What is Inter-brain Coherence?
Inter-brain coherence (межмозговая когерентность) is the phenomenon where the brain activity of two or more people becomes phase-aligned — their neural rhythms operate in a coherent mode. Coherence implies not just correlation but organized, in-phase oscillation.
Key Properties
- •Phase alignment — oscillations in phase, not just correlated
- •Coherent mode — organized, ordered brain activity across participants
- •Collective — the group functions as a unified neural network
- •Measurable — EEG coherence, HRV alignment, gamma synchronization
Why does Inter-brain Coherence matter?
Inter-brain coherence matters because it offers a way to study social interaction as it happens, rather than one brain at a time. By recording two or more people together, researchers can ask whether their brain signals become more aligned during conversation, cooperation, or shared attention.
Some studies report higher coherence during successful cooperation, teaching, or synchronized activities. However, the field is young and evidence is mixed. Shared sensory input, similar movements, and matching speech rhythms can create aligned signals without any direct link between brains, so interpretation must be careful.
How is Inter-brain Coherence measured?
It is measured with hyperscanning: simultaneous recording from several people using EEG, functional near-infrared spectroscopy (fNIRS), or, less often, fMRI. Researchers then calculate how consistently signals from related regions vary together over time, often within specific frequency bands.
Results depend strongly on analysis choices. Good studies compare real pairs against "pseudo-pairs" of people who were not interacting, to check whether coherence exceeds what a shared task alone would produce. Movement and muscle artifacts are a common problem in EEG hyperscanning.
In ONDA Life
Part 12 lists "Inter-brain coherence" as an intended marker, alongside group HRV alignment and collective dopamine surges. ONDA does not record EEG, compare a group's HRV or measure dopamine, so these describe the aim of the practice — shared attention and joint insight — not measured results.