|If only this skull |
could still talk
When did the conditions arise to allow more rapid evolution of information (technical, such as for tools but also hunting & food gathering & processing techniques, cultural info etc.) ? After all, we possess much the same genes as our ancestors did 60,000 years ago, but our world is significantly different due to evolution of information.Dediu and Levinson's paper looks in detail at the relevant literature about the discover of human fossils, evidence for tool making , etc. while my approach starts in a very different way by looking at how a network of neurons might evolve into an intelligent brain. The immediately relevant parts of my model are as follows:
- The starting point is evolutionary economics. An animal has to spend time and energy (a) gathering and eating food, (b) breeding, (c) escaping predators, (d) growing a brain and learning how to use it.
- Large brains need a significant amount of energy to work compared with other organs so have to work hard to justify their existance.
- Because everything an animal’s brain learns is lost when the animal dies, no species will evolve a brain bigger than it can use in a lifetime, because the time and energy used filling an over-sized brain with information that is never used could be better spent eating, breeding and escaping.
- Trial and error learning is time consuming (basically it involves doing something repeatedly until it is routinely done correctly) so this puts an effective limit on brain size and intelligence. There are various strategies but primates (and some other mammals) have bigger and more effective brains than average because they evolved with a long life span, and the parents spend a lot of time supervising a comparatively small number of infants. However the “cap” on how much can be learnt economically in a lifetime still limits the size of the brain.
- Humans (and even some of the other apes) tend to differ from animals because they frequently use tools.
- In evolutionary terms inventing a tool means nothing unless each generation can pass the tool making skills to the next generation. Tools which improve survival alter the evolutionary economics and so tool making could justify the development of a slightly bigger brain.
- About 5 million years simple tool making by early hominins probably helped them survive and they started to evolve slightly bigger brains. And with a slightly bigger brain they could make slightly better tools. The process was limited by the speed of genetic evolution and was very slow – and it is therefore not surprising that in the Old Stone Age hand axes were made in the same way for about a million years.
- It is reasonable to assume that family groups had some form of language for communicating with other members of the group. This can clearly be seen today in family groups of species such as bonobos, wolves, elephants and orcas.
- Say 500,000 years ago it is reasonable to assume that some kinds of meaningful communications could take place between closely related hominin groups – such as the Neanderthals, Denisovans and Sapiens forebears. This can happen in other species and recently a solitary dolphin has been observed to learn "porpoise" - See "Solitary Dolphin clicks with Porpoise Companions in the Clyde."
- Now language is a tool, and at some stage it started to be used as a tool to teach tool-making in a way that is more efficient than trial and error. Evolutionary economics means that it is now possible, with the same brain, to learn about more tools – or to learn to build better tools.
- But language is itself a tool – so if language makes it possible to build better tools it makes it possible to build a better language – which in turn makes it possible to teach how to make even better tools. (Still happens. Old fogeys like me tend to grumble because the younger generation is always changing the language!)
- What we have is a significant tipping point. Generation by generation language becomes slightly more effective, so that we can make better tools and a better language so in the next generation things get even better ... and better ... In fact what we have is what is an auto-catalysed reaction which has led to an explosive growth in our tool-making capacity in modern times with no need to an increase in brain size.
- In fact there are several possible tipping points, each of which accelerates the process. Language allows information to be passed from generation to generation so that everything a brain has learnt in a lifetime is not lost when the brain dies. Tools such as writing and now computers allows the storage of vast quantities of information. Language also makes it easier to use other humans as tools so we now use other humans to grow and deliver our food needs, build shelters, help us travel large distances, and allow us to live longer.