Invariant representations of mass in the human brain

  1. Sarah Schwettmann  Is a corresponding author
  2. Joshua B Tenenbaum
  3. Nancy Kanwisher
  1. Massachusetts Institute of Technology, United States


An intuitive understanding of physical objects and events is critical for successfully interacting with the world. Does the brain achieve this understanding by running simulations in a mental physics engine, which represents variables such as force and mass, or by analyzing patterns of motion without encoding underlying physical quantities? To investigate, we scanned participants with fMRI while they viewed videos of objects interacting in scenarios indicating their mass. Decoding analyses in brain regions previously implicated in intuitive physical inference revealed mass representations that generalized across variations in scenario, material, friction, and motion energy. These invariant representations were found during tasks without action planning, and tasks focusing on an orthogonal dimension (object color). Our results support an account of physical reasoning where abstract physical variables serve as inputs to a forward model of dynamics, akin to a physics engine, in parietal and frontal cortex.

Data availability

All data collected in this study ia available on OpenNeuro under the accession number 002355 (doi:10.18112/openneuro.ds002355.v1.0.0).

The following data sets were generated

Article and author information

Author details

  1. Sarah Schwettmann

    Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
    For correspondence
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-6385-1396
  2. Joshua B Tenenbaum

    Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Nancy Kanwisher

    Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
    Competing interests
    The authors declare that no competing interests exist.


National Institutes of Health (Grant DP1HD091947)

  • Nancy Kanwisher

National Science Foundation (Science and Technology Center for Brains,Minds and Machines)

  • Sarah Schwettmann

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.


Human subjects: All participants provided informed consent before participation. The Massachusetts Institute of Technology Institutional Review Board approved all experimental protocols (protocol number: 0403000096).

Reviewing Editor

  1. Thomas Yeo, National University of Singapore, Singapore

Version history

  1. Received: March 6, 2019
  2. Accepted: December 10, 2019
  3. Accepted Manuscript published: December 17, 2019 (version 1)
  4. Version of Record published: February 7, 2020 (version 2)


© 2019, Schwettmann et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.


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  1. Sarah Schwettmann
  2. Joshua B Tenenbaum
  3. Nancy Kanwisher
Invariant representations of mass in the human brain
eLife 8:e46619.

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