p. 31-35 Arguably the most important episode in hominin evolution occurred in East Africa around 1.9-1.8 million years ago, when hominin diversity reached its highest level, with species of the Australopithecus, Paranthropus and Homo genera all coexisting alongside each other. At the same time, the most important leap forward in human evolution appears to have occurred with the appearance of Homo erectus… which is associated with sweeping changes in brain size, life history and body size and shape. It is also the first species of hominin we know of that migrated out of the Rift Valley and into Eurasia. .. African specimens, and sometimes those from Dmanisi in Georgia, are described as Homo egaster… ‘workman’ in Greek and was used as the African specimens have all been found with stone tools… Its brain size was about two thirds of moderns humans’” .. the first hominin to have a delayed growth period during childhood… had many key adaptations required for long-distance running. More recently it has also been shown that the shape of the shoulder in H. erectus would have allowed the throwing of projectiles. H. erectus also produced a much more sophisticated set of stone tools than previous hominids, referred to as Acheulean tools. It has also been argued that H. erectus had learnt to control fire because … it is difficult to see how they could have maintained such a large, energy-intensive brain with such a small gut without access to cooked meat. [although] by by slicing meat and pounding vegetables and nuts they were able to improve the ability to chew by at least 40%. There was also a decrease in the masticatory force needed, which corresponds to the observed reduction in jaw size and strength. .. The control of fire and regular cooking was , as Rick Potts at the Smithsonian suggests, essential for the next significant increase in brain size between 600,000 and 700,000 years ago with the appearance of H. heidelbergensis and then Neanderthals and H. sapiens.”
p.152 “social groups are complex, with high stress levels, because the rewards are high. Hence, our huge brain is developed to keep track of rapidly changing relationships. My undergraduates come to university thinking they are extremely smart as they can do differential equations and understand the use of split infinitives. But I point out to them that almost anyone walking down the street has the capacity to hold the moral and ethical dilemmas of at least five soap operas in their head at any one time, and that is why we have a huge complex brain. … however many scientists think the human brain operates like a computer. However, Robert Epstein, a psychologist at he American Institute for Behavioural Research and Technology, says this is just shoddy thinking and is holding back our understanding of the human brain. He points out that humans start with senses, reflexes and learning mechanisms. What we do not start with and never have are: information, data, rules, software, knowledge, lexicons, representations, algorithms, programmes, models, memories, images, processors, subroutines, encoders, decoders, symbols or buffers – which are key design elements that allow digital computers to behave somewhat intelligently. .. “We are organisms, not computers. Get over it.”
p. 160 “One of the most interesting things about the complicated childbirth in later Homo is that mothers would have required help, called allomatermal care. So individual females who were more socially adept would get more help, and they and their infants were more likely to survive.”
p. 169 “after H sapiens evolved in Africa and spread out into Europe and Asia they seemed to do nothing special for the first 150,000 years … increasing records of symbolic behaviour, starting with microliths, shell engravings, ochre and shell beads. But it is not until about 50,000 years ago that consistent signs of creative thinking emerge – beautiful cave paintings in Spain, France and Indonesia, beautifully carved Venus figurines in German, the Czech Republic, Austria, France and Siberia, and shell beads in North Africa and Europe. Around the same time, modern humans appear that were more slender than their earlier ancestors, had had less hair and smaller, less robust skulls, they look basically like us .. the brow ridge became significantly less prominent and male facial shape became more similar to that of females … They think this must have been due to lower levels of testosterone… a second line of evidence comes from studying the relative finger lengths of our ancestors. There seems to be a strong correlation between the ratio of the length of the second and fourth fingers to aggression, promiscuity and competitiveness in humans … seems to reflect prenatal testosterone levels. A finger with a shorter index finger than the ring finger suggests higher testosterone levels. .. less likely to be reactively or spontaneously violent, and this would have greatly enhanced social tolerance. .. in early humans the smartest or the most creative people may have come to the forefront.”
p. 171 “violence within or between groups is almost non-existent among bonobos. As both these species have a common ancestor there must have been strong selection going on to feminize the bonobos. Hare and his colleagues suggest a process of self-domestication, whereby violent individuals are punished and prevented from reproducing.. on the eastern side of the Congo, where the chimps live, they are in direct competition with gorillas, whereas the bonobos on the western side have no competition.
p. 172 “it was only with the rise of agriculture that an imbalance between the sexes re-emerged, as individual men were suddenly able to concentrate enough resources to maintain several wives and many children. Indeed, the Robert Ciceri-led study does show slightly more masculine facial shapes emerging in recent agriculturalists relative to early humans and recent human foragers.”
About