Objective beauty in the classical canon

From the paper:

The main question we addressed in the present study was whether there is an objective beauty, i.e., if objective parameters intrinsic to works of art are able to elicit a specific neural pattern underlying the sense of beauty in the observer. Our results gave a positive answer to this question. The presence of a specific parameter (the golden ratio) in the stimuli we presented determined brain activations different to those where this parameter was violated. The spark that changed the perception of a sculpture from “ugly” to beautiful appears to be the joint activation of specific populations of cortical neurons responding to the physical properties of the stimuli and of neurons located in the anterior insula.

PLoS One

The Golden Beauty: Brain Response to Classical and Renaissance Sculptures

Cinzia Di Dio et al.

Abstract

Is there an objective, biological basis for the experience of beauty in art? Or is aesthetic experience entirely subjective? Using fMRI technique, we addressed this question by presenting viewers, naïve to art criticism, with images of masterpieces of Classical and Renaissance sculpture. Employing proportion as the independent variable, we produced two sets of stimuli: one composed of images of original sculptures; the other of a modified version of the same images. The stimuli were presented in three conditions: observation, aesthetic judgment, and proportion judgment. In the observation condition, the viewers were required to observe the images with the same mind-set as if they were in a museum. In the other two conditions they were required to give an aesthetic or proportion judgment on the same images. Two types of analyses were carried out: one which contrasted brain response to the canonical and the modified sculptures, and one which contrasted beautiful vs. ugly sculptures as judged by each volunteer. The most striking result was that the observation of original sculptures, relative to the modified ones, produced activation of the right insula as well as of some lateral and medial cortical areas (lateral occipital gyrus, precuneus and prefrontal areas). The activation of the insula was particularly strong during the observation condition. Most interestingly, when volunteers were required to give an overt aesthetic judgment, the images judged as beautiful selectively activated the right amygdala, relative to those judged as ugly. We conclude that, in observers naïve to art criticism, the sense of beauty is mediated by two non-mutually exclusive processes: one based on a joint activation of sets of cortical neurons, triggered by parameters intrinsic to the stimuli, and the insula (objective beauty); the other based on the activation of the amygdala, driven by one's own emotional experiences (subjective beauty).

Link

Genetic variation in Native Americans

See Figure 7 for evidence of the substructure within the Native American race.

PLoS Genetics Vol. 3, No. 11, e185 doi:10.1371/journal.pgen.0030185

Genetic Variation and Population Structure in Native Americans

Sijia Wang et al.

We examined genetic diversity and population structure in the American landmass using 678 autosomal microsatellite markers genotyped in 422 individuals representing 24 Native American populations sampled from North, Central, and South America. These data were analyzed jointly with similar data available in 54 other indigenous populations worldwide, including an additional five Native American groups. The Native American populations have lower genetic diversity and greater differentiation than populations from other continental regions. We observe gradients both of decreasing genetic diversity as a function of geographic distance from the Bering Strait and of decreasing genetic similarity to Siberians—signals of the southward dispersal of human populations from the northwestern tip of the Americas. We also observe evidence of: (1) a higher level of diversity and lower level of population structure in western South America compared to eastern South America, (2) a relative lack of differentiation between Mesoamerican and Andean populations, (3) a scenario in which coastal routes were easier for migrating peoples to traverse in comparison with inland routes, and (4) a partial agreement on a local scale between genetic similarity and the linguistic classification of populations. These findings offer new insights into the process of population dispersal and differentiation during the peopling of the Americas.

Link

Genetic structure of European Americans

NOTE: I inadvertetdly posted a draft of this post. Here is the final post; I will leave the draft online since some people already commented on it, before I noticed it.

A previous study on Europeans discovered that Caucasoid Europeans, who form a genetic cluster on a global scale can be further distinguished into subclusters that are correlated with ancestry and geography. Now, a new study on European Americans (hat tip gnxp) appearing in the free online journal PLoS Genetics has carried out a similar analysis of the genetic structure of American "Caucasians".

What I find fascinating about this new study is that an ethnic subgroup within American Caucasoids, namely Ashkenazi Jewish Americans can be distinguished at this point from other Caucasoids. Here is the clustering based on the validated set of markers from the paper:

The distinctiveness of Jewish Americans is probably due to their having a portion of Middle Eastern ancestry. We can only say that Jewish Americans are clearly genetically distinct from the other ethnic groups presented in the study, although it is unclear whether they are distinct from other groups of Middle Eastern background.

