Grand Challenge — Human Brains During Social Interactions

The first Grand Challenge of 2025 was a transatlantic session on hyperscanning — a neuroimaging technique that simultaneously measures the brain activity of multiple individuals during social interactions.

Talk 1 — Neural Mechanisms Underlying Hyperscanning (Antonia Hamilton)

Interpersonal neural synchrony has been described in many contexts where brain activity is recorded from two or more people simultaneously. However, there has been controversy over how to interpret this signal. Here I present a mutual prediction model of hyperscanning effects and argue that these studies can be informative even if there is no direct cross-brain causal mechanism.

Talk 2 — Hyperscanning: Theory, Methods, and Applications (Guillaume Dumas)

Hyperscanning provides a comprehensive framework for examining the neural underpinnings of social interaction. This talk offers an overview of the theoretical foundations, methodologies, and applications. Anchored in social psychology and embodied cognition, the framework emphasises the interdependence of social and neural processes. We explore various hyperscanning modalities — their strengths, limitations, and inter-brain connectivity measures — and introduce biophysical and deep-learning models to explain and quantify inter-brain connectivity. Finally we discuss applications in mental health, toward an “inter-personalized psychiatry”, and present a social neuro-AI roadmap for how multi-brain neuroscience may inspire a paradigm shift in machine learning.

Speakers

Prof. Antonia Hamilton leads the Social Neuroscience group at the Institute of Cognitive Neuroscience, UCL, and is Editor-in-Chief of the Quarterly Journal of Experimental Psychology. Her research interests include how and why people imitate each other, how social skills differ in autism, and the neural mechanisms of face-to-face social interaction.

Prof. Guillaume Dumas is Associate Professor of Computational Psychiatry at the Université de Montréal and PI of the Precision Psychiatry and Social Physiology Laboratory at the CHU Sainte-Justine Research Centre. His research cross-fertilises AI, cognitive neuroscience, and digital medicine, including “Social Neuroscience for AI”.