Earth Skills and Human Evolution | The cultured ape
Earth living skills and knowledge represent a central, fundamental component of being human, and have played a defining role in the evolution of our species: the human animal.
This post addresses the importance of earth living skills and knowledge in the evolution of the human animal. We’ll take a look at skills and knowledge both in terms of an adaptive potential - cultural evolution - that allowed the extraordinary colonising success of our genus, and also in the capacity of a driver for further biological evolution that led us to become to the animal we now are.
As well as providing some background and hopefully opening your eyes to just how central earth skills are to human existence, this post lays the ground for a later post on the importance of practising these skills and knowledge in modern society:
UNIQUENESS OF THE HUMAN ANIMAL
The human species relies on cultural knowledge for survival. In order to live in the natural world we require skills passed down and learnt from others, whether that’s our parents, siblings, friends, or whoever. It’s true that other animals do have culture (chimpanzees, macaques, and dolphins for example), and so this is a difference of scale not type, but we are arguably unique in our dependence on culture and certainly in its complexity (cumulative bodies of earth skills and knowledge developed over generations such as tracking, weaponry, foraging knowledge, and so on).
The key point I’m making here is that culture in the form of earth skills and knowledge is not an add-on to human ability. Rather, in the context our species’ original lifestyle, they are an integral and absolutely essential component of human existence: as much a part of our species as claws are to a lion or a deer’s innate awareness.
The only difference is that being culturally learnt, and therefore not innate, these skills can become detached and lost if they’re not taught down the generations. And so we have the classic example of the experienced adventurer who perishes in lands where local children thrive.
In fact, the human species never existed without this culture, since archaeological and paleontological evidence suggests it appeared early in the evolution of our genus, before the origin of H. sapiens (Henrich 2011).
Just stop and think about this for a moment – it’s quite a big revelation: culture in the form of earth living skills is part of the original definition of our species – as necessary to our existence as walking, digestion, or an ability to make decisions.
HUMAN ADAPTATION THROUGH CULTURE
So why is our species so unique in this respect?
As I’m sure you’re aware, over evolutionary time a species may evolve by natural selection. This happens when environmental conditions (whether through predation, competition, climate, or other factors) impose selective pressure on the species, resulting in differential survival and reproduction of individuals. This leads to genetic adaptation as a result of beneficial genes proliferating and spreading through the population.
But there are also other mechanisms of adaptation – other ways in which a species may respond to selective pressures. One mechanism is behavioural change - specifically cultural/learnt behaviour (non-cultural, innate behaviour has a genetic basis and would evolve under natural selection).
By using cultural practices (earth skills and knowledge) to change our environment we can buffer selective pressures and avoid the need to adapt genetically as a species. For example, in cold conditions lighting a fire changes the environment, eliminating the selective pressure of death by freezing; or, with respect to food, by cooking we eliminate the energetic pressures that select for increased chewing muscles or a larger digestive system. Of course, when culture is unable to bridge the adaptive lag, (the difference between genes and environment) genetic evolution or local extinction soon follows.
This buffering is known as niche construction theory (Laland & Brown 2006; Laland, Matthews & Feldman 2016), and has been a major component of human evolution since the origin of complex culture in the region of 2-3 million years ago (the oldest undeniable evidence of stone tools dates to 2.6 million years ago).
Essentially, we as a species use skills and knowledge (culture) to adapt to our environment. This is less evolutionarily costly than genetic adaptation, since it doesn’t result in loss of variation and therefore future adaptive potential – should the environment change again, culture can simply revert back. Most importantly, cultural adaptation is far faster than genetic adaptation (Dawkins 1976; Henrich & McElreath 2003). This is because culture can change within a single lifetime, rather than needing to wait for gradual selection and elimination of gene variants over generations. On top of this, unlike genetics, culture can spread horizontally as well as down the generations, uncoupling it from reproductive success and allowing far faster spread through populations.
The capacity for rapid and effective cultural adaptation is thought to be a major explanation for our species’ incredible colonising ability: allowing us to spread and thrive in diversely different environments at extreme evolutionary speed (Stock & Wells 2007). Potential evidence includes the temporal correlation of rapid hominin expansions into northern latitudes (e.g. colonisation of Northern Europe ~70,000 years ago) with the first evidence of controlled fire use, and the coincidence of major H. sapiens expansions after this time with a whole host of cultural innovations such as watercraft and ranged weaponry.
As a side note it’s worth noting that cultural practices can also alter our environment to create an even greater mismatch with our genetics, imposing new pressures that must be adapted to or face extinction. This mismatch is essentially the root of modern society’s discordance with our evolutionary heritage: the origin of many issues we currently face – but that’s another discussion altogether!
‘A new kind of replicator has recently emerged…. achieving evolutionary change at a rate that leaves the old gene panting far behind.’
HOW CULTURE MADE US HUMAN
Earth skills and knowledge also played a secondary, although no less important role in human evolution. As well as acting as a rapid means of adaptation by buffering external pressures, it in turn drove many of the evolutionary changes that we associate with being human. Sometimes referred to as culture-gene coevolution (Henrich 2011) or dual inheritance theory, below are just a few examples:
Of course, as with all evolutionary reasoning, these are only theories, however they’re very convincing – in my opinion at least!
