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bioRxiv · 10.1101/2025.06.18.660494

Inter-brain Synchronization in the Alpha Band during Minimal Tactile Interaction

Loh, C. L.·Zapata-Fonseca, L.·James, M. M.·Dumas, G.·Froese, T.
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Abstract

Researchers have begun to examine the minimal conditions required for inter-brain coupling (IBC) in humans, and brain-to-brain synchrony can emerge during technology-mediated interactions, not only in shared physical spaces. Here, we present an exploratory electroencephalography (EEG) hyperscanning study investigating whether inter-brain synchronization (IBS) can emerge under conditions of both spatial isolation and minimal interaction. We used the Perceptual Crossing Experiment (PCE), a real-time task in which paired individuals search for one another in a one-dimensional virtual tactile environment using only minimal haptic cues. Dyad-shuffled surrogate analysis identified a small set of candidate inter-brain connections, with the strongest observed connections in the alpha bands. Unsupervised clustering identified four recurrent behavioral patterns and three inter-brain connectivity patterns. Descriptively, the two less common inter-brain configurations occurred more frequently during phases characterized by greater inter-avatar separation and reduced contact, although this association was not supported after accounting for the nested structure of the data. While preliminary, these findings provide a proof-of-concept framework for relating neural synchronization to interactive behavior in a highly constrained setting. The candidate connections were not individually significant, and whether inter-brain coupling arises under such conditions remains to be tested in hypothesis-driven designs.

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Loh, C. L., Zapata-Fonseca, L., James, M. M., Dumas, G., Froese, T.. 2025-06-24. Inter-brain Synchronization in the Alpha Band during Minimal Tactile Interaction. https://doi.org/10.1101/2025.06.18.660494

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