As biologically-averse intellectuals continue to question the very existence of race, pragmatic scientists are moving into an era when not only race, but ethnicity may become genetically identifiable.

Unlike race which by definition refers to an identifiable biological cluster, ethnicity may (or may not) refer to such a cluster.

Ethnic distinctiveness is due to both culture and biology, and the relative proportions of the two factors are specific to a particular ethnic group.

When ethnic groups have split recently, co-inhabit a geographical space, frequently intermarry, etc., then it is likely that they will have small biological differences, whereas other ethnic groups may be biologically as well as culturally distinct.

We should be careful to note that there are two levels of ethnic biological distinctiveness: group distinctiveness and individual distinctiveness:

Group distinctiveness means: if you are given the photographs of ten Englishmen on one side and ten Russians on the other, you would be able to decide with a very high level of success which group represented the Russians and which one the Englishmen.

Individual distinctiveness means: if you are given the photographs of ten Englishmen and ten Russians in random order, you would still be able to sort out the Russians from the Englishmen; whether this is possible, and with what level of success is less obvious than in the previous case.

We must wait for more studies with larger samples and more markers to study the biological component of human ethnicity. At present, some groups do seem to have individual distinctiveness in a particular societal context and with a particular set of markers (e.g., Jewish vs. non-Jewish Americans), while others are less distinct (e.g., Greek vs. Italian Americans).

Genetic structure of European Americans

UPDATE (Nov 21)See also some discussion here.

PLoS Genetics (early release)

Discerning the ancestry of European Americans in genetic association studies

Alkes Price et al.

European Americans are often treated as a homogeneous group, but in fact form a structured population due to historical immigration of diverse source populations. Discerning the ancestry of European Americans genotyped in association studies is important in order to prevent false positive or negative associations due to population stratification and to identify genetic variants whose contribution to disease risk differs across European ancestries. Here, we investigate empirical patterns of population structure in European Americans, analyzing 4,198 samples from four genome-wide association studies to show that components roughly corresponding to northwest European, southeast European and Ashkenazi Jewish ancestry are the main sources of European American population structure. Building on this insight, we constructed a panel of 300 validated markers that are highly informative for distinguishing these ancestries. We demonstrate that this panel of markers can be used to correct for stratification in association studies that do not generate dense genotype data.

Link

Sea level rise and the beginning of the Neolithic

From a EurekAlert release about this paper:

The researchers created reconstructions of the Mediterranean and Black Sea shoreline before and after the rise in sea levels. They estimated that nearly 73,000 square km of land was lost to the sea over a period of 34 years. Based on our knowledge of historical population levels, this could have led to the displacement of 145,000 people. Archaeological evidence shows that communities in southeast Europe were already practising early farming techniques and pottery production before the Flood. With the catastrophic rise in water levels it appears they moved west, taking their culture into areas inhabited by hunter-gatherer communities.

Catastrophic early Holocene sea level rise, human migration and the Neolithic transition in Europe

Chris S.M. Turney et al.

Abstract

The collapse of the Laurentidenext term Ice Sheet and release of freshwater 8740–8160 years ago abruptly raised global sea levels by up to 1.4 m. The effect on human populations is largely unknown. Here we constrain the time of the main sea level rise and investigate its effect on the onset of the Neolithic across Europe. An analysis of radiocarbon ages and palaeoshoreline reconstruction supports the hypothesis that flooding of coastal areas led to the sudden loss of land favoured by early farmers and initiated an abrupt expansion of activity across Europe, driven by migrating Neolithic peoples.

Link

Anthropological Research Page status

Just a quick note to readers of the Anthropological Research Page (ARP), which used to be hosted at dienekes.angeltowns.net. Due to a problem with the host (supposed hacker attack), the ARP will no longer to be hosted in Angeltowns.

All the content of the ARP can be found in the Internet Archive, with the latest version being here. The formatting is a bit off, but otherwise all the content is preserved. I will re-upload the ARP to a suitable server once I find the time.

Waist-hip-ratio of mothers and children's intelligence

There is a related story in the New Scientist about the following article.

Evolution and Human Behavior (in press)

Waist-hip ratio and cognitive ability: is gluteofemoral fat a privileged store of neurodevelopmental resources?

