Newborn: Adult brain ratios in hominid evolution
- 1 March 1976
- journal article
- research article
- Published by Wiley in American Journal of Physical Anthropology
- Vol. 44 (2), 271-278
- https://doi.org/10.1002/ajpa.1330440209
Abstract
The ratio of newborn to adult brain size varies widely in primates. These variations provide an index of the different degrees of postnatal brain growth in the different members of the primate order. The uniquely low figure for Homo sapiens indicates a greater degree of postnatal brain growth and therefore postnatal dependence and also a greater need and opportunity for social organisation. An attempt is made to determine the newborn:adult brain ratio in a proto‐human population, Australopithecus africanus. Two possible causes of the reduction of the ratio in hominid evolution are discussed. The first is the limiting confines of the maternal pelvis adapted primarily for orthograde progression rather than parturition. The second concerns the resultant of a set of three paired variables between the members of each pair of which there exists an allometric relationship. These are the relation between brain and body size in the adult, feto‐maternal weight allometry and the relation between newborn brain‐size and birth weight.Keywords
This publication has 6 references indexed in Scilit:
- Newborn Size and Pelvic Dimensions of AustralopithecusNature, 1972
- The brain in hominid evolutionPublished by Biodiversity Heritage Library ,1971
- New Endocranial Values for the AustralopithecinesNature, 1970
- Brain‐size, grey matter and race —fact or fiction?American Journal of Physical Anthropology, 1970
- Sex differences in the pelves of primatesAmerican Journal of Physical Anthropology, 1949
- The relative size of the cranial capacity in primatesAmerican Journal of Physical Anthropology, 1941