What is so special about the human brain? | Suzana Herculano-Houzel

Translator: Jone Aliri Lazcano Reviewer: Begoña Laka

What is so special about the human brain?

Zer da giza burmuina hain berezia egiten duena?

Why is it that we study other animals

Zergatik ikertzen ditugu guk beste animaliak

instead of them studying us?

eta haiek ez gaituzte gu ikertzen?

What does a human brain have or do

Zer du giza burmuinak edo zer egiten du

that no other brain does?

besteenak egiten ez duenik?

When I became interested in these questions about 10 years ago,

Gai hauetaz interesatzen hasi nintzenean, duela 10 urte,

scientists thought they knew what different brains were made of.

zientifikoek uste zuten bazekitela garunak nola eginda zeuden.

Though it was based on very little evidence,

Ebidentzia gutxi izan arren,

many scientists thought that all mammalian brains,

zientifiko askok zioten ugaztunen garunak,

including the human brain,

baita gizakiena ere, berdin osatuak zeudela

were made in the same way,

with a number of neurons that was always

eta garunaren tamainarekiko proportzionala zen

proportional to the size of the brain.

neurona kopurua zutela.

This means that two brains of the same size,

Hau da, tamaina bereko bi garunek,

like these two, with a respectable 400 grams,

400 gramoko bi garun hauek esaterako,

should have similar numbers of neurons.

neurona kopuru bertsua izan beharko luketela.

Now, if neurons are the functional

Baina neuronak garuneko

information processing units of the brain,

informazioaren prozesamenduaren unitate funtzionalak badira,

then the owners of these two brains

garun bi hauen jabeek

should have similar cognitive abilities.

gaitasun kognitibo antzekoak izan beharko lituzkete.

And yet, one is a chimp,

Baina bata txinpantzea da,

and the other is a cow.

eta bestea behi bat.

Now maybe cows have a really rich

Posible da behiek barne bizitza

internal mental life and are so smart

sakon bat izatea, eta hain azkarrak izanik

that they choose not to let us realize it,

guri hortaz ohartzen ez uztea erabaki izana,

but we eat them.

baina guk eurak jaten ditugu.

I think most people will agree

Nirekin ados egongo zarete

that chimps are capable of much more complex,

txinpantzeek behiek baino jokabide konplexu, elaboratu eta malguagoak

elaborate and flexible behaviors than cows are.

burutzeko gai direla.

So this is a first indication that the

"Garun guztiak modu berean osatuak daude" esaldia

"all brains are made the same way" scenario

oso zuzena ez dela

is not quite right.

erakusten du lehen puntu honek.

But let's play along.

Baina jarrai dezagun.

If all brains were made the same way

Garun denak berdin osatuak baleude,

and you were to compare animals with brains of different sizes,

tamaina desberdineko garundun animaliak konparatuz gero,

larger brains should always have more neurons

garun handiek txikiek baino neurona gehiago

than smaller brains, and the larger the brain,

izan beharko lituzkete. Gero eta handiagoa,

the more cognitively able its owner should be.

orduan eta gaitasun kognitibo handiagoa izango luke garunaren jabeak.

So the largest brain around should also be

Hori horrela balitz, garun handienak

the most cognitively able.

gaitasun kognitibo handiena izango luke.

And here comes the bad news:

Eta, hemen datoz berri txarrak:

Our brain, not the largest one around.

Gure garuna ez da guztietan handiena.

It seems quite vexing.

Honek nahasgarria dirudi.

Our brain weighs between 1.2 and 1.5 kilos,

Gure garunak 1, 2 eta 1,5 kg artean pisatzen du,

but elephant brains weigh between four and five kilos,

elefanteen garunak 4 eta 5 kg artean pisatzen du,

and whale brains can weigh up to nine kilos,

eta baleen garunak 9 kg arteko pisua har dezake.

which is why scientists used to resort to saying

Guzti honengatik,

zientifikoek gure garuna berezia zela esaten zuten

that our brain must be special

to explain our cognitive abilities.

gure gaitasun kognitiboak azaltzean.

It must be really extraordinary,

Benetan ezohikoa izan behar du bai,

an exception to the rule.

arauaren salbuespena.

