There is a new paper out suggesting that the Flores hominids, known as Hobbits, were “human endemic cretins.”
From the abstract of this paper:
… We hypothesize that these individuals are myxoedematous endemic (ME) cretins, part of an inland population of (mostly unaffected) Homo sapiens. ME cretins are born without a functioning thyroid; their congenital hypothyroidism leads to severe dwarfism and reduced brain size, but less severe mental retardation and motor disability than neurological endemic cretins. We show that the fossils display many signs of congenital hypothyroidism, including enlarged pituitary fossa, and that distinctive primitive features of LB1 such as the double rooted lower premolar and the primitive wrist morphology are consistent with the hypothesis. We find that the null hypothesis (that LB1 is not a cretin) is rejected by the pituitary fossa size of LB1, and by multivariate analyses of cranial measures. We show that critical environmental factors were potentially present on Flores, how remains of cretins but not of unaffected individuals could be preserved in caves, and that extant oral traditions may provide a record of cretinism.
There are a handful of reasons to criticize these results based on the results themselves, but there is also a broader overarching reason to coming to the point that pathology explains this fossil population only as a last resort.
The authors claim that Myxoedematous endemic cretinism occurs in various places at rates approaching 5%, but his is an overstatement in two ways. First, enlarged goiter and a range of iodine deficiency outcomes occur in some populations in Central Africa and Indonesia, but full blown ME dwartism of the type they attribute to Flores is very very rare in these areas. In fact, there are only two descriptions of this conditions used in this study, attesting to the rarity of this condition.
Many of the osteological traits the authors use are also primitive traits. Primitive traits can show up in descendant populations either because of early branching (phylogenetically) or genetic changes, and are thus not good sources for phylogeny. Placing the Flores Hobbits within rather than along side a human lineage is a phylogenetic conclusion. This is a problem that will be difficult to avoid in this sort of analysis.
The authors use local stories of cretin-like people to bolster their case. These stories may or may not have relevance, but in many places in the world there are stories of not-exactly-human forms that live out in the wild. Leprechauns come to mind, but there are many other examples as well. The assertion that this is evidence in support of a particular form of pathology is very weak.
There is a broader reason to distrust pathological explanations. This is using the assumption, as suggested in the paper (especially in regards to local mythology) that the cretinoids lived on their own in the forest, even if they were part of a larger population.
What if I told you about a major corporation that was run entirely by people with Down Syndrome, severe Autism, with a board of directors entirely comprised of advanced Alzheimer patients. This corporation produced products that were packed on trucks at a loading dock staffed only by comatose or quadruplegic workers. Further, I told you that this company was quite successful.
You would not believe me.
People with various (aforementioned) disabilities can certainly live productive lives, and can be integrated into any broader system and do fine, but this requires integration and compensation. We would not assume that an accounting firm staffed entirely by people incapable of doing math or a special forces army unit staffed entirely by people with no leg or arms would function. Why, then, do we assume that a subsociety, living on their own in the forest, made up of people with severe mental and physical deficiencies would survive?
To assume that this is possible is to seriously underestimate the required capacities for humans to live as foragers. This is a commonly made, Western-biased, post-Agricultural centered, and racist mistake. The deeper assumption plays from the hero-myth of human history and evolution. “Advanced” societies, such as those with agriculture, pastoralism, cities, complex kinship systems, space ships, widget factories, etc. are assumed to be made up of people who are intrinsically (genertically and/or culturally) advanced over their hunter-gatherer forbearer’s.
Nothing could be farther from the truth. Where data are available, we tend to find that hunter-gatherer populations have measurably larger brains, notably smaller percentages of mentally disabled participants, and on direct ethnographic observations, are extra smart.
It is possible that this condition of cretinism was endemic to some population living in this area, and the cretins were sent off the forest, perhaps fed and cared for minimally, and did not actually function as an independent foraging society. I might believe that. But such a subset living on their own with sufficient persistence to leave numerous fossils and a reasonably rich archaeological record is extraordinarily unlikely.
The authors do address this idea to some extent.
ME endemic cretins escape the severe neurological deficits of neurological endemic cretins … having milder mental deficiency, greater self-reliance and a general lack of mobility deficits (Wang et al. 1982). In agricultural populations, ME cretins are well cared for, but in seasonally mobile hunter-gatherer populations, the limited mobility of cretins could lead to separation, particularly of adult cretins. Use of caves by adult cretins and lack of burial would explain the cretin remains at LB, while seasonal mobility, alternative shelters and systematic burial would explain the absence of the remains of normal individuals. A population (n=25-100) with 1% cretinism is calculated to produce 4-15 deaths of adult cretins per kiloyear, which is enough to explain the discovered remains at LB.
By the way, where Cretinism occurs in Central Africa, it occurs only among agricultural populations who have moved into the region where iodine is rare within several centuries time, and not among indigenous foragers.
This paper is discussed by Afarensis, HERE.
Obendorf, P.J., Oxnard, C.E., Kefford, B.J. (2008). Are the small human-like fossils found on Flores human endemic cretins?. Proceedings of the Royal Society B: Biological Sciences, -1(-1), -1–1. DOI: 10.1098/rspb.2007.1488