Hofman M A
Brain Behav Evol. 1983;22(2-3):102-17. doi: 10.1159/000121511.
A progressive enlargement of the hominid brain started 3-2 million years ago, probably from a gracile australopithecine form. Since then, three major transitions in degree of encephalization have taken place, leading to modern Homo sapiens. In the present study it is shown that these transitions must have occurred in rapid bursts, interspersed with long periods of little or no evolutionary change (stasis). This stepwise mode of encephalization is in accordance with the model of punctuated evolutionary change. A further inquiry has been made into the size of the cerebral cortex of hominids and into the number of cortical neurons based on estimates which were derived from allometric equations in extant mammals.
大约在300万至200万年前，原始人类大脑开始逐渐增大，可能源自纤细型南方古猿。从那时起，脑化程度发生了三次重大转变，最终进化出现代智人。本研究表明，这些转变必定是在快速爆发中发生的，期间穿插着长时间几乎没有或没有进化变化（停滞期）。这种逐步脑化模式与间断性进化变化模型相符。基于从现存哺乳动物的异速生长方程得出的估计值，对原始人类大脑皮层的大小和皮层神经元数量进行了进一步探究。
