They also suppose a sharp chronological divide between the precolonial and colonial eras, arguing that whereas "natural" demographic influences were of greater importance in the former period, human factors predominated thereafter.
他们还假定前殖民时代和殖民时代之间存在明显的时间差，认为"自然"人口影响在前一时期更为重要，而在后一时期则以人为因素为主。