Research team from the Senckenberg Centre for Human Evolution and Palaeoenvironment at the University of Tübingen combines experimental archaeology with the recording of brain waves

Tübingen, November 19, 2024 – Changes in the cerebrum may have enabled early humans to use tools with precision, thus initiating the biocultural evolution that led to the human species we know today. This was the finding of an experimental study conducted by a research team led by Dr Alexandros Karakostis from the Institute of Natural History Archaeology and the Senckenberg Centre for Human Evolution and Palaeoenvironment at the University of Tübingen. The team used a new approach: they recorded the brain waves of test subjects using electroencephalography while they used stone tools similar to those used by early humans. The results of the study were published in the journal Scientific Reports.

‘Technological innovations were crucial for the evolution of us humans,’ says Alexandros Karakostis. ‘We are interested in what cognitive developments are necessary for the use of relatively simple stone tools – and where humans and other primates differ in their abilities.’ In the experiment, the researchers investigated two different types of tool use: Firstly, the participants were asked to crack nuts using a stone as a hammer, and secondly, they were asked to cut patterns in leather using sharp-edged stone chisels. ‘We made the stone tools as exact imitations of early archaeological finds,‘ explains Simona Affinito, PhD student in Karakostis’ research group and lead author of the study. While nut-cracking with stones has also been observed in various animals such as monkeys and apes, the use of stone chisels for cutting is only known from humans.

Different cognitive prerequisites

During their efforts to fulfil the tasks, the activity patterns in the brains of the test subjects were recorded in parallel in an electroencephalogram (EEG). ‘As a result, we were able to identify clearly distinguishable activity patterns in the brain during the different behaviours and stages of tool use, similar to those of early humans,’ explains Affinito. ‘The activity in the parietal and frontal lobes of the cerebrum, especially in the planning phase, shows how important these brain regions are in advance for the execution of motor movements.’

Although both tasks required cognitive effort, Karakostis reports that significantly more extensive brain activity occurred when using the cutting tools than when cracking nuts: ‘These differences implicitly emphasise the cognitive performance required for precision tasks. They may have enabled early humans to appropriate and shape their environment in a way that was not previously possible.’ The new study lays the foundation for further research into the cognitive prerequisites for human technological progress.


Original publication:

Simona Affinito, Brienna Eteson, Lourdes Tamayo Cáceres, Elena Theresa Moos, Fotios Alexandros Karakostis: Exploring the cognitive underpinnings of early hominin stone tool use through an experimental EEG approach. Scientific Reports, (https://doi.org/10.1038/s41598-024-77452-0)

ImageSource Affinito et al., 2024, Brienna Eteson
Ein Forscher demonstriert, welche Aufgaben die Probandinnen und Probanden im Experiment ausführen sollten: links beim Nussknacken und rechts beim Schneiden von Leder mithilfe von Steinwerkzeugen.