Homo floresiensis is a genuine ancient human species and not a genetically flawed version of modern humans.
Using statistical analysis of one skeleton, researchers from Stony Brook University Medical Center in New York concluded that the creature's tiny head and brain were not the result of microcephaly.
In 2003, Australian and Indonesian scientists discovered small-bodied, small-brained, human-like fossils on the remote island of Flores in the Indonesian archipelago.
The creature's cranial capacity was just over 400 cubic centimeters, making it more similar to the brains of a chimpanzee. The skull and jawbone features are much more primitive-looking than any normal modern human.
Statistical analysis of skull shapes show modern humans cluster together in one group, microcephalic humans in another and the hobbit along with ancient hominins in a third.
The thigh bone and shin bone are much shorter than modern humans including Central African pygmies and the like.
The team dismissed the theory of 'island dwarfing' - "It is difficult to believe an evolutionary change would lead to less economical movement," said researcher Dr William Jungers.
Further analysis of the remains indicated that the 'hobbit' was about 106cm tall — far smaller than modern pygmies, whose adults grow to about 150cm. A scatterplot depicts it far outside the range of Southeast Asian and African pygmies in both absolute height and body mass indices.
"Attempts to dismiss the hobbits as pathological people have failed repeatedly because the medical diagnoses of dwarfing syndromes and microcephaly bear no resemblance to the unique anatomy of Homo floresiensis," noted researcher Dr Karen Baab.
Details appear in Significance.