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The fourth of the four half-hour broadcasts is dominated by evolutionary
psychology more than physiology, diet, activity patterns and simple
natural selection.

Again, climate change is invoked to explain further steps in human
evolution.  This time it is the ice age 150,000 to 110,000 years ago which
affected Homo heidelbergensis quite differently in their two geographic
centres.

But first there is a scene from Europe 500,000 years ago: H.
heidelbergensis in Europe attacking an Irish stag whose huge swinging
antlers concuss one of the hunters who eventually dies.  For Winston, the
key lesson from this scene is that the body of the dead hunter is
abandoned.  The absence of respect for the corpse shows that
heidelbergensis were not fully human.

The hunters were extraordinarily brave by our standards - most trips to
the butcher's was a matter of life and death.  The book tells us that some
of the surviving skeletons show signs of bone disease, infection from
broken teeth and malnourishment, but they were characteristically thick-
boned and muscular, massively built and fearsomely strong.  Their hunts
required agility, determination and ability to throw spears and use
shorter stabbing spears for the kill.

In Eurasia the ice age was freezing erstwhile pastures and reducing the
amount of land available for grazing animals (for human nutrition) and
human habitation.  Survival was achieved by abandonment of the most
inhospitable lands but also through adaptation to the encroaching cold.
Those who survived when the temperature fell to minus 30 degrees had
stocky compact bodies, less than 165cm in height (about 15cm less than
heidelbergensis), relatively short limbs to keep in valuable heat.  They
were the neanderthals and their toughness is illustrated in a memorable
sequence where a hunter tumbles down a steep slope and dislocates his
finger.  He quickly snaps it back into place!  Life was tough at the
frozen margin.  The book tells us that the floor of their living area was
filthy.  It also explains how the cold > scarce food > small group size >
strong relationships.

The images of neanderthals surprised me as I have been brought up with a
picture in my mind which I now realize was a relict of the Victorian
controversy after Darwin - a controversy in which the depiction of all
predecessors of H. sapiens as simian thugs served one side (the losing
side!) of the debate.  An unforgettable and useful corrective.

Meanwhile, back in Africa, the ice age has not lowered temperatures in the
tropics; its effect is primarily drought, caused by the locking up of
water in the huge polar ice caps.  While the neanderthals were surviving
in the freezing north, the other heidelbergensis descendants were dying,
their numbers reduced to possibly a few thousands.  Only the very smartest
and most resilient made it through this natural selection bottleneck.
Winston illustrates the force driving Homo sapiens' survival was their
imagination and foresight and how these qualities were what brought them
through the 1,000 generation-long drought.

There is a brief reference to competition between sapiens and
neaderthalensis in which Winston makes the point that in such a
competition, the loser doesn't necessarily have to fail, just succeed a
little less often.

The show ends with Cro-Magnon cave paintings: the paintings depicted
something that existed in the imagination of the artists: 'they lived not
only in caves, but in an imagined world of their own minds'.

I found this fourth episode stimulating but not as informative as the
earlier three programs.  Winston does a first rate job at presenting
humans as just another species, struggling to survive.  I would have
chosen different scenarios to illustrate what marks Homo sapiens sapiens
from its predecessors, so the program put me in a position of having to
apply constructive criticism.  I see that Winston's recent book 'Human
Instinct' has been favourably reviewed and that reflects the development
of his own thoughts.

These popular programs can do a lot to help others come to grips with the
rationale for Evolutionary Fitness.  Let your friends know when it is
screening in your area.

Keith

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