Sensory Processing — Why Some Brains Filter Differently
The fluorescent light above your desk has a flicker that nobody else seems to notice. The colleague two rows over is eating an apple and the sound travels straight through your concentration like a needle. Your shirt tag scratches the back of your neck and you cannot stop thinking about it, even though the report in front of you is due in an hour. By mid-afternoon, you are not tired in any way you can explain. You are full. Full of input, full of signal, full of a world that will not turn its volume down.
You are not being dramatic. You are not high-maintenance. You are experiencing a measurable difference in how your brain handles the single most important job it has: deciding what matters and what to ignore.
What sensory processing actually means
Every second, your nervous system receives an estimated eleven million bits of sensory information. Your conscious mind can handle roughly fifty. The gap between those two numbers is where sensory processing lives — in the brain's ability to filter, prioritise, and discard the vast majority of incoming signals so that the relevant few reach awareness.
This filtering is not passive. It is an active, energy-intensive operation performed by a network of structures that gate information between the sensory organs and the cortex. When the system works efficiently, you move through a noisy restaurant, a busy street, a cluttered spreadsheet without conscious effort. You process what matters and ignore what doesn't.
When the system is calibrated differently — when the gate lets more through, or less, or the wrong signals at the wrong time — the experience of being alive in a sensory world changes fundamentally. Things that are background for most people become foreground. The shirt tag. The fluorescent flicker. The distant siren. The cumulative load of a normal day becomes a cognitive marathon.
Sensory processing is not sensory acuity. Your hearing may test perfectly. Your vision may be 20/20. The issue is not what the organs detect. It is what the brain does with what they deliver — the same distinction we explored in visual processing differences you might not recognise, but applied across all sensory channels simultaneously.
How the brain filters sensory information
The architecture of sensory filtering centres on a structure most people have never heard of: the thalamic reticular nucleus, or TRN.
The thalamus sits at the core of the brain and acts as a relay station — nearly all sensory information, everything except smell, passes through it on its way to the cortex. But wrapped around the thalamus like a thin shell of neurons is the TRN. Its job is gatekeeping. When the cortex identifies a signal as important, it sends feedback to the TRN, which uses the inhibitory neurotransmitter GABA to suppress competing signals. Relevant information gets amplified. Irrelevant information gets damped down. The TRN is why you can follow a conversation in a crowded bar — your brain is actively suppressing every other voice so the one you care about gets through.
In 2020, Michael Halassa and colleagues at MIT published a landmark study in Nature that mapped the TRN in unprecedented detail. They discovered that it contains two distinct subnetworks of neurons — one in the core and one in a thin surrounding layer — that connect to different parts of the thalamus and appear to serve different filtering functions. The dual architecture suggests the gating system is far more specialised than anyone previously realised, with different cell populations filtering different types of sensory information through different channels.
The clinical measurement of this filtering is called P50 suppression. When researchers play two identical clicks in rapid succession and measure the brain's electrical response, a healthy gating system suppresses the response to the second click by 80 to 90 percent — the brain registers the first click and filters out the redundant repeat. In people with impaired sensory gating, that suppression drops dramatically. The brain treats the repeated signal as though it were new, consuming attentional resources that should be free for other work.
P50 gating deficits have been documented not only in schizophrenia, where they were first studied, but in ADHD, PTSD, bipolar disorder, and autism. The range of conditions involved suggests that sensory gating is not a niche mechanism. It is a foundational cognitive operation, and when it varies, the effects cascade across everything the brain tries to do.
Why some people feel everything more intensely
In the mid-1990s, psychologist Elaine Aron at Stony Brook University identified a trait she called sensory processing sensitivity — the temperamental tendency to process sensory and emotional information more deeply than average. Roughly 20 percent of the human population scores high on the trait, a figure that has been replicated across cultures and, strikingly, across more than 100 other animal species.
This is not a disorder. Aron's framework, which she summarises with the acronym DOES — Depth of processing, Overstimulation, Emotional responsivity and empathy, Sensitive to subtleties — describes a trait with genuine advantages alongside its costs. Highly sensitive individuals notice details others miss. They process information at a deeper level. They tend to be more empathic and more attuned to social nuance.
In 2014, Bianca Acevedo and Aron published the first fMRI study of sensory processing sensitivity in Brain and Behavior. When highly sensitive individuals viewed photos of people displaying emotion, their brains showed significantly greater activation in the insula — the cortical hub for body awareness and emotion integration — and in the mirror neuron system, the network associated with empathy and understanding others' internal states. They also showed stronger activation in the cingulate cortex, a key region for attention and action planning.
"Awareness and responsiveness are fundamental features of sensory processing sensitivity." — Bianca Acevedo, Stony Brook University
The finding reframes what it means to be "sensitive." It is not that the sensory organs are more acute. It is that the brain allocates more processing resources to incoming information — more attention, more integration, more emotional weight. The result is a richer experience of the world, but also a more expensive one. The processing cost accumulates across a day, and by evening the person may be depleted in a way that has nothing to do with physical exertion and everything to do with how much signal their brain processed.
