Evolutionary mismatch: just one part of the neurodivergence story

How this theory of biology explains our challenges but can't obscure our strengths

May 01, 2025

Henri Rousseau, *Exotic Landscape* c. 1910

Imagine transplanting a cactus into a marshland or a giraffe into a treeless plain. Each organism is pleasingly in sync with its original habitat, but it struggles in these new environments.

It’s a helpful analogy for considering ourselves. We humans have been catapulted from our ancestral environments into a world that transforms far faster than we can evolve.

Evolutionary mismatch is an artifact of that warp-speed transformation. It’s when an advantageous trait becomes maladaptive due to rapid environmental changes.

This phenomenon explains many of the challenges neurodivergent people face today. But the evolutionary origins of our traits also provide a framework for understanding how these traits continue to strengthen humanity today.

Our original environment

Homo sapiens emerged around 300,000 years ago in Africa and then migrated distally, interbreeding with archaic humans – like Neanderthals – along the way.

The ancient environment established our core genetic makeup. Agriculture emerged only 12,000 years ago, and the first urbanized settlements just 5,000 years ago. This means that for about 97% of human history, our genes were shaped by a pre-agricultural, hunter-gatherer existence.

That environment was highly variable. The climate swung frequently between cold glacial periods and warmer respites. Our ancestors inhabited a range of biomes: woodlands, savannas, coasts, and river valleys. They cycled through periods of famine and feast. Exploiting diverse resources through hunting, foraging, and fishing was key. This overwhelming lack of stability selected for cognitive flexibility, social cooperation, and behavioral adaptability.

Early humans also had regular exposure to parasites and bacteria, and our immune systems evolved to manage chronic low-level infestation. No space was free of contamination.

Other aspects of human existence were more constant. Scientists believe humans worked in small, mobile foraging bands of 20-50 people and expended large amounts of energy daily. Several small bands would associate to form larger groups of 100-150 people for trading, mating, support in hard times, and periodic gatherings. This nested structure is ancient and widespread across foraging societies, making us highly social and deeply reliant on smaller-group intimacy.

Evolutionary mismatch

The phenomenon of evolutionary mismatch — the cactus in the marshland, the giraffe on the treeless plain — is present in all aspects of modern life. The ancient environment that shaped us was vastly different from the one we inhabit today.

For instance:

Sugar and fat consumption. Ancient humans’ high energy needs, together with those feast and famine cycles, conditioned us to particularly crave sweet and fatty foods, since these nutrients provided calorie-dense energy but were relatively rare. Today, abundant sugar and fat contribute to obesity, diabetes, and cardiovascular disease.
Physical activity levels. Our hunter-gatherer ancestors had highly active lifestyles. Today, we’re mostly sedentary, and our bodies suffer for it. It’s not that being sedentary is per se a bad thing (hi, sloths), but it is bad for us because of the way our bodies evolved.
Social isolation. Humans evolved in small, closely knit groups that were essential defenses against predators and starvation. Isolation posed a real survival risk, so humans were conditioned to need deep social relationships. Modern life often involves isolation or superficial interaction within oversized groups (hello, social media), leading to mental health struggles such as depression or loneliness.
Hygiene and immunity. Our immune systems evolved in environments teeming with microbes. Modern hyper-cleanliness limits early exposure, which has been hypothesized to result in increased autoimmune diseases and allergies.

I could go on about the mismatch between our fight-or-flight response and the small threats of modern life (what’s up, microaggression), between our circadian rhythm and today’s artificial light exposure… but you get the point.

To be clear, this is not meant to romanticize ancient human existence or argue a return to a hunter-gatherer heyday. The fact that humans, on average, might have been physically stronger or slept better 300,000 years ago does not mean they were better off.

Henri Rousseau, *Tropical Forest with Monkeys* c. 1910

Evolutionary mismatch and neurodivergence

The mismatch concept also applies in the more targeted context of neurodivergence.

Based on genetic distribution, researchers believe that neurodiverse profiles with polygenic bases – like autism, ADHD, and dyslexia – were positively selected.1 In other words, they offered evolutionary advantages that resulted in humans passing on these genetic profiles to their offspring over many generations, onto the present day.

For instance, the DRD4-7R allele is linked to ADHD.2 This gene variant is associated with risk-taking and is “under strong positive selection in the human population.”3 It’s believed that DRD4-7R accounts for early human migration over long distances.

Here are some examples of evolutionary mismatch within neurodivergent traits:

ADHD hyperactivity, novelty-seeking, and frequent attention shifts. These traits may have been advantageous in unpredictable ancestral environments by helping individuals detect threats, explore new territories, or experiment with unfamiliar tools and food sources. But these traits often clash with modern classrooms and workplaces, which impose sedentary, routine-focused demands.
Dyslexic exploratory focus. Researchers have identified patterns of exploratory strength in people with dyslexia, and they hypothesize that a deficit in reading and writing ability may be the flipside of redirecting brain resources toward exploratory search.4 In modern society, which views reading and writing ability as fundamental to intelligence and potential, dyslexia is often seen as a deficit rather than a strength.
Autistic heightened sensory sensitivity and reduced habituation. I’ve written about the reduced habituation trait previously. Heightened sensory sensitivity may have been beneficial when detecting subtle environmental changes was crucial to survival. For instance, being a light sleeper may have helped people like me identify nighttime threats. Today’s world, filled with artificial lights, loud noises, and other relentless stimuli, creates sensory overload for autistic individuals, exacerbating anxiety and discomfort.
Autistic monotropic focus. Some problems require deep, intense focus to solve, and being oriented toward that kind of attention could have been a bonus as early humans developed solutions and methods for survival. Modern technology puts many of our survival needs just a tap or click away, and monotropic focus can now seem counterproductive.

