Cognitive Load -  How much does fNIRS really feel my mental effort

The Feeling and Knowing Taá — opening a crack for decolonization

I know this feeling very well:
I’m sitting still, apparently calm, but inside something is heavy.
The task is simple on paper — adding numbers, remembering sequences, answering quickly —
but my chest gets tighter, my breathing shorter, my forehead tenser.

There’s no sweat, no running, but my body knows: I’m overloaded.
It’s a kind of fatigue that doesn’t show up in the muscles, it shows up in the way the mind drags itself along.
The head wants to stop before the body does: that’s cognitive fatigue arriving.

This is the Taá of cognitive load:
first I feel the silent weight of mental effort,
then I know that my performance has started to drop.

I also notice that even my words have been colonized.
The language in which I learned to talk about “performance” and “productivity” was shaped to reduce me:

• to reduce my body to a machine that either delivers or fails to deliver,
  
  

• my mind to deficit or efficiency,
  
  

• my spirituality to a side superstition,
  
  

• my politics to consumption and outcome targets.
  
  

That is why so many neuroscientists still avoid asking how cognitive load is lived in the body, in history, in inequality — as if mental effort were only a number on a graph.

But when I feel my body before I think — when Taá manifests — I realize there is no separation between Neuroscience, Politics and Spirituality (Utupe, Xapiri, living memory).
What colonizes is not only history: it is the word that forces us to call exhaustion “high performance.”

Every serious study on cognitive load, when read with courage, is a crack of freedom that breaks open Zone 3 and gives the body back what it has always been: a living territory, with limits, rhythm and dignity.

The scientific question: does fNIRS really feel my mental effort?

In several recent fNIRS studies on cognitive load, participants perform tasks such as:

• N-back (remembering a sequence of letters or numbers with a delay),
  
  

• mental arithmetic at different levels of difficulty,
  
  

• or combinations of working memory and rapid decision-making.
  
  

Meanwhile, the light of fNIRS passes through the forehead and comes back carrying the signature of prefrontal hemodynamics.

The central question is straightforward:

When the task becomes harder, does prefrontal hemodynamics change in a reliable way?
In other words: does fNIRS really “feel” the increase in cognitive load?

This question is crucial for everything:

• neurotechnology-based education,
  
  

• cognitive ergonomics,
  
  

• work psychology,
  
  

• and our political–educational proposals for Latin American cities.
  
  

How the studies measure this (GLM, HRF, short-channels, ICA/PCA)

The general line in these papers follows a relatively standard fNIRS pipeline:

Tasks with graduated levels of difficulty

• for example, N-back 0, 1, 2, 3;
  
  

• or simple vs. complex calculations;
  
  

• each level is a “step” in cognitive load.
  
  

Recording the prefrontal hemodynamic response

• channels over dorsolateral and ventrolateral prefrontal cortex;
  
  

• measurement of O₂-Hb and HHb across blocks of task and rest.
  
  

Modeling with GLM and HRF

• use of a General Linear Model (GLM) to relate effort periods to hemodynamic changes;
  
  

• choice of a Hemodynamic Response Function (HRF), sometimes canonical, sometimes adjusted (as in HRfunc-type models), to capture the real shape of the blood pulse.
  
  

Short-channels to clean extracortical noise

• short channels close to the light source primarily measure superficial circulation (skin, skull);
  
  

• these signals are used as regressors in the GLM to separate cortical activity from systemic noise.
  
  

ICA/PCA to decompose the signal

• ICA helps remove clearly physiological components (breathing, heartbeat, small movements),
  
  

• PCA summarizes global patterns, distinguishing load-related variation from background variation.
  
  

In the end, the authors look for a pattern:
the higher the difficulty, the more consistent the increase (or change in shape) of the prefrontal hemodynamic response.

What is usually found: effort, limit and nonlinearity

The fNIRS literature on cognitive load shows some recurring points:

• Increasing task difficulty tends to increase prefrontal activation (more O₂-Hb, less HHb) up to a certain point.
  
  

• Beyond that level, a kind of plateau or drop appears: the brain seems to say “from here on, I can’t,” even if I keep trying.
  
  

• In some people, overload appears as an irregular, noisier hemodynamic response, suggesting cognitive fatigue.
  
  

In other words:
fNIRS does feel my effort — but it also feels when my system can no longer respond in an organized way.

If I cut this through our Reference Avatars, here I strongly sense the avatar Math/Hep, who looks at the relationship between energy, effort and statistics: how hemodynamic flow translates, in numbers, the cost of sustaining a focused Tensional Self under high load. At the same time, DANA appears as the intelligence of DNA that tries to protect the system, imposing limits on prolonged cognitive overuse.

Reading with our concepts

Damasian Mind

In Damasian terms:

• cognitive load is not just “more neurons working,”
  
  

• it is a state in which interoception and proprioception are partially silenced to sustain attention on the task.
  
  

With fNIRS, we see this “partial silencing” as hemodynamic redistribution: more blood, more energy, in specific areas — at the cost of other bodily experiences.

Tensional Selves

Each level of cognitive load summons a different Tensional Self:

• the light Self, who solves easily;
  
  

• the Self who starts to clench the jaw, hold the breath, squeeze the pencil;
  
  

• the Self who, at some point, simply gives up, enters confusion, distraction or surrender.
  
