Human Evolution

, Volume 21, Issue 3–4, pp 321–335 | Cite as

Encephalizations and Cerebral Developments in Genus Homo



As Darwin observed in the second chapter of the The Descent of Man, brain size has the more obvious and direct anatomical correlation with the outstanding cognitive capabilities of our species in comparison with its closest relatives. If we extend the comparison to other mammals, we can observe that cognitive capabilities do not seem to strictly correlate with brain dimension in absolute and in relative terms, and the encephalization quotient (EQ) is not a universal advice of the cognitive capabilities of a particular species, too. Why and how the brain size in our lineage increased dramatically in absolute and in relative way during the last 3 million years? What is the relationship between our outstanding intellective capability and the brain size? The progressive encephalization of our ancestors was the origin or the effect for the development of the intellective capabilities of living humans. Recent advances in the knowledge of intrinsic organization of cerebral cortex and in the patterns of genetic expression are able to better outline the trajectories as the metabolic and structural constraints of the qualitative and quantitative encephalic development. The new scenario led to suggest more accurate explanations of the selective mechanism acting during the evolution of our species.


Brain evolution Human evolution 



I wish to thank Michelangelo Bisconti for his continuous encouragement and invaluable discussion in preparing this review and Prof. Francesco Mallegni for inviting me to write this essay.

I am also grateful to Dario Riccardo Valenzano and Luca Sineo for useful suggestions and help.


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© Springer Science + Business Media B.V. 2007

Authors and Affiliations

  1. 1.Scuola Normale Superiore, Piazza dei Cavalieri 1PisaItaly

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