“Our Hunter-gatherer Ancestors Were, In Effect, On A Camping Trip That Lasted A Lifetime”
Has the brain evolved to run?
Our hunter-gatherer ancestors were, in effect, on a camping trip that lasted a lifetime, and they had to solve many different kinds of problems well to survive and reproduce under those conditions […]
— Cosmides and Tooby, 2013
Chris McDougall’s epic book “Born to Run” has been an inspiration to many runners and introduced its readers to the possible benefits of barefoot running and the legendary Tarahumara tribe — a seemingly superhuman band of distance runners remaining largely remaining hidden from the rest of the world.
However, for me, what I found most captivating, was the suggestion that humans have, over the millennia, evolved key physical adaptations to facilitate running large distances. Indeed, research by Bramble and Lieberman (published in Nature in 2004) argues that:
“[…] endurance running is a derived capability of the genus Homo, originating about 2 million years ago, and may have been instrumental in the evolution of the human form.”
They go on to say, that based on analysis of the evidence, our human ancestors evolved to travel long distances by running, known as endurance running.
This led me to the question, pondered over the course of my PhD research into ultra-marathoners, and running along countless trails…
If we have evolved physically, as a result of natural selection, to run long distances, then why not psychologically?
As Dobzhansky famously said ‘nothing in biology makes sense except in the light of evolution’. Perhaps this is just as relevant to the field of psychology.
To even attempt to tackle this question, we must first try to understand the following:
- What is evolution?
- How has our evolution shaped, and been shaped by, distance running?
- What is Evolutionary Psychology?
- Has human psychology evolved for endurance running?
What is evolution?
Evolution is simply change over time. The Theory of Evolution by Natural Selection was introduced to the world by Charles Darwin in 1859, in ‘The Origin of Species”. It was, and remains, stunningly beautiful in its simplicity, yet explains the enormous complexity, and variation found in living things.
Evolution states that change is a result of natural selection, involving the following three phenomena:
1. Variation: there is variation within a species, partly as a result of mutation in the genome — an organisms complete set of DNA.
2. Inheritance: variations within populations are inherited (parents pass on to offspring). Individuals may both inherit harmful variations that may limit their potential to survive and reproduce, and these are less likely to be passed on to future variation, or other, more positive, adaptions that increase the likelihood of survival long enough to reproduce more effectively than its competitors.
3. Differential reproductive success: within a species, there are differences in how many offspring are produced and whether or not they survive long enough to reproduce.
In other words, individuals poorly adapted to their environment are less likely to pass on their genes, and given enough time, a species evolves. Adaptive features tend to increase in frequency from generation to generation, causing change over time, most frequently when the environment of evolutionary adaptedness is at its most harsh.
Our genotype, or the complete set of an organism’s genes, are stored in helical DNA structures contain the genetic roadmap of instructions for almost every aspect of our being, our phenotype, from eye and hair colour to elements of our psychological make-up, including our personality.
This phenotype is a list of all of our observable traits, comprised of a myriad of features that once performed essential roles. Including some adaptations that now no longer fit our environment and may harm us, such as a tendency to crave calorifically high food, that now leads to obesity.
How has our evolution shaped, and been shaped by, endurance running?
Evolutionary biology, backed up by fossil and genetic evidence, suggests that endurance running was important in the pursuit of prey and instrumental in the evolution of hominins (species of human).
Humans perform remarkably well at endurance running thanks to a diverse set of evolved adaptations that may have been key in the survival and evolution of the human form over millions of years. Our understanding of the timeline changes frequently, as new evidence arises: the journey to us, Homo Sapiens, continues to become ever more complex.
A simplified view, lacking in the true complexity of the many interweaving, tangled, steps of our human evolution, might be as follows:
- Approximately 7 million years ago, there existed a species of ape found in forests that would ultimately give rise to humans as we currently know them, and these are our last common ancestor (LCA) with modern apes.
- 4 million years ago, Australopithecus appeared, and survived, incredibly, for at least two million years through a time of great climatic change. Fossil evidence confirms their presence in the open savannah of Africa and suggests that as a result of changing climate, and reducing forests, they developed adaptations to stand and walk upright on two legs. This bipedalism may have helped them travel further, exploring more remote areas, and facilitated a hunter-gatherer lifestyle of foraging for, and carrying, food.
- Homo Erectus arrived some two million years ago, and is usually credited with (1) the development of stone tools, (2) leaving Africa for the rest of the world, and (3) exhibiting a number of physiological adaptions that may well have appeared in response to, and to improve, endurance running.
Such physical changes, observed directly, or indirectly, in fossils from that time, appear to have occurred in response to natural selection, to facilitate long distance running, and include:
- Plantar Arch found in the foot (for energy storage and shock absorption),
- Long Achilles tendon (for energy storage and shock absorption),
- Enlarged gluteus maximus, sometimes referred to as the “glutes” (stability),
- Reduced body hair, narrow elongated body form, increased number of sweat glands (heat dissipation and management).
After a further 1 million years, some 200 thousand years ago, a mere instant in the 4.5 billion year history of the Earth, we emerged, Homo Sapiens.
In our present human form, and in the absence of spears, bows, and arrows, which did not arrive until approximately 40,000 years ago, it appears likely that the protein and fuel required to feed a rapidly developing brain was either appropriated by competition with other scavengers or through ‘persistence hunting’. Endurance running, supported by a combination of adaptations, appears to have either enabled us to run our prey to exhaustion in the heat, get close enough to throw projectile weapons, or scavenge as hunter-gatherers in the endless plains of Africa.
