Hobbit News

This report is from today’s London Independent. The source is the latest issue of Nature, so there will doubtless be other reports.

Update from Razib: Carl Zimmer and John Hawks have much more.

One point that is really confusing about the Hobbits is their small brain size. Consider the graph to the left. Human (hominids) brains keep getting larger, come rain or shine. The Hobbits, if they truly are what is claimed, radically reversed this trend. Convential explanations of island ecology seem a bit weak when set against this almost inevitable encephalization that seems to have characterized our lineage.

These papers are so HOTT right now!

I was poking around looking for something else and found this ESI special topics website. It updates every other month and provides interviews with the authors of the most highly cited papers at the time. I really think the “fronts” are interesting and could be useful. They give you a map of journal articles that seem to be forming a cluster and generating excitement within a certain field. Here’s one for hippocampal GABA(A) receptors.

I’m hoping they do a map for the RNA decapping and degradation since they have identified it as a Fast Moving Front. They have an interview with Roy Parker about P-bodies and RNA degradation here. I’ve done a little bit on the topic before. The hot topic in the social sciences is apparently “Democracy“. So check it out. ESI special topics: from Decapping to Democracy.

Fewer people graduating with science & tech degrees

Percentage of Students Earning Degrees in Science and Math Has Fallen, GAO Tells Lawmakers ($$$), but this is all you need to know:

The GAO reported that 27 percent of students obtained degrees in those fields, which are known as the STEM disciplines, in the 2003-4 academic year, compared with 32 percent in 1994-95. It also noted that the number of degrees obtained in engineering, the biological sciences, and certain technical fields declined in the past decade. The number of graduate degrees awarded in the STEM fields also declined, it said.

Percentage is crucial. More & more people go college, but it may simply be that the inclination and aptitude for technical disciplines was long ago tapped out. And frankly, my personal experience is that many of the “Studies” (but not all) are joke degrees. A friend who did biochemistry and international studies told me that the latter felt like what she could have learned in coffee shop bull sessions.

Global warming = biodiversity (in the future)

The title is tongue in cheek, some researchers now are suggesting that speciation may be proportional to a particular energetic value. R.A. Fisher wanted an “ideal gas law” for evolutionary genetics, but this is ridiculous! In any case, one issue that many of us who are interested in paleoanthropology will have noted is that Africa seems to have been the repeated mother of hominid species. That is, “erectus” left around 2 million years ago, only to be swept aside by moderns around 50,000 years ago. Why Africa twice? This might be part of the answer, and is a flip to WIlliam H. Calvin’s Ice Age driven hypothesis in .

Roaring out of Africa

This lion research is just cool. Hey, I’m human, I’m a sucker for cats, and the bigger the better:

Understanding the phylogeographic processes affecting endangered species is crucial both to interpreting their evolutionary history and to the establishment of conservation strategies. Lions provide a key opportunity to explore such processes; however, a lack of genetic diversity and shortage of suitable samples has until now hindered such investigation. We used mitochondrial control region DNA (mtDNA) sequences to investigate the phylogeographic history of modern lions, using samples from across their entire range. We find the sub-Saharan African lions are basal among modern lions, supporting a single African origin model of modern lion evolution, equivalent to the ‘recent African origin’ model of modern human evolution. We also find the greatest variety of mtDNA haplotypes in the centre of Africa, which may be due to the distribution of physical barriers and continental-scale habitat changes caused by Pleistocene glacial oscillations. Our results suggest that the modern lion may currently consist of three geographic populations on the basis of their recent evolutionary history: North African-Asian, southern African and middle African. Future conservation strategies should take these evolutionary subdivisions into consideration.

I’ve put two images of interest from the article below the fold.

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Another model on human demographic expansion out of Africa

The American Journal of Human Genetics has a paper in its pre-print section titled “A geographically explicit genetic model of worldwide human settlement history.” I quickly skimmed it (and uploaded it into the GNXP forum). I have serious issues some of the inferences made in regards to the “obvious” fit of such coalescence data with a particular demographic history. I am convinced that meta-population dynamics tend to be ignored (in part because they are just another complication) even though they can also explain the data. Nevertheless, this jumped out at me:

We further neglected key events such as spatial and temporal environmental variation. Our results thus suggest that various environmental factors tend to be spatially relatively homogenous for human migration patterns, when considered over a large geographic distance.

