Neandertal & H. sapiens sapiens interbreeding

Modern Humans, Neanderthals May Have Interbred:

“To me, what happened is that the Neanderthals were [genetically] absorbed into and overwhelmed by modern humans coming into Europe from Africa, and they disappeared through this absorption,” Trinkaus said.

Examining the bones, Trinkaus discovered certain features that he believes are Neanderthal elements incorporated into this early Homo sapien.

Features at the back of the woman’s skull and in her lower jaw, especially, “are found in high frequency in Neanderthals” but are absent in bones from older groups of Homo sapiens from Africa, he said.

The paper will be on the PNAS site sometime this week, apparently it is behind an ’embargo wall’ right now and already in circulation amongst those with special access. This is a morphology story, it seems that individuals with a mosaic of African and Neandertal traits existed in Europe ~30,000 years ago. What does this tell us? If we didn’t have the genetic evidence I think one would have to assume that the highest likelihood is that some interbreeding went on. But didn’t we learn last week that humans and Neandertals were separate and distinct lineages, with the latter contributing nothing to the genome of the former?

1) Not all regions of the genome are created equal when it comes to a particular phenotype (e.g., if you looked at Y lineages Mexican Americans should be Spaniards, if you looked at mtDNA lineages they should be Amerindians, and yet they are a mix of both when it comes to the vast majority of their genome, the Y & mtDNA just happen to be convenient for genetic analysis).

2) Selection can operate on specific regions of a genome independently from others. This is why you see “selective sweeps” across lengths of sequence while neutrality seems to be operative elsewhere.

3) There nature of genomic sequences shaped by neutral evolution vs. those subject to selective forces can differ a great deal because of the alternative dynamics at work as a function of time. The former can be far more informative about ancestry than the latter because in the case of the latter not all ancestors are created equal.

4) There are always papers in the pipeline which can modulate your priors. One should credit Trinkaus et. al. because of other pieces of data which will come to light in the near future.

Il Principe as a evolutionary force

The dynamics of Machiavellian intelligence. Abstract:

The “Machiavellian intelligence” hypothesis (or the “social brain” hypothesis) posits that large brains and distinctive cognitive abilities of humans have evolved via intense social competition in which social competitors developed increasingly sophisticated “Machiavellian” strategies as a means to achieve higher social and reproductive success. Here we build a mathematical model aiming to explore this hypothesis. In the model, genes control brains which invent and learn strategies (memes) which are used by males to gain advantage in competition for mates. We show that the dynamics of intelligence has three distinct phases. During the dormant phase only newly invented memes are present in the population. During the cognitive explosion phase the population’s meme count and the learning ability, cerebral capacity (controlling the number of different memes that the brain can learn and use), and Machiavellian fitness of individuals increase in a runaway fashion. During the saturation phase natural selection resulting from the costs of having large brains checks further increases in cognitive abilities. Overall, our results suggest that the mechanisms underlying the “Machiavellian intelligence” hypothesis can indeed result in the evolution of significant cognitive abilities on the time scale of 10 to 20 thousand generations. We show that cerebral capacity evolves faster and to a larger degree than learning ability. Our model suggests that there may be a tendency toward a reduction in cognitive abilities (driven by the costs of having a large brain) as the reproductive advantage of having a large brain decreases and the exposure to memes increases in modern societies.

I endorse Shelly Batts for the blog scholarship

Vote early and vote often for Shelley Batts. Shelley makes her pitch here. Shelley is a hard working graduate student with moral fiber.
Q: Is it permissable for believers to aid a kuffar in amassing riches?
A: It is permissable if the kuffar adds to the body of knowledge so that the believers may benefit. The prophet Muhammad, P.B.U.H., said, “Seek knowledge even unto Michigan.”

Introgression redux

I was going to continue with my review of chapter 5 of today, but time does not permit. This section was to focus on the orgination of advantageous mutations from the stochastic cauldron of generation 1 (which, as we’ve seen exhibits a 1/3 probability of immediate extinction in th subsequent generation assuming Poisson distribution of reproductive variance and fixed population size), so I will point to my older posts on introgression (of advantageous alleles):
The baby model
My fixations
Archaic-modern hybridization
Introgression in wolves & dogs
Introgression related papers
Bumping uglies with the Neandertal
These will come in handy in the near future because papers are pending which make the general conceptual framework extremely relevant.

But we're all racist

Below the fold is the full text of a paper circa 1993 that reports that freshmen college students tend to misattribute political beliefs to professors on the basis of merely factual material presented in class. The results obviously extend to other areas.

