Today, we had an engaging fNIRS workshop at RITMO. One of the tasks we explored was “hyperscanning,” a term that confused several of the non-psychology people present. I was also bewildered when I encountered this term for the first time, so here is a short blog post to explain what it is.
What is Hyperscanning?
The short answer is that hyperscanning is the simultaneous recording of neural or physiological activity from two or more people to study interpersonal brain dynamics.
The term combines the words “hyper-” (beyond/multiple) and “scanning” (here understood as brain/physiological scanning). The term arose in social neuroscience to denote concurrent multi-subject imaging/recording.
Typical hyperscanning studies use a variety of data collection methods depending on the questions and constraints. Standard neural methods include EEG, fNIRS, MEG, and fMRI; studies often supplement these with peripheral measures such as ECG and GSR, as well as motion capture and audio/video recordings to capture behavior and context.
Analytical approaches focus on quantifying interpersonal coupling and information flow. Researchers compute inter-brain synchrony or coherence, phase‑locking measures, inter-subject correlation, Granger causality to infer directional interactions, and network metrics to describe multi-participant connectivity patterns.
Applications of hyperscanning span social neuroscience, communication research, education, joint music-making and performance studies, clinical and therapeutic contexts, and investigations of teamwork and cooperation.
Practically, hyperscanning demands careful temporal synchronization across devices, robust strategies to distinguish true interpersonal coupling from common-input or stimulus-driven effects, and thorough handling of movement-related artifacts. Modality choice should reflect the trade-off between spatial and temporal resolution required by the research question.
What is fNIRS?
I find functional near-infrared spectroscopy (fNIRS) to be the most exciting brain imaging technique these days. It is based on sending near-infrared light into the scalp and measuring how it propagates through the brain. This enables monitoring of changes in cortical blood oxygenation and blood volume, which are indirect indicators of neural activity. When a brain region becomes more active, it consumes more oxygen, leading to detectable changes in the tissue’s optical properties.
fNIRS is particularly valuable for studying brain function in situations where other imaging methods may be impractical. Studies of fMRI, for example, involve large scanners and subjects lying still. Measuring electrical activity with EEG is susceptible to noise, so even eye blinks can introduce artifacts into the signal. We have tested mobile EEG several times, but in general, it doesn’t work very well when moving.
Through several projects at RITMO, we have now verified that fNIRS works well in musical settings. During Lydo 2024, we captured two violinists on stage during one of the pieces and even projected it onto the screen behind the orchestra.
Then, we moved on to an exciting research concert, MusicLab Brain, where Victoria Johnson performed a full concert with fNIRS.
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Findings from this research concert have now led to an ongoing violinist experiment, which is recruiting 30 expert violinists to explore relationships between motion and mental activity.
Moving on with fNIRS and hyperscanning
The workshop confirmed that fNIRS is an exciting technology for studies of embodied music cognition. It is portable and allows for movement while still capturing meaningful brain data. The ability to capture multiple people simultaneously through hyperscanning opens up many exciting research opportunities in the future.
CoPilot helped me with writing this post and Grammarly assisted with the language.