According to the Encyclopedia Britannica

Certainly, humans being in small groups isolated from one another, fearful of and hostile to one another and focusing on daily survival, was a contributing factor to their inability to develop better survival tools and ideas. As for those in warmer parts of the world with an abundance of easily accessible animals and vegetables, perhaps they did not need to develop tools or ideas for survival. But I believe there was an even more important factor. And that was their life span.

I believe that people do not develop their brain’s potential for problem solving and consequential thinking until after twenty years of age. And for that to even happen after twenty, the groundwork for thinking, as opposed to mimicking and doing, has to be laid. I believe that not only was the training of individual young limited to survival skills, but also that too few lived long enough to use their own brain’s development to analyze their experiences, entertain ideas, and perform trial and error, which could have brought about new solutions. As archeologists have shown, critical, evolutionary thinking happened only in the most limited sense for a very long time.

As we can see by analyzing the table, the short, average life expectancy persisted until the early twentieth century. So, how did humanity manage to create advances in knowledge, given my theory? When people began domesticating plants and animals around ten thousand years ago, disease from domesticated animals and closer contact with denser human populations brought down the average life expectancy. But population numbers went way up. Because of better nutrition, the chances of more people surviving longer was statistically ensured. Survival was no longer tied to what the environment had to offer so much as to hard work or the weather. Agricultural communities also developed specialized trades. This set of circumstances allowed more individuals to reach an age where their brains’ potential could be developed, along with having more time, in winter and growing seasons, where the potential of their brains could be put to use.

It is not surprising that with the advent of sewage systems, hygiene, antibiotics, anesthetics, and sufficiently available food in the nineteenth and twentieth centuries, record numbers of people started to live into their forties, fifties, and sixties. And it was these individuals who were directly responsible for industrial revolutions and nearly all of the scientific advances that improved the quality of life.

But that is not all that has happened as a result of scientific advancements leading to longer life spans. Another revolution — that of a morality that included strong social responsibility — started to take root.

Again, how would we explain this by looking at life span? Why were there two world wars and countless others, genocides and holocausts, slavery and child labor, together with all of these scientific advances? After all, didn’t we have an ever-growing number of these mind-developed, educated human beings? Isn’t developing the mind enough to make people more caring about other human beings? History clearly tells us no. And to this day, merely being educated does not equate with being compassionate and caring. It seems that a developed mind is insufficient for the greater causes of humanity: ending hunger and poverty, bringing peace, and ensuring equality and opportunity for self-expression to all.

The second question you may want to ask yourself is, Why did it take two million plus another ten thousand years for us to start becoming more morally responsible for our fellow human beings?

If we go back to the table, we see that today, the average life span is seventy-eight years. At the turn of the twentieth century, it was forty-seven years in the US. In most other countries, it was even less.

The answer is relatively simple. With the majority of human beings living only into their twenties and thirties, not only was there insufficient time to develop the self, but not even sufficient time to develop the mind. Moreover, survival, dominance, and the competitive nature of humanity were at the forefront of human interactions.

At the turn of the twentieth century, more food and then penicillin brought the average life expectancy to forty-seven, and the advent of universal education began to provide the foundation for the wholesale development of people’s minds. Air travel, television, atomic energy, medical breakthroughs, the Internet, and many more inventions are the clear product of the millions of human beings now afforded the opportunity to develop their minds. But world wars, religious wars, hunger and starvation, abuse, slave trade, servitude, hate, cold wars, nuclear annihilation, financially using people by not paying or underpaying them, still persisted.

It wasn’t until the mid-1950s, when the population started to reach their fifties, sixties, and beyond in large numbers to today’s average life expectancy of seventy-eight, that millions of people with developed minds began to reach an age where the full development of their selves was possible. So, it is no coincidence that there has been a greater response to global strife, hunger, and illness that is much more humane and caring than ever before.