The cultural tradition of chewing gum seems to have developed through a convergent evolution process, as traces of this habit have arisen separately in many of the early civilizations. Each of the early precursors to chewing gum were derived from natural growths local to the region and were chewed purely out of the instinctual desire to masticate. Early chewers did not necessarily desire to derive nutritional benefits from their chewable substances, but at times sought taste stimuli and teeth cleaning or breath-freshening capabilities.