Theirs may be bigger, but ours is better,

Beraiena handiagoa izango da bai, baina gurea hobea da,

and it could be better, for example,

eta hobea izan zitekeen, hau da,

in that it seems larger than it should be,

izan behar lukeena baino handiagoa omen delako,

with a much larger cerebral cortex than we should have

gure gorputzen tamainagatik izan beharko genukeena baino

for the size of our bodies.

kortex askoz handiagoa baitugu.

So that would give us extra cortex

Garun kortex estra omen dugu,

to do more interesting things than just operating the body.

gorputza kudeatzeko baino gauza interesgarriagoak egiteko.

That's because the size of the brain

Normalean, garunaren tamaina

usually follows the size of the body.

gorputzaren tamainaren araberakoa da.

So the main reason for saying that

Beraz, gure garuna beharko lukeena baino

our brain is larger than it should be

handiagoa dela esateko arrazoi nagusia,

actually comes from comparing ourselves

beste hominidoekin egindako konparaketetatik dator.

to great apes.

Gorilak gu baino 2 edo 3 aldiz handiagoak izan daitezke.

Gorillas can be two to three times larger than we are,

so their brains should also be larger than ours,

Bere garunak gureak baino handiagoak izan beharko lukete

but instead it's the other way around.

baina aurkakoa gertatzen da.

Our brain is three times larger than a gorilla brain.

Gure garuna gorilena baino hiru aldiz handiagoa da.

The human brain also seems special

Giza garuna berezia dirudi ere

in the amount of energy that it uses.

erabiltzen duen energia kantitateagatik.

Although it weighs only two percent of the body,

Gorputzaren pisuaren %2a soilik izan arren,

it alone uses 25 percent of all the energy

berak bakarrik gorputzak eguneroko funtzioetarako darabilen

that your body requires to run per day.

energia guztiaren %25 behar du.

That's 500 calories out of a total of 2,000 calories,

Hori 2000 kalorietatik 500 litzateke,

just to keep your brain working.

garuna funtzionamenduan izateko bakarrik.

So the human brain is larger than it should be,

Beraz, giza garuna beharko lukeena baino handiagoa da,

it uses much more energy than it should,

behar lukeena baino energia gehiago erabiltzen du,

so it's special.

eta berezia da.

And this is where the story started to bother me.

Orain istorio hau gogaikarri bihurtzen hasi zen.

In biology, we look for rules

Biologian arauak bilatzen ditugu,

that apply to all animals and to life in general,

animalia guztiei eta bizitzari oro har aplikatzekoak.

so why should the rules of evolution

Zergatik aplikatu beharko zaizkie

apply to everybody else but not to us?

eboluzioaren arauak espezie guztiei guri izan ezik?

Maybe the problem was with the basic assumption

Agian arazoa oinarrizko ustean zegoen,

agian garun denak ez daude berdin osatuak.

that all brains are made in the same way.

Maybe two brains of a similar size

Agian tamaina bereko bi garun

can actually be made of very different numbers of neurons.

neurona kantitate ezberdinez osatuta egon daitezke.

Maybe a very large brain

Oso handia den garun batek

does not necessarily have more neurons

agian ez du

than a more modest-sized brain.

txikiago batek baino neurona gehiago izan behar.

Maybe the human brain actually has the most neurons

Agian gizakion garunak neurona kantitate handiena du

of any brain, regardless of its size,

bere tamainak axolarik izan gabe,

especially in the cerebral cortex.

batez ere kortexean.

So this to me became

Ondorioz, guzti hau erantzun beharreko kontu garrantzitsu bihurtu zen.

the important question to answer:

how many neurons does the human brain have,

Zenbat neurona ditu giza garunak,

and how does that compare to other animals?

eta nola konpara dezakegu beste animaliekin?

Now, you may have heard or read somewhere

Posible da zuetako batzuk nonbait irakurri edo entzun izana

that we have 100 billion neurons,

100 mila milioi neurona ditugula.

so 10 years ago, I asked my colleagues

Duela 10 urte, lankideei galdetu nien

if they knew where this number came from.

ea bazekiten zifra hori nondik zetorren.

But nobody did.

Inork ez zekien.

I've been digging through the literature

Zifra horren jatorriaren bila

for the original reference for that number,

jardun nintzen erreferentzia-bibliografian,

and I could never find it.

baina sekula ez nuen aurkitu.

It seems that nobody had actually ever counted

Badirudi inork ez zuela benetan giza garunaren

the number of neurons in the human brain,

neurona kopurua zenbatu,

or in any other brain for that matter.

ez eta beste edozein garunetako neurona kopurua ere.