William D. Lassek, Steven J.C. Gaulin

Abstract

Upper-body fat has negative effects and lower-body fat has positive effects on the supply of long-chain polyunsaturated fatty acids that are essential for neurodevelopment. Thus, waist-hip ratio (WHR), a useful proxy for the ratio of upper-body fat to lower-body fat, should predict cognitive ability in women and their offspring. Moreover, because teenage mothers and their children compete for these resources, their cognitive development should be compromised, but less so for mothers with lower WHRs. These predictions are supported by data from the Third National Health and Nutrition Examination Survey. Controlling for other correlates of cognitive ability, women with lower WHRs and their children have significantly higher cognitive test scores, and teenage mothers with lower WHRs and their children are protected from cognitive decrements associated with teen births. These findings support the idea that WHR reflects the availability of neurodevelopmental resources and thus offer a new explanation for men's preference for low WHR.

Overweight and obesity in young Greek men

Obes Rev. 2007 Oct 24; [Epub ahead of print]

Prevalence of overweight and obesity in young Greek men.

Papadimitriou A, Fytanidis G, Papadimitriou DT, Priftis KN, Nicolaidou P, Fretzayas A.

We determined the prevalence of overweight and obesity in young Greek men in 2006 and examined variations related to their place of residence and educational level. Body height and weight were measured in 2568 conscripts of the Greek army, aged 19-26 years. The calculated body mass index (BMI, kg m(-2)) was correlated to their socio-demographic characteristics, i.e. level of education and place of residence (urban or rural). Overweight and obesity were defined according to the World Health Organization classification. Mean BMI (standard deviation) of the conscripts was 24.7 (4.2). The prevalence of overweight (30 > BMI >/= 25 kg m(-2)) was 28.5% and correlated positively with a higher educational level, whereas the prevalence of obesity (BMI >/= 30 kg m(-2)) was 10.4% and correlated positively with a lower educational level. Our data were compared with those of similar studies performed in the years 1969: BMI 23.8 (1.4) (P < 0.0001) and 1990: BMI 23.8 (2.9) (P < 0.0001), showing a positive secular trend for BMI in Greek conscripts in the last 16 years. In conclusion, we documented an alarmingly high prevalence of overweight and obesity among young Greek men.

Link

Long Live the 28th October 1940

How humans became warlike altruists

Via Yann, I am alerted to a new Science report on the evolution of parochial altruism. The authors describe how hypothetical genes for parochialism (P) and altruism (A) could have co-evolved. Parochial altruists (PA) risk death in combat with other groups. How could the PA combination evolve? 

The authors suggest that PA fighters do risk death, but in conflicts between groups, it is the groups with more PAs that have a higher chance of winning. Thus, while parochial altruists are selected against (because they risk their lives for their group), they are also selected for (because they kill off more members of less-PA groups in violent conflicts). Moreover, the losing side's numbers are replenished by conquerors' genes (thus becoming more PA).

The authors contend that archeologically-derived estimates of group warfare are consistent with their scenario for the evolution parochial altruism. One would think that other, more recent, historical examples could also be used, e.g., between city-state warfare in classical Greece. 

The paper's innovation is that a seemingly "irrational" behavior from selfish genes' point of view could nonetheless evolve. The genes that cause their bearers to die in patriotic battles may die, but their competing alleles on the losing side may suffer more.

Science 26 October 2007:
Vol. 318. no. 5850, pp. 636 - 640
DOI: 10.1126/science.1144237

The Coevolution of Parochial Altruism and War

Jung-Kyoo Choi1 and Samuel Bowles2*

Altruism—benefiting fellow group members at a cost to oneself—and parochialism—hostility toward individuals not of one's own ethnic, racial, or other group—are common human behaviors. The intersection of the two—which we term "parochial altruism"—is puzzling from an evolutionary perspective because altruistic or parochial behavior reduces one's payoffs by comparison to what one would gain by eschewing these behaviors. But parochial altruism could have evolved if parochialism promoted intergroup hostilities and the combination of altruism and parochialism contributed to success in these conflicts. Our game-theoretic analysis and agent-based simulations show that under conditions likely to have been experienced by late Pleistocene and early Holocene humans, neither parochialism nor altruism would have been viable singly, but by promoting group conflict, they could have evolved jointly.

Link

Domestication of barley

Genetics. 2007 Oct 18; [Epub ahead of print]

Molecular phylogeography of domesticated barley traces expansion of agriculture in the Old World.

