Invariant representations of mass in the human brain

Sarah Schwettmann, Joshua B Tenenbaum, Nancy Kanwisher
2019 eLife  
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
more » ... ain 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.
doi:10.7554/elife.46619 pmid:31845887 pmcid:PMC7007217 fatcat:gwnglu2u7jhqxh4fhl5sdkl7z4