The Hazards of Scientific Reporting

A team of paleoanthropologists, including Maeve Leakey and Fred Spoor, announced a couple of new fossils earlier this month. A small partial cranium dated at 1.55 mya that they identified as Homo erectus, and a broken maxilla dated to 1.44 mya which, based on tooth morphology, was classified as Homo habilis. The authors say the study suggests a long period of coexistence between the two species, and the possibility that habilis is not ancestral to erectus. Sadly, the anthropology section on my Google News was soon riddled with headlines, from the alarmist:

Fossil Find Challenges Evolutionary Theory - from Digital Journal

Only natural to doubt evolutionary theory - courtesy of an opinion piece in The Wichita Eagle

to the slightly more reasonable:

Fossils Could Force Rethink of Human Evolution – via Live Science

Finds test human origins theory – from BBC News

*Sigh* I can hear the creationists now. There’s controversy in evolutionary theory, even the scientists don’t know how it works, so it must be wrong. It’s no wonder the general public is confused, given the quality of “scientific reporting” going on. And while I understand that the source must be considered, and that many members of the public (or those writers reporting on the latest scientific news, apparently) won’t actually go read the original article, or listen to interviews with the researchers from Science Friday, the sensationalism and total lack of fact-checking continue to astound me.

Here’s a couple of examples from the Digital Journal piece.

The team studied an upper jaw bone of Homo habilis, finding it to be 1.44 million years old — much older than all previous discoveries of habilis bones.

No. The maxilla actually demonstrates that habilis lived much more recently than once thought. From the Nature article:

Previously, the most recent occurrence of H. habilis was at 1.65 Myr or older (OH13)…. (689)

That’s the most recent habilis fossil, and it’s roughly 200,000 years OLDER than the latest discovery. From the same Digital Journal report:

…the surprisingly small erectus skull has scientists believing erectus was not as human-like as previously believed. The skull is very similar to modern gorillas, sending researchers on the hunt now for erectus’s real ancestor.

WRONG. Digital Journal is an online news source, where “professional and citizen journalists cover news and debate issues.” So, maybe the writer is one of the “citizen journalists” who doesn’t actually read Nature.

The Nature article mentions gorillas exactly once:

The intraspecific variation of vault size in H. erectus, including KNM-ER 42700, is larger than in extant humans and chimpanzees, but smaller than in gorillas. This degree of variation may well imply that H. erectus showed marked sexual dimorphism, rather than the reduced levels that characterize the derived condition in H. sapiens. (689)

The point is that because this erectus skull is so small, the smallest ever discovered in Africa, it suggests that Homo erectus could be sexually dimorphic, meaning that males are bigger than females. This condition is seen in other primate species, including gorillas. It does not mean that the new skull is “very similar to modern gorillas”, as a Google image search, or skimming an introductory physical anthropology text, would quickly confirm.

That’s a cranial cast of an adult male mountain gorilla on the left, and the new H. erectus fossil on the right. From the anterior view, keeping in mind that these are not equally scaled, the mountain gorilla has a pronouced sagittal crest (the ridge of bone on top of the skull where the muscles used for chewing attach), and nuchal torus (the ridge along the back of the skull where the neck muscles attach), along with a prognathic face (it sticks out from the brow ridges). The new H. erectus was found with the face broken away (many erectus fossils are found in this condition elsewhere), but it obviously lacks the sagittal crest and nuchal torus, and the braincase is relatively larger. No paleoanthropologist would claim that this new fossil is very similar to a modern gorilla.

How about Live Science? It’s an

original content site that chronicles the daily advances and innovations made in science and technology…LiveScience addresses the intellectually curious audience hungry for ideas, events and things that cross the line from being merely academic to being cool, engaging and relevant in their lives. LiveScience reports amazing, real world breakthroughs, made simple and stimulating for people on the go.

Sadly, the article isn’t really any better.

The researchers identified one of the fossils as a 1.44 million-year-old partial jawbone belonging to H. habilis. Prior to the discovery, the most recent H. habilis fossil was a 1.6 million-year-old specimen discovered by paleoanthropologist Richard Leakey and his team in 1984 and dubbed “Turkana Boy.”

Nope. WT-15000 (aka. Turkana boy) is a juvenile Homo erectus.

Do these new finds really “challenge the theory of evolution?” No. They raise new questions about hominin evolution between 3-2 mya, and refute the idea that evolution is a linear progression. But scientists have long known that Aristotle’s Great Chain of Being does not exist. Evolution is not a ladder of progress, and these new fossils have expanded our vision of hominin evolution.

Susan Anton, anthropologist at New York University and co-author on the Nature study, said:

This is not questioning the idea at all of evolution; it is refining some of the specific points. This is a great example of what science does and religion doesn’t do. It’s a continous self-testing process.

Unfortunately, “scientific journalism” isn’t as self-correcting. That’s why I blog about anthropology, so that somewhere, in this vast sea of misinformation, somebody gets it right.

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Image credits: Gorilla – K. Young
H. erectus – Figure 1d in Spoor et al. (2007).

Reference: Spoor F, Leakey MG, Gathogo PN, Brown FH, Antón SC, McDougall I, Kiarie C, Manthi FK, & Leakey LN (2007). Implications of new early Homo fossils from Ileret, east of Lake Turkana, Kenya. Nature, 448 (7154), 688-91 PMID: 17687323