Saisho D, Purugganan M.

Okayama University.

Barley (Hordeum vulgare ssp. vulgare) was first cultivated 10,500 years ago in the Fertile Crescent and is one of the founder crops of Eurasian agriculture. Phylogeographic analysis of five nuclear loci and morphological assessment of two traits in >250 domesticated barley accessions reveals that landraces found in South and East Asia are genetically distinct from those in Europe and North Africa. A Bayesian population structure assessment method indicates that barley accessions are subdivided into 6 clusters, and that barley landraces from 10 different geographical regions of Eurasia and North Africa show distinct patterns of distribution across these clusters. Using haplotype frequency data, it appears that the Europe/North Africa landraces are most similar to the Near East population (FST = 0.15) as well as wild barley (FST = 0.11) and are strongly differentiated from all other Asian populations (FST = 0.34 to 0.74). A neighbor-joining analysis using these FST estimates also supports a division between Europe, North African and Near East barley types from more easterly Asian accessions. There is also differentiation in the presence of a naked caryopsis and spikelet row number between eastern and western barley accessions. The data support the differential migration of barley from two domestication events that led to the origin of barley - one in the Fertile Crescent and another further east, possibly at the eastern edge of the Iranian Plateau - with European and North African barley largely originating from the former while much of Asian barley arising from the latter. This suggests that cultural diffusion or independent innovation are responsible for the expansion of agriculture to areas of South and East Asia during the Neolithic Revolution.

Link

On the James Watson Black IQ controversy

There are two issues regarding the recent controversy started by James Watson's comments about the intelligence of Africans.

The scientist, who won the Nobel prize for his part in discovering the structure of DNA, was quoted in an interview in The Sunday Times saying he was “inherently gloomy about the prospect of Africa” because “all our social policies are based on the fact that their intelligence is the same as ours - whereas all the testing says not really.”

The first issue is that Watson's statements, whether one agrees with them or not should not be punished, and represent a valid stance to the problem of population differences in intelligence. Of course institutions (such as the Cold Spring Harbor lab) have the right to choose who works for them, but they also have the responsibility to foster free speech.

One would be sympathetic to CSH's condemnation of Watson if it was done on scientific grounds. For example, a scientist denying the fact of evolution could not reasonably expect to have no reprecussions in his career. Institutions are expected to make sure they don't promote bad science, which is not necessarily unorthodox science (which should be encouraged), but rather unargued or anti-empirical science.

However, CSH's stance has been motivated by political or social considerations. How could it be otherwise, since the identification of intelligence-fostering genes differentiating populations has not come about yet. The prudent stance is to be agnostic about this issue, until such genes are discovered, or their continued non-discovery makes one doubtful of their existence.

The second issue is that Watson's factual comments are entirely accurate! Sub-Saharan Africans do indeed have lower intelligence than people in western societies. That is an observable fact (fact F). What is not certain is whether or not this fact is due to inherent genetic deficiencies (position A) or due to environmental or socio-cultural problems (position B). Social policies should take into account F while the scientists figure out whether A or B explains F.

As an analogy, a cook has to take into account that his knife is blunt before he figures out whether it is blunt because it was made poorly or from repeated use.

According to Watson:

A priori, there is no firm reason to anticipate that the intellectual abilities of people geographically separated during their evolution should prove to have evolved identically. Our wanting to reserve equal powers of reason as some universal heritage of mankind will not be enough to make it so.

Once again, Watson's comments are reasonable. Notably they do not identify which populations may have inherent (evolutionary) differences in intelligence, nor do they attempt to quantify the importance of such differences. They simply state the -a priori sensible- stance of a scientist that a phenomenon (e.g., the evolution of cognitive ability) would not have proceeded in the same way under different circumstances.

UPDATE: A post-controversy article by James Watson in the Independent. Excerpt:

We do not yet adequately understand the way in which the different environments in the world have selected over time the genes which determine our capacity to do different things. The overwhelming desire of society today is to assume that equal powers of reason are a universal heritage of humanity. It may well be. But simply wanting this to be the case is not enough. This is not science.