So I came up with my own way to count cells in the brain,

Garuneko zelulak kontatu ahal izateko formula bat sortu nuen.

and it essentially consists of

Oinarrian zera egin behar da:

dissolving that brain into soup.

garuna disolbatu, zopa bihurtu arte.

It works like this:

Horrela funtzionatzen du:

You take a brain, or parts of that brain,

garun bat edo garun zati batzuk hartu

and you dissolve it in detergent,

eta garbigarritan disolbatzen da.

which destroys the cell membranes

Honek ehunak suntsitzen ditu

but keeps the cell nuclei intact,

baina zelularen nukleoa osorik mantentzen du.

so you end up with a suspension of free nuclei

Horrela, nukleoarekin soilik geratzen zara.

that looks like this,

Nukleoak itxura hau du, zopa baten antzekoa da.

like a clear soup.

This soup contains all the nuclei

Zopa honek, arratoi baten garuna zenak,

that once were a mouse brain.

nukleo guztiak ditu.

Now, the beauty of a soup is that because it is soup,

Zoparen edertasuna zera da, zopa denez,

you can agitate it and make those nuclei

berau nahastu dezakezula, eta horrela nukleo guzti horiek

be distributed homogeneously in the liquid,

likidotan homogeneoki banatu.

so that now by looking under the microscope

Soluzio homogeneo honen

at just four or five samples of this homogeneous solution,

lau edo bost lagin mikroskopiotik behatzean,

you can count nuclei, and therefore tell

nukleoak kontatu ahal dira, eta garun horrek

how many cells that brain had.

zenbat zelula zituen jakin.

It's simple, it's straightforward,

Sinplea da, erraza, eta benetan azkarra.

and it's really fast.

So we've used that method to count neurons

Metodo honekin dozenaka espezieren

in dozens of different species so far,

neuronak kontatu ditugu,

and it turns out that all brains

eta zera ikusi dugu,

are not made the same way.

garunak ez daudela modu berean osatuta.

Take rodents and primates, for instance:

Azter ditzagun karraskariak eta primateak.

In larger rodent brains, the average size

Karraskarien garun handienetan, handitu egiten da

of the neuron increases,

neuronen batezbesteko tamaina.

so the brain inflates very rapidly

Beraz, garuna azkar puzten da

and gains size much faster than it gains neurons.

eta tamainaz handitzen da, neuronak gehitu baino.

But primate brains gain neurons

Primateen garunak, berriz,

neuronak gehitzen ditu neuronen tamaina handitu barik.

without the average neuron becoming any larger,

which is a very economical way

Garunari neuronak gehitzeko modu oso ekonomikoa da.

to add neurons to your brain.

The result is that a primate brain

Beraz, primate baten garunak

will always have more neurons than a rodent brain of the same size,

neurona gehiago izango du tamaina bereko karraskari batenak baino.

and the larger the brain,

Garuna gero eta handiagoa izan,

the larger this difference will be.

gero eta handiagoa izango da aldea.

Well, what about our brain then?

Zer gertatzen da gure garunean?

We found that we have, on average,

Zera aurkitu dugu: batez beste 86 mila milioi neurona ditugu.

86 billion neurons,

16 billion of which are in the cerebral cortex,

Hauetako 16 mila milioi garun kortexean aurkitzen dira,

and if you consider that the cerebral cortex

Kontuan hartuz kortexean daudela

is the seat of functions like

kontzientzia, arrazonamendu logikoa,

awareness and logical and abstract reasoning,

abstraktua eta antzeko funtzioak,

and that 16 billion is the most neurons

eta ez dagoela 16 mila milioi neurona baino gehiago

that any cortex has,

duen kortexik,

I think this is the simplest explanation

uste dut hau dela

for our remarkable cognitive abilities.

gure aparteko gaitasun kognitiboen azalpen sinpleena.

But just as important is what the 86 billion neurons mean.

86 mila milioi neurona horien esanahia ere garrantzitsua da.

Because we found that the relationship

Aurkitu genuen garunaren tamainaren

between the size of the brain and its number of neurons

eta bere neurona kopuruaren arteko erlazioa

could be described mathematically,

matematikoki deskribatu daitekeela.

we could calculate what a human brain

Giza garun bat karraskari batena balitz

would look like if it was made like a rodent brain.

nolakoa izango zen kalkulatu ahal izan genuen.

