In anthropology it is commonly accepted that the evolution of larger brains was associated with the reduction of posterior teeth. Factors ranging from diet to cognitive ability have been used to explain this inverse correlation between cerebral complexity and masticatory structures. Aida Gómez-Robles and colleagues have analyzed brain and teeth changes using a multiple-variance Brownian motion approach, providing evidence against a brain-teeth phylogenetic association. Brain shape was analyzed by using eight linear variables as measured on endocasts. Teeth shape was analyzed through geometric morphometrics. The study found that endocranial proportions and dental geometry are largely characterized by similar rates of variation, which are indicative of a neutral and non-directional pattern of evolution. Brain size and tooth size show different rates of change throughout the phylogenetic tree, and the hypothesis of a reciprocal and inverse correlation is not supported. This seems to suggest independent factors at environmental and/or genetic level. Two characters show faster rates of change in specific lineages, and are probably associated with specific selective and adaptive processes: brain size in early Homo and brain globularity in Homo sapiens. The first result suggests that brain evolution in the genus Homo is strongly based on size increase rather than on changes of specific cortical proportions. However, caution is needed in this sense: the study is based on simple linear metrics such as arcs and chords, and reflects only the external appearance of endocranial anatomy. Despite these limitations, this result is consistent with other kinds of evidence. The second result reflects an exception to this size-only pattern of change: the globular brain shape in modern humans. Parietal lobe variations are again an issue.
apes Atapuerca Australopithecus brain-artefact interface brain atlas brain biology braincase brain size brain thermoregulation CENIEH Cercopithecoids chimpanzee China cognitive archaeology corpus callosum cortical folding cortical surface cranial thickness diploic channels eLearning embodiment encephalization endocranial ontogeny endocranial volume evo-devo extended mind fossil endocasts Frederick Coolidge frontal bone frontal lobes functional craniology geometric morphometrics hemispheric asymmetries Holocene Homo erectus human ethology human genus intraparietal sulcus Konrad Lorenz Institute language Le Moustier macaque Malu Cave mammals metopic suture Mezmaiskaya modern humans myopia Neandertals occipital lobes orbits paleoneurology Pan paniscus Pan troglodytes parietal bone parietal lobes petalia Philipp Gunz Phillip Tobias photography precuneus primate brain sexual dimorphism shape analysis Simon Neubauer social primatology species concept subparietal sulcus sulcal patterns sulci symbolic thinking Taung child University of Colorado University of Liverpool visuospatial integration
- Losing Key DNA Made Us Modern Humanshttps://www.scientificamerican.com/article/losing-key-dna-made-us-modern-humans/
- DECODING MIMBRES PAINTINGThis extended abstract represents a summary introduction to a work in progress, which will culminate in a publication and exhibition at The Los Angeles County Museum of Art in 2018. It briefly outlines our discoveries and interpretations, which will be more fully presented, referenced and discussed in the forthcoming catalog. This presentation is available f […]
- Craniovascular traitsThis month we have published a review on craniovascular traits and anthropology, freely available to download from the Journal of Anthropological Sciences. The article describes many vascular traits that can be analyzed on skulls, through the traces they leave on the bone surface or within the bone itself. The traces of the middle meningeal vessels, […]
- Incredible New Evidence for Peopling of the Americas 130,000 Years AgoIt is pretty well agreed that Homo sapiens spread out of Africa about 100,000 years ago and traveled across Asia about 60,000 …Continue reading →
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- How to become a super memorizer – and what it does to your brainNew research shows that we can train our brains to become memory champions To many of us, having to memorize a long list of items feels like a chore. But for others, it is more like a sport. Every year, hundreds of these ‘memory athletes’ compete with one another in the World Memory Championships, memorising hundreds of words, numbers, or other pieces of inf […]
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