Evolutionary anthropologists argue that human physiology, honed over hundreds of thousands of years for active, nature-rich hunter-gatherer lives, is poorly suited to the chronic pressures of industrialized environments. This mismatch, they say, is contributing to declining fertility and rising rates of inflammatory disease, and should prompt a rethink of how cities and societies are designed.
Human biology evolved over hundreds of thousands of years to cope with the demands of hunter-gatherer life, which involved frequent movement, short bursts of intense stress and daily exposure to natural environments. By contrast, industrialization has transformed human surroundings within just a few centuries, adding noise, air and light pollution, continuous sensory input, processed foods, microplastics, pesticides and long periods of sitting, according to a new review in Biological Reviews.
The paper, by evolutionary anthropologists Colin Shaw of the University of Zurich and Daniel Longman of Loughborough University, argues that modern stressors such as traffic, workplace pressure, social media and persistent noise activate the same biological pathways that once helped humans escape predators.
"In our ancestral environments, we were well adapted to deal with acute stress to evade or confront predators," Shaw says in a statement released by the University of Zurich. "The lion would come around occasionally, and you had to be ready to defend yourself — or run. The key is that the lion goes away again."
Today, many pressures do not subside so quickly. "Our body reacts as though all these stressors were lions," Longman explains in the university release. "Whether it's a difficult discussion with your boss or traffic noise, your stress response system is still the same as if you were facing lion after lion. As a result, you have a very powerful response from your nervous system, but no recovery."
In their review, Shaw and Longman contend that this environmental mismatch is undermining evolutionary fitness, defined as the ability to survive and reproduce. They highlight falling fertility rates across much of the world and growing rates of inflammatory and autoimmune conditions as indicators that modern environments are straining human biology.
One widely studied example, they note, is the decline in sperm count and sperm motility reported since the 1950s. The researchers point to studies suggesting links between these trends and environmental pollutants, including pesticides, herbicides in food and microplastics.
"There's a paradox where, on the one hand, we've created tremendous wealth, comfort and healthcare for a lot of people on the planet," Shaw says, "but on the other hand, some of these industrial achievements are having detrimental effects on our immune, cognitive, physical and reproductive functions."
Shaw emphasizes that biological evolution proceeds far more slowly than technological and environmental change. "Biological adaptation is very slow. Longer-term genetic adaptations are multigenerational — tens to hundreds of thousands of years," he says. As a result, the authors argue, the mismatch between human physiology and modern living conditions is unlikely to resolve itself through natural selection alone.
Instead, they call for deliberate cultural and environmental changes to reduce chronic stress and bring living conditions closer to those in which humans evolved. That includes treating access to nature as a public health priority, protecting or restoring landscapes that resemble ancestral environments and redesigning urban spaces to limit harmful exposures such as noise and light pollution.
"One approach is to fundamentally rethink our relationship with nature — treating it as a key health factor and protecting or regenerating spaces that resemble those from our hunter-gatherer past," Shaw says in an interview published by Phys.org. Another, he adds, is to design "healthier, more resilient cities" that take human physiology into account.
Shaw, who co-leads the Human Evolutionary EcoPhysiology research group, says his team’s work can help identify which stimuli most strongly affect blood pressure, heart rate and immune function, and share that information with policymakers. "We need to get our cities right — and at the same time regenerate, value and spend more time in natural spaces," he says.
