From Two Brains to a Constitution

What might eight young neuroscientists discover if they begin by asking how two people can do together what neither of them can do alone?

Imagine eight students entering a neuroscience congress.

They could begin by talking about neurons.

Electrical potentials.

EEG.

Oscillations.

Synapses.

Brain networks.

But Ivo Leiva-Cisterna could begin with a much simpler question:

Can two people do together something that neither of them could do alone?

Someone might quickly answer:

“Yes.”

Then another question would follow:

How do we know?

It is precisely here that neuroscience stops being only something we learn and starts becoming a tool for thinking.

During FALAN 2026 in Santiago, Chile, eight students from Brain Bee Chile will have the opportunity to come into contact with one of the major neuroscience meetings in Latin America and the Caribbean.

BrainLatam’s proposal for this encounter is not to give them an answer about society.

It is to do something perhaps more difficult:

begin with the brain and keep asking questions until the question itself becomes too large to fit inside it.

First question: can we observe two brains at the same time?

Yes.

In the previous blog, we discussed hyperscanning: simultaneously recording the brain activity of two or more people while they interact.

But the work of Ivo Leiva-Cisterna and colleagues, published in 2025 in Social Cognitive and Affective Neuroscience, took a particularly interesting step.

The researchers did not want only to observe that two brains became more synchronized during a cooperative task.

They wanted to ask:

What if we experimentally modify that synchronization? Does cooperation change as well?

Sixty participants, forming 30 pairs of people who did not previously know each other, performed a task in which they had to coordinate their response times in order to succeed together.

Some pairs took part in a sensory entrainment condition.

Others performed the task without that protocol.

In the experimental condition, rhythmic visual stimulation was delivered at 16 Hz or 40 Hz, either synchronized or with temporal offsets between the two participants.

The goal was to modulate neural activity across the pair and observe what happened to their coordination.

And what happened?

Pairs exposed to the entrainment protocol showed, overall, a higher rate of cooperation than the control group.

The clearest behavioral effect appeared in the 16 Hz conditions.

Importantly, participants did not simply become faster.

The main change concerned how closely their responses aligned with one another.

They coordinated better.

The authors interpreted the overall findings as evidence that interbrain synchronization may have a functional contribution to cooperative coordination, rather than being merely a by-product of two people receiving similar stimuli.

It is a provocative result.

But we need to preserve the same scientific humility as in the previous blogs.

There were 30 pairs.

One specific task.

One specific visual stimulation paradigm.

And the study itself contained important nuances.

So:

16 Hz is not “the frequency of cooperation.”

And neural synchrony is not Jiwasa.

But now we have a powerful experimental question.

Second question: where was the cooperation?

Was it in person A’s brain?

In person B’s brain?

On the screen?

In the synchronization?

In the rules of the task?

Or did it emerge from the relationship among all of these?

Person A could not succeed alone.

Person B could not either.

To succeed, each person had to produce a movement while taking the other person’s action into account.

So the outcome did not belong entirely to A.

Nor entirely to B.

It appeared in the coordination:

A ↔ B.

This is an excellent doorway through which to introduce Jiwasa to the students.

Not as an answer.

As a question.

Is there something that only begins to exist when there is a “we”?

Third question: are there two brains or two bodies?

Now we can make the problem more difficult.

The participants had EEG electrodes placed on their heads.

But the button was not pressed by a floating brain.

It was pressed by a body.

Eyes perceived the stimulus.

Hands responded.

Autonomic systems maintained the organism.

Previous experience influenced attention, trust, and strategy.

So we ask:

Can we understand that cooperation by studying only two brains?

Probably not.

The brain participates.

But it participates within an organism.

This is where BrainLatam proposes the Body-Territory.

Not as a variable measured by Leiva-Cisterna and colleagues.

As a hypothesis for asking whether the relevant unit for understanding human action may need to include the organism situated within its material, historical, cultural, and relational conditions.

Now we no longer have only:

brain ↔ brain.

We have:

Body-Territory ↔ Body-Territory.

Fourth question: did the two bodies arrive at the experiment as equals?

No.

Even if everyone received the same screen.

Each person arrived with a history.

A language.

A repertoire.

A way of trusting.

A history of cooperation.

A body trained within a particular territory.

This leads to a question that eight young Latin Americans can understand without any equation:

If we change the territory in which a person grows up, do we also change what they learn to perceive as possible?

A child with adequate nutrition, stable schooling, safety, books, sport, access to nature, and time available encounters one field of possibilities.

Another child living with food insecurity, violence, and lack of infrastructure encounters another.

We do not need to say that one has “a better brain.”

The question is different:

Were they offered the same possibilities for movement?

Here APUS returns.

And perhaps so does another BrainLatam idea:

You can be massified by the choices you never had.

Because before choosing between A and B, A and B must first have appeared as possibilities.

Fifth question: where does territory end?

At the door of the house?

At the neighborhood?

At the city?