Neurodiversity makes us stronger

And yet, while mismatch explains why certain traits cause friction today, it doesn’t mean those traits lack value. The reality is, as ever, nuanced.

Though corporate success isn’t the only, or best, measure of value, it’s often the one society takes most seriously. And so, for instance, it’s striking that many CEOs have dyslexia and see it as an important differentiator. It makes sense that an orientation toward exploration — of new ideas, methods, strategies — would benefit a CEO, right? This fact subverts the conventional wisdom that excelling in reading and writing is fundamental to modern success.

And even if individual traits can misfire in modern contexts, what happens when they’re pooled into a group?

There are certain universal principles that hold true across unrelated domains. These are the ones that really excite my pattern-seeking mind. And that’s the case for the diversity = strength principle.

Diverse groups are more adaptive, resilient, and effective than homogenous, one-size-fits-all groups.

We see this everywhere:

In the ravages of monoculture crop production and the benefits of ecosystem diversity
In the resilience of distributed computer networks
In groups of human problem solvers
In investment portfolio optimization
In microbiome health
In in-species genetic diversity as a shield against disease
In gender and ethnic diversity as a predictor of better business performance

This principle should logically extend to neurodiversity, although I haven’t found any peer-reviewed research addressing it.

However, support for this idea comes from our early ancestors.

To use a couple traits discussed above as examples, dyslexic exploratory focus logically complements autistic monotropic focus. Cognitive exploration produces new ideas. Monotropic focus mines those ideas for effective implementation. A hunter-gatherer team with both profiles would be well-situated to explore new environments and develop them effectively.

Perhaps as circumstantial support of this theory, there is little polygenic overlap between dyslexia and autism, and they rarely co-occur. Dyslexia and ADHD, on the other hand, have high comorbidity,5 which makes intuitive sense given the similarity between exploratory focus and novelty-seeking behavior.

Evidence from corporate neurodiversity programs

It doesn’t take a great mental leap to predict the benefits of neurodiversity today. Exploratory orientation, attention-shifting, novelty-seeking, deep focus, and sensory sensitivity each result in seeing things others don’t and thinking of things others aren’t.

For instance, an overly uniform team is susceptible to groupthink, blind spots, and cognitive bias; a neurodiverse group would be better equipped to resist those pitfalls and generate a wider range of ideas.

Companies, ever eager to achieve marginal advantage to boost competitiveness and profitability, are already experimenting with this hypothesis.

A growing number of businesses, including Hewlett Packard, Microsoft, Ford, EY, Caterpillar, IBM, JPMorgan Chase, and Lego, are making efforts to enhance neurodiversity among their workforces.

And business case reports and pilot programs show measurable improvements when teams are neurodiverse.

For instance, an EY pilot program found:

Quality, efficiency and productivity were comparable, but the neurodiverse employees excelled at innovation. In the first month, they identified process improvements that cut the time for technical training in half. They learned how to automate processes far faster than the neurotypical account professionals they trained with. They then used the resulting downtime to create training videos to help all professionals learn automation more quickly.

In another example, a Hewlett Packard program reported a 30% productivity boost in teams that integrated neurodiverse individuals.

As I look through these corporate case studies, I notice a concentration in the UK, Australia, and New Zealand. That’s not a coincidence. Those countries have government programs and policies aimed at supporting neurodivergent individuals in the workforce, which has fostered environments conducive to such initiatives.

Australia, for example, has a National Autism Strategy focused on supporting and empowering “Autistic people to thrive, in all aspects of life.”

I can’t help but compare those government initiatives with the current trend in my country, the US, of dismantling DEI and defunding programs and research that focus on support and inclusion.

The takeaways

Before closing, an important caveat: Neurodiverse people often feel a need to defend their existence. No one needs to justify their existence, and the point of this post is not – absolutely not – to defend people who need no defending.

A greater understanding of context, history, science, processes, and society is worthwhile for its own sake. That belief animates my work here.

So I find it worth observing that millions (billions?) of people alive today – that is, most (or all?) of humanity – may owe their existence to the simple fact that our neurodiverse ancestors worked in harmony. Our ancestors’ complementary traits enabled humans to overcome ever-present threats to species extinction, threats from which every other archaic human species perished.

At critical points in their existential fight to survive, our ancestors contributed strengths that created a sum greater than its parts. Those same strengths still shape how we meet today’s challenges.

Thanks for reading Strange Clarity, where I write about neurodivergence, cognition, and the hidden architectures of thought.

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