Limitations of genetic ancestry testing

From the EurekAlert release about an upcoming Science article:

Some of the tests’ limitations identified by Bolnick and her co-authors include:

• Most tests trace only a few of your ancestors and a small portion of your DNA,
  
• Tests are unlikely to identify all of the groups or locations around the world where a test-taker’s relatives are found,
  
• Tests may report false negatives or false positives,
  
• Limited sample databases mean test results are subject to misinterpretation,
  
• There is no clear connection between DNA and racial/ethnic identity,
  
• Tests cannot determine exactly where ancestors lived or what ethnic identity they held.
  

Neanderthals had same version of FOXP2 "language gene" as modern humans

Via National Geographic:

A team of European researchers tested Neandertal bones recovered from a Spanish cave for a certain gene, called FOXP2, that has been dubbed "the speech and language gene."

It's the only gene known so far that plays a key role in language. When mutated, the gene primarily affects language without affecting other abilities.

The new study suggests that Neandertals (often spelled Neanderthals) had the same version of this gene that modern humans share—a different version than is found in chimpanzees and other apes.

"From the point of this gene, there is no reason to think that Neandertals did not have language as we do," said the study's lead author, Johannes Krause of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

"Of course many genes are involved in language, so we can't say from this result alone that Neandertals spoke just as modern humans do," Krause added.

Genome-wide detection of positive selection

Nature 449, 913-918 (18 October 2007) | doi:10.1038/nature06250; Received 8 August 2007; Accepted 13 September 2007

Genome-wide detection and characterization of positive selection in human populations

Pardis C. Sabeti et al.

With the advent of dense maps of human genetic variation, it is now possible to detect positive natural selection across the human genome. Here we report an analysis of over 3 million polymorphisms from the International HapMap Project Phase 2 (HapMap2)1. We used 'long-range haplotype' methods, which were developed to identify alleles segregating in a population that have undergone recent selection2, and we also developed new methods that are based on cross-population comparisons to discover alleles that have swept to near-fixation within a population. The analysis reveals more than 300 strong candidate regions. Focusing on the strongest 22 regions, we develop a heuristic for scrutinizing these regions to identify candidate targets of selection. In a complementary analysis, we identify 26 non-synonymous, coding, single nucleotide polymorphisms showing regional evidence of positive selection. Examination of these candidates highlights three cases in which two genes in a common biological process have apparently undergone positive selection in the same population:LARGE and DMD, both related to infection by the Lassa virus3, in West Africa;SLC24A5 and SLC45A2, both involved in skin pigmentation4, 5, in Europe; and EDAR and EDA2R, both involved in development of hair follicles6, in Asia.

Link

Conservation of frequently used words in Indo-European languages

I wonder what implications -if any- this finding has on attempts to date the PIE language before the dispersal of its speakers. After all, PIE is constructed based on words found in several (at least two) daughter languages, and thus will tend to use words that are conserved more (since they have survived in more than one language). The implication of this article is that conserved words are replaced at a slower rate. Hence, it is important to take into account the rates of evolution of different terms when trying to figure out how long ago two languages shared a common ancestor.

Nature 449, 717-720 (11 October 2007) | doi:10.1038/nature06176; Received 30 April 2007; Accepted 17 August 2007

Frequency of word-use predicts rates of lexical evolution throughout Indo-European history

Mark Pagel et al.

Greek speakers say "ουρα", Germans "schwanz" and the French "queue" to describe what English speakers call a 'tail', but all of these languages use a related form of 'two' to describe the number after one. Among more than 100 Indo-European languages and dialects, the words for some meanings (such as 'tail') evolve rapidly, being expressed across languages by dozens of unrelated words, while others evolve much more slowly—such as the number 'two', for which all Indo-European language speakers use the same related word-form1. No general linguistic mechanism has been advanced to explain this striking variation in rates of lexical replacement among meanings. Here we use four large and divergent language corpora (English2, Spanish3, Russian4 and Greek5) and a comparative database of 200 fundamental vocabulary meanings in 87 Indo-European languages6 to show that the frequency with which these words are used in modern language predicts their rate of replacement over thousands of years of Indo-European language evolution. Across all 200 meanings, frequently used words evolve at slower rates and infrequently used words evolve more rapidly. This relationship holds separately and identically across parts of speech for each of the four language corpora, and accounts for approximately 50% of the variation in historical rates of lexical replacement. We propose that the frequency with which specific words are used in everyday language exerts a general and law-like influence on their rates of evolution. Our findings are consistent with social models of word change that emphasize the role of selection, and suggest that owing to the ways that humans use language, some words will evolve slowly and others rapidly across all languages.

Link