Flores skeletons: Irrational scientists or imaginary species?

Greg Laden reviewed The Fossil Chronicles in the January-February, 2012, American Scientist issue. On July 4, 2012 we submitted a 4100 word response. Subsequently the Editor, David Schoonmaker, allotted 500 words online. Our full critique appears here.

After studying the Liang Bua Cave skeletons in 2005, we were denied further access to what Laden calls “one of the most important finds of the past hundred years.” These bones do not represent a new species, but are important because they spotlight paleoanthropology’s idiosyncrasies.

The Fossil Chronicles recount Dean Falk’s long-running disagreement with Ralph Holloway about the interpretation of fossil hominin endocasts, plus her speculations about the endocast of LB1, the only known skull from Liang Bua Cave. Laden adds further gratuitous disparagement of Ralph Holloway, unacceptably unprofessional in AS.

Laden parrots Falk’s conclusions about these remains: “Homo floresiensis is normal, although very different than expected, just as Taung was different than expected.” But evidence for evolution over two centuries comprises >200 fossil hominin skulls, not two. Some finds were celebrated as ancestors for decades, then rejected later. Piltdown’s fraudulent skull presented the reverse of Taung’s pattern, blocking acceptance of the Dart’s insight for three decades. Ramapithecus beguiled most professionals and students nearly as long, illustrating a “bandwagon effect” in human ancestry reconstruction, among professionals and journalists.

For truth Laden substitutes consensus: “The history of the study of human evolution shows that surprising findings make well-educated and otherwise rational people behave irrationally for a time, until everyone eventually settles on a new view.” Such statements explain the bandwagon effect. Questioning majority view is “irrational,” imposing a penalty with that label, while joining the majority carries easier access to funding and publication, as for “Homo floresiensis” advocates.

Many supposedly “unique” features of LB1 (short stature, low humeral torsion) are shared with other extant humans; others (mandibles lacking external chins, rotated premolar teeth) are common in Flores Rampasasa among extant Australomelanesians, while LB1’s tiny brain, marked asymmetry, and unusually short femora signal developmental abnormality. Our hypothesis, offered in 2006, remains constant: LB1 is an abnormal individual from a relatively recent Flores population. Contradictorily, supporters of “H. floresiensis” originally held that it evolved from H. erectus isolated on Flores over more than 800,000 years, then switched in 2007 to attribute its small brain and short stature to African ancestors a million years before reaching Flores.

The idea that the Liang Bua Cave skeletons represent a new species has – unlike Taung but strikingly like Piltdown and Ramapithecus – decidedly not been a minority viewpoint championed bravely by a few dissidents against widespread opposition. From the first the new diminutive species was a popular, widely romanticised interpretation. Its few critics are held, as by Laden here, to be irrational. This situation will change, but only when there is more general realization that “wrapping events into a good story that supports one’s case” per Sloman’s review in the same AS issue, is alien to the best traditions of science, however appealing to bandwagoneers.

Robert B. Eckhardt, Ph.D.
Professor of Developmental Genetics and Evolutionary Morphology
Department of Kinesiology
University Park, PA 16802 USA

Maciej Henneberg, Ph.D., D.Sc., FAIBiol
Wood Jones Professor of Anthropological and Comparative Anatomy
Medical School
University of Adelaide
Adelaide, SA 5005