When Teaching is Evaluated on Political Grounds

Stanley Coren
University of British Columbia, Vancouver BC, CANADA V6T IZ4

Psychologists and other behavioral scientists who teach courses containing material on individual differences often find themselves presenting research findings that are politically unpopular in today’s social climate. For example, segments of most introductory psychology courses deal with intelligence and mental abilities. An honest treatment of this material requires that evidence be presented indicating that both environmental and genetic factors determine intelligence. The evidence for heritable factors in intelligence is supported by data from selective breeding studies using animal subjects, from twin studies, and from family studies. In exploring the implications of this work the lecturer generally presents the evidence that different racial groups score differently on intelligence tests, and then analyzes the factors that contribute to this observed difference. Most researchers (and most textbooks) agree that although environmental factors are important, genetic contributions cannot be ignored, since they play a large role in determining group differences in mental abilities scores./1/ The case is quite similar in the discussion of sex differences in cognitive abilities. There are systematic differences in the pattern of abilities displayed by males and females on standardized tests. Although many of these differences may be environmental in origin or reflect differences in the socialization of males and females, some ability differences appear to be genetically determined. It appears that the disparity between male and female scores on certain abilities measures are the direct consequence of hormonal, neurological, and even brain structure differences between the sexes. The conscientious lecturer interested in presenting the full picture must discuss these physical differences as well as the environmental factors./2/
Potential Evaluation Problems

Unfortunately, in the current political climate on college and university campuses, it appears that the teaching of research on ability differences among racial or sexual groups may have implications for the careers of faculty members. The potential problem arises in institutions that use teaching evaluations as part of the data upon which decisions about tenure, promotion, and merit pay increments are based. This became clear to me during the course of some committee deliberations at my institution, the University of British Columbia (UBC) in Vancouver, Canada.

The UBC psychology department follows teaching evaluation procedures that are common in many universities. One important component in the evaluation process is the mandatory distribution of a questionnaire to every student at the end of each course. Traditionally, students are asked to comment on their perception of a number of aspects of the course and the instructor. Items addressed include the fairness of evaluation procedures, instructor preparation and interest in the material, clarity of delivery, availability during office hours, rapport with the class, and so forth. Comments are numerically coded and summarized. These summaries then become apart of the instructor’s permanent file. Student evaluations have often played a pivotal role in tenure and promotion deliberations pertaining to particular faculty members. They are most likely to have a major impact when the candidate is borderline in some other respects, in which case the teaching evaluations may swing the decision in one direction or another.

Probably as a response to social pressures within the university, the UBC teaching committee decided to “modernize” the current course evaluation questionnaire. This revision involved the deletion of several objective items, such as whether the course was organized logically, or whether the final grade was based upon several evaluations or tests rather than a single assessment. More disturbing was the introduction of several items involving issues of sex and race. Thus students were asked to assess whether the instructor used “examples or stories that were demeaning to members of certain racial or cultural groups” or demeaning either to women or to men. Additional items highlighting racial or sexual identity were also included.

To some faculty members the inclusion of such potentially “political” items in the questionnaire seemed inappropriate, for terms like “demeaning” involve certain assumptions and interpretations in which the listeners’ biases are as much a factor as the content of the lecture. A student who is told that one racial group does not do as well as another on certain mental abilities tests may well interpret those remarks as “demeaning” to that group. (As president Harry S. Truman once quipped, “I never did give anybody hell. I just told the truth and they thought it was hell.”) The committee revising the questionnaire did not perceive any such risk. The chairman of the committee felt that students know the difference between opinion and scientific data and would not negatively evaluate an instructor for presentation of data, no matter the conclusion reached. Thus, despite objections, several items involving race and sex were included in the revised teaching evaluation questionnaire.
Some Concerns

I was quite concerned about the inclusion of such items. My major trepidation was that students would mistake the conclusions reached in presenting material dealing with race and sex as reflecting the attitudes of the instructor rather than objective reporting of scientific data. I was also concerned that such questionnaire items are based upon the presumption that we can ask students of eighteen and nineteen years of age, who are less than a year beyond high school, to answer difficult questions about what constitutes racist or sexist content in a course and whether their lecturer is guilty of purveying such content. Given that society as a whole and many academics and scholars have struggled with these issues for many years and still have not reached a consensus, the validity of this presumption seems dubious. If student judgments lack validity or, worse, if they are biased by the conclusions reached by the research under discussion, this could prove quite disastrous for faculty members who teach about individual and group differences in behavior.

