The ape human split is a bit of a moving target. In the 1970s and early 1980s, there were geneticists who placed it at very recent (close to 4 million years ago) and palaeoanthropologists, using fossils, who placed it at much earlier. During the 1980s, the ape-human split moved back in time because of the importance of sivapithecus, then later in time when Sivapithecus slipped and fell out of the hominid/hominin (human ancestor) family tree. Meanwhile the geneticists were moving towards a more and more recent split. At one point not too long ago, all the evidence converged with the split being around five million years ago. The fossils and the genes agreed, and there were rumors (but nothing published) saying that palaeoanthropologists working in Ethiopia were prepared (soon) to announce that one of the fossils dating to this time had “less then fully developed” bipedalism.But science marches on, and the kinds of questions we are asking of the human fossil record are more detailed than the fossil record usually gives up in a mere few decades of research. So new finds came along and everything changed again. Now, there is a new paper by Richmond and Jungers suggesting that one of the earliest hominid, Orrorin tugenensis, was just as bipedal as any australopith, yet is much farther back in time than, and in many ways, different from our genus (Homo). Continue reading Early, somewhat controversial hominid walked like an Australopith
Tag Archives: Anthropology
Geographic Patterns of Genome Admixture in Latin American Mestizos
Significant cultural and physical differences … the stuff of race and ethnicity … are prominent when people move across continents or between them. Eventually, the ponderous events of history, which involve occasional foldings in the continuum of human variation, causing apparent patchiness, are offset by the frequent events of human activities, resulting in genetic and cultural admixtures. What colonialism, invasion, and migration do is undone.A new study out in PLoS Genetics examines this phenomenon for Latin America, with a study of genetic admixture. Continue reading Geographic Patterns of Genome Admixture in Latin American Mestizos
Evidence for an ancient lineage of modern humans
It almost seems like there are two separate research project under way regarding the evolutionary history of Homo sapiens. One focuses on recent humans, tends to use DNA as a major source of information, and from this base projects back into the past. This approach tends to confirm the idea that humans share an African origin with a subsequent spread from Africa, with various degrees of complexity in that series of historical events. The other focuses on early human remains, sometimes including remains that would be placed by some in a separate species or sub species. This sort of approach typically results in a similar conclusion regarding the African origin.But the two populations … modern or recent humans and humans several tens of thousands of years old do not necessarily share a history that has been coherently assembled by researchers. Of course, they shared an actual history, but do the lines linked together to make reconstructed phylogentic trees from these two data sources match up or integrate in any sensible way? Not really.A new paper coming out in the Journal of Human Evolution shares some light on how we might connect these similar but unintegrated reconstructions. Continue reading Evidence for an ancient lineage of modern humans
Colonization of the New World
There is a fairly new paper in PLoS on the colonization of the New World. It is the latest in a series of attempts to synthesize biogeography, climate change related paleoenvironmental reconstruction, genetics, and archaeology. Continue reading Colonization of the New World
Why the Hobbits of Flores Were Probably Not Broken People
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.
Continue reading Why the Hobbits of Flores Were Probably Not Broken People
Wild Gorillas Gone Wild
This is a photograph of wild western lowland gorillas copulating in, sort of, the missionary position. This shot was taken in the Nouabale-Ndoki National Park in the Republic of Congo. Continue reading Wild Gorillas Gone Wild
Lemur Family Tree Mapped
A DNA phylogeny based on over 200 species of lemurs and related species is now available. Continue reading Lemur Family Tree Mapped
The Potato and Human Evolution
Fallback foods are the foods that an organism eats when it can’t find the good stuff. It has been suggested that adaptive changes in fallback food strategies can leave a more distinct mark on the morphology of an organism, including in the fossil record, than changes in preferred food strategies. This assertion is based on work done by the Grants and others with Galapagos Island finches, by Richard Wrangham and me with hominids, and by Betsy Burr and me with rodents. Continue reading The Potato and Human Evolution
What did the immediate ancestor of chimps and humans look like?
Comparing living chimpanzees to living humans, in reference to the species that gave rise to these two closely related species, is one way to frame questions about the evolution of each species. Continue reading What did the immediate ancestor of chimps and humans look like?
