Alpha-Band Inter-brain Connectivity during Minimal Tactile Interaction: An Exploratory Hyperscanning Study

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.