So, a rodent brain with 86 billion neurons

Karraskari baten garunak 86 mila milioi neurona izango balitu,

would weigh 36 kilos.

36 kg pisatuko lituzke.

That's not possible.

Hori ezta posible.

A brain that huge would be crushed

Hain garun handia bere pisuak zanpatuko luke,

by its own weight,

and this impossible brain would go

eta garun hau

in the body of 89 tons.

89 tonatako gorputz batekin etorriko litzake.

I don't think it looks like us.

Horrek ez luke gure antzik izango.

So this brings us to a very important conclusion already,

Guzti honek ondorio nagusi batera garamatza:

which is that we are not rodents.

ez garela karraskariak.

The human brain is not a large rat brain.

Giza garuna ez da arratoi garun erraldoi bat.

Compared to a rat, we might seem special, yes,

Arratoi batekin alderatuta bereziak izan gaitezke,

but that's not a fair comparison to make,

baina ez da alderaketa justua,

given that we know that we are not rodents.

baitakigu ez garela karraskariak.

We are primates,

Primateak gara,

so the correct comparison is to other primates.

beraz alderaketa justua beste primateekin litzateke.

And there, if you do the math,

Kalkuluak hau ematen du:

you find that a generic primate

86 mila milioi neurona lituzkeen primate batek

with 86 billion neurons

would have a brain of about 1.2 kilos,

gutxi gora behera 1,2 kg-ko garuna edukiko luke

which seems just right,

onargarria dena,

in a body of some 66 kilos,

eta 66 kg-ko gorputza.

which in my case is exactly right,

Horixe da nire kasua hain zuzen ere.

which brings us to a very unsurprising

Guzti honek harrigarria ez,

but still incredibly important conclusion:

baina garrantzitsua den beste ondorio batera garamatza:

I am a primate.

primate bat naiz.

And all of you are primates.

Eta zuek guztiak primateak zarete.

And so was Darwin.

Darwin ere primatea zen.

I love to think that Darwin would have really appreciated this.

Darwinek hau benetan gustukoa izango zuen.

His brain, like ours,

Bere garuna, gurea bezala,

was made in the image of other primate brains.

beste primateen garunaren itxurara egina zegoen.

So the human brain may be remarkable, yes,

Beraz, giza garuna apartekoa da

but it is not special in its number of neurons.

baina ez da berezia neurona kopuruaren aldetik.

It is just a large primate brain.

Primate handi baten garuna baino ez da.

I think that's a very humbling and sobering thought

Pentsamendu apal eta erakusgarria dela uste dut,

that should remind us of our place in nature.

naturan dugun lekua gogoratzen digun pentsamendua.

Why does it cost so much energy, then?

Zergatik behar du hainbeste energia?

Well, other people have figured out

Beste batzuk ikertu dute

how much energy the human brain

gizakiaren eta beste espezieren garunek behar duten energia.

and that of other species costs,

and now that we knew how many neurons

Badakigunez garunen neurona kopurua,

each brain was made of, we could do the math.

kalkulua egin dezakegu.

And it turns out that both human

Aurkitu da

giza garunak eta beste garunek kantitate bera erabiltzen dutela:

and other brains cost about the same,

an average of six calories per billion neurons per day.

batezbeste 6 kaloria eguneko mila milioi neuronako.

So the total energetic cost of a brain

Beraz, garun baten gastu energetikoa

is a simple, linear function

neurona kantitatearen funtzio lineal sinple bat da,

of its number of neurons,

and it turns out that the human brain

eta giza garunak

costs just as much energy as you would expect.

espero zitekeen beste energia erabiltzen du.

So the reason why the human brain

Beraz, giza garunak hainbeste energia

costs so much energy is simply because

erabiltzearen arrazoia sinplea da,

it has a huge number of neurons,

neurona kantitate ikaragarria dugula.

and because we are primates

Primateak garelako, neurona asko ditugu gure tamainarako

with many more neurons for a given body size

than any other animal,

beste animaliekin alderatuta.

the relative cost of our brain is large,

Gure garunaren gastu erlatiboa izugarria da

but just because we're primates, not because we're special.

baina hori primateak garelako da, ez bereziak garelako.

Last question, then:

Beraz, azken galdera:

how did we come by this remarkable number of neurons,

Nola heldu gara neurona kopuru izugarri horretara?

and in particular, if great apes

Eta, are gehiago, primateak gu baino handiagoak izanik,

are larger than we are,

why don't they have a larger brain than we do, with more neurons?

zergatik ez dute gurea baino handiagoa eta neurona gehiago dituen garuna?

