The reality of what it means to be human.

I love Horizon the occasional BBC programme, it is often invaluable when looking at aspects of reality. Just last month they did a particularly interesting programme called, What makes us human? It was hosted by Prof Alice Roberts who was both pregnant herself and an anatomist.

It started with assertion that we share 99% of our DNA with Apes, but we look and act totally differently. It then asked -what it is that makes us human?

Given Prof Roberts dual interests, it was not surprising that they looked at the physical aspects of both species to find out the real differences. In particular they looked at the differences between human and Apes and their babies.

It was a very interesting progression;

  • Although Apes and humans have the same bone structure, they differ in the shape and proportion of these bones.
  • The main difference is that humans walk upright and have larger heads.
  • Ape babies ( and indeed most animal babies) are born with more of the skills that they need to survive than human babies, who are helpless when they arrive. In animal terms they are born prematurely.
  • Human childbirth is made very difficult because of the large head of our babies, and the compromises made in our design, cause by a pelvic structure that is needed to make walking on two legs possible and efficient.
  • This was called the obstrective dilemma, but further research has indicated that this is not the whole story. New studies indicate that the complex human baby needs more energy than the mother is capable of providing via the placenta beyond a certain stage of development. The baby has to be born and complete development outside the womb.
  • Because the baby is born helpless it learns from those nurturing it. If it grew up isolated without stimulation it would probably have the same intelligence as a chimp.
  • The nurturing and stimulation and teaching increases those connections which increases flexibility in the brain. We benefit from the wisdom of previous generations and move forward. Whilst the more competent ape babies just play in the jungle. Humans have more behaviour that is learned and less preprogrammed from the beginning. This gives us amazing flexibility.
  • We also co-operate with each other, sometimes altruistically, and exchange ideas which apes do not. They will work together only if it benefits both.
  • Human brains have 40% more connections between cortical neurones than apes. There are 100 trillion connections in every brain. It is these connections that seem to be the key to intelligence and flexibility.
  • Mapping of the human genome has revealed that one key difference between our brains and ape brains is that one gene that seems to be involved in brain development, SRgap2, is quadrupled in humans. This has a dramatic effect on the connections within brains, therefore intelligence.

All very interesting stuff, but is it the whole story?

There is no mention of the role and level of memory, there is no mention of the capacity for abstract thought or the ability to over ride genetically determined behaviour. There is no mention at all on the consciousness that I always believed  was what made us human. Let alone mention of the extras we seem to carry such as soul and spirit. This progression may explain some of the biological animal side of us, but as to a definitive study as to what really makes us who and what we are it only scratches the surface.

What do you think?

Marian

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