  

fNIRS captures this transition: the curve stops being clean and predictable, and starts to carry the mark of exhaustion.

Zones 1 / 2 / 3

• Zone 1: comfortable automatisms — low load, low novelty;
  
  

• Zone 2: optimal effort — enough challenge to learn, but without collapse;
  
  

• Zone 3: chronic overload — continuous effort without rest, exhaustion masked by meritocratic discourse.
  
  

Good pedagogy and good politics should keep most learning experiences in Zone 2, not on the edge of Zone 3.

Where science adjusts our ideas

The colonial view of productivity would say:
“Those who can endure more cognitive load are better, more intelligent, more deserving.”

Evidence-based neuroscience shows something else:

• there is a physiological limit to sustainable load;
  
  

• surpassing this limit chronically is associated with errors, burnout, illness;
  
  

• people in contexts of poverty, racism and inequality live with higher baseline cognitive load (constant worry, vigilance, insecurity).
  
  

In other words:
“failure” is not lack of effort — very often it is excess effort in a system without support.

A mirror in Latin American art

When I think of crushing cognitive load, I remember songs like “Construção” by Chico Buarque, where a worker lives an absurd day of demands until he collapses. Without describing neuroimaging, the song captures a body exhausted by repetitive, dehumanizing tasks — a poetic portrait of cognitive and existential Zone 3.

This art reminds us that mental load is not just lab data:
it is concrete life, it is people trying to think with almost no inner space in a world that demands too much.

Normative implications for education, work and policy in LATAM

Schools

• It is not enough to talk about “more content” and “better performance.”
  
  

• We need curricula that respect Zone 2, with pauses, enjoyment, body in movement.
  
  

Work

• Measuring cognitive load with fNIRS in work settings can help show, with data, what the body already knows: workdays and task demands are excessive.
  
  

Urban and digital policies

• Noisy environments, constant multitasking and the bombardment of digital notifications push entire populations to the edge of saturation.
  
  

• Neuro-rights need to include the right not to live in permanent cognitive saturation.
  
  

Decolonial Neuroscience

• Instead of using fNIRS to “extract more performance” from people, we can use it to justify laws and practices that protect internal time, attention and enjoyment.
  
  

Scientific search keywords

“fNIRS cognitive load prefrontal cortex N-back mental arithmetic GLM HRF short-channels ICA PCA mental workload”

If I return to my own body, I realize:
when the head asks for a truce, fNIRS only confirms what Taá already knew.
True science here is not about forcing me to endure more —
it is about learning to design worlds where thinking does not mean destroying myself from the inside.

When Two Brains Receive the Same World - Cooperation, synchrony, and the shared rhythm of attention

Embodied Singing -Voice, interoception, and Body-Territory in vocal expertise

Pleasant Odors and the Breath that Organizes Us - How smell organizes brain–body coupling

Architecture That Thinks With Me - Turning corners and the attentional cost of built environments

Auditory Approach Bias From Birth - How newborns and adults code the desire to listen

Beta Waves and the Moment I Truly Decide - The prefrontal cortex as the space where "feeling" becomes "choosing"

How My Brain Encodes Voice in Midlife - F0, listening effort, and the vitality of human hearing

Learning Beside Another Brain - Hyperscanning and the pedagogy of co-presence

Reproducibility in fNIRS - When can I trust the hemodynamic curve I see?

HRfunc and the True Shape of the Hemodynamic Response - Why every brain breathes light in its own way

Mixed Reality and Decision-Making - How the brain evaluates prototypes and hybrid worlds

Intense Exercise and the Awakening of Zone 2 - The hemodynamics of effort and the body that generates intelligence

Buttoning a Shirt - Everyday actions as windows into attention, gesture, and consciousness

Depression, tDCS, and the Prefrontal Cortex - Reigniting silent circuits

Designing fNIRS Studies in Real-World Environments - Why science must step outside the laboratory to exist

Transformers and Virtual Short-Channels - AI cleaning brain signals and retelling hemodynamics

Mental Fatigue and Performance - When the head gives up before the body

Cold Water and the Brain - Oxygenation, cold, and the consciousness of the limit

Walking After Stroke - Cognitive–motor interference in everyday life

Balance and the Cerebellum in Parkinson’s Disease - Movement, tensions, and reorganization of the Body-Territory

Freezing of Gait and the Loss of the Body’s Own Quorum - When the body stops trusting the next step

Children With Cochlear Implants - Learning to hear through the brain, not just the device

Emotional Processing in Children With Oppositional Behavior - Regulation, conflict, and the birth of Tensional Selves

Mild Cognitive Impairment - Early hemodynamic signs and presence in the world

Pain, Apathy, and Depression in Dementia - When feeling and thinking stop walking together

Cognitive Load - How much does fNIRS really feel my mental effort?

The Brain in Daily Life -Assisted horsemanship, sport, and embodied enjoyment

Linguistic Jiwasa - When language thinks the world

Dialogical Multiplication and Indigenous Psychology - How to let psychology listen without erasing the Other

The Feeling and Knowing Taá of Christmas 

Republican Capitalism of Spirits without Bodies

NIRS fNIRS EEG ERP Multimodal NIRS-EEG

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