“Our expanding knowledge of the hominin tree, in combination with the archaeological record of sub-Saharan Africa and the reconstruction of ancient human genomes change our understanding of human cognitive evolution. Previously, it was thought that the modern human mind appeared in Europe from about 50 000 years ago. There is now evidence that our ancestors who lived in southern Africa about 100 000 years ago thought in ways similar to us today,’ said Marlize Lombard of the Centre for Anthropological Research at the University of Johannesburg. “Another new development is that Homo naledi has been dated to between about 236 000 and 335 000 years ago, and shared the landscape with early Homo sapiens who eventually became the sole survivor. With the reconstruction of the full genome of a young boy buried 2000 years ago along the KwaZulu-Natal coast we were able to push back the origins of Homo sapiens in Africa to between about 350 000 and 260 000 years ago.”
Lombard, along with Anders Högberg of the Department of Cultural Sciences at Linnaeus University and Peter Gärdenfors of the Cognitive Science group at Lund University, was presenting a preliminary outline of the ideas and themes they will include in their book which aims to “explore the remarkable journey of a hungry mind, learning to think like a human”. The book will explore human cognitive evolution from a multi-disciplinary perspective. It will look at the evolution of technologies and their link to brain and socio-cultural developments.
“Humans are the only beings who continuously want to learn more. Our learning activities improve our ability to predict and control, which gives us a competitive edge as a species,” said Lombard.
“We want to understand how humans evolved to want to know more. How we became a curious species. How our minds became equipped to think like humans today,” she continued. “We also want to develop new theoretical thinking about how we developed from a socio-technical perspective. Our hypothesis is that our unique way of thinking evolved as a result of the interconnectivity between human society and technology. Society today is completely dependent on technology, which is an extension of our bodies and our collective minds. We therefore suggest a holistic, socio-technical perspective.”
“Technology and social development are interwoven,” said Högberg. “Technology changed society and society changed technology. Social behaviour and technological invention combined to create something new.”
Among the areas the group will investigate is the development of causal thinking and causal network thinking in humans embodied in things like co-operation and collaboration, the division of labour as well as teaching and learning.
“Humans and chimps share 98.8% of DNA,” said Gärdenfors, “yet the two species developed differently.”
“Humans advanced more in terms of society and technology. They began to think like humans – with more advanced causal thinking, planning for future goals and imagining what to do tomorrow; co-operation with others; understanding what others feel, want and know, and actively transferring knowledge. There are traces of teaching in early stone tools and humans are still the only species that actively teach.”
“The ability to transfer and interpret knowledge makes us substantially different from other species,” added Högberg.
Thinking like a woman
Another area which the group will investigate is how nutrient intake was linked to the development of the modern brain.
“To facilitate our perpetual appetite for knowledge, humans are born with large, energetically expensive brains. Modern human brains experience rapid growth – by the age of five years the child’s brain is 90% of adult size and weight. Our brains allow us to process information, remember, imagine, and create new things and new knowledge with increasing complexity,” said Lombard.
“Our ancestral mothers had to eat increasing quantities of specific foods in order for us to become who we are today,” she continued. “Healthy brains need omega 3 and 6 fatty acids, iron, iodine, copper and zinc.”
“There is strong evidence from hunter-gatherer populations that women gathered foods rich in such brain-selective nutrients including eggs, shell fish, and certain types of nuts, berries and insects. Currently the earliest evidence for shellfish foraging comes from the southern Cape at about 165 000 years ago, where we also find early evidence of modern human thinking.”
Cooking food also was a major development from both a nutritional and social aspect.
“We know that there was use of fire from about 300 000 years ago for both cooking and light,” said Gärdenfors. “Cooked food has higher calories and the process eliminates more toxins so that a broader range of food can be eaten.”
But cooking food also had other consequences. “It required expert knowledge and teaching, and led to the division of labour resulting in a more complex society involving collaboration and negotiation,” said Gärdenfors. “The sharing of food led people to gather and thereby giving more time for interaction and language development.”
The use of tools played a substantial role in human development. The use of sharp cutting tools – stone flakes – meant that meat could be cut from cadavers and transported. Again facilitating co-ordination of working tasks as well as increased co-operation.
“There was a co-evolution of tools and causal thinking,” said Gärdenfors, “with tools helping to shape causal thinking. We developed advanced tools and techniques that help us feed our hungry minds and control our environments.”
“The oldest evidence of stone-tool use was 3.39 million years ago in Ethiopia and the oldest flake knapping thus far has been recorded at 3.3 million years ago in Kenya, so that we may accept the technology for stone cutting was in general use by about 3 million years ago. The use of sharp-edged stone flakes literally changed the world,” said Högberg. “Not only did they require the development of techniques and teaching to make them but they meant that humans did not need to eat directly from carcasses, they did not have to eat all at once, and food could be moved to safer locations. This meant that tasks needed to be co-ordinated and people needed to trust others to do assigned tasks.”
“Technology therefore changed people’s behaviour. There was a new shared culture of behaviour based on a technological breakthrough.”
“All of this indicates that cultural, technical and social interaction was there from much earlier than we thought – it is who we are,” said Högberg.
“We believe there is evidence of the evolution of the socio-technical mind which is older than the oldest fossil of the human lineage found to date,” he added.
“We hope this work will add to the theoretical knowledge of how we as humans want to know more. And of how we have been nourishing our minds over several million years to become the only mammal to successfully inhabit and control most of the global landmass and to explore the universe beyond,” said Gärdenfors.