It turns out that we started making more stuff as more of us started making it past early adulthood, around 30,000 years ago.
Here’re some ideas from a NYT article about our perceptions of life expectancy.
Life expectancy is just an average that fluctuates with the risks we face and it changes throughout our lifetimes, making it a frequently misunderstood concept.
For example, more dying infants bring down the life expectancy number a lot. This often leads to the false conclusion that most humans died quite young in the distant and not-so-distant past.
But actually by just surviving childhood you’d have a good shot at old age.
Now scientists have concluded we started living longer more frequently starting around 30,000 years ago in the Upper Paleolithic, part of the era called the Stone Age. And studying present day “primitive” tribes shows those surviving childhood live into their 50s and beyond.
The life spans of ancient humans, their ancestors, and close relatives were studied by examining teeth from 768 fossils representing three million years of primate evolution.
By looking at wear and other signs of aging in the teeth, the fossils were split into groups of old and young adults, researchers found that between 100,000 and 30,000 years ago, there were about four old adults for every 10 young adults, but then around 30,000 years ago there were 20 old adults for every 10 young adults.
So starting about 30,000 years ago there were more people living past 30, and human culture began flourishing.
More people living longer coincided with a big jump in making stuff not directly needed for day-to-day existence – clay figurines, carvings from bone, wood and stone, cave art, jewelry making, and complex burial practices. Longer human lives seem to have made this flourishing possible.
More time alive seems to allow us to progress and make more stuff.