One recent writer, David Horrobin (2002), suggests that the Great Leap Forward could have resulted from the emergence of a set of genes that created schizophrenia. Schizophrenia is a devastating illness which has the most unusual side effect of producing high levels of creativity amongst most first, second and third level relatives of those unfortunate enough to be suffering from full blown schizophrenia. Schizophrenia may be, suggests Horrobin, the yeast that turned a relatively dull species into the creative problem solvers that humans have subsequently become. Whether this was actually the reason, or one of several partial reasons, for the sudden mushrooming of creativity, we do not as yet know. But we do know of its dramatic implications. “Calling it a revolution is no exaggeration” explains Stephen Pinker (1997), “All other hominids came out of the Comic Strip B.C., but the Upper Palaeolithic people were the Flintstones. They were us. Ingenuity was the invention.” David Horrobin went on to put it even more strongly. “Instead of being uniform we became diverse; instead of being relatively stable, we created constant change; instead of being egalitarian, we began more and more to differentiate from the rest with those with special skills in technology, art, religion, and psychopathic leadership.”

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The new technologies used for DNA analysis in the last ten to fifteen years have enabled scientists to peer much further back into deep history and see with some clarity what probably happened. Before the Great Leap Forward the number of humans at any one time was probably very small –for long periods Homo sapiens might have numbered less than ten thousand people. Within the genes of those few people were encapsulated all the predispositions and adaptations accumulated over the nearly seven million years of human history. These are the very same mental processes that you are using as you try to comprehend what all these ideas mean. In all probability Howard Gardner’s Multiple Intelligences, namely – linguistic and mathematical thinking, spatial analysis, musical ability, kinesthetic (touch), interpersonal and intrapersonal skills and spiritual thought – all emerged in Africa about the time of the Great Leap Forward. Certainly these varied forms of intelligence were all there amongst the Hadza, and were expressed in the art to be seen on the cave walls of the Kalahari put there maybe forty thousand years ago by the Bushmen. In mental and anatomical terms those people had to have been very much like ourselves.

The savannah has left a big impression on us, even in 2005. Psychologists have carried out a number of controlled experiments on children and adults to discover what environments we prefer to live in. The results are interesting. Using photographs of varying kinds of landscape, each with no man-made artifacts to be seen, and no other people, it has been found that almost all children under the age of eight – in whatever culture or region they live – select the savannah as the preferred living space; older people have some additional preference for forests as well, but no one opts for the desert. In his design for English country estates the eighteenth century architect Capability Brown was playing to a deep, evolutionary conditioned sense of what is safe and congenial – we like open vistas, with clumps of trees, some water and a sense that we appear safe.

These are differences in the way men and women perceive certain phenomena – in what they actually see, and in how they relate to the environment and each other. These are essentially differences on a spectrum, rather than being exclusively male / female characteristics. Over the course of millennia the distinctions may be becoming less precise, but to many researchers and intuitive observers they are very real.

Men evolved a focus to their vision that more easily fixes on, and holds to, objects at a distance whereas women have comparatively poor long-distance vision but remarkable peripheral vision – the ability to see things all around them. It is still that way now, even though few men exercise such vision in the hut, and women’s peripheral vision is more often employed finding those things that men have lost, rather than searching for berries or edible roots. While it is obvious that many of our physical features (the coccyx as the last vertebra of the monkey’s tail, or an appendix to creatures no longer eating a surfeit of grass) are redundant, we humans are slow to see in ourselves processes and features that evolved in different times, for different purposes. Being only slightly flippant, to remind a serious reader of this Paper of the delicious taste of a Raspberry Pavlova, or of a dark chocolate ice cream, is to activate a sense in their taste buds that will send each of us energetically searching for such foods – even though we don’t need them. Only by such a compelling sense of potential “taste satisfaction” did our ancestors go that extra mile in search of rare sugars, or fats, or salt…

At some stage in the distant past the menopause began to occur earlier in human females than it does in other primates. Scientists have conjectured that this has to do with the vulnerability of very young children, and the enormous demands this places on mothers. Whereas most primate females remain fertile to within a period of time just long enough to wean a baby (in human terms that would be only three or so years) humans experience the menopause two-thirds of the way through life, effectively giving grandmothers many extra years to help their daughters raise the next generation.

In this, as in so many other instances, the more we discover about our senses and susceptibilities the more deep seated we find these to be.