How Our Brain Filters Reality and What Happens When We Lift the Filters

Our everyday experience of the world feels solid and real, but what if it’s only a sliver of what’s truly out there?

Neuroscientists Marjorie Woollacott and Marina Weiler, in their study “Neural Filters to Conscious Awareness and the Phenomena That Reduce Their Impact,” suggest that our brains act like radios, tuned to a specific frequency of reality.

Built-in neural filters limit what we perceive, keeping us focused on a narrow slice of existence. Yet, under certain extraordinary conditions—like near-death experiences, deep meditation, or psychedelic journeys—these filters can weaken, potentially revealing a broader, more wondrous reality.

What Are Neural Filters?

Imagine your brain as a gatekeeper, carefully sifting through the flood of information that bombards us every moment. Neural filters are the brain’s tools for deciding what makes it into our conscious awareness and what gets left out.

According to Woollacott and Weiler, these filters include sensory receptors, the ascending reticular activating system (ARAS) paired with the thalamus, the default mode network (DMN), and the left hemisphere language centers.

Together, they sculpt our perception, narrowing it to a manageable stream of sights, sounds, and thoughts. They’re like the settings on a radio dial, locking us onto a single station while countless others hum just out of reach.

The Filters That Shape Our Reality

Our journey begins with sensory receptors—the eyes, ears, skin, nose, and tongue that connect us to the world. These receptors are incredible, but they’re limited. Our eyes, for instance, can only see a tiny fraction of the electromagnetic spectrum—visible light—while bees buzz around seeing ultraviolet patterns on flowers, and snakes sense infrared heat. Our ears catch sounds between 20 Hz and 20,000 Hz, but dogs perk up at whistles we’ll never hear. Right from the start, our perception is filtered, leaving vast swaths of reality invisible and silent to us.

Next in line are the ascending reticular activating system (ARAS) and the thalamus, a dynamic duo that controls what reaches our conscious mind. The ARAS, tucked in the brainstem, keeps us alert and decides what’s worth paying attention to—think of it as a bouncer at a club, letting some stimuli in while turning others away.

Ever tune out a ticking clock until someone mentions it? That’s these gatekeepers at work, filtering out the noise so you can focus on what matters.

Then there’s the default mode network (DMN), a web of brain regions that lights up when we’re not focused on the outside world—when we’re daydreaming, reminiscing, or lost in thought. It’s the voice in your head spinning tales about who you are and how you fit into the world.

The DMN ties our experiences to a sense of self, but it can also trap us in loops of worry or fantasy, filtering reality through the lens of “me, myself, and I.” It’s like a narrator who won’t stop talking, coloring everything we perceive.

Finally, the left hemisphere language centers—like Broca’s and Wernicke’s areas—help us make sense of the world by naming and categorizing it. Language is a superpower, letting us communicate and think abstractly, but it also boxes our experiences into neat little packages.

A tree becomes “tree,” and we stop noticing its swaying branches or rustling leaves. These centers filter our perception through concepts, sometimes blinding us to the raw, unfiltered essence of things.

Together, these filters limit us to a narrow range of energy frequencies, anchor us in space and time, and prioritize the stories we tell ourselves. They’re survival tools, keeping us grounded—but they might also keep us from seeing the bigger picture.

How Filters Limit Our Perception

Picture reality as an infinite ocean, and our consciousness as a small bucket dipping into it. These neural filters decide how much water that bucket holds and what stays out. They restrict us to a sliver of the electromagnetic spectrum, a slice of sound waves, and a linear sense of time ticking forward.

They focus us on immediate dangers or tasks, drowning out subtler signals—like the intuition that nudges you before your phone rings. Woollacott and Weiler argue that this filtered reality is practical but incomplete, a tiny station on the vast dial of existence.

What happens when these filters loosen their grip? Woollacott and Weiler point to three phenomena that can reduce their impact: near-death experiences, deep meditation, and psychedelic compounds. Each offers a glimpse beyond the veil.

Imagine your heart stops, your brain flickers, and suddenly you’re floating above your body, watching doctors scramble to save you. Near-death experiences (NDEs) often defy explanation—people report vivid visions, a tunnel of light, or meetings with loved ones long gone.

Research suggests that during NDEs, brain activity shifts dramatically, possibly shutting down the usual filters. The ARAS might falter, the thalamus might go quiet, and the result is an unfiltered flood of awareness—peaceful, expansive, and untethered from the body.

Now picture sitting in stillness, your breath slow and steady, your mind settling like dust after a storm. Deep meditation—practices like mindfulness or transcendental meditation—can quiet the chatter of the DMN and soften the grip of language. Studies show that advanced meditators experience reduced activity in these filtering regions, leading to states of unity or timelessness. It’s as if the radio static fades, and a clearer, broader signal comes through—a sense of being part of something vast and unbroken.

Finally, consider a dose of psilocybin—the magic in certain mushrooms—or LSD, substances that twist perception into kaleidoscopic wonder. These psychedelics disrupt the DMN and other networks, scrambling the brain’s usual filters. Users describe colors pulsing with life, time stretching or collapsing, and their sense of self dissolving into everything around them. Neuroscience backs this up: brain scans show a chaotic, hyper-connected state where the normal boundaries of perception melt away, tuning the mind to frequencies it rarely hears.

What We Experience When Filters Fall

When these filters weaken, the bucket overflows, and reality transforms.

Wider Awareness: People feel connected to the universe, as if the walls between self and other dissolve into a single, shimmering whole.

Transcendence of Time and Space: Time might loop or vanish, and space expands beyond the body’s edges, defying our usual coordinates.

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Ego Dissolution: The “I” fades, replaced by a boundless “we”—a unity that feels both strange and familiar.

Nonlocal Information: Some report sudden insights or knowledge—like knowing a loved one’s thoughts miles away—hinting at a mind unbound by the five senses.

These experiences might tap into a deeper layer of consciousness, one that exists beyond the brain’s usual constraints.

As Marjorie Woollacott and Marina Weiler in their study suggest, these filters might also blind us to a grander reality. Near-death experiences, deep meditation, and psychedelics offer a peek beyond, where awareness widens, time bends, and the self melts into the all.