The four sensory processing styles most adults have never heard of
Occupational therapist Winnie Dunn developed the most widely used clinical framework for understanding individual differences in sensory processing. Her model is built on two axes: neurological threshold — how much input your nervous system requires before it responds — and behavioural response — whether you passively absorb or actively manage your sensory environment.
The intersection produces four patterns.
Sensory sensitivity — low threshold, passive response. You notice everything. The buzzing light, the ticking clock, the shift in someone's tone of voice. You feel overwhelmed but do not actively flee or seek change. Instead, you absorb and accumulate until the load becomes unbearable.
Sensory avoiding — low threshold, active response. You notice everything and you take action to control it. Noise-cancelling headphones. Dim lighting. Specific fabrics. Routines that minimise surprise. You manage your environment because the alternative is overload.
Sensation seeking — high threshold, active response. You need more input to feel engaged. You crave movement, loud music, strong flavours, intense experience. Your nervous system requires stronger signals to activate, and you go looking for them.
Low registration — high threshold, passive response. You miss things. Signals arrive and fail to register. You do not notice your name being called. You walk past objects in plain sight. Not because you are not paying attention, but because your nervous system's threshold for activation is higher than the signal strength.
Most people sit somewhere in the middle on both axes, with tendencies toward one or two quadrants depending on the sensory domain. You might be a sensory avoider for sound but a sensation seeker for movement. The profile is not a single point on a single scale. It is a pattern — and for those at the extremes, it shapes daily life in ways that are invisible to everyone else and often invisible to themselves, because they have no frame of reference for what "normal" filtering feels like.
Why sensory overload triggers emotional shutdown
If you have ever reached a point in a busy day where the next sound, the next question, the next notification pushed you from functional to flooded — where the emotion that arrived was disproportionate to the trigger — the mechanism is not mysterious. It is architectural.
Sensory processing and emotional regulation share critical neural infrastructure. The insular cortex processes both bodily sensations and emotional states. The anterior cingulate cortex coordinates both sensory attention and emotional responses. When sensory input overwhelms the gating system, these shared circuits become saturated. The amygdala — the brain's threat detector — interprets the overload as danger. Cortisol and adrenaline spike. The prefrontal cortex, which should be applying rational control, loses its grip as the stress response commandeers the resources it needs.
This is the neuroscience of the sensory meltdown, and it happens in adults as well as children — though adults have more developed prefrontal circuitry to delay and mask the response. An adult in sensory overload may not scream or cry. They may go quiet, withdraw, snap at a colleague, or feel a wave of anxiety that seems to come from nowhere. The trigger was not the email or the offhand comment. The trigger was the cumulative sensory load that had been building all day, and the email was simply the signal that exceeded the gate's remaining capacity.
If you have read our piece on emotional dysregulation, the connection will be clear. Emotional regulation depends on the brain's ability to accurately sense what the body is experiencing — a capacity called interoception — and to apply prefrontal control before the emotional response escalates. When sensory processing differences mean the body is running at a higher baseline of arousal, the regulatory system starts every interaction closer to its ceiling. Less headroom means less tolerance. Less tolerance means faster overwhelm. The emotional explosion at the end of the day is not a failure of character. It is a predictable consequence of a sensory system that has been running at capacity since breakfast.
How sensory processing differences overlap with ADHD
A 2025 systematic review and meta-analysis published in the Journal of the American Academy of Child and Adolescent Psychiatry, examining over 5,000 participants across 30 studies, found that individuals with ADHD experience significantly higher sensory sensitivity, sensory avoidance, sensory seeking, and low registration compared to controls. Every quadrant of Dunn's model was affected. The authors concluded that sensory processing should be systematically explored in the evaluation of anyone referred for ADHD, even though current clinical guidelines do not specifically address it.
This is not a coincidence. The attentional gating system that filters sensory information runs on the same prefrontal and thalamic infrastructure that regulates attention more broadly. When attentional regulation is variable — the core feature of ADHD — sensory filtering becomes variable too. The person with ADHD does not just struggle to sustain focus on a boring document. They also struggle to suppress the irrelevant background — the hum of the air conditioning, the movement in peripheral vision, the texture of the chair against their skin.
An important nuance emerged from a 2019 study published in Frontiers in Integrative Neuroscience. Sensory over-responsivity — the tendency to react too strongly to sensory input — appeared higher in adults with ADHD, but the effect disappeared when co-occurring anxiety was controlled for. Sensory craving and sensory under-responsivity, by contrast, remained characteristic of ADHD regardless of anxiety status.
