{
  "abstract": "Limb dominance is a human behavioral characteristic with many cultural, practical, scientific and clinical implications. Yet why the dominant limb performs better across a range of motor skill-requiring tasks remains unanswered. Is it because of an intrinsic hemispheric advantage or instead is it the result of life-long practice with the dominant side? We tested these alternatives using two tasks. The first was 3D reaching with either an inertial challenge or the need to use a stick-like tool. The second required participants to write with their dominant and non-dominant elbows. We applied a novel geometric analysis to quantify movement-trajectory shape. We show that (1) tool-use unmasks markedly inferior control in the non-dominant arm, and this is because tools impose the need to generate unfamiliarly shaped movement trajectories; and (2) there is no general dominant limb motor control advantage, only task-specific experience or practice. These results reframe dominance as predominantly about learned control of tool kinematics rather than baseline asymmetry in control of limb dynamics.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Neurology, David Geffen School of Medicine, University of California",
    "Departments of Neurology, Neuroscience, and Physical Medicine and Rehabilitation, School of Medicine, Johns Hopkins University",
    "Santa Fe Institute"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 3,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Ahmet Arac",
      "orcid": "0000-0002-8788-4915"
    },
    {
      "affs": [
        0
      ],
      "name": "Nicolas Y. H. Jeong Lee",
      "orcid": "0009-0000-8934-2135"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "John W. Krakauer",
      "orcid": "0000-0002-4316-1846"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5xajjxcxbfgtx.bib",
  "cited_by": 6,
  "doi": "10.1073/pnas.2601569123",
  "fulltext_url": null,
  "id": "5xajjxcxbfgtx",
  "issns": [
    "0027-8424",
    "1091-6490"
  ],
  "landing_url": "https://doi.org/10.1073/pnas.2601569123",
  "language": "en",
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2805|Hemispheric Asymmetry in Neuroscience"
    ]
  ],
  "openalex": "W7166721928",
  "pdf_url": "https://www.pnas.org/doi/pdf/10.1073/pnas.2601569123",
  "pmcid": "PMC12632506",
  "pmid": "41279646",
  "published": "2026-06-30",
  "publisher": "National Academy of Sciences",
  "ris": "https://research.draconitic.com/paper/5xajjxcxbfgtx.ris",
  "sources": [
    {
      "first_seen": "2026-11-04T13:21:11Z",
      "native_id": "W7166721928",
      "source": "openalex",
      "url": "https://doi.org/10.1073/pnas.2601569123"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "openalex:2805|Hemispheric Asymmetry in Neuroscience",
      "subfield": "neuroscience"
    }
  ],
  "title": "Arm dominance is an emergent effect of practice executing complex trajectory shapes required by tools and objects",
  "title_text": "Arm dominance is an emergent effect of practice executing complex trajectory shapes required by tools and objects",
  "type": "peer-reviewed",
  "updated_at": "2026-11-09T13:21:14Z",
  "url": "https://research.draconitic.com/paper/5xajjxcxbfgtx",
  "venue": "Proceedings of the National Academy of Sciences",
  "versions": []
}