The conditions required for rapid evolutionary change to occur in human populations exist. But, given that measurable alterations in a trait over time can occur for many reasons – including those related to shared culture or environment – or randomly (“genetic drift”), studies demonstrating this phenomenon are rare.
发生短期进化演变的条件同样存在于人群中。但鉴于包括共同文化或环境——或随机因素（“基因漂变”）在内的多重原因均可造成某种特质随时间推移发生可以衡量的变化，因此证明这种现象的研究非常罕见。区分各种变化的来源是人类今天所面临的挑战。