When people of different generations create together, brain activity changes
Measures of brain synchrony predicted participants feelings of loneliness and social closeness
image:
An intergenerational dyad draws together. Without prompts and through collaboration, they create a shared drawing. While they draw, their brain activity is recorded using functional near-infrared spectroscopy (black head coverings and armbands) and their body movements are tracked using video-based motion capture (colorful overlays of skeletons). The participants depicted in this photograph have provided written consent for their likeness to be published alongside open-access online research outputs.
view moreCredit: Ryssa Moffat (CC-BY 4.0, https://creativecommons.org/licenses/by/4.0/)
When people of different generations create art together, their brains show initially show more synchrony, and the synchrony can predict feelings of loneliness or social connection, according to a study published August 20th in the open access journal PLOS Biology by Ryssa Moffat from ETH Zurich in Switzerland, and colleagues.
Loneliness—a perceived feeling of social isolation—is a growing health risk. Policy makers and health practitioners are working on methods to create meaningful social interactions to bring people together, especially between generations. But while intergenerational interactions can increase wellbeing in older adults, the physiological changes resulting from them are unknown.
To better understand changes in the brain that might come as intergenerational relationships are formed, the authors of this pre-registered study collected data from 31 intergenerational pairs, recruiting adults over 70 and pairing them with adults between 18 and 35, and comparing them with 30 same generation pairs of younger adults. The pairs were tracked over six sessions in a creative drawing program, where participants drew on their own or together without talking. At each session the researchers measured participants’ loneliness and attitudes toward the other person in their pair and how socially close they felt to their partner. They also recorded the participants’ brain activity using functional near-infrared spectroscopy, and then calculated the synchrony in brain activity between people.
The authors found that brain synchrony between pairs was higher when the pairs were drawing together instead of alone. Synchrony between pairs in the right inferior frontal cortex and right temporoparietal junction while intergenerational pairs drew alone was predictive of loneliness. However, synchrony between pairs in the right inferior frontal cortex while intergenerational pairs drew together and same generation pairs drew alone predicted social closeness. While brain synchrony increased over the sessions between same-generation pairs, it decreased between intergenerational pairs. Although the study was limited to only six drawing sessions, and the scientists were unable to include same generation pairs of older adults, the authors suggest that brain synchrony is dynamic and changing as social connections are forged for people of all ages.
Ryssa Moffat states, “My motivation to study social interactions between seniors and young adults grew from positive experiences getting to know seniors around the world. The idea for this project really gained momentum when I read statistics about the growing proportion of older adults globally and learned about the risks of loneliness and social isolation. It was clear that understanding how brains adapt to each other as people form intergenerational relationships would be valuable for promoting social connection.
“Six months after the end of the study, we invited the participants to an event where we displayed their artworks and shared preliminary results. Watching the pairs of participants find each other and peruse the artworks looking for their own was heartwarming. For me, it really reinforced the value of researching how social connections form.”
Author Guillaume Dumas adds, “Hyperscanning has often been used to capture brief moments of interaction. Here, we show that it can also track the dynamics of relationship formation over time, bringing the field closer to the complexity of real social life.”
“Interpersonal neural synchrony is not a simple ‘more is better’ signal. Our findings support this emerging subtler view where inter-brain coupling is dynamic and context-sensitive.”
Author Emily S. Cross notes, “This was an incredibly ambitious and high-risk project since its inception- and it is awesome to see how brilliantly Ryssa led this work from start to finish. In my eyes, this study is a shining example of a basic science question being studied in such a way that the societal impact is obvious and immediate. The fact that Ryssa also orchestrated such a wonderful feedback and results-sharing event with the participants was the cherry on top. It's just so wonderful to see this work being recognised and celebrated—all kudos go to Ryssa!”
In your coverage, please use this URL to provide access to the freely available paper in PLOS Biology: https://plos.io/4aQcW5S
Citation: Moffat R, Dumas G, Cross ES (2026) Social interactions between people of same and different generations shape longitudinal changes in interpersonal neural synchrony, loneliness, and social connection. PLoS Biol 24(8): e3003899. https://doi.org/10.1371/journal.pbio.3003899
Author countries: Switzerland, Canada
Funding: see manuscript
Journal
PLOS Biology
Method of Research
Experimental study
Subject of Research
People
Participants mingling and exploring the gallery of co-created drawings at an event held six months after the last data collection.
