{
  "abstract": "Siblings typically represent the longest-lasting social relationships. Second-person neuroscience provides a framework for studying the neural mechanisms of real-time, reciprocal social interactions. Yet, most studies have focused on simplified coordination tasks, limited brain regions, and did not investigate neural dynamics between siblings. In the first study investigating brain synchrony between siblings to date, we used fMRI hyperscanning to simultaneously record brain activity in 50 same-sex healthy young adult sibling pairs while they played a complex collaborative problem-solving Tetris game requiring continuous non-verbal complementary coordination. Brain synchrony was quantified using inter-subject correlation across 36 regions of interest (ROIs) of the social brain atlas.\n\nThe interacting sibling pairs showed significantly higher brain synchrony than randomly permuted non-sibling pairs in 19 ROIs (FDR-corrected p < .05). These regions were primarily located within the higher-level theory of mind subnetwork (including bilateral temporo-parietal junction, precuneus and dorsomedial prefrontal cortex), and intermediate-level subnetwork (including anterior insula, inferior frontal gyrus). Greater synchrony in the left temporo-parietal junction significantly predicted better cooperative performance, suggesting that shared neural modelling of a partner's intentions supports effective collaboration. Synchrony in frontal and temporal regions was weakly modulated by cooperative and competitive sibling relationship characteristics; however, these effects did not survive correction for multiple comparisons and should be interpreted cautiously (uncorr. p < .05).\n\nThis study provides first evidence that real-time cooperation between siblings is supported by inter-brain synchrony in core social brain networks. We highlight the value of ecologically valid hyperscanning approaches for investigating neural mechanisms of cooperation in long-term relationships, advancing the field of relational neuroscience.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 5,
  "authors": [
    {
      "name": "Lucia Hernandez-Pena"
    },
    {
      "name": "Arezoo Taebi"
    },
    {
      "name": "Julia Koch"
    },
    {
      "name": "Klaus Mathiak"
    },
    {
      "name": "Lisa Wagels"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/d8zfzdnq04kae.bib",
  "cited_by": 0,
  "doi": "10.31234/osf.io/kjc5s_v1",
  "fulltext_url": null,
  "id": "d8zfzdnq04kae",
  "issns": [],
  "landing_url": "https://osf.io/preprints/psyarxiv/kjc5s_v1/",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "bepress",
      "Behavioral Neuroscience"
    ],
    [
      "bepress",
      "Cognitive Neuroscience"
    ],
    [
      "bepress",
      "Cognitive Psychology"
    ],
    [
      "bepress",
      "Developmental Psychology"
    ],
    [
      "bepress",
      "Neuroscience"
    ],
    [
      "bepress",
      "Problem Solving"
    ],
    [
      "bepress",
      "Social Cognition"
    ],
    [
      "bepress",
      "Social Development"
    ],
    [
      "bepress",
      "Social and Behavioral Sciences"
    ],
    [
      "bepress",
      "Social and Personality Psychology"
    ],
    [
      "openalex",
      "3207|Action Observation and Synchronization"
    ]
  ],
  "openalex": "W7223577393",
  "pdf_url": "https://osf.io/kjc5s/download",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-25",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/d8zfzdnq04kae.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:20Z",
      "native_id": "kjc5s",
      "source": "osf",
      "url": "https://osf.io/preprints/psyarxiv/kjc5s_v1/"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "bepress:Cognitive Neuroscience",
      "subfield": "neuroscience"
    }
  ],
  "title": "Brain synchrony between interacting sibling pairs during real-time cooperation: an fMRI hyperscanning study",
  "title_text": "Brain synchrony between interacting sibling pairs during real-time cooperation: an fMRI hyperscanning study",
  "type": "preprint",
  "updated_at": "2026-10-30T12:19:20Z",
  "url": "https://research.draconitic.com/paper/d8zfzdnq04kae",
  "venue": "PsyArXiv",
  "versions": []
}