What Happens Between Two Brains When We Begin Acting Together?
What Happens Between Two Brains When We Begin Acting Together?
Remember a conversation in which two people began understanding something together. What changed between the first question and that moment when a possibility emerged that neither of them had imagined alone?
BrainLatam Special Series | 8th Symposium on Neuroscience and Cognition at UFABC — 2026
WHEN A CONVERSATION CHANGES DIRECTION
Perhaps you can remember a conversation that began with a question.
Someone presented an idea. You responded with a different perspective. There was a pause. Someone asked an unexpected question.
Suddenly, a possibility emerged that seemed not to exist before that encounter.
Pay attention to your memory.
Perhaps someone's facial expression changed. Perhaps your breathing became calmer. Or perhaps the decisive moment was a disagreement.
What happens between two organisms when they begin constructing a shared understanding?
This question connects directly with the 8th Symposium on Neuroscience and Cognition at the Federal University of ABC (UFABC), scheduled for November 16–19, 2026, under the theme “The Brain in Context: Contemporary Challenges in Interdisciplinary Neuroscience.”
In previous articles, we explored relationships among mammals and different forms of organization in complex systems.
Now we can investigate those moments when two brains participate in a living interaction.
TWO BRAINS ARE NOT ONE LARGER BRAIN
For a long time, many social neuroscience experiments investigated people individually.
A participant observed images, listened to stories, or answered questions.
These studies produced fundamental knowledge.
But a real conversation introduces something additional: each person continuously changes the conditions encountered by the other.
An unexpected answer can transform the next question.
Silence can produce a different interpretation.
Someone's gaze can redirect the encounter.
Throughout this process, two organisms remain distinct, yet their actions become interdependent.
This distinction inspired research capable of simultaneously recording brain activity from two or more people.
The approach is known as hyperscanning.
Its importance lies in making it possible to investigate interaction as it happens, rather than studying only individual responses to predefined stimuli.
WHAT DOES SYNCHRONIZATION MEAN?
Imagine two people clapping to the same rhythm.
Their movements may exhibit temporal correspondence.
Now imagine two people watching the same movie.
Certain events may evoke similar neural responses.
In both cases, we may observe some form of alignment.
But there is an important difference between responding to the same stimulus and reciprocally influencing another person.
Synchrony between brain signals, often called inter-brain synchrony, describes temporal or statistical relationships between activities recorded in different individuals.
It does not, by itself, demonstrate mutual understanding, cooperation, or shared consciousness.
Two people may exhibit similar responses because they receive comparable stimuli, perform the same task, or share physiological conditions.
For this reason, we must also investigate what actually happens during the interaction.
A DISCOVERY FROM UFABC ITSELF
There is a particularly relevant connection with the symposium.
In 2023, Amanda Yumi Ambriola Oku, Eneyse Dayane Pinheiro, Raimundo da Silva Soares Junior, and João Ricardo Sato, researchers affiliated with UFABC, published a study on interactions between teachers and students.
The research used fNIRS hyperscanning and concepts from graph theory to analyze relationships between brain activities during educational situations.
This brings our question into a familiar environment.
Imagine a teacher explaining a concept.
A student expresses uncertainty. The teacher changes the explanation. Another example transforms the student's understanding.
What could we investigate in this encounter?
Perhaps the correspondence between particular brain signals.
But also speaking turns, questions, hesitations, and changes in understanding.
Learning takes place in individual organisms, yet its conditions can be continuously transformed through relationships.
WHEN TWO CHILDREN SEARCH FOR A SOLUTION
In August 2026, Raimundo da Silva Soares Junior and João Ricardo Sato published another study, this time examining coupling between brain activities during collaborative Tangram solving by pairs of children.
Tangram is a puzzle consisting of geometric pieces that can be combined to create different shapes.
Imagine two children sitting in front of the pieces.
One tries a particular combination.
The other notices a different possibility.
The first child changes their choice.
The exploratory study used fNIRS to investigate this kind of naturalistic interaction.
As with other early-stage investigations, its findings must be interpreted in light of the number of participants, the experimental protocol, and the limitations of the measurements.
Nevertheless, the research highlights an important scientific possibility:
We can observe the construction of a solution while different participants reciprocally modify their actions.
And we can ask whether neural indicators add information beyond behavioral observations.
A CHILEAN STUDY TEACHES US TO QUESTION APPEARANCES
In 2026, researchers associated with Universidad Adolfo Ibáñez in Chile, including Lukas Valenzuela and Vicente Soto, investigated ten pairs of Latin American friends.
The participants completed cooperative Jenga activities, watched videos, and rested.
The researchers simultaneously recorded their brain activity using mobile EEG.
During the cooperative task, they found an increase in certain measures of synchrony.
But an additional analysis revealed something fundamental.
Part of this increase could be associated with shared task characteristics, without necessarily indicating a partner-specific connection.
Other measures provided more specific evidence of coupling between members of the pairs.
Two brains can appear synchronized without necessarily sharing the same information.
The study reinforces the importance of experimental controls, spectral analyses, and comparisons with artificially constructed participant pairs.
