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We humans with our likes and dislikes, our senses and our sensibilities, didn’t fall ready-made from the sky; nor were we born with minds and bodies that bear no imprint of the history of our species.  The way we interact today at a social and cultural level is in many ways the result of organisational skills developed by our distant ancestors out on the savannah of Africaover the course of millions of years.1


Only in the past twenty or so years have techniques been developed in genetics that now help explain why we behave as we do.  Mutations which in any one generation lead to behaviours more likely to enhance the individual’s chances to survive and reproduce, are the ones which are most likely to be transmitted into the next generation.  Mutations can be either beneficial or harmful, and less than ten percent of these will be passed on to affect the anatomy or the functionality of the organism.  Over time such behaviours and thought processes enter the human genome and are passed on to us hundreds and maybe thousands of generations later as preferred ways of doing things.


Show a baby a snake and imply that it is dangerous, and this activates a deep-seated, evolutionary warning system which means that, for ever thereafter, the child will always be extremely cautious in dealing with snakes2.  All over the world youngsters master a breath-taking array of competences with very little, if any, instruction because of such evolutionary predispositions.  They understand space, and rarely fall off a table top; they quickly associate the colour red with fire, and potential danger, and green with grass and safety.  Babies distinguish facial expressions from the first weeks of life; they bond with smiles, and retreat from glares.  At four months a baby will turn to a man if he hears a male voice, and correctly turn to a woman if the voice is female.  By six months babies have an instinctive sense of number.  By the age of five children have formed powerful theories of how the world works, and how their minds function.


All these predispositions mean that the brain is essentially an ‘intelligent system’.  This enables the youngest child to learn very fast ─ not simply through trial and error, but by linking a single experience to an inherited predisposition, which then activates a powerful, and often permanent, neural network.  These early intuitive theories of cause and effect ─ what follows from what ─ help youngsters to successfully negotiate their immediate environment.  Such naïve theories have remarkable staying power for, as the child grows and experiences a wider and more complex world where events are nothing like so obvious, so black or white, the unreflective child is remarkably stubborn in upgrading his mental assumptions.  To a child it’s easy to make the mistake that a ton of lead is heavier than a ton of feathers yet, years later as an adult, the unreflective child may well make the same mistake3.


Sex and survival are the most basic of human instincts, but contrary to public perception we humans are moderately careful over our choice of a mate.  It appears that we mate intelligently, and largely according to genetic suitability.  It seems that it all comes down to a sense of smell, and the pleasure of kissing.  Analysing the logs kept by volunteers of who they most enjoyed kissing, and who they didn’t, a very strong correlation was found showing that your preferred ‘kissing partner’ had chromosomes sufficiently different to your own that if you mated you would produce a healthy child.  The one you didn’t like had chromosomes so similar to your own that any offspring would likely to be unhealthy.  In the heat of a passionate exchange how do you work that out!  ‘You’ don’t, but your tongue is busy analysing the saliva of the person you are kissing and sends an appropriate message to the brain… ‘keep going, this is a good one!’ or ‘stop right away!’  Smell ─ especially the smell of stale sweat — is another powerful indication of mating suitability!  We sniff out suitable mates, and are repelled by those that it would not be good for us to mate with.


Through our eyes, ears, noses and tongues, we are equipped with an exquisite array of techniques to help us behave in intelligent ways.  We are both empowered by the experiences of our ancestors ─ but we are constrained as well.  Driven to live in ways that are utterly uncongenial to our inherited traits and instincts simply drives people mad.


Thesis 4:     24th August 2006