Are plants conscious? | Stefano Mancuso | TEDxGranVíaSalon

We already know that plants have all our senses (they can see, hear, touch, smell and see) without the organs usually associated with them and they have some more specific exclusive senses. We also know that they have very important and intense social lives. But, are plants intelligent? Can they solve problems, communicate, and navigate their surroundings?

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Thank you to everyone for being here.

I'm sorry I cannot speak
in your wonderful language,

but it's all the same a pleasure
to be here in this wonderful place,

the right place to speak about plants.

OK, let's start immediately
because we have not too much time.

And I will show you now four slides
in a very fast sequence.

This one.

This one.

This one.

And, the last one.

Well (Laughs), this one ...

It's a very easy psychological test

we did some years ago
to the university students.

We asked these university students
to tell us what they saw in the slides.

And 96% of the people interviewed

told us that they saw just
deers, elks, frogs,

and for the last slide,

98% of the people will tell you

that there is an adult man
and a young girl.

Well, all these slides have in common

the fact that 80% of the slides
is made by plants.

But our brain is filtering out
all this stuff about plants.

And, it's a well known
feature of our brain.

It's called Plant Blindness.

It's the inability to see or notice
the plants in the environment.

It's a kind of tool that protects
our brain to be overloaded

with a lot of information
about this useless green stuff.

We evolved in a forest

and it was much more important for us

to be aware of animals and other humans,

and not to be overloaded with
all this information about green.

Well, this was a nice tool
at the beginning of our evolution,

but today, it's a problem.

Today, this Plant Blindness prevents us,
for example to know this data,

this is the unbelievable data,

99.7% of the biomass
of the planet is made by plants.

So, everything that -
I would say that the life of the planet,

it's a green place, it's a green life.

All the animals altogether,
human included, is just 0.3%.

So it's unbelievable that we don't know,
actually, how these plants work

and we are all the time underestimating
their amazing abilities.

Well, let's have a look at the beginning,
how a plant is made.

A plant is a sessile organism.

Sessile means that it cannot move.

The plants cannot move
from one place to the other.

But they can move a lot.

Ops, I'm sorry, I do not know
what's happened.

And the second, the second point
is that plants have no organs.

This is an unbelievable difference
with the animals.

So I mean - animals
concentrate specific functions

inside specific organs.

So we have eyes to see,
we have lungs for breathing,

we have the stomach to digest and so on.

But the plants evolved
not to have any organs,

because having an organ is too dangerous,

for plants that have to be predated,
to be eated by animals.

So you can imagine
that a single insect,

just eating a little bit of your brain
would be enough to kill you, no?

Ah, so this is why the plants
have no organs.

But, having no organs doesn't mean
that they have not the function.

This is an important point.

In other words, plants are able
to see without eyes,

they are able to hear without hearing,

they are able to taste, and to smell,

and to breath without the organs.

And they are also able
to make calculations,

memorize, learn without brain.

Now the point about plants
is that they cannot move.

But actually, they move a lot.

There are passive movements in plants,

like in this pine cone, no?

The opening and the closing
of a pine cone,

that has been used for the production
of new passive materials.

Or, this very nice Erodium cicutarium.

This is a seed, that you can see.

Just with the change
in the humidity it's turning,

and uses this ability
to enter in the soil,

and so it's like a spermatozoa,
it works very well,

and you can see that some of them
are also able to enter in the soil.

Now, what is amazing about that

is that they do this
without using any energy.

So they have no muscles,
look, it was able to enter.

So, they use no energy,
they have no muscles,

and it's just the way the material is made

that is amazing, that makes possible
this wonderful movement.

Of course, there are active movements,
some of them are very fast,

like in the case of the venus flytrap,
dionea, it's a carnivorous plant,

we know that it's a very
fast movement.

Many of them can be exhibited

just by making a faster -
the time lapse,

the so called... the time lapse technique.

And so we can see this graceful movement

like in this case,
this a young bean moving,

it's just three hours of time,
it's not a week.

So the plants move a lot,
and we can see here,

this growing of some flowers, no?

They grow altogether and even
this growing together is important,

because it's an important moment
of their social life.

So they are really learning
how to stay together

during this first phase of their life.

And now I would like to put
our argumentation a little bit further.

Can we tell that plants
are conscious organisms?

So because I'm pretty sure
that they are intelligent,

I will not discuss with you about that.

Plants are intelligent,
and they are able to solve problems,

and this is my preferred
definition of intelligence.

Now the point is, are plants conscious?

Consciousness is - are plants aware of
their position in the environment?

So, it's a problem to find
right definitions about consciousness.

It's normally defined
by removing something.

Michio Kaku is a quite famous physicist.

And he wrote recently this book
"The Future of The Mind,"

and as a physicist, he gave
a definition of consciousness

that's quite understandable.

Michio Kaku: Consciousness is

the number of feedback loops
required to create a model

of your position in space,
with relationship to other organisms,

and finally in relationship to time.

Stefano: So, consciousness is just
your ability to build a model of yourself

in relation to the space,
to the other organisms, and to the time.

Are plants able to do that?

OK. Let's have a look.

First of all ...

Michio Kaku: So think
of the consciousness of a thermostat.

I believe that even a lowly thermostat
has one unit of consciousness.

That is, it senses
the temperature around it.

And then we have a flower,

a flower has maybe,
ten units of consciousness.

It has to understand the temperature,
the weather, humidity,

where gravity is pointing.