1) ENCEPHALISATION (brain enlargement): made possible by meat eating and cooking
The most commonly cited example is that development of cooking (and other food processing) practices (Wrangham 2009), coupled with greater foraging efficiency and more meat eating (likely partly due to innovation in hunting technology), resulted in a nutritionally denser diet. This allowed a reduction in relative gut size, and in turn energetic reallocation for the evolution of our (relatively) extraordinarily large brain. This theory is known as the expensive tissue hypothesis (Aiello & Wheeler 1995). No wonder our society is so obsessed by cooking programmes!
Diagram from Aiello & Wheeler (1995)
2) EVOLUTION OF SCIENTIFIC THOUGHT: driven by tracking ability
In his book ‘The Art of Tracking: The Origin of Science’ Louis Liebenberg suggests that the development of complex tracking ability (in particular speculative tracking, beyond simply following track and sign) may have been the selective driver that led to the evolution of the capacity for scientific thought and speculative deduction: defining aspects of our species’ potential.
I thoroughly recommend the book – it highlights the fundamental importance of tracking and awareness to our species and in my opinion dispels the idea many of us have that as a species we’ve somehow transcended our animal nature. It places the seemingly detached aloofness of modern human society firmly within the context of our indigenous past.
3) LANGUAGE: driven by the need for cultural transmission fidelity
There is an idea that the origin of language may actually have been driven by pressure for increasingly reliable transmission of skills and knowledge between generations. As cumulative culture became more and more complex, fidelity of transmission between individuals would’ve become a limiting factor to that complexity. Evolution of language solves this problem by allowing easy conveyance of cultural skills and knowledge from one individual to another.
4) ENCEPHALISATION: driven by tool making
Brain scanning studies have shown that individuals experience remodelling of specific brain regions with the progressive acquisition of knapping (stone tool making) skills (Hecht, et al., 2014). Notably these areas are of evolutionarily recent origin and similar trends are observed in brain development of the hominin lineage. This suggests that the evolution of these brain areas may have been at least partly driven by stone tool making.
Interestingly, different brain areas are stimulated when making different tools (e.g. Acheulian versus Oldowan technologies), suggesting that tool making may have been an important factor in ensuring continued evolution of encephalisation over time, preventing stasis at developmentally-imposed maximums (Stout et al. 2008).
These brain areas also appear to be closely linked with language and action planning, potentially meaning that tool making may have paved the way for these other capacities, but it’s hard to say which came first, and an iterative back-and-forth pattern of evolution is probably most likely.
WHAT THIS ALL MEANS
Earth skills and knowledge were a key turning point in the evolution of the hominin lineage, representing the start of our rapid adaptive success and unique divergence from the rest of the animal kingdom. They’re a fundamental and essential component of our species, fitting alongside, not below, the domain of physiological and other biological factors that we share with non-human animals. It’s in this way that we are most unique from other animals.
The key point I’m trying to make here is that for the human animal in its original context as a component of the natural ecosystem, earth skills and cultural knowledge comprise as important and central a part of our existence as do our biological attributes. They’re consequently an equally important aspect of the definition of being human – that is how we existed and survived, no two ways about it.
Of course culture takes another form in our modern society. Simply put, the cultural we now survive by are the skills and knowledge that allow us to survive off the net of society we’ve constructed and rely on. But this doesn’t negate the importance of our ancestral culture, not least in acknowledgement of the many obvious flaws of, and human degradation imposed by, our modern culture. See this article on the importance of practicing earth skills in a modern world – the depth of some reasons may surprise you.
Our ancestral culture, like our ancestral physical ability, also represents a gateway towards the expression of a greater human existence and higher, less tangible potential. Through tracking and earth living we begin to experience and develop an awareness innate to our species, of intuition and an understanding of the world far beyond that which can be imagined in the context of modern society. It is through the disciplines and ideas that make up human evolution (and perhaps only so) that we are able to reach the full extent of human potential. Again, a topic for a future post!
I hope this post might have made you think a little about the role of earth living skills: a major component of being human, not simply a hobby.
REFERENCES AND FURTHER READING
Aiello, L. C., & Wheeler, P. (1995). The expensive-tissue hypothesis: the brain and the digestive system in human and primate evolution. Current anthropology, 36(2), 199-221.
Dawkins, R. (1976). The selfish gene. Oxford university press.
Hecht, E., et al. (2014). Acquisition of Paleolithic toolmaking abilities involves structural remodeling to inferior frontoparietal regions. Brain Struct Funct .
Henrich, J. (2011). A cultural species: How culture drove human evolution. Psychological Science Agenda, 25(11).
Henrich, J., & McElreath, R. (2003). The evolution of cultural evolution. Evolutionary Anthropology: Issues, News, and Reviews, 12(3), 123-135.
Laland, K. N., & Brown, G. R. (2006). Niche construction, human behavior, and the adaptive-lag hypothesis. Evolutionary Anthropology, 15, 95–104.
Laland, K., Matthews, B., & Feldman, M. W. (2016). An introduction to niche construction theory. Evolutionary ecology, 30(2), 191-202.
Liebenberg, L. (1990). The Art of Tracking Tbe Origin of Science. South Africa: David Philip Publishers
Wells, J. C., & Stock, J. T. (2007). The biology of the colonizing ape. American Journal of Physical Anthropology, 134(S45), 191-222.
Wrangham, R. (2009). Catching fire: How cooking made us human. Basic Books