This site is not maintained. Click here for the new website of Richard Dawkins.


← Quest for Fire Began Earlier Than Thought

Helga Vieirch's Avatar Jump to comment 9 by Helga Vieirch

What Michael Chazan et. al. are suggesting is that the use of fire was associated with the species Homo erectus from quite an early stage; which is extremely suggestive, since it is this species that showed the first really significant increase in brain volume.

Homo erectus was -probably- the first human species that migrated out of Africa, and it was successful in adapting to extreme variations in environment and climate all over Eurasia. This new evidence that this species used fire before leaving Africa is significant, since use of fire has long been associated with this species elsewhere, but evidence that it dates from the period prior to the migration out of Africa has been fairly tenuous until now.

Wrangham's cooking hypothesis is just the tip of the iceberg as far as the analytical implications of fire control and use among humans is concerned. This includes its significance in understanding our cognitive evolution.

You have to remember that hunter-gatherers use fire not just for cooking, heat, and defence, but also for environmental management. Controlled burning to keep ecosystems in a mosaic of stages of secondary growth was used by humans on every continent to increase ecosystem diversity and biomass, and to manage it in ways conducive to human food preferences.

A nontrivial degree of mental sophistication is implied. Just imagine the mind that can integrate knowledge of

a) variation of ecological zones and species diversity within each,

b) large data bases about plant succession communities over many decades,

c) together with information on animal behaviour and reproduction, as well as

d) detailed knowledge of both long and short term animal and plant response to burning at varying times of year, (for instance, how many people even today still know that plant growth in a grassland will be stimulated by a fire, and so show a flush of green even in the absence of rain at the end of a dry season, thus attracting grading animals?).

The kind of mind that can do this could certainly figure out how to hit two specific kinds of stones together to spark a fire (they were making stone tools anyway, so this would have been blindingly obvious to them), and even how to create enough heat through friction applied to dry sticks to start a fire (something every 10 year old child knows how to do among the hunter-gatherers I lived with).

The thing that gets my imagination fired up, (smiles) however, is the degree to which the use and control of fire was one of the critical technologies that set up new and fairly severe selection pressures, pressures which served to drive up brain size in our ancestors. Conceivably it also drove the evolution of a bigger and more effective pre-frontal cortex, so that strategic thinking and long term planning became essential if a human group was to leave as many survivors as groups that were also learning to manage their environments. Mere use of fire for cooking and keeping warm shrinks in significance compared to the use of fire to enhance ecosystem productivity.

It is a burning question. One might even say, incendiary!

Sat, 07 Apr 2012 21:25:32 UTC | #932947