At the country?

Think of Chile.

The Andes.

The desert.

The ocean.

Water.

Mining.

Forests.

Temperature.

Air quality.

Earthquakes.

Distance.

These conditions are not merely background.

They participate in the possibilities of living.

So we might ask the students:

Can a body exist independently of the Biome that provides water, food, temperature, air, and the conditions that allow life to continue?

If the answer is no, the path changes again.

From brain, we moved to body.

From body, to territory.

From territory, to Biome.

We might represent it like this:

brain → body → relationship → territory → Biome.

A Constitution has still not appeared.

Sixth question: who organizes part of these possibilities?

Now the State enters.

Who decides where schools will exist?

Hospitals?

Sanitation?

Transport?

Green areas?

Environmental protection?

Connectivity?

Research?

School meals?

Who defines rights and obligations?

Who organizes a large part of the collective conditions within which a Body-Territory will develop?

The State does not produce every condition of life.

But it modifies many of them.

So an almost unavoidable question appears:

If territorial conditions modify what a body can do, does the State also participate indirectly in constructing the possible movements of its citizens?

Now neuroscience has encountered politics.

Not because an EEG can tell us how to govern.

But because studying causality taught us to keep asking:

what came before?

Seventh question: what unit does the State see?

A person may appear to the State as:

an ID number.

An address.

Income.

A diagnosis.

A school registration.

A beneficiary.

A voter.

A taxpayer.

But what disappears when the same person is divided across different databases?

Their relationship with territory?

Water quality?

Commute time?

Exposure to violence?

Access to the Biome?

Community networks?

Educational possibilities?

Perhaps we can ask the eight students:

Can the State understand a person by looking only at the documents it created to represent them?

And then introduce, explicitly as a BrainLatam proposal:

What if we experimented with thinking of the Body-Territory as the minimum unit of recognition by the State?

We are not claiming that neuroscience has demonstrated that this must be the correct constitutional organization.

It has not.

We are constructing a political hypothesis from a sequence of causal questions.

Eighth question: what if you had to write a Constitution?

Only now do we arrive at the Constitution.

We did not begin by telling the students what it should contain.

We began with:

EEG.

Then:

two brains.

Then:

cooperation.

Then:

two bodies.

Then:

territory.

Then:

Biome.

Then:

State.

Only now might we ask:

If you were writing a new Constitution after this conversation, what would you ask before writing the first article?

Perhaps one student would talk about education.

Another about health.

Another about water.

Technology.

Cities.

The economy.

The environment.

Democracy.

The answers may be different.

That is desirable.

The goal is not to make eight students repeat BrainLatam.

That would contradict everything we are proposing.

The goal is to expand their constitutional APUS:

to make questions appear that may not have been available at the beginning of the conversation.

Where the article ends and BrainLatam begins

Leiva-Cisterna and colleagues studied 30 dyads performing a cooperative task and used rhythmic visual sensory stimulation to modulate interbrain synchronization.

The entrainment protocol was associated with increased synchronization at the target frequencies and improved behavioral coordination, with a particularly pronounced effect in the 16 Hz condition.

Up to this point:

Leiva-Cisterna and colleagues.

The article did not study:

Body-Territory.

APUS.

Jiwasa.

Biome.

State.

Constitution.

From this point onward:

BrainLatam.

Our hypothesis is that this study offers an extraordinary pedagogical opportunity to let a question grow.

If we can experimentally ask how two organisms coordinate an action, we can begin to investigate which conditions expand or restrict that coordination.

If the organism depends on territory, we can ask how territory participates in its possible movements.

If territory depends on ecological conditions, we encounter the Biome.

And if institutions systematically modify those conditions, we encounter the State.

Not as the result of a brain frequency.

As a new scale of the question.

Perhaps neuroscience cannot write a Constitution.

Nor should it attempt to do so alone.

But perhaps it can help a generation ask:

What conditions must exist so that different Body-Territories can participate in constructing a collective movement without some having to disappear so that others may exist?

And then perhaps the question we do not need to hand to the eight students already answered will emerge:

What should be the minimum unit that a State recognizes before it begins to organize a society?

Perhaps someone will answer:

the individual.

Another:

the family.

Another:

the community.

Another:

the territory.

And perhaps someone will ask:

Why separate what has never existed separately?

At that moment, Body-Territory may stop being a definition offered by BrainLatam.

And become a hypothesis the students themselves decide is worth investigating.

Neuro Challenge Latam

Begin with one simple question:

What can two people do together that neither of them can do alone?

Then keep asking “what does that depend on?” until you reach the State.

Will your final question still be about the brain?

Scientific Reference

Leiva-Cisterna, I., Barraza, P., Rodríguez, E., & Dumas, G. (2025). Sensory multi-brain stimulation enhances dyadic cooperative behavior. Social Cognitive and Affective Neuroscience, 20(1), nsaf104. https://doi.org/10.1093/scan/nsaf104