My long-range concern was that the knowledge that such politically charged items are to be used in teaching evaluations would inevitably serve to “muzzle” faculty. The likeliest targets are young faculty who know that their teaching ratings will affect their chances for promotion and tenure. In effect, the inclusion of “sensitive” items could eventually cause faculty simply not to teach certain substantive areas. The fear motivating such behavior is that lectures that reach politically unpopular conclusions will lead some students to apply labels of “sexist” or “racist” to the lecturer.
An Empirical Assessment

As an experimental psychologist it seemed to me that the best way to address this issue would be to collect some data from the very students who would be called upon to evaluate faculty members. In this way I could either clarify the problems inherent in this form of teaching evaluation, or set my own misgivings to rest.

My test sample consisted of 198 students enrolled in an introductory psychology class. There were 109 women and 89 men; the mean age was 18.7 years. Each received a questionnaire. Students were told not to put their names on the survey form, just as they are not required to sign the teaching evaluation questionnaires. The introduction to the survey reads:
University Teaching Questionnaire

Recently, the public and press have brought to light some issues that are important to the normal functioning of the university. Two, which have been mentioned many times, are:


In the minds of many people there are some topics that are appropriate and others that are inappropriate topics for university and college classes.

It has been occasionally suggested that some professors may let their own personal views enter into their teaching, and these views might be inappropriately presented as fact.

Both of these issues are controversial and many individuals hold different viewpoints about them. We are interested in your opinions about these issues.

Below you will find some sample descriptions of lectures that might be given in an introductory psychology course. Consider what you feel your own reactions would be to such lectures and briefly answer the questions below them.

Four simple lecture summaries were presented in paragraph form:


Professor W gives a lecture about learning. In it he notes that simple repetition does not improve learning. He concludes that rereading the textbook several times will not result in good comprehension. He suggests several working techniques and activities that he feels will improve memory.

Professor X gives a lecture about intelligence. In it he describes some evidence for biological factors, such as genes, that affect intelligence. He suggests that although culture and experience are important in determining scores on intelligence tests, genetic factors can be used to explain some portion of the differences in IQ scores that are obtained when different races take intelligence tests.

Professor Y gives a lecture about aging. In it he notes evidence that older individuals have difficulty learning certain material and solving certain problems. He suggests that these differences may reflect a slowing in thinking processes in elderly people.

Professor Z gives a lecture about sex differences. In it he notes evidence that males consistently score better than females on spatial and mathematical tests. He suggests that while societal and environmental contributions should not be ignored, some portion of these sex differences in ability may be due to genetic factors or differences in the brain structure of males and females.

After each lecture summary, several questions were asked. The first was simply, “Is this material appropriate for a psychology course?__Yes__No.” The second and third questions were much more open-ended: “What are the professor’s reasons or motives for presenting this subject matter?” and “What does this lecture tell you about Professor__ ?”

The results of this survey supported my fears about how students would evaluate faculty members who present unpopular conclusions. The relevant lectures, of course, are 2 and 4. Although each lecture summary contains subject matter that is often taught in introductory psychology courses, lectures 2 and 4 also deal with the more politically sensitive issues of race and sex differences in intelligence and mental abilities.

Before looking at the data, it is important to note that the viewpoints expressed by Professors X and Z in lectures 2 and 4 are quite consistent with data in the behavioral literature. They agree with the conclusions of many researchers and are in accord with several large literature reviews./3/ Many textbooks for introductory psychology courses also present material of a similar nature. Notice as well that these lecture summaries are clearly moderate in tone, and do not contain anything inflammatory or demeaning to any group. Nevertheless, the results suggest that these eighteen- and nineteen- year-old students saw the lectures as much more negative and problematic.
Lecture 2: Evidence for a Genetic Contribution to Intelligence

In lecture 2 Professor X suggests that there is a genetic contribution to intelligence. Although he acknowledges contributions from culture and environment, he concludes that the genetic contribution to intelligence might account for “some portion” of the differences observed in IQ scores between the races. An amazing 38 percent (76/198) of student evaluators felt that this was not an appropriate topic for a psychology course. Furthermore, in the question on the professor’s motives for presenting this material and the question about what this lecture indicated about Professor X, 24 percent (48/198) specifically mentioned “racist,” “racism,” or notions of “racial superiority” as motivating the presentation of this material. Thus the very discussion of genetic and racial differences in intelligence, if the conclusion is that they exist, renders the lecturer a racist in the minds of nearly one-quarter of these students.
Lecture 4: Evidence for Sex Differences in Cognitive Skills

