In the constantly dynamic environment that surrounds us, our visual system performs an extraordinary feat: it differentiates not only shapes and colors but also the intrinsic physical nature of the materials we perceive. A groundbreaking new study from researchers at the Massachusetts Institute of Technology reveals an unprecedented division within the human brain’s visual cortex dedicated to processing two fundamental categories of matter: “things” — solid objects — and “stuff,” which encompasses flowing, amorphous materials such as liquids or granular substances.
This discovery hinges upon the detailed examination of neural activity as participants observed a series of specially designed video clips depicting both rigid objects and malleable materials interacting in various physical contexts. Utilizing advanced functional magnetic resonance imaging (fMRI) methods, the researchers meticulously charted the brain’s responses, uncovering discrete cortical regions finely tuned to the unique physical dynamics of these material types. Notably, regions within both the ventral and dorsal visual pathways exhibited this subdivision, a finding that challenges previous understanding, which largely treated object perception as a monolithic function.
Traditional neuroscience has predominantly focused on how the brain processes solid objects, often categorized as “things,” emphasizing regions such as the lateral occipital complex (LOC), known for its role in recognizing three-dimensional shapes. Complementing this, the frontoparietal physics network (FPN) in the dorsal pathway has been associated with analyzing physical interactions like mass and stability. However, the processing of “stuff” — materials without fixed shapes, characterized by fluidity and deformation — has remained relatively unexplored until now.
The differentiation is essential, not merely as a perceptual curiosity but as a critical neural adaptation to the demands of interaction with the physical world. Solid objects afford affordances, such as grasping or manipulating with hands directly, whereas “stuff” often necessitates indirect interactions using tools or containers. This functional divergence in physical engagement is mirrored in the brain’s specialized processing streams, enabling the planning and execution of actions appropriate to the material encountered.
In their experiments, lead author Vivian Paulun and colleagues harnessed sophisticated visual effects software typically employed in cinematic industries to generate over a hundred meticulously crafted video stimuli. These animations simulated realistic interactions of “things” and “stuff,” showing objects bouncing, tumbling, or flowing under gravity, confined within transparent enclosures or cascading down stairs. This approach allowed the researchers to isolate the sensory features relevant to each category, independent of confounding factors such as context or background.
Scanning participants’ brains during the viewing sessions revealed that while both the lateral occipital complex and the frontoparietal physics network activated for both categories, they harbored distinct subregions exhibiting a pronounced preference: some areas responded more robustly to the solid, rigid objects, while neighboring areas were selectively tuned to flowing, deformable materials. This fine-grained anatomical dissociation provides compelling evidence that the brain encodes the material world in a multi-dimensional manner, sensitive not merely to shape but to physical properties underlying object behavior.
The authors propose that this neural stratification mirrors artificial physics engines used in computer graphics and gaming. In such systems, rigid bodies are typically represented by static meshes, optimized for stable interactions, whereas fluids and granular materials are simulated as aggregations of particles following complex fluid dynamics. Drawing this parallel, the brain’s architecture may similarly separate computational models for “things” and “stuff,” optimizing perception and prediction for different material types.
Beyond perceptual disparities, this specialization may underpin the execution of motor plans tailored to material properties. For instance, regions responsive to rigid objects might interact with motor circuits involved in grasping or manipulation, whereas those representing fluids or malleable substances could engage pathways responsible for tool use or indirect handling strategies. Testing these hypotheses could unveil deeper insights into sensorimotor integration and adaptive behavior.
Importantly, the study opens new research avenues focused on the neural correlates of material qualities such as viscosity, elasticity, and compliance. The frontoparietal physics network may contain differentiated zones sensitive to variations in fluid viscosity or granular flow dynamics, while the lateral occipital complex might encode subtle deformations and shape changes in deformable solids. Exploring these features will refine understanding of how humans perform complex material recognition under naturalistic conditions.
This research also raises fundamental questions about the developmental and evolutionary origins of such specialized processing. Did these cortical distinctions emerge to support complex tool use and environmental manipulation unique to humans? Moreover, understanding aberrations in this system could inform clinical approaches to sensory processing disorders or neurorehabilitation strategies focused on motor planning.
The collaborative endeavor, spearheaded by neuroscientists Nancy Kanwisher, Vivian Paulun, RT Pramod, and Josh Tenenbaum, combines cutting-edge neuroimaging with conceptual insights at the intersection of cognitive neuroscience, computational modeling, and material perception. Their findings extend the boundary of visual neuroscience by revealing that the brain not only identifies objects by shape but also internalizes their physical essence, a duality essential for effective interaction with the tangible environment.
Published in the prestigious journal Current Biology, this study draws substantial support from both German and American research agencies, highlighting the international recognition of its significance. With the publication dated July 31, 2025, the article marks a pivotal moment in understanding the neural basis of material perception, potentially influencing fields ranging from robotics to virtual reality.
As the investigation progresses, the research team intends to examine how the identified cortical regions communicate with motor planning centers during active manipulation tasks, thereby elucidating how perception seamlessly transitions into action. Moreover, future work may analyze whether these neural circuits adapt or restructure with experience, such as learning new tool-use skills or exposure to novel materials, shedding light on brain plasticity in the domain of material cognition.
This exploration of brain function underscores a fundamental truth: perception is not merely passive reception but an active interpretation sculpted by physical principles and behavioral imperatives. By unraveling how the brain segregates “stuff” and “things” into distinct processing streams, this study paves the way for a more nuanced understanding of human interaction with the complex, fluid world around us.
Subject of Research: Neural mechanisms underlying the visual processing of physical materials, specifically the dissociation of cortical regions responding to solid objects (“things”) and flowing substances (“stuff”).
Article Title: Dissociable Cortical Regions Represent Things and Stuff in the Human Brain
News Publication Date: 31-Jul-2025
Web References: DOI: 10.1016/j.cub.2025.07.027
Image Credits: MIT
Keywords: Neuroscience, Cognitive Neuroscience, Visual Perception, Sensory Perception, Brain, Cognition, Perceptual Processes, Psychological Science