Darwin and the Voyage: 08 ~ The Gauchos
We’re half way through Darwin Month, and only a tiny ways through the voyage. Need to hurry up! So, let’s skip ahead a bit and hit the Gauchos…. (This is a modified version of a post from my old blog). Continue reading Darwin and the Voyage: 08 ~ The Gauchos
Interesting News Items (with commentary)
Bats; Signaling in the Rain Forest; Sumatran Tiger Body Parts; Humans in the New World 20,000 years ago. Continue reading Interesting News Items (with commentary)
Darwin and the Voyage: 07 ~ South of the Tropics
Eventually, the Beagle headed south to the area of Uruguay and Argentina, still on the Atlantic Coast, where extensive mapping of the coastal waters was required. Continue reading Darwin and the Voyage: 07 ~ South of the Tropics
Are We In The Anthropocene? No.
Proposals to give the latter part of the present geological period (the Holocene) a new name … the Anthropocene … are misguided, scientifically invalid, and obnoxious. However, there is a use for a term that is closely related to “Anthropocene” and I propose that we adopt that term instead. Continue reading Are We In The Anthropocene? No.
Biology of Color Preference
Color is funny. Anthropologists have long known that different cultures have different relationships, linguistically and in day to day practice, to the color spectrum. For example, the Efe Pygmy Hunter-Gatherers of the Ituri Forest describe things as white, black, or red, and that’s it. They live in a world of green, so it does not get a mention. Going with the model for “Eskimos” having a hundred words for snow because snow is so important in their environment, one would expect that the Efe would have a hundred words for green. On the other hand, the Efe Hunter-Gatherers must have a fairly primitive culture, compared, say, to those of us living in Coon Rapids Minnesota, that of course they have fewer words for different colors.
Of course, this is all a bunch of hooey. First, we don’t call them “Eskimos.” We call them “Inuit.” “Eskimo” is a bad word. It would be like calling the Irish “Drunken Leprechauns.” Second, the “fact” that the Inuit have a hundred words for snow is simply not true. It is an Urban Legend. Third, the great variation in something — any thing — does not necessarily demand a rich lexicon to describe it. You — yes, you — rely heavily on computers, right? Many computer users presumably need to have a concept of “memory” and the memory their computers use — related to the choices you make when buying or using a computer, where and how you store your documents, etc. But this concept is often appallingly simplified. I know many people who can’t distinguish between storage of data on a hard drive from storage of data in RAM. And there are many kinds of hard drive and many kinds of RAM. And then there is processor cache, video memory, and so on. There are probably over two dozen kinds of memory, it matters to any computer user, and most computer users have either one word for memory or two. (“Memory” or “Hard drive” and “Memory”)
Finally, if the Efe are Primitive, then I’m a monkey’s uncle. Indeed, both are untrue. The Efe are far from primitive and I’m a monkey’s great great great …. great great nephew, not uncle. The Efe have one of the largest brain to body ratios of any people. I’ve never met an Efe man who knew fewer than four different languages. I’ve never met an Efe who was not very smart. I can’t say any of these things for the population living in Coon Rapids, or even Edina, Minnesota.
So why do the Efe not seem to even have a word for the color green?
I can think of two answers to that question. One is that they do but have not bothered to teach this to us. I spent years living with them, and there were basic, day to day things that I learned right up to the last day I was with them. Sure, linguists presumably asked them about this, but that means little considering that only a handful of linguists have actually worked with them. The other explanation is that this is a stupid question. We only think that one needs a large number of words for the color green (if you are an Efe) because we mistakenly think the Inuit have a hundred words for snow.
Then there is the issue of gender and color. I am not color blind, but I am a man. Therefore I have only a few words for color. Let’s see. There’s black and white, green red and yellow, and pretty much that’s it. OK, maybe purple as well. Brown is a form of lightish black. I am not color blind. I’m simply not that interested.
Boys = blue, girls = pink. We know this because these are the colors of clothing, decorations and wall paper or paint in nurseries, etc. Anthropologists will tell you that this blue/pink gender thing is cultural, and that you can find exceptions to it, even reversals, if you look around the world and across history. For instance, the color association with the emperor of Rome was some girley color like purple.