It must be remembered that the picture painted above lacks the full intricacy likely involved over the millenia, and fails to include either the multiple migrations out of Africa or the interbreeding between more than one human species. Indeed in August 2018, research published in the National Geographic shared evidence of a skeleton identified from 90,000 years ago, incredibly with parents of two different species, a Neanderthal mother, and Denisovan father.
Another important, key fact regarding our endurance prowess is that though quadrupeds such as cheetahs, horses, and dogs, are much faster sprinters than us, we are able to run much longer distances, and sustain higher speeds, and may be regarded as exceptional endurance runners in the animal kingdom(Bramble and Lieberman, 2004).
What is Evolutionary Psychology?
According to Evolutionary Psychologists, the human brain has evolved, like the rest of our body parts, to solve the problems specific to our ancestry. To gain a full insight into the workings of these psychological adaptations we need to understand why they evolved via natural selection.
The linguist and cognitive psychologist, Steven Pinker (2004) suggests that
“learning itself must be accomplished by innate circuitry, and what is innate is not a set of rigid instructions for behavior but rather programs that take in information from the senses and give rise to new thoughts and actions”
Though not all Evolutionary Psychologists have one single view, a common stance might be as follows:
- Evolution has designed the architecture of both the body and the mind through natural selection.
- As humans, we almost all, have similar physical and psychological mechanisms.
- Psychological mechanisms evolved to meet the needs of ‘adaptive problems’ from our evolutionary past.
Adaptive problems that needed solving may have impacted human psychology in relation to endurance, including migration in response to dramatic climate changes resulting in habitat and food loss, changing tribe populations, or competition from other groups or species, and different hunting and gathering methods. It is not hard to imagine new psychological profiles, including resilience, personality, or motivation, would be needed to meet the new environments, and challenges faced.
Evolutionary Psychologists tends to argue that there are only limited domain-general mechanisms, and that the brain is not infinitely malleable. This is due to the fact that the mechanisms would not have been consistently selected as jack of all trades master of none, but rather would be specific to those challenges face, or would not have been selected over many generations.
It is therefore argued that the mind, like the body is modular, comprised of many domain-specific psychological mechanisms that evolved to solve specific adaptive problems. It is a widely accepted view that our psychology, including our personality, our mental toughness, and our motivation play a key role in endurance performance, with research suggesting at least 50% of which is inherited.
Has human psychology evolved for endurance running?
There are a number of points that suggest, yes, it has.
In terms of evidence, our brain, our ‘wetware’, unlike bones, does not preserve well. However, we can see from the shape of the brain cavities in the fossils so far uncovered, that little has changed in the overall anatomy of the brain in the last 200 thousand years. If endurance running was key in our past, and we evolved psychologically to meet this need, we still have those adaptations.
Research (including my own), exploring both aerobic and mental factors, suggests that there is little or no difference in either mental toughness, personality or motivation, between those that compete in ultra-marathons and those that don’t. This suggests that the apparently uncommon ‘ultra-marathoner’ is similar psychologically to everyone else. The only differences my research identified was that the ultra-marathoner is open to new challenges, and is aerobically fit, as a result of extensive training.
There is nothing stopping us ALL psychologically from being an ultra-marathoner.
A recent article suggests fatigue, which is likely to be driven by both psychological and physiological factors, would benefit from exploration through an evolutionary lens. The impact of fatigue on the perception of effort, and the subsequent impact on when we cease effort, are driven by factors evolved in accordance with natural selection.
Very different psychological measures could have adapted to meet the endurance requirements of each environment. As a result, though endurance may have been crucial to the survival of the human species, there may be no one trait, or set of traits, that predicts successful performance.
Endurance running was important in the evolution of early hominins, with key physiological adaptions evolving over millions of years to benefit long distance running, it can therefore be the case that we have also evolved psychologically to facilitate the performance feats of endurance.
What does this mean to us?
Our journey is not only where we have come from, but where we are going to.
Endurance is likely to continue to play a key role in the development of Homo Sapiens. As a race, we will have future challenges, both environmental, on earth, and in longer-term space travel to reach even our nearest planetary neighbours.
We have physical, and most likely psychological adaptations, that have evolved to solve the problems and promote behaviour to overcome the challenges of our evolutionary past. Endurance, and running in particular, played a key role in this survival and the development of our ancestors, enabling us to evolve the form we now have, and to outlast other human competitors that challenged us along the way.
Barring illness, injury, or any other physical challenges, with the right training, we all have the equipment — psychological and physiological — to run a very long way.
If you are open to the challenge, then accept that you are ‘Born to run’
This post also appeared on medium
Boullosa, D. A., & Nakamura, F. Y. (2013). The evolutionary significance of fatigue. Frontiers in Physiology,4. doi:10.3389/fphys.2013.00309
Bramble, D. M., & Lieberman, D. E. (2004). Endurance running and the evolution of Homo. Nature,432(7015), 345–352.
Cosmides, L., & Tooby, J. (2013). Evolutionary Psychology: New Perspectives on Cognition and Motivation. Annual Review of Psychology Annu. Rev. Psychol., 64(1), 201–229.
Darwin, C. (1859). The Origin of Species. Oxford: Oxford University Press, 155, 158.
Horsburgh, VA, Schermer, JA, Veselka, L, Vernon, PA 2009 ‘A behavioural genetic study of mental toughness and personality’ Personality and Individual Differences, vol, 46, p. 100–105.
McDougall, C. (2009). Born to run: A hidden tribe, superathletes, and the greatest race the world has never seen. New York: Alfred A. Knopf.