When Minds Align: Brains Synchronize Within Milliseconds During Collaboration

Have you ever felt a moment of effortless coordination with a partner, where everything just clicks? New research shows that sensation has a measurable neural basis: when two people collaborate on a shared task, their brain activity can rapidly synchronize.

Cognitive neuroscientist Denise Moerel of Western Sydney University led an experiment designed to separate the effects of simply doing the same task from the effects of true social collaboration. The study paired participants into 24 teams and asked each pair to jointly decide how to sort 16 black-and-white patterned shapes that varied across four features: shape (round or square), pattern (wavy or straight), contrast (high or low), and pattern size (small or big). Teams chose two features as sorting rules and were allowed to talk and plan during that phase.

After agreeing on their rules, teammates sat back-to-back and continued the task without speaking, each viewing a shared workspace on their own screen. Researchers recorded electroencephalograms (EEGs) during this back-to-back phase to measure how closely participants’ neural signals aligned.

The EEG results revealed a clear time course. In the first 45–180 milliseconds after a shape appeared, participants across the entire group exhibited similar brain responses — a likely reflection of shared visual processing. By about 200 milliseconds, however, that uniform response diverged: neural activity remained aligned within actual teammate pairs but not across the whole group. Furthermore, pairwise synchrony strengthened as the session continued, suggesting that working together reinforced shared neural patterns.

To confirm this effect was specifically tied to collaboration (not merely to following the same sorting rules), the researchers compared "real pairs" with "pseudo-pairs" — participants from different teams who happened to use similar categorization schemes but had never collaborated. Although pseudo-pairs sometimes applied identical rules (for example, sorting by shape and pattern), their neural alignment was substantially weaker than the alignment observed between real teammates.

"The results highlight that social interactions play a central role in shaping neural representations in the human brain," the authors write, noting the approach could have promising applications for understanding group collaboration, communication, and decision-making.

Published in PLOS Biology, the study indicates that something specific about the social experience of collaborating — beyond adopting the same rules — promotes tighter neural synchrony. These findings may help explain why people sometimes feel "in sync" during teamwork and could inform research on collaborative learning, remote teamwork technologies, and brain-based measures of group dynamics.