A short history of your attention span

A few years ago, when I was very deep into evolutionary biology, I started to notice something strange about ducks.

I was writing up the experiments for my dissertation and I used to take a walk by the canal every morning before lunch to clear my head. It was springtime. The ducks had hatched their babies. And every day I’d notice the same strange thing.

Not all the ducklings behaved in the same way.

All the duck mamas were swimming about, followed by six (or so) ducklings that shadowed their every move. There would also be one or two other ducklings ‘following’. But they seemed keen not to follow mama duck. They seemed keen to get themselves into everything and everywhere mama duck wasn’t swimming.

As the days went by, I looked out for the duck mamas on my walk. It wasn’t one mama duck who had these two ‘types’ of ducklings. It was all of them.

And I wondered if this might be an evolutionary mechanism. If every mama duck has eight (or so) babies, and six of them stay close but two are wild explorers, how would that work? If mama duck is in an environment full of predators and dangers, the little explorers are not likely to survive and have ducklings of their own.

But if the environment is safe, these little pioneers can grow and drive further duck expansion into new territories.

The ducklings seemed to be on a noticeable spectrum when it came to adventurousness. And I wondered, if what I was noticing was a mechanism, could it be seen in other animals? And what about humans?

Today’s humans are expected to be like the shadowing ducklings. Stay close to the adults, follow the rules. Sit still in school. These are good children. But there are others. Children who have a pathological inability to follow rules, sit still and learn what they’re supposed to.

We can identify gene variants that make it more likely that children will be ‘little explorers’ (we’ll call them that, it feels kinder than alternatives. Such as ‘bastards’). We have even begun to explore the mechanisms that affect whether these genes express (ie. have an effect) or don’t.

But it might surprise you to learn that the gene variants that lead to little explorers were once positively selected for. That’s to say, having Attention Deficit Hyperactivity Disorder, wasn’t so much a disorder as a survival advantage.

There are theories as to why.

The hunter/farmer hypothesis

Can’t sit still. Zones out anything considered uninteresting. Able to hyperfocus on things they do find interesting. These are characteristics of ADHD that are not classroom friendly. It’s characteristics like this that often lead to teachers or parents recommending interventions for children who behave in this way. But these same characteristics might have provided an advantage to our ancestors who were hunter-gatherers. Noticing and hyperfocusing on prey animals. Moving constantly to avoid being preyed on themselves.

The human genome in Europe is well-studied and around 80% of us carry genes from the Yamna people. This mysterious group – also named pit grave people for their method of burying their dead – came west from central Asia and the Caucasus about 6-8 thousand years ago. They would have found Europe populated by settled groups of Anatolian farmers, who may have been living in fixed, agriculture-focused groups for as long as 25,000 years. The Yamna people were horse-herders, and lived a nomadic existence until they came west, at which point they seem to have assimilated. Perhaps murderously.

As the farmers already living in Europe had followed this lifestyle for at least 10,000 years before the Yamna arrived, it’s quite possible that the two groups would have seen different gene variants (alleles) selected for. Survival would have depended on different factors for the two groups, and would have done so for a not insignificant amount of time. Some people believe that typical ADHD characteristics might be retained from when our lifestyles were quite different and required different ways of thinking.

Nomads

Before we’re born, we spend nine months in the womb getting exposed to our mother’s microbiome. The bacteria she is in contact with shapes our genome to some extent. After we’re born we’re normally exposed to bacteria and our own microbiome starts to develop. Since the discovery of antibiotics and antibacterials, we’ve seen a huge increase in autoimmune disorders across the developed world. That’s not to say they’re a bad thing – little more than 100 years ago, many people died of what today would be minor infections and tuberculosis was a slow death sentence. Millions of lives have been saved since we learned to harness the power of antibiotics.

But it has led to a growing body of evidence that suggests that the bacteria we’re exposed to in early development windows can have a profound effect on how our immune systems develop, and even the way our brains function.

Humans are a very adaptable species. It makes sense that under conditions where we might expect to live and die in a settled community, our microbiomes might moderate gene expression to maximise our chances of survival in this environment. Likewise, if our mothers live a nomadic existence, our bodies might hold off on defining brain pathways, with the negatives of slower development balanced with a greater mental adaptability after we come into the world.

It seems likely that ADHD might be a condition that is similarly moderated. Not least because it is often comorbid with other disorders that have an even clearer link to immune system irregularities, such as allergies and autism.

Slower development

fMRI scans of ADHD brains often show lesser connectivity than the brains of their non-ADHD peers. This sounds like a bad thing, but it isn’t necessarily. Humans have a long childhood with which to soak up all the information they’ll need to function in the world they are born into. Having the opportunity to extend this childhood with more flexible brain connectivity could actually be an advantage, assuming the child is appropriately challenged.

In fact, in later life, the brains of the most creative people actually look quite similar to those of people with ADHD. When comparing how highly creative people approach tasks, a recent study paired them against a control group of high-IQ individuals. The brains of the high IQ individuals showed the same brain areas activating. They produced results efficiently, and in predictably similar ways. The brains of the creative group showed something different. The brain areas that activated were all over the place, suggesting, in the words of the lead researcher “They were making their own roads.”

Einstein and Da Vinci

Albert Einstein appears to have shared some characteristics that when taken together suggest ADHD. He was dishevelled and had a famously messy desk. He was a very slow developer as a child. He didn’t speak until he was three years old and his parents worried that he might be stupid. Most famously of all, he didn’t make existing processes more efficient, like a high-IQ individual might. He made his own roads, and revolutionised our understanding of physical laws with his theory of general relativity.

Leonardo Da Vinci has likewise been hypothesised to have been firmly on the ADHD spectrum. He started vast numbers of projects in a wide variety of fields. He finished few, and those he did finish often took years to complete. He was relentlessly curious. And his innovations in engineering, anatomy and art didn’t merely build on existing knowledge. They transformed them.

We can’t retroactively give either man a diagnosis. But the idiosyncrasies of both personalities, and their lasting breakthroughs make it clear that there are multiple ways of working. Ways of seeing the world. Ways of pushing boundaries.

Designing for neurodivergence

While neurodivergent personalities were once treated as though they were lesser or needed to be corrected, today we are beginning to understand that experiencing the world differently doesn’t mean that an individual has lesser capabilities. In the case of Einstein and Da Vinci, they were just making roads the rest of us couldn’t see.

Might the product teams of the future benefit from treating neurodiverse colleagues as assets rather than challenges? After all, if innovation is the goal, every mother duck likely needs to deal with a couple of little explorers, even if they bring the occasional headache.

We probably can’t expect to nurture a Da Vinci or an Einstein on every team. But we could make diversity of thought work harder for us. Nature’s already doing it, after all.