What happens in your brain when you taste food

So I had this very interesting experience

five years ago.

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

as we do every other day,

but this time, we found this fancy,

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

I'm talking Kenyan, single-origin coffee

that we splurged and got.

And that was when the problem
started already.

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

to our regular and much cheaper coffee,

which made me imagine a life
based solely on fancy coffee

and I saw our household budged explode.

(Laughter)

And worse ...

I also feared that this investment
would be in vain.

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

Unfortunately, especially for my husband,

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

with a specialty in food science.

(Laughter)

Alright?

So without further ado,

I mean, I just put him to the test.

I set up an experiment

where I first blindfolded my husband.

(Laughter)

Then I brewed the two types of coffee

and I told him that
I would serve them to him

one at a time.

Now, with clear certainty,

my husband, he described
the first cup of coffee

as more raw and bitter.

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

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

(Laughter)

The second cup of coffee,
on the other hand,

was both fruity and delightful.

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

Little did my husband know, however,

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

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

(Laughter)

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

that had suddenly gone
from horrible to fantastic.

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

Of his bias in favor of the fancy coffee

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

Alright, so, having saved
our household budget,

and finishing on a very good laugh,

me especially --

(Laughter)

I then started wondering
just how we could have received

two such different responses
from a single cup of coffee.

Why would my husband
make such a bold statement

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

(Laughter)

The striking answer is

that I think you would have done the same.

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

assessing what's reality
behind these answers

that we receive.

Because how are we
going to make food tastier

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

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

When I drink a cup of coffee,

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

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

Wavelengths of light
are converted to colors.

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

and categorized as one
of five basic tastes.

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

Molecules in the air
are detected by receptors in my nose

and converted to odors.

And ditto for touch, for temperature,

for sound and more.

All this information is detected
by my receptors

and converted into signals
between neurons in my brain.

Information which is then
woven together and integrated,

so that my brain recognizes

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

And only then,

after all this neuron heavy-lifting,

do we consciously experience
this cup of coffee.

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

People tend to think
that what we experience consciously

must then be an absolute
true reflection of reality.

But as you just heard,

there are many stages
of neural interpretation

in between the physical item

and the conscious experience of it.

Which means that sometimes,

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

Like what happened to my husband.

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

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

while the information that does

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

And people, they have a lot of biases.

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

you could probably have done
better than my husband,

you could probably have assessed
those coffees correctly,

then you're actually
suffering from a bias.

A bias called the bias blind spot.

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

(Laughter)

And yeah, we can even be biased

about the biases that we're biased about.

(Laughter)

Not trying to make this any easier.

A bias that we know in the food industry

is the courtesy bias.

This is a bias where we give an opinion

which is considered socially acceptable,

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

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

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

do they now?

(Laughter)

Or are they saying they like it

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

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

I wouldn't know.

But worse, they wouldn't
even know themselves.

Even trained food assessors,

and that's people who have been
explicitly taught

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

may still be biased
to evaluate products sweeter

if they contain vanilla.

Why?

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

It's because even these
professionals are human,

and have eaten lot of desserts, like us,

and have therefore learned to associate
sweetness and vanilla.

So taste and smell
and other sensory information

is inextricably entangled
in our conscious mind.

So on one hand, we can actually use this.

We can use these conscious experiences,

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

to sweeten our products.

But on the other hand,

with these conscious evaluations,

I still wouldn't know

whether people actually liked
that sugar-reduced milkshake.

So how do we get around this problem?

How do we actually assess what's reality

behind these conscious food evaluations?

The key is to remove the barrier
of the conscious mind

and instead target the information
in the brain directly.

And it turns out

our brain holds a lot
of fascinating secrets.

Our brain constantly receives
sensory information from our entire body,

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

like the taste information
that I constantly receive

from my gastrointestinal tract.

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

It will alter my behavior
without my knowledge,

and it can increase
the diameter of my pupils

if I experience something I really like.

And increase my sweat production
ever so slightly

if that emotion was intense.

And with brain scans,

we can now assess
this information in the brain.

Specifically, I have used
a brain-scanning technique

called electroencephalography,

or "EEG" in short,

which involves wearing a cap
studded with electrodes,

128 in my case.

Each electrode then measures
the electrical activity of the brain

with precision down to the millisecond.

The problem is, however,

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

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

that contains a lot
of electrical activity all the time.

To do my research,

I therefore need
to minimize all this noise.

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

First off,

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

to avoid too much muscle movement.

I also ask them to, meanwhile,

stare at the center of a computer monitor

to avoid too much
eye movements and eye blinks.

And I can't even have swallowing,

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

over a glass bowl,

and then I constantly let
taste stimuli onto the tongue,

which then drip off into this bowl,

(Laughter)

and then, just to complete
this wonderful picture,

I also provide my participants with a bib,

available in either pink
or blue, as they please.

(Laughter)

Looks like a normal
eating experience, right?

(Laughter)

No, obviously not.

And worse,

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

so I need to repeat this taste procedure

multiple times.

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

that I provide for participating,

or maybe the second time,

they're thinking about Christmas coming up

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

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

So I repeat this taste
procedure multiple times.

Sixty, in fact.

And then I average the responses,

because responses unrelated
to taste will average out.

And using this method,

we and other labs,

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

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

Turns out this occurs within the first
already 100 milliseconds,

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

And next up, we also investigated

the taste difference between sugar
and artificial sweeteners

that in our setup taste extremely similar.

In fact, they tasted so similar

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

while the other half simply couldn't.

But amazingly,

if we looked across
the entire group of participants,

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

So with EEG and other
brain-scanning devices

and other physiological measures --

sweat and pupil size --

we have new gateways to our brain.

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

to see through the biases of people

and possibly even capture
subconscious taste differences.

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

before they've become conscious of it,

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

We can measure people's
facial expressions,

we can measure where they're looking,

we can measure their sweat response,

we can measure their brain response.

And with all these measures,

we are going to be able
to create tastier foods,

because we can measure
whether people actually like

that sugar-reduced milkshake.

And we can create healthier foods
without compromising taste,

because we can measure the response
to different sweeteners

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

to the response from sugar.

And furthermore, we can just help
create healthier foods,

because we can help understand
how we actually sense food

in the first place.

Which we know surprisingly little about.

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

but we strongly suspect
that there are more,

and in fact, using our EEG setup,

we found evidence that fat,

besides being sensed
by its texture and smell,

is also tasted.

Meaning that fat could be
this new sixth basic taste.

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

and I'm just dreaming here,

but could we then one day

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

Or maybe we figure out that we can't,

because we subconsciously detect calories

via our receptors
in our gastrointestinal tract.

The future will show.

Our conscious experience of food

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

And by studying this total sensation,

conscious and subconscious alike,

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

Thank you.

(Applause)