How your brain knows the difference between a ball and water

When you see a ball bounce off the stairs, your brain will be different in the same way as you see a water cascade.

A new MIT study found that our brains draw a clear line between solid “things” such as objects and solid “things” such as “objects” such as liquid or sand. Professional areas of the brain’s visual cortex illuminate each area, helping us understand and interact with the physical world around us.

Different materials, different brain reactions

The study was published on July 31 Current Biologyreveals that both the ventral and dorsal visual pathways of the brain contain different regions that respond more strongly to things or things. This marks the first time scientists have observed a clear neurodivision between solid and non-alcohol material treatments.

“When you look at something liquid or something slimy, you interact with it in a different way than a rigid object,” said Nancy Kanwisher, professor of cognitive neuroscience at MIT. “With a rigid object you can pick it up or master it, and with something liquid or something slimy, you may have to use tools to handle it.”

Experiment: See things and things

Lead writer Vivian Paulun now joins the University of Wisconsin at the University of Madison, creating more than 100 video clips showing solid and non-silicone materials in motion: sliding, bounce, swing and flowing. Participants watched the clips within a fMRI scanner, and the researchers tracked the activity of the visual cortex.

The results show that:

• Strong response of lateral occipital complex (LOC) to rigid and deformable substances
• Frontal physical network (FPN) responds to “things” and “things”, but each region has a different subregion
• Each visual pathway shows functional separation, sub-regions favor solid or non-acyl material types

Paul said, “We have never seen this before because no one has asked about it before.”

Why the brain may need this split

The study shows that the brain may handle these categories similarly to the artificial physics engines used in animation and video games. In these systems, solid objects are considered mesh and fluids are represented as particles. Researchers believe that the human brain may use similar mental algorithms.

Paulun notes: “Perhaps the brain is similar to an artificial game engine, with separate calculations representing and simulating ‘supper’ and ‘thing’.

The next step in brain and matter research

Future studies will examine the relationship between these brain regions and motor planning, such as whether it is related to areas that process rigid materials. The researchers also plan to explore how the brain processes specific features such as fluid viscosity or object elasticity.

This kind of work can reshape how we understand human perception, robotics and even AI. Because at the end of the day, your brain not only sees the world, so it simulates how to act on the world.

Magazine: Current Biology
doi: 10.1016/j.cub.2025.07.027
Article title: Separable cortical areas represent things and things in the human brain
release: July 31, 2025

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