The implication is clinically significant. If the sensory difficulty is driven by anxiety, the path forward involves managing the anxiety. If it is driven by gating differences intrinsic to ADHD, the path involves environmental modification and sensory strategies. The two look identical from the outside but respond to different approaches. A dimensional profile that separates attentional regulation from emotional regulation from sensory-motor integration can help distinguish which system is actually driving the difficulty.
Why the open office is a cognitive disaster for some brains
The sensory processing differences described above do not stay in the laboratory. They follow people to work.
Research on workplace noise paints a stark picture. At 65 decibels and above — the typical ambient level in an open-plan office — cognitive load increases sharply as the auditory system begins competing with working memory for processing resources. One in five workers loses more than 30 minutes per day to noise disruption. Studies show that a noisy environment generates up to 40 percent more errors on memory and concentration tasks. A single overheard phone conversation is enough to severely degrade the cognitive performance of everyone within earshot.
For someone whose sensory gating system is already working harder than average — whether because of ADHD, high sensory processing sensitivity, or a pattern of sensory avoiding — the open office is not a minor inconvenience. It is a sustained cognitive assault. Every sound the gate fails to suppress drains attentional resources that were needed for the actual work. The person appears to be underperforming. In reality, they are spending cognitive capital on filtering that their colleagues spend for free.
Gloria Mark, Chancellor's Professor of Informatics at UC Irvine, has demonstrated that any interruption — including noise-driven ones — requires an average of 23 minutes for full re-engagement with the original task. For the sensory-sensitive worker in an open office, those interruptions are not occasional. They are continuous. The mathematics of lost productivity are not subtle.
What you can do about sensory processing differences
If you recognise yourself in this article — if the world feels louder, brighter, more textured than it seems to for the people around you, or if you regularly reach a point of overload that feels disproportionate to what actually happened — the research points toward several convergent strategies.
Know your pattern. Not all sensory processing differences are alike. The person who is sensory avoiding needs a fundamentally different strategy from the person with low registration. Understanding whether your nervous system runs hot or quiet, and whether you manage it actively or passively, changes what interventions will work. CognitionType maps your processing style across seven cognitive dimensions, including sensory-motor integration, attention and rhythm, and emotional regulation — giving you a specific picture of how your sensory system interacts with the rest of your cognitive architecture, and what to prioritise in response.
Control your environment before it controls you. Noise-cancelling headphones are not a luxury for the sensory-sensitive adult — they are a cognitive tool. Adjustable lighting, seating choice, texture-friendly clothing, and deliberate breaks from high-stimulation environments are evidence-supported strategies for managing sensory load. The goal is not to eliminate input. It is to keep it within a range your gating system can handle.
Move with complexity. Complex movement practices — yoga, tai chi, martial arts, dance — do more than reduce stress. They strengthen the sensory-motor integration system that coordinates proprioceptive, vestibular, and tactile input with cognitive processing. Research shows medium-to-large effect sizes for both anxiety and emotional regulation from mind-body exercise, and the mechanism runs partly through sharpening interoceptive awareness — the body's ability to accurately report its own state. For more on how different types of movement target different cognitive systems, see how exercise changes your cognitive profile.
Protect the regulatory system. Sleep deprivation impairs prefrontal function and heightens amygdala reactivity — a combination that makes sensory overload both more likely and harder to recover from. Magnesium and omega-3 status each affect the neurochemical environment in which sensory gating operates. The foundations matter before the strategies do.
Name it. Much of the distress that accompanies sensory processing differences comes not from the differences themselves but from the absence of a framework. When you do not know why the office is unbearable, why the party drains you, why the drive home is the best part of your day, you default to self-criticism: too sensitive, too difficult, too much. A dimensional understanding of sensory processing replaces that narrative with something more accurate and more useful.
The dimension that hides in plain sight
Sensory processing disorder remains absent from the DSM-5, a decision that continues to draw criticism from occupational therapists and researchers who work with sensory differences daily. Lucy Jane Miller, who founded the STAR Institute and convened the SPD Scientific Work Group, spent decades building the evidence base for recognising sensory processing as a distinct clinical dimension. The debate is far from settled.
But you do not need a diagnostic label to have a sensory processing pattern that shapes your life. General population studies estimate that approximately 20 percent of individuals experience at least one significant difficulty in a sensory processing domain. The figure rises sharply in people with ADHD, autism, anxiety, and PTSD. The experience is common. The language for it is not.
Your brain's filtering system is not a switch. It is a dimension — one that varies across individuals, across the lifespan, and across the day. Where you sit on that dimension determines how much of the world gets through, how much cognitive energy you spend managing the input, and how much is left for the work you actually care about.
The world was not designed for the brain that filters differently. Understanding how yours works is the first step toward building a life that accommodates the brain you actually have.
CognitionType is an informational assessment, not a clinical diagnosis. If you suspect sensory processing differences, ADHD, or any other condition is affecting your daily functioning, we encourage you to seek formal evaluation from a qualified clinician. A cognitive profile is a complement to clinical assessment, not a replacement.