As I stated above, meta-population dynamics, local extinctions and recolonizations, are issues that the authors seem to ignore when it comes to ignore their there results, especially given that environmental parameters are likely to be very relevant to marginal groups. They even allude to what seems like an abortive extra-African colonization in the Levant by anatomically modern H. sapiens sapiens which ended in local population extinction. But, the idea that humans are relatively buffered from environmental variation is roughly correct, and I’m talking about “humans” in a very broad sense. Our genus, Homo, broke out of the African continent almost immediately after its genesis. Dmanisi shows that beyond a shadow of a doubt.

The ol' ball and chain

Given that some of the readers here are actual, like, scientists, this article on the relationship between marriage and scientific success may be of interest. Actually, the only interesting part is the intro:

Several years ago, Satoshi Kanazawa, then a psychologist at the University of Canterbury in Christchurch, New Zealand, analyzed a biographical database of 280 great scientists–mathematicians, physicists, chemists, and biologists. When he calculated the age of each scientist at the peak of his career–the sample was predominantly male–Kanazawa noted an interesting trend. After a crest during the third decade of life, scientific productivity–as evidenced by major discoveries and publications–fell off dramatically with age. When he looked at the marital history of the sample, he found that the decline in productivity was less severe among men who had never been married. As a group, unmarried scientists continued to achieve well into their late 50s, and their rates of decline were slower.

“The productivity of male scientists tends to drop right after marriage,” says Kanazawa in an e-mail interview from his current office at the London School of Economics and Political Science in the United Kingdom. “Scientists tend to ‘desist’ from scientific research upon marriage, just like criminals desist from crime upon marriage.”

Kanazawa’s perhaps controversial perspective is that of an evolutionary psychologist. “Men conduct scientific research (or do anything else) in order to attract women and get married (albeit unconsciously),” he says. “What’s the point of doing science (or anything else) if one is already married? Marriage (or, more accurately reproductive success, which men can usually attain only through marriage) is the goal; science or anything else men do is but a means. From my perspective, scientists are no different than anybody else; evolutionary psychology applies to all humans equally,” he adds.

The rest is a bunch of quotes from dudes bitching about how they can’t meet women; read at your own risk.

Related: Kanazawa on domestic violence and the sex ratio

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Happier homes => Hotter daughters?

Jeez, how long has it been since we had a good chat about comely girls? Via Dienekes, this article shows that in a sample of early 20-something girls at a Scottish university, daughters of happily married parents (HM) had more attractive and feminine faces than those whose parents either had separated pre-puberty (S) or had remained married but unhappily (UM). Color pictures in PDF here (L-to-R: S, UM, HM). As for body shape, the HM daughters had lower BMI (i.e., were slimmer) and lower waist-to-hip ratio (WHR, i.e., a more hourglass figure) than the other two groups. The authors make it clear that theirs is a correlational study that remains agnostic on the causal mechanisms, though Dienekes’ post & comments discuss possibilities.

First, though, there’s an interesting wrinkle: the authors and some of their references argue that the independent variable is presence of father (or parental cohesion), which yields the order S -> UM -> HM. The dependent variables are the markers of attractiveness, etc. However, the functions do not always turn out to be monotonic — some curves decrease and switch to increasing like a U. Table 2 in the article summarizes the rank-ordering on the 3 facial markers. For “attractiveness,” the order is UM -> S -> HM. For “health,” it’s UM -> S = HM. And for “masculinity,” it’s UM = S -> HM. Thus, if our graph has “parental cohesion” on the x-axis, the curve would be U-shaped for “attractiveness” and “health,” though J-shaped for “masculinity.” For body shape, Figure 2 shows that one variable, “impedence” (a measure of % body fat), wasn’t significantly different among the groups. “Waist-to-chest ratio” (WCR) is a measure of the inverted-triangle shape of the upper body, something that men don’t pay much attention to. The two important variables are BMI and WHR. On the latter, HM had significantly more hourglass figures than UM, though the S didn’t differ significantly from either. On BMI, the HM were significantly slimmer than S, and apparently UM are in between.

