The brain has an estimated processing power of one exaflop — one billion-billion calculations per second — which it computes using just the energy of a dim lightbulb. That is efficiency AI developers can only dream of.

But technology affects our mental productivity too. Economists tend to focus on the positive link between innovation and economic growth. Neuroscientists are, however, uncovering more details on the deleterious impact gadgets can have on human cognition that, in turn, brings negative repercussions for the economy. This week I hone in on one such dynamic.

Over the past two decades, digital tools have proliferated, enabling us to stay informed, entertained and connected at all times. New technologies, formats and rapid content creation mean we can access more stimuli per unit of time than ever before.

Daily screen time — on devices such as computers, laptops, tablets, mobile phones, televisions and consoles — increased by two hours between 2012 and 2019 to around 11 hours, according to a global study. The total time we spend plugged in has likely risen since, with an increase in remote working, podcast consumption and new digital layouts.

The human mind, however, was never designed to process all this data at once. Rather than boosting our cognitive productivity, this throughput has been linked to mental fatigue, impaired memory, stress and broader mental health problems.

Yet in our highly digitalised economy, business models depend on capturing and holding human attention. Indeed, corporate competition across multiple channels for this limited resource has meant the value of attention has risen.

This is reflected in research by Thales Teixeira, professor at the University of California San Diego and founder of consultancy Decoupling.co. He tracks the price of gaining 1,000 impressions on TV adverts during the Super Bowl and US prime time as a proxy for the cost of attention. The cost of both has surged, particularly following the internet boom as consumer focus was fragmented across other media and platforms. 

(The average cost of a 30 second advert at this month’s Super Bowl reached $8mn, up from just above $2mn in 2022.)

With the high premium on our attention, businesses constantly adapt their strategies to keep us engaged, notes Pierluigi Sacco, a professor of biobehavioural economics at the University of Chieti-Pescara.

“Platforms and media discover that shorter, more stimulating content captures more engagement, so they optimise for it,” he says. “Audiences adapt to that rhythm. Then the next generation of content has to be even shorter and more intense to compete.”

One manifestation of this dynamic is the rising popularity of the reel format — snappy videos that often play automatically. (It is so addictive that I’m told some users batch-download reel videos to scroll through on occasions when they don’t have internet connectivity.)

Another example comes from Hollywood. In an interview last month, actor Matt Damon noted a dumbing down effect in the way Netflix advises filmmakers to accommodate viewers’ fragmented attention. The streaming service now asks for a big action set piece “in the first five minutes” and for the plot to be reiterated “three or four times in the dialogue because people are on their phones while they’re watching”, he said.

This shift towards bite-sized content is also occurring in education, journalism, comedy and politics.

But this isn’t just a benign change in taste or boost in convenience; it has a neural dimension, notes Chieti-Pescara’s Sacco. “The brain adapts to the reward structure it encounters. When the dominant information environment delivers constant novelty in small, high-stimulation doses, the capacity for sustained attention doesn’t just go unused, it gets actively harder to deploy.”

This may contribute to the perceived decline in our attention over time, alongside information overload, digital distractions and our constant flitting between devices. A 2022 survey by King’s College London found that 49 per cent of UK adults feel their attention span is shorter than it used to be. Forty-seven per cent feel “deep thinking” has become a thing of the past.

Studies that monitor people’s attention in their real-world environment show that since 2004, the average time people stay focused on a single task has dropped from about 2.5 minutes to roughly 47 seconds, according to data tracked in Attention Span, a book by Gloria Mark, professor of informatics at the University of California, Irvine. Broader factors, such as stress and lifestyle changes, may play a part too, she says.

“I have been interviewing many people, and a repeated theme I hear is that they have trouble reading books now, whereas years earlier they didn’t,” says Mark.

The vicious circle also affects learning. A viral social media post humorously describes how someone with a 1,200-day streak learning Spanish on the language app Duolingo could barely string sentences together when they visited Spain.

Niels Van Quaquebeke, professor of leadership at Kühne Logistics University, describes this as the Duolingo-isation of education. “If tech has its way, learning could drift towards the same model: tiny, gamified tasks, streaks, badges and endlessly bite-sized exercises. Highly efficient, highly scalable and potentially deeply hollow.”

In other words, there appears to be a downward spiral between the economic incentives to capture our attention, and our ability to pay attention.

Tech shapes our cognition in other ways too. The “Google effect”, for instance, refers to a 2011 academic study that found that humans treat the internet as a form of random-access memory. This means we remember fewer easily searchable facts as a result. It’s possible that freeing up working memory can boost our productivity, though storing less information can also lead to shallower thinking.

Mithu Storoni, a neuroscientist and author of Hyperefficient, a book about optimising the human brain, warns of a similar dynamic with AI. “If users offload too much cognitive effort to AI they risk weakening the mental muscle for synthesis, contextual judgments and curiosity, which is what distinguishes us from [large language models] in the first place,” she says.

And as I argued in the February 16 edition of this newsletter last year, technology is straining our brain health, capacity and agility.

Technology is designed to create efficiency. It allows us to search, retrieve and analyse data faster, freeing us for higher thinking.

But humans have an inbuilt evolutionary tendency to conserve cognitive energy and seek out dopamine hits. Market economies optimise for this. As mental friction is engineered away, the tools we need for deeper cognition risk atrophying. For example, sustained concentration helps strengthen attention, tackling long texts deepens comprehension and forming arguments without prompts builds originality.

It’s worth exercising some personal discipline in how we use technology. As the saying goes, we shape our tools — and thereafter our tools shape us.

Send your reflections to freelunch@ft.com or on X @tejparikh90.

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Free Lunch on Sunday is edited by Harvey Nriapia