Brain size of Homo floresiensis and its evolutionary implications

Daisuke Kubo, Reiko T. Kono, Yousuke Kaifu

Research output: Contribution to journalArticlepeer-review

67 Citations (Scopus)


The extremely small endocranial volume (ECV) of LB1, the type specimen of Homo floresiensis, poses a challenge in our understanding of human brain evolution. Some researchers hypothesize dramatic dwarfing of relative brain size from Homo erectus presumably without significant decrease in intellectual function, whereas others expect a lesser degree of brain diminution from a more primitive, small-brained form of hominin currently undocumented in eastern Asia. However, inconsistency in the published ECVs for LB1 (380-430 cc), unclear human intraspecific brain-body size scaling and other uncertainties have hampered elaborative modeling of its brain size reduction. In this study, we accurately determine the ECV of LB1 using high-resolution micro-CT scan. The ECV of LB1 thus measured, 426 cc, is larger than the commonly cited figure in previous studies (400 cc). Coupled with brain-body size correlation in Homo sapiens calculated based on a sample from 20 worldwide modern human populations, we construct new models of the brain size reduction in the evolution of H. floresiensis. The results show a more significant contribution of scaling effect than previously claimed.

Original languageEnglish
Article number20122893
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1760
Publication statusPublished - 2013 Jun 7
Externally publishedYes


  • Brain-body scaling
  • Endocranial volume
  • Homo floresiensis
  • Relative brain size

ASJC Scopus subject areas

  • General Biochemistry,Genetics and Molecular Biology
  • General Immunology and Microbiology
  • General Environmental Science
  • General Agricultural and Biological Sciences


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