When we realized how much expensive it is

Garunean hainbeste neurona izateak

to have a lot of neurons in the brain, I figured,

ze gastu zekarren ikusita,

maybe there's a simple reason.

arrazoi sinple bat zegoela bururatu zitzaidan.

They just can't afford the energy

Beraiek ez dute nahikoa energia

for both a large body and a large number of neurons.

gorputz handia eta neurona kopuru handia mantentzeko.

So we did the math.

Kalkulua egin genuen.

We calculated on the one hand

Primate batek janari gordina janez

how much energy a primate gets per day

eguneko zenbat energia lortzen duen

from eating raw foods,

kalkulatu genuen.

and on the other hand, how much energy

Gero, zenbat energia beharko lukeen

a body of a certain size costs

tamaina zehatz bateko gorputz batek

and how much energy a brain of a certain number of neurons costs,

eta neurona kopuru konkretu batek kalkulatu genuen.

Konbinaketak behatu genituen,

and we looked for the combinations

of body size and number of brain neurons

primate baten gorputz tamaina eta garun-neurona

that a primate could afford

kopuruaren arteko konbinaketak

if it ate a certain number of hours per day.

egunean ordu zehatz batzuk jaten emanez gero.

And what we found is that

Zera aurkitu genuen:

because neurons are so expensive,

neuronak hain garestiak direnez,

there is a tradeoff between body size and number of neurons.

gorputzaren tamaina eta neurona kantitatea konpentsatzen dira.

So a primate that eats eight hours per day

Egunean 8 ordu jaten pasatzen dituen primate batek

can afford at most 53 billion neurons,

gehienez ere 53 mila milioi neurona izan ditzake,

but then its body cannot be any bigger

baina bere gorputza ezin da

than 25 kilos.

25 kg baino handiagoa izan.

To weigh any more than that,

Hori baino astunagoa izateko, neurona gutxiago izan behar ditu.

it has to give up neurons.

So it's either a large body

Beraz, edo gorputz handi bat daukagu,

edo neurona kopuru handi bat.

or a large number of neurons.

When you eat like a primate,

Primate batek bezala jaten baduzu, ezin dituzu bi gauzak izan.

you can't afford both.

One way out of this metabolic limitation

Muga metaboliko honetatik askatzeko modu bat

would be to spend even more hours per day eating,

eguneko ordu gehiago jaten pasatzea litzateke.

but that gets dangerous,

Baina hori arriskutsua da,

and past a certain point, it's just not possible.

eta puntu batetik aurrera ezinezkoa.

Gorilek eta orangutanek esaterako,

Gorillas and orangutans, for instance,

afford about 30 billion neurons

30 mila milioi neurona dituzte,

by spending eight and a half hours per day eating,

eta egunean 8 ordu eta erdi jaten pasatzen dituzte.

and that seems to be about as much as they can do.

Hori da antza lor dezaketen gehiena.

Nine hours of feeding per day

Badirudi egunean 9 ordu jaten pasatzea dela

seems to be the practical limit for a primate.

primate baten muga praktikoa.

What about us?

Eta gurea?

With our 86 billion neurons

and 60 to 70 kilos of body mass,

Gure 86 mila milioi neuronekin

eta gure 60-70 kg-ko gorputzekin,

we should have to spend over nine hours

egunean 9 ordu baino gehiago pasa beharko genituzke

per day every single day feeding,

egunero gure elikadura beharrak asetzen,

which is just not feasible.

eta hau ezinezkoa da.

If we ate like a primate,

Primateek bezala jango bagenu,

we should not be here.

ez ginateke hemen egongo.

How did we get here, then?

Orduan, nola heldu ginen hona?

Well, if our brain costs just as much energy

Gure garunak hainbeste energia erabiltzen badu,

as it should, and if we can't spend

every waking hour of the day feeding,

eta ezin badugu jaten eman esna gauden ordu bakoitza,

then the only alternative, really,

dugun aukera bakarra

is to somehow get more energy

alimentu berdinetatik

out of the same foods.

energia gehiago lortzea da.

And remarkably, that matches exactly

Harrigarria badirudi ere, hori bat dator

what our ancestors are believed to have invented

duela milioi eta erdi urte

one and a half million years ago,

gure arbasoek asmatu zutela uste denarekin,

when they invented cooking.

janaria prestatzearekin alegia.

