Catching Fire: How Cooking Made Us Human by Richard Wrangham
I learnt about the rat food experiment in Catching Fire: How Cooking Made Us Human by Richard Wrangham. It is a short book - barely 200 pages - and yet it is the sort of book that you end up talking about for days - and will probably think about for a lot longer. Apart from the central idea (that the discovery of how to make and control fire shaped the latter years of our human evolution) there are lots of interesting snippets which are ideal for discussion over, say, dinner. I learnt why chocolate tastes so good, for instance, why women like to go shopping while men go straight for the kill, and humans have the largest primate brains.
After looking at the evidence that all humans need to cook - an exclusively raw diet tends to lead to an energy shortfall and infertility - Richard Wrangham then goes on to examine the way the human body seems to be adapted to a cooked diet. Our teeth, jaw and digestive system are much smaller than other similarly sized primates. A smaller digestive system requires less energy to operate - energy that could be diverted to the brain, which in turn could become larger.... All by evolution of course.
Until two million years ago the earth seems to have been a culinary-free planet. After that came only three periods of rapid evolutionary change: Homo erectus evolved 1.8 million years ago, Homo heidelbergensis 800,000 years ago and then, finally, Homo sapiens came along 200,000 years ago. Richard Wrangham explains that since the last two the changes are small they are not likely to correspond to change in diet, and so it is most likely that the first tentative steps into barbecue culture came with the habilines who evolved into Homo erectus. Homo erectus had left the relative safety of a nocturnal nest in the trees for a campsite on the ground next to the fire, consequently he would have been able to lose his insulating layer of fur which in turn means he would be able to travel long distances, quickly, in the warm part of the day. Huddling around a fire would also have selected for calmer individuals more able to tolerate, and be tolerated by, others. This could have led to increased social interaction and eventually language, which in turn could have led to male-female bonding.
The division of labour between men and women is ubiquitous across all human societies. Women gather and process the vegetable and small-animal staples while men go after the more desirable meat and honey. They then share the food. Women share with close relatives, men share out the spoils of a hunt amongst other men who in turn share their portion with their close relatives. This pattern of behaviour is unique to humans. A shared male-female bond ensures the male has a meal after a day's hunting, and the female cook is protected from other males stealing her cooked food.
This week I read a very interesting article on the BBC News website by James Friel posing the question 'Why are couples so mean to single people?' According to Catching Fire the singletons in human society are pitied because they do not have a partner to do their cooking for them. The singleton hunters come home hungry, and since they have no mate their only option is to beg or steal from someone else's pot. Sex has little to do with it - promiscuous behaviour is tolerated more than an empty hearth. It turns out that the old adage is right: the way to a man's heart is through the stomach - as long as what is offered to that stomach is well-cooked and ready on time.
Thanks to Profile Books for my copy - and my apologies for taking so long to getting round to reading it!