Smart Soil, Dumb Story

An interesting study links your dirt to your IQ. Half of it’s brilliant. Half of it’s the oldest lie in the book. Let’s dig in.

Photo by Zbynek Burival on Unsplash

A dear friend from the regenerative farming community shared an article with me last week, and the headline intrigued me — but the findings, on a subtle level, disturbed me.

The study, published in Scientific Reports in 2025 — “Exploring geospatial link between soils and national intelligence quotient” — laid two maps on top of each other. One showed how fertile the soil is across 126 countries. The other showed each country’s average IQ score. And wouldn’t you know it, the colors lined up. Rich soil, higher scores. Poor soil, lower scores. The authors ran their statistics and found a real correlation — soil fertility, they reported, could account for about a third of the difference in national intelligence around the globe.

On its face, it’s a seductive idea, and one that lives close to my own bones. I have spent thirty years arguing that the terrain underneath us shows up in the bodies on top of it. That the soil feeds the plant, the plant feeds the person, and you cannot grow a well-nourished brain out of depleted ground. So part of me wanted to stand up and cheer. See? The dirt matters. It was always the dirt.

But I sat with it a little longer, the way I’ve learned to sit with anything that flatters me too quickly. And the deeper I went, the more I felt that particular itch at the back of the neck — the one that shows up when a piece of data is true enough to be dangerous.

Because here is the thing about data. We can manipulate it to manipulate people. We can take a real signal and wrap it around an old, ugly story, and because there’s a kernel of truth at the center, the whole thing goes down smooth. So the question I kept circling wasn’t is this study right? The question was: how do we use what’s real in here for good — and not for one more flavor of separateness, one more us-versus-them, one more reason to look across a border or across a table and decide that some people simply have less light in them than others?

Let me show you the two trapdoors I found. And then let me tell you what I saw with my own feet.

The instrument walked into a cathedral and could only measure the doorknobs.

The soil they measured isn’t the soil I know

The first problem is that the study never actually measured living soil. Not once.

Their “Soil Fertility Index” scores dirt by its type — its birth certificate. The great black prairie soils get the top mark. The leached red soils of the tropics get the bottom mark. Then they nudge it for pH and call it a day. That’s the whole instrument.

Which means a deep prairie soil in Iowa earns an elite score whether it’s intact virgin grassland or a glyphosate-drenched, tilled-to-powder monoculture that hasn’t felt an earthworm move through it in twenty years. The index cannot see erosion. It cannot see the collapse of the microbiome. It cannot see the chemical load, the dead fungal networks, the organic matter we’ve burned off and shipped downriver. It scores the soil’s potential on paper and stays utterly blind to what we’ve actually done to the ground.

The authors half-admit this themselves, tucked into the back of the paper, where they note that future research should really look at soil health — the biological and physical integrity of the whole living system — rather than soil fertility. Translation: we measured the dirt’s pedigree, not its pulse.

So, to my regenerative people: this study would pin a blue ribbon on some of the most degraded farmland on the continent. It mistakes a high yield this season for a healthy terrain, which is the exact lie regenerative agriculture exists to expose. The soil order is not the terrain. The terrain is what’s alive in it, and what we’ve taken out.

The IQ data has a rotten root

The second trapdoor is the one that actually turned my stomach, and I’m not going to dress it up.

The “national intelligence” numbers in this study don’t come from anything you’d recognize as careful science. They trace back to a dataset assembled by a man named Richard Lynn. Lynn spent his career bound up with the Pioneer Fund and the journal Mankind Quarterly — two of the longest-running engines of eugenics and scientific racism we have — and he built these very rankings to argue, out loud, for a racial hierarchy of human intelligence. The numbers themselves are notoriously unreliable. Some countries’ “IQ” rests on a single small, unrepresentative sample. Others were simply estimated from their neighbors. The paper even cites, in its own reference list, a 2023 critique of how shaky these national estimates are — and then uses them anyway.

I don’t believe the soil scientists who wrote this paper set out to write race science. They’re agronomists who fell in love with a map. But intent isn’t the issue. When you build your analysis on Lynn’s data, you inherit Lynn’s worldview whether you mean to or not. The map ends up looking like “cold northern countries are smart, hot equatorial countries are not,” and it looks that way because that is precisely the picture eugenicists spent a century manufacturing. This dataset is one of the tools they built to do it.

That’s the manipulation hiding inside the manipulation. A real-enough geographic pattern — because poverty and colonial extraction and malnutrition and yes, degraded soil, really do cluster in space — gets measured with a poisoned ruler, and out the other end comes a number that whispers the oldest lie in the book: some people are just born with less.

What I saw with my own feet

Now I’ll commit the cardinal sin of the academy and offer you an anecdote.

