The Brain of the H. floriensis "Hobbit"

The brain of the diminutive ancient human, Homo floresiensis, resembled that of Homo erectus or perhaps even Australopithecus and not the brain of a modern human with a disease or developmental disorder, new findings published in the 4 March 2005 issue of the journal Science suggest.

H. floresiensis evidently crossed the sea to reach the Indonesian island of Flores, where its bones were found near tools and some evidence for the use of fire. If the tools and other artifacts are related to H. floresiensis, they would suggest surprisingly advanced behaviors for a tiny hominin with an ape-sized brain.

A U.S., Australian and Indonesian research team analyzed three-dimensional representations of the H. floresiensis brain, reconstructed from the recently discovered skull known as LB1. Dean Falk and colleagues compared this "virtual endocast" with endocasts from great apes, Homo erectus, Australopithecus africanus, Paranthropus aethiopecus, and Homo sapiens, including a pygmy and a human with abnormal or "microcephalic" brain growth.

Although LB1's brain/body size ratio is more like that of Australopithecus, the brain's overall shape is closest to that of H. erectus, the authors report.

LB1's brain does show some differences from H. erectus, such as an expanded temporal lobe. The authors suggest in the 3 March 2005 Science Express that these differences are consistent with the idea that this species was capable of higher cognitive processing despite its tiny brain, although more research is necessary to determine whether this was the case.

— Kathy Wren

3 March 2005