On the increase of cranial capacity in mankind's lineage: Augments and elaborations

Abstract

Some available zoological and paleontological data on the scaling of brain and body sizes seem to suggest alternating phylogenic bouts, within a lineage, of (1) short episodes of cranial capacity increase without much body increase, termed augments, and (2) long intervals of elaboration of adult form often with much body size increase but with modest cranial capacity increase, termed elaborations. To account for the adult brain-body characteristics of existing primate species, secondary processes are postulated to supervene after prolonged elaboration and lack of augment: preservative, progressive and regressive conservation as well as extinction. The augmentation-elaboration hypothesis as applied to mankind's lineage and to his near relatives, as seen in australopithecine and hominine fossil finds dated through the last three million years or so, suggest categorization of these fossil specimens as being from either a present “sapient elaboration”, or a “humane augment” of the Pleistocene, or a “habiline elaboration” of the Pliocene-Pleistocene, or the later portion of an “australopithecine elaboration” that may have begun in the Middle or Upper Miocene.