So, aside from perhaps BMI, the facial and bodily markers suggest that the underlying cause increases thusly: UM -> S -> HM. Call it “home harmony.” The biological correlate of this in the literature the authors cite is response to stress (cortisol), so perhaps in the sample the daughters of UM parents experienced greater stress from the arguing, bickering, and so on, compared to the daughters of S parents, who at least weren’t frequently fighting in the daughter’s presence. Remember, the sample was of university students, so it likely didn’t include those from the underclass or the lower end of the working class. That suggests that, above a certain threshold of SES, having antagonistic parents stay together produces more dissonance in the home than if they separated, at least from the daughter’s p-o-v.

Now on to the possible causes. Well, the first is what I just mentioned: the prevailing view that differences among father absent or father present homes reflect differences in stress during childhood. Humans have evolved a common set of responses, and those who happen to grow up without fathers turn out a different way from those who grow up with fathers. This is an environment / chance explanation. But as mentioned at the lead author’s webpage and in the comments at Dienekes’ post, there is also a (not mutually exclusive) genetic explanation: fathers who are apt to easily leave their wife & children, or who are too unruly for the wife to bother staying with, could be this way in part due to genes (perhaps for response to testosterone) which they pass on to their daughters.

Moreover, since it’s usually not impossible to read warning signs about who’s less reliable & dependable than who else, we could also look at the mothers who mate with the more flight-prone males. Such females would likely show a greater propensity for risk-taking or thrill-seeking, presumably heritable, so assortative mating could be exacerbating the genetic influence of father. It would be interesting to take a large sample of males from S, UM, and HM parents and ask them who they were most attracted to among the S, UM, and HM female composite faces. That would settle whether there was an assortative mating effect. It would also be interesting to genotype those from S vs HM parents to see if the former were more likely than expectation to have the 7R allele at the DRD4 locus — if so, that would suggest involvement of heritable personality traits like novelty-seeking, impulse control, and so on, in both the dissolution of the marriage as well as the suite of behavioral outcomes of the daughter. It might also suggest why the daughters of S parents were judged more attractive than those from UM parents — presumably the S parents were more “wild child”-like than the UM parents who had to “wimp out” to some degree in suppressing their impulses to split up. Perhaps greater “wild child”-ness increases one’s sexiness score (since “sexy” usually connotes something more exciting or thrilling than just “attractive” or “beautiful”). The prototype here would be Angelina Jolie, who looks more than a bit masculine, who’s well known to be possessed of a thrill-seeking disposition, and whose parents divorced when she was a baby.

To close, why would a tinge (though not an excess) of masculinity and rebelliousness make a female sexier, when these usually serve to make males sexier? These traits mix a “danger” component with the “beauty” component, which creates the thrill. My hypothesis is that, assuming the “cheesecake theory” of aesthetic pleasure popularized in — that art, cuisine, etc. are human devices to directly stimulate our evolved pleasure centers — we enjoy stimulating not just the “relaxation” (or parasympathetic) division of our nervous system, but occasionally the “danger” (or sympathetic) division as well. Things that highly stimulate these divisions are, respectively, the beautiful and the sublime in an older terminology. Those whose aesthetic preferences lead them to want more than others to stimulate their “danger” system would appreciate a greater dosage of dangerous, masculine traits in females. Rawrrr.

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Evolutionary genomics and the human brain

PLOS Genetics has a nice review titled The Jewels of Our Genome: The Search for the Genomic Changes Underlying the Evolutionarily Unique Capacities of the Human Brain. It is short and pithy and hits the major points (e.g., SNPs vs. duplications vs. gene expression), so I see no reason to offer any commentary or review of an an already satisfactory commentary and review. If you want original research articles in this area, go here. Some of the material is even open access now.
Update: John Hawks has more.