Credit
Ryssa Moffat (CC-BY 4.0, https://creativecommons.org/licenses/by/4.0/)
Social brain research offers new insights into how strangers become friends
ETH Zurich
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With the help of portable brain-scanning technology (fNIRS), the ETH researchers recorded the brain activity of two people while they were drawing at the same time. The lightweight caps fitted with sensors measure changes in blood flow in the brain – while allowing participants complete freedom of movement. The colourful lines show how the participants’ body movements were also captured, to be analysed in near future.
view moreCredit: (Image: PLOS Biology / Social Brain Sciences Lab)
What happens in the brain when two people engage in joint creative activity and build a new relationship with one another in the process? ETH cognitive scientist, Ryssa Moffat investigated this question. She is a postdoctoral researcher at the Social Brain Sciences Lab within the Chair of Cognitive and Social Neuroscience.
Her study has now been published in the journal PLOS Biology. The setting was as follows: over a period of six weeks, 61 pairs met six times to engage in drawing together. The participants came from a younger age group (18 to 35 years) and an older age group (70 to 85 years) and were divided into 31 cross-generational pairs and 30 pairs of the same age.
When two minds engage with one another
At the outset, the participants did not know each other and first had to become familiar with one another. At each session, the pairs first drew individually on separate sheets of paper, then drew together twice on a single sheet of paper. They were free to decide whether to take turns or draw simultaneously. They were allowed to converse throughout the session but were instructed to remain silent while drawing.
At each session, the researchers recorded participants’ brain activity with the help of wearable brain sensors. This enabled the researchers to investigate how the process of getting to know one another was reflected in the pairs’ brain activity. At the same time, the mobile sensors ensured that participants could move and respond to each other naturally, as in everyday life, without distorting the recorded signals.
The similarity of the brain activity was particularly crucial for the ETH researchers: to what extent do the brains of two people synchronise during an encounter? And how does this synchronisation change over the course of repeated meetings? The focus was not on whether a pattern of brain activity corresponds to a specific subjective feeling such as liking or irritation.
Stronger feelings of closeness, more similar brain activity?
Moffat was interested in what researchers call ‘inter-brain synchrony’: when people perform a shared task such as drawing, each person's brain reacts continuously to the other person's actions – and the brains can be said to be 'synchronised' when similar changes in brain activity occur simultaneously in both people
Previous studies on inter-brain synchrony suggested that the activity patterns of two brains become increasingly similar as people grow more familiar with one another. Accordingly, the ETH researchers led by Ryssa Moffat initially expected that synchrony would increase over time, as the pairs adjusted to one another while engaging in drawing.
But the researchers were surprised: although the participants in cross-generational pairs felt closer to one another over the course of weeks, their patterns of brain activity did not become increasingly similar.
An unexpected age difference
“In the cross-generational pairs, brain synchrony was higher at the start – and it decreased from week to week,” as researcher Moffat shares. “In the same-age pairs, it was the other way round: they started with lower synchrony, which increased over the course of the six weeks.” Regardless of this trend, however, one thing became clear over the course of the weeks: in both groups, brain synchrony was higher when the couples drew together than when the individuals drew separately.
Consequently, collaboration led to greater synchronisation of brain activity – initially in a similar manner for both groups. It was only over the course of the six weeks that the difference became apparent: while the brains of the same-age pairs showed increasingly similar activity, this synchronisation tended to decline in among the intergenerational pairs.
Anticipating rather than being in sync
How can this difference be explained? A definitive answer is still pending. Thanks to the portable brain-scanning technology, Moffat can state that when two people come to feel closer, it’s not a given that their brains ‘tick’ alike.
Moffat’s study takes a different approach here from many earlier studies on brain synchrony. These assumed that two people experiencing something together process similar stimuli – and that their brains therefore react in similar ways. Researchers refer to this model as ‘Common Cognitive Processing’.
By contrast, Moffat’s explanatory approach assumes that two people learn to better anticipate their counterpart’s behaviour and adapt to it: What will the other person say next? How will they react to my suggestion? In research, this model is known as ‘Mutual Prediction’.
This model may explain the age differences that emerged in the study. This is because, as Moffat explains, the participants’ life experiences also play a role in mutual prediction: “The participants of the same age were mostly students with similar daily routines and quickly found topics they had in common. Younger and older people, on the other hand, first had to work out what they could actually talk about.”