A CONVERSATION CAN BRING PEOPLE CLOSER OR MAKE THEIR DIFFERENCES MORE VISIBLE
In 2024, Sebastian Speer and colleagues investigated conversations between friends and strangers using simultaneous functional magnetic resonance imaging.
The researchers observed different trajectories.
Among strangers, neural and linguistic patterns tended to become more similar as conversations progressed.
Among friends, there was greater differentiation and exploration of varied topics.
These findings reflect the specific conditions of that experiment and do not establish a universal rule.
But they raise a surprising question:
Could understanding someone involve both discovering similarities and allowing differences to emerge?
The possibility of exploring distinct perspectives also contributes to relationships.
Perhaps a conversation transforms its participants precisely because they do not need to finish thinking in the same way.
THE BODY ALSO PARTICIPATES IN CONVERSATION
A conversation takes place between brains, but also between bodies.
Breathing, heart rate, posture, movement, and facial expressions may change during an interaction.
Researchers associated with Universidad Diego Portales in Chile, including Stefanella Costa-Cordella, Josefina Mattoli-Sánchez, and Francisco J. Parada, participated in a review on embodied hyperscanning.
This approach combines brain and bodily measurements to investigate social interactions.
The goal is not to assume that all physiological responses must synchronize.
It is to understand how different processes may relate to one another throughout an encounter.
Imagine two people talking after a difficult situation.
One remains agitated.
The other listens.
Their physiological rhythms may be different, and that difference may participate in the interaction.
Being together does not necessarily require feeling everything in the same way.
WHEN CONTEXT CHANGES THE MEANING OF SIGNALS
Among the researchers announced for the symposium is Rafael Naime Ruggiero, from UNIFESP, who investigates oscillations and synchronization across brain networks.
His research brings us closer to an essential methodological consideration.
Synchronization within a single brain and synchronization observed between different brains are not equivalent phenomena.
We must also consider that hemodynamic signals, such as those recorded by fNIRS, can be influenced by systemic physiological processes.
Breathing, blood circulation, and movement may affect the measurements.
For this reason, multimodal investigations must interpret each signal according to its specific properties.
The scientific challenge is not to find synchrony in every situation.
It is to understand which processes it represents, when it appears, and what happens when it disappears.
CAN FIVE PEOPLE PRODUCE MORE THAN FIVE ANSWERS?
Let us imagine five participants trying to solve a problem.
In the first stage, each person works separately.
In the second, everyone follows a common instruction.
In the third, any participant can propose an alternative and change the collective direction.
Disagreements may emerge.
Someone may identify an error that others have overlooked.
Perhaps the group discovers an unexpected solution.
This hypothetical protocol could record decisions, movements, speaking turns, EEG, fNIRS, ECG, and breathing.
As a representative of Artinis & NIRx and Brain Products, BrainLatam connects researchers with technologies for functional neuroimaging, electroencephalography, and multimodal investigation.
But we must distinguish what these instruments can measure from what we seek to understand.
They do not directly detect freedom, belonging, or collective consciousness.
These concepts require definitions, behavioral measurements, and complementary interpretations.
JIWASA: UNDERSTANDING TOGETHER WITHOUT THINKING ALIKE
At BrainLatam, we propose Body-Territory (Corpo-Território) as an indivisible unit of existence, sensitivity, and participation in the world.
Our original formulation of Jiwasa explores the possibility of shared agency that preserves the uniqueness of participants.
This does not mean searching for a collective brain.
Nor does it mean turning neural synchrony into proof of a shared consciousness.
We can approach Jiwasa as a question about the conditions under which different people can participate in transforming a collective We.
A conversation may involve agreement without genuine participation.
Another may contain disagreements while expanding everyone's possibilities.
This distinction remains philosophical and institutional, although some of its aspects may inspire experimental investigations.
THE MOMENT WHEN SOMETHING NEW BECOMES POSSIBLE
Let us return to the conversation you remembered at the beginning.
Perhaps someone asked a question you had not yet learned how to formulate.
Perhaps you offered an experience the other person did not know.
The outcome did not need to be an identical idea in two brains.
It may have been a different transformation in each participant.
Neuroscience can already investigate aspects of these interactions with increasingly sophisticated temporal and spatial measurements.
Yet questions about meaning, understanding, autonomy, and subjective experience remain open.
Perhaps the next discovery lies precisely within the relationships we do not yet know how to measure.
When two people begin understanding something together, what changes within each of them—and what becomes possible between them?
Jiwasa: the possibility of Being many without anyone having to stop Being.
About This Series
This article is part of a special series by BrainLatam, a sponsor of the 8th Symposium on Neuroscience and Cognition at the Federal University of ABC (UFABC), scheduled for November 16–19, 2026, in São Bernardo do Campo, Brazil.
The article engages with research conducted at UFABC itself, contributions from Latin American researchers studying hyperscanning, and topics announced for the symposium, particularly Rafael Naime Ruggiero's investigations of brain synchronization.
