|
Sunday, March 30, 2008
On the most recent bloggingheads.tv you can watch Paul Bloom explaining why he thinks the propensity for theism is an innate bias of our species. Several years back Bloom wrote a piece for The Atlantic, Is God an Accident?, where he makes a similar case. But the general outline of Bloom's line of thinking is actually most powerfully argued in Scott Atran's In God's We Trust. The cognitive psychologists and anthropologists who work within this paradigm operate under some background assumptions in regards to our mental architecture. First, human cognitive states are strongly biased by innate tendencies which have a biological origin. Perception and language acquisition are easily explained by nativist treatments, but Atran and others have argued that more obscure biases such as folk biology also exist, while other domains such as theory of mind are broadly accepted within the scholarly community.
One can conceive of a model where on a lower structural level a set of biological parameters interact with exogenous inputs to generate a set of psychological biases. But the subsequent mental skills are not independent, and I suspect broadly distributed ones contingent upon environmental inputs such as language are among the least encapsulated from other cognitive domains. It seems rather clear that language aptitude is one of the components which can be used to explain the facility for mathematical abstraction, but it can not explain the totality of this skill. Cognitive anthropologists have also noted that preliterate peoples have extreme difficulties with comprehending the logic or rationale behind syllogistic reasoning (see Kluge: The Haphazard Construction of the Human Mind), suggesting that there are strong cultural preconditions to particular styles of thinking which may seem natural to us. Even though language, reading and writing all are learned, they are also facilities which we as humans have an innate aptitude for because of our neurobiology (language is obviously "more innate" insofar as it seems that our priming is so strong that it might emerge out of any conventional socialization processes, which literacy is historically and culturally contingent). Another working assumption of Bloom, Atran & co. is that a great deal of our cognition is implicit. Again, this is well accepted among the community of scholars. It stands to reason that our conscious mind lives under the illusion that it is all that there is, but a substantial body of work tells us that most of our conscious decisions are strongly influenced and primed by subconscious background parameters. Not only does this include priming an individual immediately prior to a psychological task, but it also includes the enormous swath of territory which falls under the category of intuitive thinking. A dense network of background connections and implicit inferences is often an outsized shadow of the visible chains of reflective rationality. Even in structurally transparent and deductive disciplines such as mathematics the dark-net of subconscious facts and assumptions loom large in the process of creativity. The fact that psychological biases have many different upstream neurobiological and environmental parameters, as well as the syngergistic nature of cognition which produces subsequent cognitive abilities (e.g., mathematics or painting which includes perspective), means that a hypothesis that posits a God Module is obviously going to be false. There are god modules such as the medulla oblongata, but only insofar as they are necessary for the proper functioning of a human in general. But it seems highly unlikely that there is one localized region of the brain which is specifically the causal element for belief in God (i.e., if said region is damaged atheism ensues, but most other cognitive function is left unscathed). This assumption doesn't derive simply from an a priori understanding of how the mind works; we can see it in how the phenotype of theism plays out. The pathological character of many aphasia sufferers is pretty obvious; in contrast the avowed attitude toward the God hypothesis is characterized by a rich range of opinion in terms of both plausibility and character. In other words, religion is more properly characterized as a quantitative trait which exhibits a wide range of continuous variation, subject to a norm of reaction. Do note that I said avowed attitude; when it comes to theism there are many ways to evaluate belief or lack thereof. Despite wide variations in verbal descriptions of the particular flavor of deity believers assent to, psychologists know that the implicit model of most humans in regards to supernatural agents is strongly constrained. This is one of the main reasons that many cognitive scientists believe that our mental architecture is rigged toward a belief in god; not only do the gods which individuals from widely disparate societies model in their mind's eye differ from the entities which they avow a conscious belief in, but those psychological constructs exhibit a very strong universal central tendency. In other words, the human model of a god, or supernatural agent if you will, seems to be predicated on the various elements of universal neurobiology. Unless strongly constrained by experimental or observational methodologies as in natural science, or a rigorous formalism as in mathematics, our species tends to reason extremely sloppily so that inferences unmoored from experience or unchanneled by formalism invariably explore an enormous sample space of possibilities starting from the same axioms. That humans tend to conceive of the same god-construct despite lack of communication or outside input suggests that the channeling is occurring on an