To cook is to use fire

Janaria prestatzea sua erabiliz

to pre-digest foods outside of your body.

elikagaiak gorputzetik kanpo aurrez liseritzea da.

Cooked foods are softer, so they're easier to chew

Elikagai egosiak leunagoak dira, murtxikatzeko errazagoak

and to turn completely into mush in your mouth,

eta errazago bihurtzen dira papila ahoan.

so that allows them to be completely digested

Horrela estomagoan erabat liseritu

and absorbed in your gut,

eta xurgatzen dira.

which makes them yield much more energy in much less time.

Honela, denbora gutxiagoan energia gehiago sor dezakegu.

Beraz, janaria prestatzeak

So cooking frees time for us to do

neuronekin gauza interesgarriagoak

much more interesting things with our day

egiteko denbora ematen digu.

and with our neurons

Ez dugu etengabe janarian, janaria biltzean eta jatean

than just thinking about food,

looking for food, and gobbling down food

all day long.

pentsatu behar.

So because of cooking, what once was

Beraz, janaria prestatzen dugulako,

behin eragozpen handi bat izan zen garun handi hau

a major liability, this large,

dangerously expensive brain with a lot of neurons,

neuronez beteta eta energia gastu handia duen garun hau,

could now become a major asset,

oso baliagarri bihurtu da,

now that we could both afford the energy for a lot of neurons

neurona piloarentzako energia lortu dezakegulako

eta eurekin gauza interesgarriak egiteko astia izan.

and the time to do interesting things with them.

So I think this explains why the human brain

Honek azaltzen du eboluzioan zehar

grew to become so large so fast in evolution,

zergatik hain azkar hazi zen giza garuna, handia egin arte,

all of the while remaining just a primate brain.

primate garuna izaten jarraitzen zuen bitartean.

With this large brain now affordable by cooking,

Janaria prestatzeak garun handi hau eskuragarri egin

we went rapidly from raw foods to culture,

eta elikagai gordinetatik kulturara,

agriculture, civilization, grocery stores,

nekazaritzara, zibilizaziora, dendetara,

electricity, refrigerators,

elektrizitatera, hozkailuetara,

all of those things that nowadays

eta egun ditugun gauzetara heldu gara.

allow us to get all the energy we need

Honela gauza gara

for the whole day in a single sitting

egun guztia iraun ahal izateko energia

janari azkarreko gustuko lekuetan kolpetik lortzeko.

at your favorite fast food joint.

So what once was a solution

Behin konponbide bat izan zena

now became the problem,

orain arazo bihurtu da.

and ironically, we look for the solution in raw food.

Ironikoki, orain konponbidea elikagai gordinetan bilatzen dugu.

So what is the human advantage?

Zein da gizakiaren abantaila?

What is it that we have

Zer daukagu beste animaliek ez daukatena?

that no other animal has?

My answer is that we have the largest number

Nire erantzuna hau da: garun kortexean

of neurons in the cerebral cortex,

neurona kopuru handiena dugu eta uste dut hori dela

and I think that's the simplest explanation

for our remarkable cognitive abilities.

gure gaitasun kognitibo ezohikoen azalpen sinpleena.

And what is it that we do that no other animal does,

Zer egiten dugu beste animaliek egiten ez dutena,

and which I believe was fundamental

nire ustez oinarrizkoa dena,

to allow us to reach that large,

garun kortexean ditugun neurona kantitate izugarri horrek

largest number of neurons in the cortex?

posible egiten duena?

In two words, we cook.

Bi hitzetan: janaria prestatu.

No other animal cooks its food. Only humans do.

Beste animaliarik ez dago janaria prestatzen duenik.

Gizakiek bakarrik egiten dute. Horrela heldu ginen gizaki izatera.

And I think that's how we got to become human.

Giza garuna ikertzeak elikagaiez nuen pentsaera aldatu dit.

Studying the human brain changed the way I think about food.

I now look at my kitchen,

Orain sukaldea begiratu eta gurtu egiten dut.

and I bow to it,

and I thank my ancestors for coming up

Arbasoei eskertzen diet

with the invention that probably made us humans.

ziurrenik gizaki egin gaituen asmakizuna sortzeagatik.

Thank you very much.

Mila esker.

(Applause)

(Txaloak)