The 82nd Annual Meeting of the American Association of Physical Anthropologists (2013)


A QUANTITATIVE APPROACH FOR THE LATE PLEISTOCENE HOMININS BRAIN SIZE

ALEXIA SERRANO-RAMOS1, JUAN-MANUEL JIMÉNEZ-ARENAS1,2 and JOSÉ-ANTONIO ESQUIVEL-GUERRERO1,2.

1Prehistory & Archaeology, Universidad de Granada (Spain), 2Institute for Peace & Conflicts Research, Universidad de Granada

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As a general rule, brain size has experienced considerable increase from H. habilis to anatomically modern humans (AMH). Nevertheless, it is often stated, especially in popular science, that Neanderthals had the largest brains. We evaluate whether the Neanderthal’s endocraneal volume is significantly larger than that of AMH and if the differences in body mass (BM) and endocranial volume (EV) are related to latitude (LAT) and/or time (TIME).

We created a database containing 411 individuals of whom 43 are Neanderthals and 339 Pleistocene (161) and Holocene (207) AMH.

The results of our study show that Neanderthals have smaller brains than the Pleistocene AMH despite the fact that the latter are smaller in body mass. However, the Holocene AMH (7 populations) have smaller brain sizes than those of Neanderthals. Nevertheless, both taxa have brain size ranges that overlap substantially (>45.22%), and their means are therefore indistinguishable from a statistical point of view. On the other hand, while the AMH's body size seems to fit ecogeographic assumptions (Bergmann’s rule) [logLAT on logBM (R=0.258; p=<0.001)], Neanderthal size variability seems to respond rather to a temporal pattern of increase [logEV on logTIME (R=-0.604; p=<0.001) and logBM on logTIME (R=-0.579; p=<0.002)]. The most recent populations of AMH have smaller brain sizes. This fact could be linked with genetic variations, such as Microcephalin, a specific regulator of brain size, because this gene has continued evolving beyond the emergence of AMH.

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