I have spent a fair amount of time living and working within five to ten degrees of the equator — exactly the band this study paints as dim. And what I found there was not a deficit of intelligence. I found social systems of startling sophistication. Infrastructure improvised out of almost nothing and made to last. A resourcefulness that would humble most of the people I know who score well on tests. A way of weaving human life into the living world that wasn’t sentimental or backward but advanced — leadership that thinks in relationships and generations rather than quarters and yields.

Those are forms of intelligence. Ecological intelligence. Relational intelligence. The capacity to hold an entire living system in your hands and not break it. By any honest reckoning, that is harder and more refined than running an extractive monoculture that posts a beautiful number this year and a dead field in thirty.

The IQ test has no column for any of it. It was built in a particular place, to sort people for a particular kind of economy, and it measures one narrow slice of cognition — fast, abstract, decontextualized puzzle-solving — as though that slice were the whole of the human mind. So when it walks into a community that has organized water and food and kinship and ecology into something that’s hummed along for centuries, it scores the place low and calls the place dumb. The instrument walked into a cathedral and could only measure the doorknobs.

And I’ll say the part the academy hates: my time on that ground is not softer evidence than their correlation coefficient. In some ways it’s harder. They measured a proxy of a proxy — contested numbers standing in for “intelligence” standing in for human worth — from a desk, through a software layer, never once touching the earth they were ranking. I went and stood in it. Their number never left the spreadsheet.

I went and stood in it. Their number never left the spreadsheet.

The soil is already in your nervous system

Photo by Ricardo Soria on Unsplash

And here the irony cuts almost too clean. The soil doesn’t only feed the brain from the outside in, through the food on your plate. It reaches further in than that.

There’s a humble bacterium that lives in healthy dirt — Mycobacterium vaccae — and when researchers exposed mice to it, it lit up a specific cluster of neurons in the brain that produce serotonin, and the animals behaved as though they’d been given an antidepressant. The lead scientist, Chris Lowry, has spent years on this, and the throughline of his work is almost unbearably simple: a healthy immune system, fed by contact with the living microbial world, helps protect mental health. As one write-up of his research put it, dirt may be “nature’s original stress-buster.” The first hint came from oncology, of all places — lung cancer patients given this soil organism reported real improvements in quality of life, and the trail led back to the ground.

Which means the microbes in living soil are part of the same conversation as the neurotransmitters that modern medicine spends billions trying to nudge with pills. We have been treating the symptom at the very end of a chain whose first link is the dirt — the dirt we’ve sterilized, paved, sprayed, and severed ourselves from. We took our hands out of the soil and then wondered why the nervous system started to fray.

So when I say hands in the soil could be a kind of medicine, I don’t mean it as a metaphor or a mood. I mean it close to literally. Hands in the ground. Nutrient-dense food grown in living dirt. The removal of the ultraprocessed garbage that hijacks the whole system. Exposure to the actual light-and-dark cycles of the natural day — sunrise on your skin, true darkness at night — instead of the flat overhead glare and the screen-glow we marinate in. Time under trees, green in the eye. And underneath all of it, metabolic order: lowering the chronically high insulin that we now know roughly doubles the risk of major depression and quietly erodes mental acuity and resilience.

That’s my version of the CDC. Not the agency — the prescription. Circadian rhythm, diet, community. Light and dark in their right order. Food that came from somewhere alive. And belonging, because isolation is its own deficiency disease. None of it is exotic. All of it is being stripped from us at scale, and then sold back to us one prescription at a time.

So how intelligent are we, really?

Which brings me, with some heat, back to the map.

My own country scores near the top of that “intelligence” chart. And yet we have the lowest life expectancy of any wealthy nation on earth, and it has been falling, not rising — dragged down year after year by what researchers bluntly call “deaths of despair”: drug overdose, alcohol, and suicide. We hold the highest suicide rate of any rich country. We are, by the study’s own measure, one of the “smart” ones.

So I’ll ask the question the map never thinks to ask: how intelligent is a society that is killing itself faster every year? That has the resources to do nearly anything and chooses ultraprocessed food, fluorescent light, chronic isolation, and a pill at the end of every chain? Whatever that test is measuring, it is not measuring wisdom. It is not measuring whether a people knows how to keep itself alive. By that standard — the only standard that finally matters — the scoreboard is upside down.

The intelligence I actually care about

Because the intelligence I’m most interested in was never going to show up on that test anyway. It doesn’t come from a book. It comes from a soul.

The intelligence I’m most interested in doesn’t come from a book. It comes from a soul.

Emotional intelligence — the capacity to feel your own interior accurately, to sit with another person’s pain without fleeing it, to repair a rupture, to stay in connection when it would be easier to harden and walk away — is, to my mind, the most underrated and most desperately needed intelligence we have. And it is precisely the one our culture has spent generations failing to cultivate, measure, or honor. We built whole education systems and economies around the fast, abstract, testable kind of smart, and we let the other kind — the relational, the felt, the wise — wither for lack of water.

