Old brains yield their secrets

Professor Lyn Wadley, Wits. (Supplied)

Professor Lyn Wadley, Wits. (Supplied)

There is a widespread misconception that early people were primitive and thought differently from us. But how can one know about ways of thinking thousands of years ago? Archaeological information is usually gleaned from objects whereas the human brain isn’t preserved in fossils. 

However, the innovative research done by archaeologist Professor Lyn Wadley is giving us some answers. 

“Archaeologists can access the minds of people from the past using proxies for brain power,” explains Wadley. She replicated everyday Stone Age tasks, showing that they involve complex cognition. 

“Certain technologies, for example making compound adhesives, hafting tools, heat treating rocks and setting snares, cannot be performed without modern cognitive attributes. These include analogy, multi-tasking, abstract thought, and planning for action that is out-of-sight,” she says.

Wadley notes that since the tasks first appeared between 160 000 and 70 000 years ago, we know that people living then — the first anatomically modern people who lived in South Africa — had minds like ours. Her methods to reach this conclusion are a global first.

Using National Research Foundation (NRF) grants, Wadley excavated Rose Cottage Cave in the Free State, and later Sibudu Cave, KwaZulu-Natal. These were long term and large excavations, producing artefacts ranging in age from 100000 to 25000 years. 

At both sites, there were stone tools with visible traces of red ochre and plant gum adhesives. This initial excavated material was analysed microscopically at the University of the Witwatersrand (Wits). Compound adhesives were discovered and it was revealed that different adhesive recipes were used. 

“Compound adhesive manufacture requires a number of complex mental attributes, not least multi-tasking because fire temperatures, sticky gum and other hafting requisites must be manipulated simultaneously,” says Wadley. 

The path was then set to explore other Stone Age technologies, such as snares, for additional mental attributes. Bones and botanical remains were identified with the help of faunal experts and archaeobotanists.

It was a countrywide and international collaboration as specialists were brought to Wits from France, the US, Canada and Australia. “Where this wasn’t possible, the archaeologically-recovered items were temporarily exported for analysis,” she says.

The hypothesis testing involved experiments and replications using ingredients and methods from the past, as far back as 100 000 years ago. 

“The end products of the experiments required collaborations with scientists able to perform tests to support or refute hypotheses about past behaviour,” says Wadley.

Beyond proxies for complex cognition, the multidisciplinary research stemming from the artefacts is giving us information about environmental conditions, changing environments, technology, hunting methods, spatial patterns, pyrotechnology and the use of plant materials. 

The 77 000 year old Sibudu plant bedding, an unanticipated discovery, is the earliest occurrence of preserved plant bedding. It is 50 000 years older than previous examples. 

Wadley is a Stone Age archaeologist and has been excavating sites dating from 100000 to 3000 years ago. At 66, she works from Wits, has a PhD in Archaeology and an A rating by the NRF (the only archaeologist with this accolade). 

She is passionate about education within the academic environment. With South Africa’s rich archaeology, it is startling that only three universities have archaeology departments. 

Culture and national pride aside, the possibilities for heritage tourism alone are immense. “Our incredible heritage cuts across race, age and every sector of society. These people were the ancestors of all of us,” says Wadley.