Face-to-face communication helps infants tune in

How do children learn the secret of good communication? It can’t be too easy, because the world is rife with misunderstandings and crossed signals. Too often, people go through the motions of exchanging information, but never really listen to each other. In recent years, researchers have looked to the brain for answers. They’ve confirmed that good communicators don’t just trade words. They also mirror each other’s brain activity patterns. And nonverbal cues may play a crucial role during the process. So talking to babies is important, but it isn’t — by itself — enough to establish a high quality, “brain-to-brain” connection. How do we know these things, and what, exactly, do we need to do to help babies “tune in”? Here are the details: What researchers have learned about brain-to-brain synchrony.

What is “brain-to-brain synchrony”? Also called “neural synchrony” or “inter-brain neural synchronization,” brain-to-brain synchrony describes the tendency of two brains to engage in similar patterns of activity at the same time. One example is when you watch a scary movie with a companion. When a monster pops out, you both experience a startle reflex, jumping in your seat, gasping involuntarily, maybe even feeling fear. Your physiological reactions and emotional responses parallel each other — what researchers call physiological and behavioral synchrony. But of course these reactions are the the result of brain activity, and so we’d expect to see some similarity in your patterns of brain activity, too. This type of brain-to-brain synchrony is non-interactive, in the sense that you aren’t necessarily communicating with the person next to you in the movie theater. But because you tend to respond to similar environmental triggers in similar ways, your brains will tend to synchronize. You’re both processing the same type of information, with similar biological machinery.

Another type of synchrony is interactive — what happens when you are directly engaged with your companion. Maybe one of you is talking. Maybe you both are. Or maybe you’re communicating nonverbally — with facial expressions or gestures. Regardless, there are messages being sent, and it makes sense that this would also give rise to inter-brain synchrony. For instance, if you tell me, “I missed my train,” your words are accompanied by thoughts and feelings, and a lot of processing in the language centers of your brain. When I hear you speak the words, I use my own language centers to decipher your message. I may observe your emotional cues as well, and even feel some empathic, second-hand frustration for you — the result of activitating some of the same parts of the brain that you are using to tell your story.

How can we tell if neural synchrony is happening? One way is to record changes in blood flow to the brain — something researchers can do with the help of functional magnetic resonance imaging (fMRI). This method allows us to see which parts of the brain are most active at any given time, but collecting the data is a hassle. Your study subjects have to be willing and capable of lying still in a tube…while hearing lots of weird, loud noises. As you can imagine, this isn’t baby-friendly, or even child-friendly. So fMRI studies are usually focused on adult subjects. By contrast, it’s a lot easier to track brain activity via electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS). Study subjects wear caps (of electrodes or sensors), but otherwise are free to move around and interact with each other. No matter which method is used, however, the basic principles are the same. You record brain activity, and then see if different individuals show time-matched similarities. With non-interactive synchrony, the syncing may be more or less simultaneous, because people are reacting to the same stimuli and the same time. With interactive synchony, we might expect to see a bit of a time lag between individuals. When I hear you say, “I missed my train,” it will take me a moment to detect your words and start processing them, so my brain will mirror yours after a brief delay.

Sometimes, too, a listener might anticipate the speaker’s brain activity. For example, this might happen if your child is listening to you read a familiar story. She predicts what you will say next — so that her brain patterns change just prior to yours.

Why should we care about brain-to-brain synchrony? For decades, researchers have shown that behavioral and physiological synchrony is associated with better child outcomes in the long-term. When parents and children are in sync, kids tend to develop better empathic and moral reasoning skills. They show greater communication competance, and higher levels of self-control. They are also less likely to have behavior problems. This hints that neural synchrony will also be linked with better child functioning, and recent studies have supported the idea. For example, neural synchrony between parents and children is predictive of better emotional regulation.

But if researchers are correct, there are also important short-term advantages. Brain-to-brain synchrony appears to be a marker of high-quality social interactions — the sort of interactions that lead to successful communication and cooperation. So let’s take a closer look.

When you listen to someone talking — really listen and pay attention — your brain activity tends to match up with that of the speaker. To date, the only studies I’ve seen concern adults only — not children or infants. But the research is pretty intriguing. For example, in a study using functional magnetic resonance imaging (fMRI), researchers made an audio recording of a woman telling a spontaneous, 15-minute long, personal story. They scanned her brain as she spoke, so they had a picture of how her brain activity had changed — in real time — during her narrative. Then they scanned the brains of 14 adult volunteers…while these folks were listening to a playback of the story. Would listeners mirror the brain activity of the storyteller? That’s exactly what Greg Stephens and his colleagues found. But the degree of mirroring depended on how well each participant had listened. Before leaving the lab, each listener had been quizzed on the content of the woman’s story — asked to recount as much as he or she could remember. And this turned out to be predictive of brain-to-brain synchrony: The folks who came away with more story details were the individuals who showed higher levels neural mirroring. Similarly, Ido Davidesco and his colleagues have reported links between mirroring and listening quality among adult science students. Using electroencephalography (EEGs), Davidesco’s team recorded electrical brain activity in 36 young adults as they listened to science lectures. Then, post-lecture, each student took a multiple choice test to assess his or her grasp of the material. Not only did students show brain-to-brain synchrony with their teachers, they also showed brain-to-brain synchrony with their fellow students. And students with higher levels of neural synchrony performed better on the multiple choice tests.

There is also evidence — in both adults and children — that brain-to-brain synchrony is linked with cooperation. It’s been reported in numerous studies: People are more likely to experience brain-to-brain synchrony when they are actively engaged in cooperative or collaborative tasks. And sometimes this synchrony is predictive of performance — how much teams accomplish together. For example, imagine a mother and her 5-year-old child seated at a table with tangram puzzles. An experimenter instructs them to create a series of designs with the tangrams — specifying that they must work together on the project. The mother and child are both wearing caps that are wired up to a monitor — technology that measures brain activity using dual-functional near-infrared spectroscopy (fNIRS). What happens next? Trihn Ngyuen and her colleagues performed this experiment on 42 mother-child pairs, with each duo alternating between the cooperative task and a solitary version of the task (where mother and child each worked alone and out of sight of each other). And the results were clear. Not only did brain-to-brain synchrony increase during the cooperative task. It also predicted how well each team performed. Mothers and children solved…