For Moffat, this means: “Greater brain synchrony can also mean that two people are making a particularly strong effort to understand one another.”
Who leads, who follows?
These efforts are particularly called for at the outset of a relationship: when younger and older people meet for the first time, they initially find it harder to predict their counterpart’s behaviour, explains Moffat. “Peers often find common ground more quickly or already have it. Over time, however, they become more playful, surprising each other in their conversations and thereby making it harder for their counterpart to predict their behaviour.”
In a second study published in the journal Acta Psychologica the researchers provide insights into why brain synchrony differs between younger and older people.
In this study, they examined the same encounters and measurement data from a different perspective: they investigated which recurring patterns of shared brain activity emerged during the encounters. The researchers identified seven so-called ‘two-brain states’ that remained remarkably stable throughout the entire six-week study period.
One state was particularly noteworthy and lasted significantly longer in the intergenerational pairs than in the same-age pairs. In this state, the synchronisation between the two brains was comparatively low. What stood out instead was a particularly strong connection within a single person’s brain – an internal synchronisation between two areas in their own frontal lobe.
The researchers cautiously interpret this as an indication of a division of roles: the person with the stronger internal synchronisation was more likely to adapt their behaviour to that of the other. In most cases, this was the younger person – while the older person tended to take a leadership role. The researchers also found that same-age pairs were more likely to draw at the same time, whereas intergenerational pairs took turns more often.
New ground for social brain research
“Our study is the first to show, over a period of several weeks, how brain activity develops in younger and older people,” concludes Ryssa Moffat. Previous studies have focused on parent-child, teacher-pupil, doctor-patient and romantic relationships. Older people have so far been largely overlooked in social brain research. Over the long term, Moffat’s research could also reveal “how strangers become acquaintances and perhaps even friends”.
Journal
PLOS Biology
Article Title
Social interactions between people of same and different generations shape longitudinal changes in interpersonal neural synchrony, loneliness, and social connection
Lab-grown brain models gain a sense of place
UC Irvine researchers engineer human neocortex in which cells take on regional identity, mimicking early development
Irvine, Calif., Aug. 20, 2026 — The human brain is often described as one of the most complex structures in biology, and much of its power comes from how it’s organized. Its outer layer, the cerebral cortex, is not one uniform sheet. As the brain develops, it divides into distinct areas that each take on different jobs, from movement and vision to memory, language and social understanding.
Scientists call this process “arealization,” and they believe it underpins much of what the brain can do. It may also help explain what goes wrong in some conditions that affect brain development.
That organization draws interest well beyond neuroscience. Engineers have long borrowed ideas from the brain – which builds itself without a blueprint and runs on very little power – for work in computing and robotics. But the biology has been hard to study because most of this patterning happens before birth.
Even early in development, the human brain has a sense of place. Chemical signals help tell developing cells where they are, contributing to differences between areas at the front and the back of the cerebral cortex.
Until now, scientists have had difficulty reproducing that organization in lab-grown models of the human brain.
Researchers at the University of California, Irvine have developed a new approach that lets them engineer lab-grown human brain tissue with a defined regional identity, producing organoids with characteristics of either the front or the back of the developing cerebral cortex. The advance could help scientists better understand how the human brain develops and what happens when that process is disrupted in neurodevelopmental disorders.
In a study published today in Cell Stem Cell, the UC Irvine-led team created human neocortical organoids – small, three-dimensional tissues grown from human stem cells that copy important features of the developing cerebral cortex. Each organoid was steered to take on the identity of either a front or a back region.
“Brain organoids have become powerful tools for studying human development, but the human brain is a highly organized space,” says lead author Momoko Watanabe, Ph.D., assistant professor of anatomy and neurobiology in the UC Irvine School of Medicine and a faculty member of the Sue & Bill Gross Stem Cell Research Center. “By introducing regional identity into these models, we can begin asking questions about development and disease that were difficult to address with conventional organoids.”
Giving brain tissue a biological compass
The cerebral cortex is the brain’s outer layer and is involved in functions ranging from movement and sensory processing to language and higher-level thinking. But not every part of the cortex develops in the same way.
During early development, chemical signals help create a kind of biological map, guiding different regions toward distinct identities.
Ordinary brain organoids copy many features of developing brain tissue, but they usually miss this step. Each one ends up with a patchwork of random regions rather than a clear front or back.