A current study in the journal Current Biology claims to have found a non-culturally generated (but nonetheless culturally modified) gender difference in color preference.
The long history of color preference studies has been described as “bewildering, confused and contradictory”. Although recent studies … tend to agree on a universal preference for ‘blue’, the variety and lack of control in measurement methods have made it difficult to extract a systematic, quantitative description of preference. Furthermore, despite abundant evidence for sex differences in other visual domains, and specifically in other tasks of color perception … there is no conclusive evidence for the existence of sex differences in color preference. This fact is perhaps surprising, given the prevalence and longevity of the notion that little girls differ from boys in preferring ‘pink’. Here we report a robust, cross-cultural sex difference in color preference, revealed by a rapid paired-comparison task. Individual color preference patterns are summarized by weights on the two fundamental neural dimensions that underlie color coding in the human visual system. We find a consistent sex difference in these weights, which, we suggest, may be linked to the evolution of sex-specific behavioral uses of trichromacy.Anya C. Hurlberta and Yazhu Linga. “Biological components of sex differences in color preference.” Current Biology. Volume 17, Issue 16, 21 August 2007, Pages R623-R625.
I think the study design is good and the results convincing, that there is a sex difference in color preference along one aspect of the way color is perceived. Here is what the difference looks like in the figure the researchers provide:
As implied in the summary, this difference corresponds to male-female differences in visual processing. This is believable.
The ultimate (evolutionary) explanation that the researchers give is weaker. It is a fairly typical post-hoc Environment of Evolutionary Adaptedness argument. Females prefer or are more perceptive of red because they are gathering berries found in a background of green leafy stuff. Or, alternatively, females evolved to be sensitive to social signals (blushing).
We speculate that this sex difference arose from sex-specific functional specializations in the evolutionary division of labour. The hunter-gatherer theory proposes that female brains should be specialized for gathering-related tasks and is supported by studies of visual spatial abilities. Trichromacy and the L-M opponent channel are ‘modern’ adaptations in primate evolution thought to have evolved to facilitate the identification of ripe, yellow fruit or edible red leaves embedded in green foliage. It is therefore plausible that, in specializing for gathering, the female brain honed the trichromatic adaptations, and these underpin the female preference for objects ‘redder’ than the background. As a gatherer, the female would also need to be more aware of color information than the hunter. This requirement would emerge as greater certainty and more stability in female color preference, which we find. An alternative explanation for the evolution of trichromacy is the need to discriminate subtle changes in skin color due to emotional states and social-sexual signals; again, females may have honed these adaptations for their roles as care-givers and ’empathizers’ .
Why do I say this is a weak post-hoc argument? For the simple reason that a reversal of their findings could be equally well explained. The game sought by hunter-gatherers is distinguished from a green foliage-rich background by its reddish-brown hue. Most meat actually collected by male hunter-gatherers is not from shooting an animal dead with an arrow, but by wounding it and following an often very subtle blood (red) trail. Also, among the Efe, men gather wild fruit about as often as do women, and the food women gather from the wild tends to be either green or underground. If the Efe were the forager culture used to represent the human past by modern evolutionary psychologists, many of the ultimate, evolutionary, explanations attached to various findings would be very different.
Regarding the blushing: Since white skin against which blushing is most obvious is a recent mutation (and a rather harmful one at that), I think this argument can be rejected out of hand. Nonetheless, this is a good piece of research, well done, and of great interest.
HURLBERT, A., LING, Y. (2007). Biological components of sex differences in color preference. Current Biology, 17(16), R623-R625. DOI: 10.1016/j.cub.2007.06.022
Four Stone Hearth Blog Carnival 33
Welcome to the Four Stone Hearth Blog Carnival #33, ‘specializing’ in the four fields of anthropology. The previous edition of 4SH can be found at Testimony of the Spade, and the next edition will be hosted by Our Cultural World. The main page for Four Stone Hearth has additional information on the carnival, and you can submit entries via Blog Carnival.