In this lecture Professor Z suggests that there are differences between males and females in spatial and mathematical ability. Although acknowledging the contribution of social and environmental factors, he concludes that “some portion” of these differences may be due to physiological or genetic differences between males and females. Again, the results are quite distressing. Thirty-one percent (62/198) of the class felt that this was a topic that was not appropriate for a psychology course. There was a strong difference between male and female respondents. Forty eight percent (52/109) of females, while only, 11 percent (10/89) of males, felt that the topic was inappropriate. In the discussion of motives, or what this lecture indicated about Professor Z, 26 percent (51/198) mentioned “sexist,” “sexism,” “anti-women,” “putting women down,” or the equivalent as the primary motivation for the presentation. Again, there was a strong difference between the sexes, with 94 percent (48/51) of the sexism charges coming from female students. Thus, in the minds of more than a quarter of all the students, and nearly one-half the female students, simple presentation of data and conclusions that are accepted in the experimental psychology literature makes the lecturer a sexist.
Implications for Faculty Assessment

The conclusions that can be reached based on these data should be obvious–and somewhat frightening. It is quite clear that many students, especially the freshmen tested here, cannot separate the scientific evidence presented by an instructor from the instructors own opinions. Also, they make one variety of the “fundamental attribution” error so well-known to social psychologists./4/ In this case, the error involves the belief that the conclusions reached by the lecturer are the conclusions desired by the lecturer. In other words, the observer (here the student) believes that the lecturer must be driven by internal motives consonant with the data he presents.

Based on the data described above, what can we conclude about how students would describe Professor X if asked whether he “used examples that demeaned any racial or cultural group?” How would students evaluate Professor Z if they were asked whether he used any “examples that demeaned women?” Obviously, many students would describe Professor X as a racist and Professor Z as a sexist.

These data, if they are a valid indicator of how students form opinions about instructors based upon the presentation of particular material in class, have dire implications for faculty members whose courses include the topic of individual differences. In light of teacher evaluation forms that require students to draw conclusions about the political and social attitudes of their professors based upon the content of lectures, this situation can have only one outcome. If faculty members are aware of or suspect there are student biases about such material, then a sizable proportion of junior faculty will refuse to teach this material. The same is probably true for s
enior faculty, who know that poor teaching ratings might adversely affect decisions about merit pay increases.

Where up to a third of your students wilt negatively evaluate you simply for presenting data that reflect the dominant thinking and empirical results reported in the literature, perhaps it is better to select a book that reaches the “politically correct” conclusions. And in lectures, perhaps it is better to “tailor” the data to reach those same conclusions. Or perhaps it is better not to bring up the topic at all, and thus be absolutely sure that no charges of racism or sexism can be leveled at you.

We must ask ourselves and our teaching evaluation committees: What are political questions doing on an instrument that is supposedly designed to evaluate teaching effectiveness? By allowing political interpretations to form a component in our teaching evaluations we effectively subvert the ideal of dispassionate research and teaching. Teacher assessments based on the student’s political or social interpretation of the empirical data or on how well the conclusions accord with his preconceptions and social attitudes must lead to suppression of unpopular data.

It seems that the academic establishment has not recognized what Adlai Stevenson knew about the public psyche. He observed, “You will find that the truth is often unpopular and the contest between agreeable fancy and disagreeable fact is unequal. For, in the vernacular, we are suckers for good news.”/5/ If teaching evaluations use student opinions about the social or political implications of the material taught, then behavioral scientists will soon find themselves pressured to teach only the “good news” that there are no differences in the abilities of racial or sexual subgroups–even if this involves ignoring or suppressing the bulk of the research data. Thus the evaluation of teaching ability will become nothing more than the evaluation of how well a faculty member’s lectures conform to the political norm. It is sad to think that humorist Josh Billings may have been correct when he said, “As scarce as the truth is, the supply has always been in excess of the demand.”


1. These issues have been covered extensively elsewhere, as in Robert Plomin, “Environment and Genes: Determinants of Behavior,” American Psychologist 44.2 (1989), or the sprightly debate in H.J. Eysenck, The Intelligence Controversy (New York: Wiley, 1981).
2. For an excellent and remarkably balanced review, see Diane F. Halpern, Sex Differences in Cognitive Abilities (Hillsdale, N.J.: Erlbaum Associates, 1986).
3. See Robert Plomin, Nature and Nurture: An Introduction to Behavioral Genetics (Pacific Grove, Calif.: Brooks/Cole, 1990).
4. See L. Ross, “The Intuitive Psychologist and His Shortcomings: Distortions in the Attribution Process,” in Advances in Experimental Social Psychology, ed. L. Berkowitz (New York: Academic Press, 1977).
5. Adlai Stevenson, New York Times, 9 June 1958.

