Making new connections: An fNIRS machine learning classification study of neural synchrony in the default mode network
Grace Qiyuan Miao, Ian J. Lieberman, Ashley L. Binnquist, Agnieszka Pluta, Bear M. Goldstein, Rick Dale, Matthew D. Lieberman
Study at a glance
AI-extracted from the abstract| Characteristics | Between-subject naturalistic experiment |
|---|---|
| Sample size | 140 |
| Population | 70 pairs of strangers |
| Interventions | Shallow conversation Deep conversation |
| Topics | Default mode network |
| Key findings | Strangers in deep conversations reported feeling more connected than those in shallow conversations, replicating prior work. Default mode network neural synchrony, particularly in medial prefrontal cortex and right temporoparietal junction, predicted self-reported connection, and machine learning classified high- versus low-connection dyads at 64.5% accuracy. The authors suggest deeper conversations may foster stronger social bonds with measurable neural correlates. |
Abstract
Abstract Successfully making connections with others is crucial to navigating the social world and general well-being, yet little is known about connection formation and its neurocognitive underpinnings. Increasingly, neuroscientists use interpersonal ‘neural synchrony’ within the default mode network (DMN) to measure when two or more people subjectively experience something in similar ways. DMN synchrony as ‘seeing eye-to-eye’ is typically observed when multiple people are passively observing the same stimulus. In this study, we tested whether the same DMN synchrony as ‘seeing eye-to-eye’ pattern holds during social interactions. We conducted a between-subject naturalistic experiment with 70 pairs of strangers engaged in either shallow or deep conversations while brain activity was measured with functional near infrared spectroscopy (fNIRS). Stranger dyads successfully formed connections, as indicated by composite connection scores. Replicating Kardas et al. (2021), those in the deep conversation condition felt more connected than those in the shallow conversation condition. DMN neural synchrony significantly predicted self-reported connection, with synchrony in the DMN subregions of medial prefrontal cortex (mPFC) and right temporoparietal junction (TPJ) each correlating significantly with connection. Using machine learning classification, we distinguished high-versus low-connection dyads based on DMN neural synchrony and the perceived depth of conversation with 64.5% accuracy across 1,000 iterations. This effect was primarily carried by right TPJ, which alone classified connection strength at 62.6% accuracy. We consider implications related to the growing loneliness crisis and the importance of understanding how social connections can be formed and fostered in an era of increased social isolation. Significance Statement The current loneliness epidemic has serious consequences on health and well-being. Forming interpersonal connections is crucial for alleviating loneliness, yet little is known about its neural basis. Neural synchrony, a potential biological marker of people being on the ‘same page’, may be an indicator of social connection. We recorded brain activity as strangers engaged in a get-to-know-you conversation and found that neural synchrony—specifically within the default mode network (DMN) and subregions including medial prefrontal cortex (mPFC), and right temporoparietal junction (TPJ)—predicted self-reported connection. Machine learning accurately classified high- and low-connection dyads based on DMN synchrony and perceived conversation depth. These findings suggest that deeper conversations, though more effortful, may foster stronger social bonds with measurable neural correlates.
Comparable studies
Other experimental studies on default mode network, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Functional connectivity of default mode network components: Correlation, anticorrelation, and causality Healthy subjects | 2008 | Observational study using resting-state fMRI and seed correlation analysis | |
| Patterns of Brain Activity Supporting Autobiographical Memory, Prospection, and Theory of Mind, and Their Relationship to the Default Mode Network Healthy subjects | 2009 | Experimental study using fMRI | |
| Dynamic reconfiguration of the default mode network during narrative comprehension Human subjects | 2016 | Experimental study | |
| Broadband Cortical Desynchronization Underlies the Human Psychedelic State Healthy human participants | 2013 | Experimental study | |
| The brain on art: intense aesthetic experience activates the default mode network Human observers | 2012 | Observational study with fMRI and behavioral analysis |
Citations in the library
Cites 4
- 20 years of the default mode network: A review and synthesis Neuron May 10, 2023
- On the relationship between the “default mode network” and the “social brain” Frontiers in Human Neuroscience 2012
- The default mode network: where the idiosyncratic self meets the shared social world Nature Reviews Neuroscience January 22, 2021
- Synchrony and subjective experience: the neural correlates of the stream of consciousness. Trends in Cognitive Sciences May 15, 2025