1Anthropology, Indiana University, 2Cognitive Science, Indiana University, 3Human Evolution, Stone Age Institute, 4Anthropology, Columbia University
April 18, 2020 8:15AM, Diamond 5
Although Neanderthal endocrania are not smaller than those of modern humans on average, they are generally longer (anterior-posteriorly) relative to their height (inferior-superiorly), and tend to have a pronounced occipital protuberance. These differences have long been used to suggest Neanderthals might have differed significantly behaviorally from modern humans, such as possibly having less linguistic ability, poorer executive function, and/or smaller episodic and working memory capacity. However, the extent to which these morphological differences are actually large enough to merit meaningful behavioral implications is not clear. To put them into the context of known populational variation in human brain shape, we have compared shape differences between Neanderthal (specifically: LaChappelle, LaFerrassie, LaQuina 5, and Saccopastore 1) vs. modern human endocrania, to shape differences between a standard modern human brain atlas based on American and European subjects (MNI152) vs. one based on 2020 modern Chinese subjects (CHINESE2020). Morphological registration and quantification of localized shape differences was accomplished using Advanced Normalization Tools (ANTs). We find that on average the morphological differences are only slightly greater than that found between the MNI152 and CHINESE2020 atlases. Specifically, the average (root mean squared) Jacobian scaling difference for Neanderthal vs. modern human voxels was 16%, whereas the equivalent for the MINI152 vs. CHINESE2020 was 13%. Given the lack of clear cognitive differences between Chinese and American/European populations, this calls into question the suggestion of significant cognitive differences between Neanderthal and modern humans. The extent to which surface morphology may hide internal morphology will be evaluated.
This research was supported in part by grant 52935 from the Templeton Foundation titled: “What Drives Human Cognitive Evolution?”