This great quantitative gain produced some qualitative loss. Over time the average brain, once 1500 cc., regressed to less than 1400 cc. With increased numbers and increased leisure the creative segment of society began a whole series of dazzling accomplishments. They invented the wheel, writing , the smelting of metals and more. Although now in the minority, there are probably more creative individuals in the populous world today than the Cro-Magnons could have mustered at any one time.
Cultural accomplishments can still accumulate while the innate condition of man regresses.
Since the beginning of agriculture there have been twenty-six identified civilizations. They include the Egyptian, Babylonian, Greek and Roman. Every one of them broke down or died out expecting so far only the youngest our own. A common factor, which appeared in the late stages of many of these failed civilizations, was the gradual dying our of their abler peoples, the types who had initiated the civilizations and might have sustained them. They failed to reproduce sufficiently.