Our ancestors have been making stone tools for millions of years. They were probably using organic tools for millions more.
This sort of technology helped them take over the world. Armed with Oldowan and Acheulean tools, Homo erectus spread across the Old World.
But what prompted them to make these tools in the first place? Was there some great pioneer? Some particularly clever innovator? A Steve Jobs of the Palaeolithic?
Or does the actual answer lie in the genes of our ancestors?
Testing chimps
Culture is the ability to learn technology and behaviour from one another. This "saves the progress" of civilisation; ensuring each generation doesn't have to start from scratch.
Ultimately, culture means that innovations can accumulate over time. Each generation builds on the inventions of the previous. As such, culture is kind of a big deal. And chimps have it ( further proof of their imminent, evil attempt at world domination). For years, scientists had knew that different chimpy groups made different sets of chimpy tools. But whether or not this counted as culture was hotly debated.
A series of rigorous tests finally confirmed that the variation in chimp technology really was a case of culture. They did this by ruling out all the alternatives. For example, compared the culture of chimps living in similar environments; showing that the variation wasn't just a response to the environment. The scientists even compared the genes of the chimps to show that the variation in technology didn't have a genetic basis.
All of this showed that chimps really do have culture. But crucially, we haven't demonstrated this in our ancestors.
Homo erectus genes
Around 1.8 million years ago our ancestors began making a set of fancy tools called " handaxes". They're pretty cool. So cool that Homo erectus kept making them for a million years.
Could this be because the drive to make handaxes was actually in there genes? That's what a new paper suggest. It notes that the alternatives explanations (like genetics) for the the transmission of these tools hasn't been ruled out. We only accepted chimp culture because they were ruled out, so why should we accept it for Homo erectus if they haven't?
Environment can be ruled out as handaxes don't change much, despite the fact that the environments their manufacturers lived in did. The tools made by Homo erectus in France are recognisably the same as those from South Africa. This leaves two alternatives for the transmission of handaxes from one generation to the next: culture or genetics.
Genes can't really be ruled at this time since we don't have any genetic material from Homo erectus. They were making these handaxes more than a million years ago. By contrast, the oldest DNA we've managed to recover from our hominin family is only ~400,000 years old.
There may be some alternative ways to test for the influence of genetics. For example, you could compare the tools made by two nearby groups of Homo erectus. Such groups would likely be interbreeding, so their toolkit should be identical if genes are responsible for it.
Arguments for genes
As well as pointing out that genetics hasn't been ruled out, the authors of this new paper also note there is some positive reasons to think that genetics may be involved.
The key piece of evidence is the consistency of handaxes. They remain very similar for a very long period of time. On top of that, there isn't as much variation as would be expected between the tools. The fact that people don't learn from each other perfectly means that there should be slight differences between how people make tools. Yet this degree of variation isn't present in the tools.
Personally though, I think this is mostly bollocks.
For starters, there's the fact that these handaxes are a minority of the tools made by these people. Whilst there are some exceptional sites, many sites from this period don't even have any handaxes. Of those that do, they typically represent <20% of the artefacts recovered. Clearly, they may not be the most representative way to study our ancestors. On top of that there are many alternative explanations for why handaxes remained unchanged (like people rectifying the mistakes they may have picked up when they initially learnt how to make them).
Nevertheless, I do think the authors raise some very interesting points about the fact that genetics and tool use hasn't even been considered; let alone ruled out. I think it's very likely that there are some key genes linked to our ability to make tools. Maybe even specific tools. I'm just very doubtful you could find a handaxe in the genome.
So don't let my casual use of profanity fool you. I'm very interest in seeing where this goes.
tl;dr
Genes could have influenced tool making, but it hasn't been shown. One way or the other.
References
Corbey, R., Jagich, A., Vaesen, K. and Collard, M., 2016. The acheulean handaxe: More like a bird's song than a beatles' tune?. Evolutionary Anthropology: Issues, News, and Reviews, 25(1), pp.6-19.
Santonja, M. and Villa, P., 2006. The Acheulian of Western Europe. Axe Age Acheulian Tool-making from Quarry to Discard Approaches to Anthropological Archaeology. London: Equinox, pp.429-478.
Whiten, A., Goodall, J., McGrew, W. C., Nishida, T., Reynolds, V., Sugiyama, Y., ... & Boesch, C. (1999). Cultures in chimpanzees. Nature, 399(6737), 682-685.