The UC Irvine team found a way to introduce it.
By exposing the developing organoids to carefully selected signals early in their growth, researchers could steer some toward characteristics associated with the front of the cortex or toward characteristics associated with the back.
They then examined individual cells to determine whether those differences resembled actual human development. Their analysis of more than 200,000 cells showed that the organoids reproduced molecular characteristics associated with different regions of the prenatal human cortex.
In effect, the researchers gave lab-grown cortical tissue a biological compass, a reproducible sense of front or back.
Seeing fragile X syndrome in a new way
The team then used the new model to investigate fragile X syndrome, a genetic condition and a leading inherited cause of intellectual disability that’s also associated with autism spectrum disorder.
The researchers wanted to know whether fragile X syndrome might affect not only individual brain cells but also the broader developmental patterns that help organize those cells across the cortex. They found that it did.
Two proteins important to brain development, called SOX4 and SOX11, normally appear at different levels in front and back tissue. That difference showed up reliably in organoids grown from donors without the condition. In organoids modeling fragile X syndrome, it largely disappeared. The broad front-to-back patterning was still there, but this particular difference had flattened out.
Other researchers have reported the same flattening in donated brain tissue from people with autism; the usual gap in SOX4 and SOX11 levels between the cortex’s front and back is smaller than expected.
The findings do not show that disrupted brain patterning causes autism. Instead, they highlight a potential developmental process that researchers can now investigate in a human tissue model with greater spatial detail.
A more human-relevant model of brain development
The potential applications extend beyond fragile X syndrome.
Neurological and neurodevelopmental disorders do not necessarily affect every part of the brain in the same way. By giving organoids defined regional characteristics, researchers can begin studying not only what changes in a disorder but also where those changes emerge during development.
In addition, the platform contributes to growing efforts to develop human tissue-based research models that can complement animal studies. Because important aspects of human brain development differ from those of other species, stem cell-derived organoids can provide researchers with another way to investigate processes that are difficult to study directly in people or reproduce in animals.
The researchers say the approach could be used to examine how genetic and environmental factors affect different regions of the developing cortex and, over time, help scientists probe disease mechanisms and potential therapeutic strategies.
Watanabe’s lab at UC Irvine builds human brain organoid models to study brain development and neurological disease. It’s part of a broader interdisciplinary effort at UC Irvine spanning anatomy and neurobiology, stem cell biology, developmental biology, tissue engineering, mathematics and computational approaches.
Authors include Yuan-Chen Tsai, Hajime Ozaki, Xinyi Wang, Axel A. Almet, Isabella Fleming, Kaori Shiraiwa, Matthew Jung Min Noh, Caihao Nie, Sunnyana Trejo, Bret Kiyoshi Sugita, Jiya Dalal, Ruben Alberto Gonzalez, Briana De Jesus, Gregory Li-Min Chen, Michael J. Gandal, Qing Nie and Momoko Watanabe.
The research brought together investigators from UC Irvine’s School of Medicine, School of Physical Sciences, Charlie Dunlop School of Biological Sciences, Sue & Bill Gross Stem Cell Research Center and NSF-Simons Center for Multiscale Cell Fate Research, along with a collaborator at the University of Pennsylvania.
The research was supported, in part, by the National Institutes of Health, National Science Foundation, California Institute for Regenerative Medicine, Simons Foundation and FRAXA Research Foundation.
About the University of California, Irvine: Founded in 1965, UC Irvine is a member of the prestigious Association of American Universities and is ranked among the nation’s top 10 public universities by U.S. News & World Report. The campus has produced five Nobel laureates and is known for its academic achievement, premier research, innovation and anteater mascot. Led by Chancellor Howard Gillman, UC Irvine has more than 36,000 students and offers 224 degree programs. It’s located in one of the world’s safest and most economically vibrant communities and is Orange County’s second-largest employer, contributing $7 billion annually to the local economy and $8 billion statewide. For more on UC Irvine, visit www.uci.edu.
Media access: Radio programs/stations may, for a fee, use an on-campus studio with a Comrex IP audio codec to interview UC Irvine faculty and experts, subject to availability and university approval. For more UC Irvine news, visit news.uci.edu. Additional resources for journalists may be found at https://news.uci.edu/media-resources.
Journal
Cell Stem Cell
Article Title
Morphogen-guided neocortical organoids with anteroposterior areal identity
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