2026 ECNP Congress

PS04-4180

Social processes in dyadic interaction: a systematic review of second-person neuroscience

You Na Lee — Y. Li, I. Heinig, P. Kanske · Institute for Clinical Psychology and Psychotherapy, Chair of Clinical Psychology and Behavioral Neuroscience, Dresden, Germany

2026 ECNP Congress

Introduction

Social neuroscience has emerged as one of the most rapidly advancing fields of the last decade, reflecting a growing interest in the biological underpinnings of human social behavior[1] [2] [3]. Foundational work in the field established the importance of multilevel analysis—linking neural, hormonal, and behavioral processes—and underscored the need to study social cognition as a dynamic, integrative phenomenon [4] [5]. However, findings across tasks, imaging modalities, and clinical groups remain fragmented. This review examines how social affective and cognitive processes, particularly cooperation, inter-brain synchronization, joint action, interpersonal touch, empathy and theory of mind (ToM), are implemented neurally during live dyadic interaction. This review also evaluates how these mechanisms differ across contexts and in clinical groups including autism spectrum disorder (ASD), chronic pain, depression, and individuals with different attachment styles.

Aims

To synthesize neural mechanisms and inter-brain synchrony patterns underlying social interaction across neuroimaging modalities and to identify how these mechanisms vary by task domain and clinical population.

Methods

A systematic search identified 70 human neuroimaging studies involving real-time dyadic interaction using fMRI, fNIRS, EEG, or MEG. Studies were grouped by social process (communication n = 22; cooperation/competition n = 8; inter-brain synchrony n = 19; interpersonal touch n = 4; joint action n = 3; social affect n = 8; social cognition n = 6). Results were extracted narratively due to heterogeneity. Descriptive statistics quantified the prevalence of regions and frequency bands reported across modalities, tasks, and clinical subgroups.

Results

Across studies, the most consistently reported regions activated during social interaction were the dorsolateral prefrontal cortex (dlPFC), temporoparietal junction (TPJ), inferior frontal gyrus (IFG), insula, superior temporal cortex, and somatosensory areas. fNIRS studies showed robust prefrontal and TPJ synchrony during cooperative and communicative interaction. fMRI studies highlighted posterior superior temporal sulcus (pSTS), medial pre-frontal cortex (mPFC), insula, and reward‑related regions (amygdala, nucleus accumbens) during joint action, interpersonal touch, and pain empathy. Finally, EEG studies showed task‑specific inter‑brain synchrony: delta‑theta coupling during cooperation and joint action, and alpha‑gamma synchrony during communication and affective sharing.

Clinical subgroups demonstrated condition‑specific alterations. ASD groups showed reduced STS activation and atypical IPL lateralisation during turn‑taking and joint action. Chronic pain and fibromyalgia were associated with altered insula and somatosensory responses during dyadic pain tasks. Individuals high in attachment anxiety or avoidance showed differential prefrontal engagement during social cognition, and depression was associated with altered activity within fronto‑parietal regions during interactive tasks.

Conclusions

Across modalities and tasks, dyadic social interaction recruits a flexible but coherent network centred on dlPFC, TPJ, IFG, insula, and STS, with inter‑brain synchrony reflecting reciprocal engagement. Neural coupling varies systematically with task context and clinical status, suggesting that altered synchrony or atypical recruitment of TPJ, dlPFC, and insula may index disruptions in social connectedness. These findings demonstrate that second‑person approaches can detect mechanistic differences across typical and clinical populations and offer a foundation for future translational applications targeting social functioning.

References

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  2. Cacioppo, J. T., & Decety, J. (2011). Social neuroscience: challenges and opportunities in the study of complex behavior. Annals of the New York Academy of Sciences, 1224(1), 162–173. https://doi.org/10.1111/j.1749-6632.2010.05858.x5
  3. Schilbach, L. (2022). Second-person neuroscience. Current Opinion in Psychology, 44, 101293. https://doi.org/10.1016/j.copsyc.2021.11.002
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