Small Hobbit Brain Means Little
Central in the debate whether Homo floresiensis (nicknamed hobbits) were human is the matter of their small brains. Could diminutive human-like skeletons really be human with such small skulls? (cf. 03/04/2005).
Scientists at the University of Cambridge conducted a detailed analysis of brain size vs. body size for a number of primates. They found no clear trend, reported PhysOrg. “The results show that while brains evolved to be larger in both relative and absolute terms along most branches of the primate family tree, the opposite happened along several lineages.” Some South American capuchin monkeys compare with African apes in ratio of brain to body size, while gorillas, with large brains, have a compensating larger body, bringing the ratio down. “Our analysis, together with studies of brain size in island populations of living primates,” the researchers said, “suggests we should perhaps not be surprised by the evolution of a small brained, small bodied early human species.”
There goes decades of bigoted evolutionary anthropology ranking humans by brain size (11/09/2007, bullet 3). This has nothing to say about evolution (cf. with birds, 09/07/2005). If evolution is the explanation for brain/body ratios going both ways, it explains nothing. The article said that “sometimes individuals with smaller brains are favoured by natural selection,” even though selection usually favored big brains in primates. Then again, brain size shrank in mouse lemurs, marmosets and mangabeys. “In contrast, the study found no overall trend to increase body size, suggesting that brain and body mass have been subject to separate selection pressures in primates.” Look how flexible evolution is; it explains everything. If big brains are usually so favored by selection, why didn’t brain size increase in every kind of animal over time? As a law of nature, natural selection has the strange property of producing opposite outcomes. It’s not just Stuff Happens; its Contradictory Stuff Happens.
Did evolutionary theory provide understanding here? No; as usual, researchers were surprised by what they found: “The argument raised has been that the evolution of such a small brain does not fit with what we know about primate brain evolution,” they article said. Rather than providing an explanatory framework that can make predictions, evolution is a Gumby explanation that continually gets stretched and squished to fit the data after discoveries are made (12/14/2004, 07/22/2006, 08/14/2006, 10/26/2006, 09/06/2007, 01/23/2009).
Look at another recent example: Charles Q. Choi in Live Science told about a controversial theory that claims “The evolution of the distant ancestors of humans and other primates may have been driven by dramatic volcanic eruptions and the parting of continents.” Wow. Volcanos made you what you are today. One problem with this “absurd” theory is that it has “resulted in all sorts of contradictory centers of origin.” Moreover, Choi said that “fossils often serve as an incomplete record for what and when animals actually existed.” Keep that sentence in mind when you hear someone pointing to fossils as proof of evolution. Satisfied? Vote if you think evolution is increasing our understanding of nature. For a good joke, look at the last sentence of Choi’s article.
The obsession with brain size is misguided, anyway (08/05/2006). As we have noted many times before, it’s quality, not quantity that counts (11/09/2007, 03/12/2008). Was Tom Thumb any less human because of his small stature? There have been examples of living humans doing pretty well with shrunken and damaged brains (e.g., 07/22/2009). There’s some redundancy built in (08/28/2001). Crows have small brains but show a lot of intelligence (05/26/2009, 08/11/2009). Blue whales have huge brains but are not correspondingly better philosophers than humans. We see large differences in morphology between living human tribes (Watusi vs pygmy, Inuit vs Vietnamese). It is certainly within the range of variation for an inbred tribe, stranded on a small island, subject to local diseases, to grow physically smaller. It doesn’t mean they were stupid or less evolved. If we could have talked to Bilbo and Frodo on the island of Flores, we might have been impressed with their cognitive abilities.
A small brain that performs well could be taken as a good example of miniaturization. Human engineers pride themselves on packing more oomph in smaller devices; look how USB drives have progressed from 56k to 4GB, while getting smaller and cheaper, in a few years. It’s not just the hardware. The software is often more indicative of design. There are plenty of large-brained humans walking around today with self-inflicted buggy code. Put them in an Indonesian cave without their Bud Light and see how long they survive.