And the cost of that neglect is everywhere you look. The mess we are in globally is not a deficit of IQ. Nobody is suffering for want of logic puzzles. We are suffering from a famine of emotional intelligence — broken relationships, disconnection, loneliness metastasizing into despair, whole nations talking past each other and reaching for the nearest enemy. The deaths of despair I named earlier aren’t a failure of cleverness. They’re a failure of belonging, of being felt and held, of knowing how to be with our own and each other’s suffering. That is an EQ wound, not an IQ one.

We are not suffering from a deficit of IQ. We are suffering from a famine of emotional intelligence.

And it loops right back to the soil, the way everything in the terrain eventually does. Emotional intelligence isn’t conjured in the abstract. It grows in bodies that are fed and regulated, in nervous systems that aren’t perpetually inflamed, in communities where people are actually in contact with one another and with the living world. Strip the terrain — the soil, the food, the light, the belonging — and you don’t just dim the kind of intelligence a test can score. You starve the kind it can’t. The kind that was holding us together in the first place.

That’s the intelligence those communities near the equator were so rich in, and it’s the intelligence the spreadsheet was structurally incapable of seeing. A soul’s intelligence doesn’t fit in a cell on a chart. But you can feel its presence in a room in about four seconds, and you can feel its absence in a culture coming apart at the seams.

So what do we do with it — for good?

Photo by julien Tromeur on Unsplash

There is something real in this study, and we don’t have to throw it away to refuse the rot. The real thing is this: depleted terrain suppresses human flourishing. Strip the soil, poison the food, break the infrastructure, sever the connection between people and the land that holds them — and you absolutely diminish what a human body and mind can become. That part is true. I’d stake my life’s work on it.

But the honest version of that truth doesn’t sort humanity into smart nations and dim ones. It does the opposite. It says that an enormous amount of human capacity is being quietly throttled right now — not by anything innate, but by what’s been done: the mining of soil, the extraction of wealth, the manufactured isolation. And nearly all of it is recoverable. That’s not a story about who deserves to rise. It’s an indictment of how much we’re losing, and a map back.

Soil and infrastructure and connection are not separate columns in a spreadsheet, the way the researchers treated them. They feed each other. Rich soil grows nourishing food, nourished people build and learn and care, and that care rebuilds the soil. It’s a loop. A terrain. You lift one part and it tugs the others up with it. Lift several at once and they don’t just add — they compound.

So we take this study and we flip it on its axis. We let it remind us that the ground beneath us matters more than we’ve been told. And then we refuse, absolutely, the trapdoor it leaves open — the one that turns “your terrain was depleted” into “you are lesser.” Those are opposite stories told over the same map. One says the gap was done to people and can be undone. The other says it’s written into them and can’t. Every honest bone I have says the first one is true.

And this is the part that genuinely hurts my heart. We are finally having the conversations I’ve waited my whole career to hear — about soil and the microbiome, about food as medicine, about light and circadian rhythm, about metabolic health as mental health, about belonging as a biological need. The door is opening. And then a study like this lands in the middle of it, and I watch it split clean down the seam depending on whose hands catch it. In the right hands it’s hopeful, even thrilling — look how deep the roots of our wellbeing go, look how recoverable so much of this is. In the wrong hands it’s a fresh coat of paint on a very old cruelty — a way to look at suffering people and call it their nature. Same study. Same map. The fork is entirely in us.

And here is the part that keeps me writing this instead of hurling the study across the room: the right-handed version is already underway. The grassroots are moving. If you want to watch it happen, sit down with the documentary trilogy — *Kiss the Ground*, its sequel *Common Ground*, and the new final chapter *Groundswell* — where ordinary farmers and eaters and neighbors are putting their literal hands back in the dirt and watching dead fields come back to life, and the people who tend them come back to life right alongside. That is the whole equation in a single frame. Heal the soil — the IQ side, the nutrients, the metabolic order, the cognition. Heal the connection — the EQ side, the belonging, the meaning, the return to something living. Not one or the other. Both. From the ground up, which is the only direction anything real has ever grown.

Heal the soil. Heal the connection. Not one or the other — both, from the ground up.

We don’t rise by deciding who’s smart and who isn’t. We rise by tending the terrain — all of it, everywhere, together. The dirt under the so-called brilliant and the dirt under the so-called dim is the same dirt, asking for the same thing.

Tend the soil. Tend the human. There was never a line between them, and there was never a line between us.

If this stirred something in you, I wrote a small book about where to begin tending your own terrain — soil, body, and soul. You’ll find *Tend the Terrain* at drnasha.com.