Stefano: Well, so,
for Michio Kaku, the sensing, no?

It's the first level of consciousness.

Plants are unbelievably more
sensitive than animals.

A single plant is able to detect

at least 20 different chemical
and physical parameters all the time.

Among them, there are all the --
our common sense, let's say,

but also something a little bit strange,

as electrical gradient,
chemical gradient, magnetic fields,

and, or, heavy metals
and so on, pathogens.

So we know that plants, for example,

are very sensitive to gravity.

And as every living organism
on the Earth,

we can see here maize
growing according to gravity.

But it's less well known that plants
are also able to sense vibrations.

And so we can see here
how the roots of the plants

grow toward the source of sound.

So they are able to sense the sound,
and they are able to grow

toward the source of the sound.

And also, they are able to
produce a sound.

(Clicking)

This kind of click is very amplified sound

of a growing ... growing roots.

So, when the roots during -

this is just in real time,
so it's few times, few seconds.

A growing root is producing
specific sounds

that probably are used
by the other root apex,

to have information about
the position of the roots in the soil.

Well, let's go on to the second point,

to the first level
of consciousness, space.

Michio Kaku: And then finally
we go into the reptilian brain,

which I call level-one consciousness,

and reptiles basically have
a very good understanding

of their position in space.

Especially because they have to
lunge out, and grab pray.

Stefano: OK, so, reptiles are
very well aware of the space.

Is this the same for the plants?
Let's have a look.

This is a, uh, this is a cuscuta plant.

Cuscuta plant is a parasitic plant

that needs to find a host
in a very short time before dying.

And you can see how this plant
is immediately directing

towards the tomato plant, finds it

and parasitising the tomato plant.

Well, this is quite trivial.

It's just a chemical driving
the information up to the plant.

It's volatile.

But, look at this case.

This is the same plant
that has to take a decision,

because it's in the middle,
between wheat and tomato.

And all the time, it's choosing tomato.

Well, because tomato, it's
much much easier to parasitise.

But if there is no tomato,
even wheat can work.

OK, and this is something simple.

Let's, let's do something
a little bit more curious.

This is a bean in my lab
and this is a support.

You can see how it is moving,
for reaching the support.

So I mean, this plant knows exactly
where the support is, the pole is.

And it's trying to do
all its best for reaching it.

I don't know if you can see,

but the apex of the shoots
already made a kind of hook

in the right position, even if the plant
didn't touch until now, the support.

And you can see also the movement,

it's a wonderful movement.
It's just, in this case, just passive,

just based on multi traders,
look at the hook, in the apex.

And, almost ...

Eh?

Another try, and it's not enough.

And you can almost feel the effort, no?

And, and look at the leaves now,
that they reach the support.

Now, it's much much quieter, calmer.

Anyway, so we know that the bean
is aware of the pole.

OK? It's the result of something
more impressive

because, look in this case,
I am putting a pole among two beans.

So, there is the sensing phase.

They know there is a pole
and they start to compete.

And look when the first one
is winning, the winner,

the other one changes direction.

So, you can repeat
this experiment 100 times,

and 100 times you will get
the same result.

So, this means that the second plant
is not just aware of the support,

it's also aware of another
organism, of another plant,

and it is aware of what
the other plant is able to do. OK?

Great. Social life.

Michio Kaku: Then we have level-two
consciousness, the monkey consciousness.

The consciousness of emotions,
social hierarchy.

Where are we in relationship to the tribe?

Stefano: OK. I don't want to
spend too much time,

because the social life of the plants
is very well known.

Plants are social organisms,

at any level of their evolution,
from Chlamydomonas -

this is a single algae, unicellular algae
that shows weird behaviour.

So, a kind of social movement
like the one of the hands.

These winged shoots, look how
they oscillate altogether.

OK, this is a, this is something
very easy to do, but it's not easy at all.

You need to be in sync
with your neighbor to do this,

so you need to be well aware of what
the movement of your neighbors are.

And kin recognition.

It's something unbelievably interesting.

So we know that today
that plants have different behaviour

according to the degree
of relativeness of the other plants.

So, normally, for example, beans,
the very common bean, are cooperating,

when they are in the same pot,
they are related.

But when the two plants are unrelated,
they are normally competing.

And, in a wood, it's a huge network

of plants interacting each other.

For example, we know that -
this is a graph showing that a single tree

is linked to 47 different trees,
and they use

this network for sharing information,

for sharing even food and water,
nutrients and water.

Well, there is much more with plants.

We have not too much
time to show all of the -

the wonderful things about plants.

Plants, for example, are able to memorize.

They are able to memorize and to learn.

We demonstrated just a few months ago
that it's possible to teach

a mimosa sensitive plant
not to close anymore

when there is a non dangerous stimulus.

And, this sensitive plant is able to
maintain the information for 40 days.

So I mean, the memory lasts
at least 40 days. That is a lot.

And in the average, the memory
of an insect is just 24 hours.

Even for me, 40 days is a lot.

(Laughter)

And so, it's amazing to see that

plants are able to
maintain information for so long.

And, just a last thing.

From my point of view,

intelligence and consciousness are
real biological phenomenons.

So they can be studied, as real,

they need to be studied as
real biological phenomenons.

And it's something
like reproduction, I mean,

reproduction is completely different
in bacteria, phangiae, and humans. OK?

But there is a common background

that means that the phenomenon
is reproduction,

it's the same for intelligence,
it's different, but always the same.

Thank you very much.

(Applause)