Conversation is not simply an exchange of words between two independent brains. During social interaction, our perception, attention, movement, language and even patterns of brain activity can become coordinated. Research into mirror neurons and interbrain synchrony offers intriguing insights into the neural processes associated with this coordination.
When two people are deeply engaged in conversation, a great deal is happening beyond the words being exchanged.
We attend to facial expressions, gestures, tone of voice and timing. We anticipate when the other person is about to stop speaking. We adjust our own responses. Our attention shifts together. At times, even patterns of activity in our brains appear to become coordinated.
Two areas of neuroscience are particularly interesting in this context: mirror neurons and interbrain synchrony.
Mirror neurons
Mirror neurons were first identified in studies of monkeys. Certain neurons were found to become active both when an animal performed an action and when it observed another performing a similar action.
Evidence for a comparable mirror system has subsequently been found in humans.
The discovery attracted enormous interest because it suggested a possible neural mechanism connecting our own actions with our perception of the actions of others.
Mirror systems have been associated with processes such as action observation, imitation and learning. Researchers have also explored possible connections with language, empathy and our ability to understand the intentions and emotions of others.
Some of the stronger claims made about mirror neurons remain debated, however. It would be too simple to describe them as the neurological basis of empathy or social understanding.
Their importance lies in something more modest but still fascinating: our brains do not respond to other people’s actions as if they were entirely unrelated events. Observing another person can activate some of the same neural systems involved in acting ourselves.
Mirror neurons and conversation
This has obvious relevance to conversation.
Conversation involves far more than decoding words. We continuously attend to gestures, facial expressions, posture, tone of voice and other non-verbal signals.
We also coordinate our behaviour.
One of the most remarkable examples is conversational turn-taking. In a flowing conversation, people routinely anticipate when another person is approaching the end of their turn and begin responding with remarkably little delay.
Processes involving perception, prediction and action are continually working together.
Mirror systems may form part of the neural machinery that supports this social coordination, although precisely how they contribute is still being investigated.
Interbrain synchrony
An even more intriguing area of research concerns interbrain synchrony.
Traditionally, neuroscience studied one brain at a time. Researchers are now increasingly able to study the activity of two or more brains simultaneously while people actually interact. One approach, known as hyperscanning, allows researchers to examine relationships between the neural activity of participants during social interaction.
Studies have found that aspects of brain activity can become temporally aligned during activities such as conversation, cooperation, joint attention, music-making and other forms of coordinated activity.
This phenomenon is often described as interbrain synchrony or interpersonal neural synchrony.
It does not mean that two brains literally become synchronised in every respect, nor that they somehow become a single brain. Rather, particular patterns of neural activity can become correlated or coordinated as people interact.
Two brains in conversation
This is particularly interesting when thinking about conversation.
When two people converse, each person’s behaviour continually changes what happens in the other. A facial expression changes how a remark is interpreted. A pause affects whether the other person continues speaking. A question redirects attention. A puzzled expression may cause someone to explain an idea differently.
Conversation becomes a continuous feedback process.
The two brains remain physically separate, but the cognitive processes taking place within them are not entirely independent. Each person is continuously perceiving, predicting and responding to the other.
Interbrain synchrony provides one measurable indication of this coordination.
This does not mean that synchrony necessarily produces better conversation. Nor does greater synchrony automatically mean greater understanding, empathy or agreement. The relationship between neural synchrony and the quality of social interaction is more complicated than that.
But it does challenge the simple picture of two isolated brains independently processing information while messages pass between them.
What does this tell us about interthinking?
This has an interesting connection with interthinking, the idea that language can be used to think collectively.
Interbrain synchrony is not the same thing as interthinking.
Two people could presumably show some degree of neural synchrony without engaging in the kind of joint exploration and development of ideas that interthinking describes. And finding synchrony between two brains does not demonstrate that a thought somehow exists independently between them.
The neuroscience therefore does not prove interthinking.
What it does provide is another reason to question the idea that conversation consists simply of two independent minds exchanging already completed thoughts.
During interaction, attention, perception, prediction, behaviour and neural activity can become dynamically coupled. What happens in one person affects what happens next in the other, which in turn feeds back into the first.
If a conversation also involves questioning, exploring, challenging and building upon each other’s thoughts, that coupling becomes especially interesting. New thoughts may emerge through a process in which neither participant’s thinking is entirely independent of the other.
This is much closer to the picture suggested by interthinking: separate minds, but thinking that develops through interaction.
Not a group mind
None of this requires the idea of a mysterious collective or group mind.
Individual brains remain individual brains. Mirror neurons do not allow us literally to experience another person’s mind, and interbrain synchrony does not fuse two brains together.
The more interesting point is that human cognition is deeply social.
Our brains evolved in a world of other people. They are extraordinarily sensitive to other people’s actions, expressions, voices and responses. When we interact, our behaviour and aspects of our neural activity can become coordinated.
Conversation is therefore not simply something that happens between two already completed thinking systems.
The interaction itself can become part of what shapes what each person perceives, understands and thinks next.
Mirror neurons and interbrain synchrony do not prove that we literally share thoughts or possess a collective mind. They point towards something subtler: when people interact, their brains and behaviour are not operating entirely independently. Conversation is a dynamic process of mutual attention, prediction and response, and this coordination may help create the conditions in which we can think together.
Detailed Resources
- Harvard Business Review: The Neurochemistry of Positive Conversations by Judith E. Glaser and Richard D. Glaser (2014)
Posts that link to this post
- Interthinking Is Real How conversation becomes part of the thinking process
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