How does interpersonal neural synchrony change as people build social connections? A study published in PLOS Biology examined this question by tracking brain synchrony, loneliness, and perceived social closeness during a six-week creative drawing programme involving younger and older adults.
Visual summary of each session
(Source: https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3003899)
Study Design
The study included 122 participants forming 61 dyads: 31 intergenerational pairs, consisting of one younger and one older adult, and 30 same-generation pairs of younger adults. Initially strangers, participants met for six weekly sessions, during which they completed individual and collaborative drawing tasks.
Brain activity was recorded simultaneously using two Cortivision Photon Cap fNIRS systems. The researchers analysed interpersonal neural synchrony (INS) between the inferior frontal gyrus (IFG) and temporoparietal junction (TPJ), using wavelet transform coherence (WTC). Participants also reported their loneliness and perceived social closeness throughout the programme.
Key Findings
Brain synchrony differed between individual and collaborative drawing. In both groups, INS was greater during collaborative drawing than during individual drawing in several pairs of brain regions.
Synchrony followed different trajectories across sessions. During collaborative drawing, INS involving the right TPJ decreased across sessions in intergenerational dyads, whereas it increased in same-generation dyads. These changes occurred in specific region pairs, rather than across all measured connections.
Social measures changed over time. Across the six sessions, reported loneliness decreased by approximately 1% per session, while perceived social closeness increased by approximately 4% per session. Intergenerational dyads reported lower loneliness and greater social closeness overall than same-generation dyads.
The analyses also linked perceived social closeness to INS between the right IFG of one participant and the right TPJ of the other. Greater similarity in loneliness levels between dyad members was associated with higher INS between their right IFG regions during collaborative drawing, but lower INS during individual drawing.
Conclusion
The findings show that interpersonal neural synchrony during repeated social interactions varies with both the activity and the generational composition of a dyad. Changes in synchrony were also associated with measures of social connection, highlighting the complex relationship between neural coordination and the development of social relationships.
Source
Based on: Moffat, R., Dumas, G., & Cross, E. S. (2026). Social interactions between people of same and different generations shape longitudinal changes in interpersonal neural synchrony, loneliness, and social connection. PLOS Biology, 24 (8), e3003899.
Learn more about Photon Cap in hyperscanning research
The study utilized fNIRS technology to capture brain activity during naturalistic interaction. If you’re interested in how Photon Cap supports this type of research, check out our previous articles:
Moving beyond average interbrain synchrony: dynamic two-brain states during collaboration
Cardiac synchrony in same-generation and intergenerational dyads: a longitudinal fNIRS study
Hyperscanning with the Photon Cap: The Role of Neural Synchrony During Social Interaction