BrainLatam's original interpretations do not necessarily represent the positions of the researchers or event organizers.
Official event website: https://www.even3.com.br/viii-simposio-em-neurociencia-e-cognicao-da-universidade-federal-do-abc-761401/
References — A Second Reading of the Article
1. Studying two brains simultaneously allows researchers to investigate interactions that individual experiments cannot fully represent.
Hakim, U. et al. (2023). Quantification of inter-brain coupling: A review of current methods used in haemodynamic and electrophysiological hyperscanning studies. NeuroImage, 280, 120354.
The review presents methods used in hyperscanning studies and highlights methodological differences that affect the interpretation of synchrony.
https://doi.org/10.1016/j.neuroimage.2023.120354
2. UFABC researchers investigate how brain activity may relate to interactions between teachers and students.
Oku, A. Y. A.; Pinheiro, E. D.; Soares Jr., R. S.; Sato, J. R. (2023). Analyzing teacher-student interactions through graph theory applied to hyperscanning fNIRS data. Progress in Brain Research, 282, 123–143.
The study applies fNIRS and graph theory to investigate patterns of brain interaction in an educational context.
https://doi.org/10.1016/bs.pbr.2023.10.005
3. Collaborative problem-solving can be investigated while two children construct a solution together.
Soares Junior, R. S.; Sato, J. R. (2026). Inter-brain coupling during naturalistic collaborative Tangram solving in child dyads: an exploratory fNIRS hyperscanning study. Brain Structure and Function, 231, Article 128.
The UFABC study explores relationships between brain signals during a joint geometric puzzle-solving activity.
https://doi.org/10.1007/s00429-026-03187-5
4. Not every increase in synchrony during a task represents a partner-specific connection.
Valenzuela, L.; Cavallaro, R.; Mangeng, A.; Pérez-Arenas, X.; Carollo, A.; Esposito, G.; Medel, V.; Soto, V. (2026). Aperiodic activity shapes inter-brain synchrony during cooperative puzzle solving: dissociable task-enhanced and partner-specific spectral signatures. NeuroImage, 338, 122116.
Involving Latin American participants and Chile-based researchers, the study distinguishes shared task effects from measures more specific to individual pairs.
https://doi.org/10.1016/j.neuroimage.2026.122116
5. Understanding someone can also involve exploring differences, rather than merely increasing neural similarity.
Speer, S. P. H. et al. (2024). Hyperscanning shows friends explore and strangers converge in conversation. Nature Communications, 15, 7781.
The study identifies different trajectories in conversations between friends and strangers, highlighting the importance of relational context.
https://doi.org/10.1038/s41467-024-51990-7
6. Investigating interactions also requires considering bodily movements and physiological processes.
Grasso-Cladera, A.; Costa-Cordella, S.; Mattoli-Sánchez, J.; Vilina, E.; Santander, V.; Hiltner, S. E.; Parada, F. J. (2025). Embodied hyperscanning for studying social interaction: A scoping review of simultaneous brain and body measurements. Social Neuroscience, 20(3), 163–179.
Involving researchers affiliated with institutions in Chile, this review explores studies combining brain and bodily recordings during interactions.
https://doi.org/10.1080/17470919.2024.2409758
7. Neural synchrony should not automatically be confused with the sharing of information.
Varlet, M.; Grootswagers, T. (2024). Measuring information alignment in hyperscanning research with representational analyses: moving beyond interbrain synchrony. Frontiers in Human Neuroscience, 18, 1385624.
The paper discusses limitations of conventional synchrony measures and proposes analyses focused on representational content.
https://doi.org/10.3389/fnhum.2024.1385624
8. A conversation can transform the internal models used by two people to solve a shared task.
Koike, T.; Okazaki, S.; Sumiya, M.; Nakagawa, E.; Hirotani, M.; Sadato, N. (2025). The neural basis of sharing information through goal-directed conversation: A hyperscanning functional magnetic resonance imaging study. Cortex, 187, 74–97.
The study investigates brain activity patterns and coupling during conversations required for joint task-solving.
https://doi.org/10.1016/j.cortex.2024.11.026
9. Investigating synchronization across brain networks contributes to understanding cognitive and clinical mechanisms.
Ruggiero, R. N. Academic profile and research areas. Federal University of São Paulo.
The Brazilian researcher investigates neural mechanisms and brain oscillations associated with cognition and behavior.
http://lattes.cnpq.br/5372318020253092
10. Investigating the brain in context can bring neuroscience closer to the relationships that shape our experiences.
UFABC (2026). 8th Symposium on Neuroscience and Cognition — The Brain in Context: Contemporary Challenges in Interdisciplinary Neuroscience.
The symposium promotes interdisciplinary dialogue among studies of the brain, body, behavior, and environment.
Conceptual note: Body-Territory, 5D Consciousness, and Jiwasa are original conceptual formulations developed by BrainLatam. The cited studies support specific aspects of neurophysiological and behavioral interactions but do not constitute experimental validation of these proposals.
BRAINLATAM · W45/2026 · BLOG 05 · ENGLISH EDITION
