The early history or the human race is most clearly and reading studied by observing the stages of human technological progress.that is why it was a long-standing convention to devide early history into broad periods according to the hard materials-stone copper bronze. and iron in that order from which cutting tools and weapons were made . THEN AS KNOWLEDGE OF THE PAST INCREASED THE broad periods were further subdevided the stone age was devided into the old (paleolithic) period and the new (neolithic) period when it was noticed that the technique or sharpening flint and other stone changed from flaking to griding