Cognitive and archaeological aspects of hunter-gatherer fire making
“The art of making fire was described by Darwin as one of the greatest achievements of humankind. Humans are the only species who are obligatory fire makers and users. There is evidence of fire making in both the Neanderthal and Homo sapiens archaeological records from at least 100 000 years ago in Africa and Europe. We taught ourselves how to control and contain fire, and to use it to stay warm and scare off predators. Without using fire in one way or another, humans may be disadvantaged or even die,” said Marlize Lombard of the Palaeo-Research Institute, University of Johannesburg.
Lombard, along with Anders Högberg of the Department of Cultural Sciences, Linnaeus University and Peter Gärdenfors of the Cognitive Science Group, at Lund University, was presenting the latest update on their long-term STIAS project on the ‘Archaeology of The Hungry Mind’ (or becoming Homo sapiens). The project evolved through a collaboration started at a STIAS workshop in 2013 that posed the question ‘How did Homo become Docens?’
The project focuses on how we learnt to think and teach like humans, exploring human cognitive evolution from multidisciplinary perspectives as well as looking at the evolution of technologies and their link to brain and socio-cultural developments.
“One of our aims has been to develop a holistic model of human cognitive evolution that considers ecology, biology, technology and sociology,” said Högberg. “And our work with geneticists has pushed back the genetic origins of Homo sapiens to about 300 000 years ago.”
“Becoming Homo sapiens represents a complex evolutionary history,” added Lombard. “300 000 years ago, Neanderthals thrived in Eurasia whilst Homo sapiens inhabited Africa. We then spread across the globe – by 70 000 years ago we were in India, 50 000 years ago in Australia and by 15 to 20 000 years ago we reached the Americas.”
“Although Neanderthal DNA is currently less than 1% in humans in Africa, 2% in Western Europe and 3% in America and Asia, the Neanderthals remain our closest relatives,” she added.
“Belonging to the Homo clade, we are part of a large, interesting group of beings all of whom made and used tools to a greater or lesser extent. Homo sapiens are distinguishable because we do certain things differently from other living creatures – we find solutions to new and old problems (both real and imagined); we have uniquely evolved bodies; we cannot survive without technology; and, we use social learning including teaching.”
“Many animals use social learning including observation, emulation and imitation,” added Högberg, “but only humans actively teach.”
Understanding how Homo sapiens learnt how to do certain things, who did what and what tools were used gives us insight into their cognitive development.
“The invention, production and use of different Stone Age techniques require different levels of causal and social reasoning,” said Högberg.
Striking or drilling
In their latest work the group has analysed fire-making techniques in terms of the causal, social and prospective reasoning required. The two techniques analysed – the strike-a-light or stone-percussion technique and the fire-drill or wood-friction technique – are still used by hunter-gatherer populations, with fire-drills the most used.
Gärdenfors explained that it’s possible to examine the cognitive aspects of the techniques and to unpack the types of reasoning involved. A socio-causal framework is used to grade the difficulty involved in the thinking process with higher levels of thinking including demonstrating, communicating abstract ideas, explaining relationships and narrating unique to Homo sapiens.
“Immediate and prospective planning depends on the executive functions in the pre-frontal cortex,” he explained. “This is the most developed part of the brain since we departed from primates. There is early evidence of prospective planning in hominins – for example, we know that 2.5 million years ago tools were transported over distances which gives us early traces of prospective planning.”
Although both fire-making techniques require thinking, preparation in terms of collecting tools, practice and learning, the fire-drill technique requires more complex cognitive processes in terms of knowledge about the materials needed, how they need to be prepared for their function, as well as the need for practice or rehearsal and co-operation with others.
Gärdenfors also pointed out that although the strike-and-light technique could have evolved accidentally, fire drilling required greater teaching and learning – “Making fire by wood friction was less easy to discover by accident.”
“Fire drilling requires more complex forms of cognition including demonstration, learning and co-operation which only occurred later in evolution,” he said.
Based on this cognitive interpretation as well as geographic distribution, archaeological and ethnographic data the group suggests that the strike-a-light technique – initially confined to Europe – may have been invented by Neanderthal populations who lived in cold, high-latitude regions in Europe. While fire-drill techniques, on the other hand, represent a rudimentary form of a symbiotic technology, which requires more extensive prospective and causal reasoning skills. Since about 100 000 years ago Homo sapiens in Africa had the capacity for high-level causal reasoning, similar to humans today – and it seems likely they invented the fire-drill technique.
Adapting to circumstance
The group pointed out that although dissimilarities in the brains and genomes of both species may connect to how higher-grade causal reasoning developed differently in Homo sapiens and Neanderthals, such differences do not imply that aspects of Neanderthal cognition were inferior to that of Homo sapiens, or vice versa. Instead, they show contextual adaptive variation.
“Although brain capacity and genes were different between Neanderthals and Homo sapiens,” said Lombard. “It seems clear that different capacities evolved to cope with different landscapes.”
The ability to make fire led to fitness advantages – making food less poisonous and easier to digest, widening the foraging range and quality with less energy expenditure and making it possible to survive in different climatic conditions. “Without heat it would be difficult to exist as a global species,” said Lombard.
Fire played an important role in sophisticated technological processes in southern Africa during the Middle Stone Age – including burning grass bedding to sanitise cave dwellings from 200 000 years ago, roasting plant foods from 170 000 years ago, heating rocks for knapping 160 000 years ago and roasting ochre to obtain better colour saturation by 100 000 years ago.
They also emphasised that these skills would have developed in multiple Homo sapiens societies independently, since they all had the necessary cognitive capacity by at least 100 000 years ago.
In discussion the group tackled aspects of the cognitive development and abilities of animals, human’s relationship to the natural world and if this work can increase our understanding of how humans learn today.
“Our focus is on humans and the things that humans can do,” said Gärdenfors. “That doesn’t mean we don’t recognise that animals have capacities humans don’t have.”
Lombard added: “We did this project to satisfy our curiosity about the evolution of the human mind, exploring how we became Homo sapiens.”
“From about 2.8 million years ago humans started to control nature,” said Högberg. “We need to fully understand the relationship between hominids and nature – it’s a theoretical challenge.”
The group’s work was presented in two previous seminars (see https://stias.ac.za/2019/11/archaeology-of-a-hungry-mind-fellows-seminar-by-marlize-lombard-anders-hogberg-and-peter-gardenfors/ and https://stias.ac.za/2018/12/how-we-learnt-to-think-like-humans/ and has resulted in many journal articles.
Michelle Galloway: Part-time media officer at STIAS
Photograph: Noloyiso Mtembu