為我們能測量人們對於 不同增甜劑的反應，

and find the sweetener that gives the response that's more similar

並找出最接近糖的增甜劑。

to the response from sugar.

And furthermore, we can just help create healthier foods,

此外，我們能創造出更健康的食物，

because we can help understand how we actually sense food

因為我們能協助人們了解 我們一開始是如何感知食物的。

in the first place.

Which we know surprisingly little about.

我們對此竟然所知甚少。

For example, we know that there are those five basic tastes,

比如，我們知道有五種基本味道，

but we strongly suspect that there are more,

但我們強烈懷疑應該還有更多，

and in fact, using our EEG setup, we found evidence that fat,

事實上，用我們的 EEG 計畫，

我們找到證據證明，

besides being sensed by its texture and smell,

除了能感受到脂肪的 質地和氣味之外，

is also tasted.

也能嚐得出來。

Meaning that fat could be this new sixth basic taste.

意思是，脂肪可能是 新的第六種基本味道。

And if we figure out how our brain recognizes fat and sugar,

如果我們能了解我們的大腦 如何辨認出脂肪和糖，

and I'm just dreaming here,

我只是在作夢，但也許有一天，

but could we then one day

create a milkshake with zero calories that tastes just like the real deal?

我們可以創造出和真奶昔 味道完全一樣的零卡奶昔？

Or maybe we figure out that we can't,

或許我們做不到，

because we subconsciously detect calories

因為我們會透過 我們消化道中的接收器，

via our receptors in our gastrointestinal tract.

在潛意識中偵測到卡路里。

The future will show.

等著看未來的結果吧。

Our conscious experience of food

我們對於食物的意識體驗

is just the tip of the iceberg of our total sensation of food.

相對於我們對食物的 完整感覺，只是冰山一角。

And by studying this total sensation,

藉由研究完整的感知系統，

conscious and subconscious alike,

包括意識的和潛意識的，

I truly believe that we can make tastier and healthier foods for all.

我真心相信，我們能為大家 創造出更美味、更健康的食物。

Thank you.

謝謝。

(Applause)

（掌聲）