Posted in Uncategorized

Promiscuous Girl

O believers!
If kuffar flesh is beauteous it is permissable for the faithful to partake of it without nikah….

Q: Is a beauteous kuffar female permissable or unclean?
A: Lo! A beauteous kuffar female is both permissable and unclean! If the kuffar women entreat the believers, let it be known that that the faithful are commanded to hit them hard and hit them often so long as the believers are sufficiently freaky! As the kuffar woman is unclean let it be stated that it is enjoined upon the believers that they wash themselves thoroughly and redouble their salat.
-Ibn Hanbal

Asian Nazis

I just wasted 15 minutes exploring the Uncyclopedia after seeing a referral from the entry on Asian Nazis. A lot of the other stuff is pretty funny too. Check out this snip from the entry on Bangladesh:

Bangladesh holds the world record for the only country which has more people than mosquitos. Mosquitos are the second largest ethnic populace of Bangladesh. The human population is made up of 49% males, 43% females, 6% hermaphrodites and 2% George W. Bush look alikes. The current list of famous Bangladeshis include the pop band The Bangles, the lovable canine actor Benji, [redacted]. Bangladesh hopes to produce another famous person, of an equal calibre, by approximately 2025 AD.

Intermediate progenitor hypothesis

A recent Perspective in Nature Reviews Neuroscience presents an alternative to the radial unit hypothesis of cortical expansion. As you may recall, one of the major alterations in gross brain structure as you move toward primates and those particular primates that we hold dear is the large increase in cortical surface area. The increase is not accompanied by a proportional increase in skull size because the increased amount of cortex is folded in on itself to form sulci (crevices) and gyri (hills). Smooth brains are called lyssencephalic. Wrinkly brains are gyrencephalic.

The radial unit hypothesis suggests that the increase in the size of the neocortex is due to an increase in the cells that both give birth to most cortical neurons and provide the scaffold for those newborn neurons to climb to their proper position in the cortex. These radial glia lie next to the ventricles (fluid filled cavities in the middle of your brain, one of the earliest neural structures to form) in an area called the ventricular zone (VZ) and are attached to the ventricles and to the outer surface of the developing cortex. Strangely enough, the area one layer further away from the ventricles is called the subventricular zone (SVZ). During cortical neurogenesis, neurons are created next to the radial glia and migrate up the scaffold. More cortex space can be created by producing more scaffolds. More scaffolds can be made by increasing the amount of time radial glia divide symmetrically to produce only more radial glia rather than neurons or reducing the number of radial glia that die after they are produced. A and B below.

But one potential issue with the radial unit hypothesis is that the ventricles should grow proportionally to the neocortical growth through evolution. This isn’t the case. To circumvent this problem, the intermediate progenitor hypothesis suggests that the immediate product of asymmetric radial glia division is an intermediate progenitor rather than a neuron (C above). These intermediate progenitors migrate to the SVZ just above the radial glia and divide symmetrically some more to produce a crop of intermediate progenitors. Wherever you want more cortical neurons you let more intermediate progenitors be produced. Eventually these cells in a way that produces differentiated neurons and they migrate up to their proper position in the cortex. My favorite piece of evidence for this hypothesis is shown below. You can sort of predict where a cortical fold will be by measuring the thickness of the SVZ early in development. Thinner SVZs will be below sulci, and thicker ones will be below gyri.

Not knowing enough to really critique, my only obvious issue is that it doesn’t seem like their criticism of the radial unit hypothesis has to be so. It seems possible to me for radial glia to proliferate without increasing the size of the ventricles that much. As far as I know, noone has shown that the ventricle surface is so jampacked with radial glia feet that it can’t accomodate a few more. Also worth noting is that both hypotheses suggest that putting off neurogenesis to produce more progenitors might underlie cortical expansion in humans. So at this point, both hypotheses might lead to similar predictions about the particular genes involved.

Buzsaki and Wilson

For the die-hards. I taped the Buzsaki and Wilson lectures at the Visualizing and Recording Large-Scale Ensembles short course at SFN. Quality isn’t really great and a lot of it doesn’t make sense without the slides, but, hey, it’s there if you want it:

Buzsaki Intro and Lecture (mostly about multi-unit recording and unit isolation)
Wilson Lecture (more about the same, but focus on tetrodes and some data)
Buzsaki vs. Wilson (Breakout group with some questions, interesting to hear them converse and joke. Best sound quality I think.)

Posted in Uncategorized