Tuesday, February 19, 2013

Thinking like a tortoise


The average lifespan in a hunter-gatherer society is 32 years. If you think you'd like the simplicity and ecological integrity of a hunter-gatherer lifestyle, be sure to take your mobile phone and not wander too far away from a hospital.

Culture, medical and biological science in particular, changed things dramatically. A century-and-a-half ago life expectancy at birth was 50 years, with child mortality being the most significant limiting factor.

By the time I was born, life expectancy at birth was pushing 70 years, with the age-range 14-65 accounting for most mortality.

These days it's the fact that us old folks are living longer that accounts for the ever-increasing life expectancy. A US citizen who makes it to 60 can reasonably expect to live another 25 years.

The survival curve is becoming, as they say, more rectangular. More and more people survive childhood and middle age, then we all fall of the mortality cliff together.

Which brings us, I suppose, to the "fiscal cliff." More of us are on Social Security, Medicare and Medicaid. Young workers pay to keep us oldsters ticking. By the time they reach our age, they can probably expect to live to 100. Or forever. How will we deal with that as a society?

Our species spent most of its evolutionary history as hunter-gatherers, ready victims of natural predators, pathogens and each other. Natural selection presumably optimized our biology for a quick, risky rise to sexual maturity followed by an early demise. Now it's decades of science versus millions of years of tooth and claw. I invite you all to my 85th birthday party, eight-and-a half years hence. BYOE. (Bring your own Ensure.)