In the evolutionary radiation of the human genus, we have observed changes in both brain size and proportions. Some of these morphological differences are thought to be associated with functional variations, in physiological or cognitive aspects, while some others are the secondary results of cortical or cranial structural constraints. Most archaic human species, like Homo erectus and H. heidelbergensis, display larger brains when compared with earlier hominids, but specializations in their cortical proportions, if there are any, are difficult to recognize. In contrast, after or during Middle Pleistocene, more derived species like H. sapiens and H. neanderthalensis show changes in overall brain size but also in specific cerebral regions. Functions associated with body cognition, visuospatial integration, tool use, language, and social structure may be involved in these paleoneurological changes. Nonetheless, a proper evaluation of cognitive differences must take into account not only the cerebral components, but also the associated mechanisms underlying technological extension. Brain-body prosthetic capacity can have represented, indeed, a crucial adaptation to become obligatory tool users. These processes involve both genetic and environmental effects, and they are probably influent at phylogenetic (species) and historical (populations) level, bridging biological and cultural factors through epigenetic feedbacks that are still poorly known and scarcely investigated.

在人类属的进化辐射中，我们已经观察到大脑大小和比例的变化。这些形态差异中的一些被认为与生理或认知方面的功能变异有关，而另一些则是皮质或颅骨结构约束的次要结果。与早期的原始人相比，大多数古老的人类物种（例如直立人和海德堡人）显示出更大的大脑，但是它们的皮层比例（如果有的话）的专业化很难辨认。相反，在中更新世之后或期间，更多的衍生物种，如智人和尼安德特人显示整体大脑大小的变化，但在特定的大脑区域也变化。这些古生物学变化可能涉及与身体认知，视觉空间整合，工具使用，语言和社会结构有关的功能。尽管如此，对认知差异的正确评估不仅必须考虑大脑成分，而且还应考虑技术扩展的相关机制。实际上，大脑身体的修复能力已成为成为强制性工具使用者的关键适应方法。这些过程涉及遗传和环境影响，它们可能在系统发育（物种）和历史（种群）水平上具有影响力，通过尚不为人所知且很少研究的表观遗传反馈将生物学和文化因素联系在一起。