innate level. Additionally, not only do theists no matter their affiliation agree upon an intuitive model of God, but so do atheists. Paul Bloom has noted that the offspring of secular parents are usually innate Creationists. Many of the ideas bracketed within "religion" are very natural and intuitive. In our gut we know them to be "true" without deep reflection or analysis. Atheism can not exist without theism because it is simply a negation of the latter. It is a conceit of many atheists that children are naturally unbelievers and that they are indoctrinated into a religious system of belief. This is correct; children are indoctrinated into a system of belief, but more specifically they are indoctrinated into a system, not a belief. That in almost all human societies a supernatural model of the world is numerically dominant strongly suggests that these sorts of belief do not necessarily need the institutional scaffolding of established churches or professional priesthoods. Rather, it seems that these features of religion are secondary and subsequent, and that they operate upon the preexistent assumptions of the population. Some atheists live under the delusion that the withering of organized religion will result in the collapse of belief in God or the supernatural; this is not so. Though the extremely high rates of theism in some societies may be an upper bound contingent upon social and historical conditions, in no society does it seem there exists an inverse dynamic where theism is extant at trivial levels. Note that even after 70 years of state sanctioned atheism Russians have now swung back to a default affiliation with their historical religious identity as Orthodox Christians. This is not to say that Russians are a religiously fervent people; rather, the high levels of atheism espoused during the Soviet era was a function of a skewing of the environmental inputs which shifted the median value of the trait distribution. With the norm relaxed the distribution has shifted back. The plausibility of theism doesn't need to be something we note only in terms of macrosocial metrics in regards to religious affiliation cross-culturally. As I imply above, theism is at root a psychological phenomena, and the bundle of biases and presuppositions which our biology confers upon us stack the deck in terms of weighting the plausibility of god concepts. This applies to atheists as well. We might not believe in god on the conscious level, but that does not mean that we are immune to the priming affect of agents, and likely supernatural agents as well. The folk wisdom about there being no atheists in foxholes is a reflection of this assumption. Now I'm not going to tell anyone who says they don't believe in god that deep down they really do believe in god; rather, I simply believe that many of the psychological characteristics which prime one for finding god plausible are present in those who consciously assert that they don't believe in gods. For example many atheists may feel unnerved in cemeteries despite a materialist world-view; the psychological response may be a result of social conditioning, but it is also possibly a cognitive reflex at an intersection of environmental inputs (think snake aversion as something similar). So far I have alluded to biology & psychology, but what about the higher-level social sciences? Paul Bloom and most cognitive scientists are focused on the first two disciplines, so they tend to strongly adhere to a model that religion is a byproduct of our cognitive architecture. An analogy might be the heat given off by the functioning of a car's engine; the heat is not a designed product of the various components of the engine, but it is an inevitable byproduct of the physical processes entailed by combustion. Similarly, theism may not be an adaptation to any exogenous selection pressure, but the intersection of various adaptive psychological characters such as agency detection, theory of mind and folk biology necessarily lead to the plausibility of supernatural agents within the minds of most humans. Because of Bloom's disciplinary focus he tends to not be very open toward a functionalist explanation for theism; that theism (or religion) is an adaptive trait which increases individual fitness. Insofar as explanations at a lower level of organization are preferable to those at a higher level, I think that Bloom's skepticism is warranted. But even cognitive anthropologists who tend to focus on the psychological dimensions of theism can't dismiss the social aspects of religion, and a substantial body of social science research implies that variation in religious belief might track other social variables. Instead of repeating the functionalist explanations elucidated by scientists such as David Sloan Wilson (see Darwin's Cathedral), I think it is easy to illustrate the relation of these various theories by using an analogy with narrative. Despite the attempts of authors who dabble in "experimental fiction" it seems pretty obvious that a great story has a dimension of temporal permanence derived from the timelessness of the primary themes and styles. The Epic of Gilgamesh speaks to us even after 4,000 years, and many of its motifs are still extant in the heroic fantasy genre. Despite the lack of qualitative originality in plot and the constraints upon the plausible range of the psychology of characters we continue to consume fiction because our brains are attracted to particular themes arranged in a familiar structure. One could contend that fiction is a waste of time, but it seems likely that the same mental ticks which draw us to compelling stories are useful in other areas of life. But narrative is not only a byproduct of our promiscuous mental functioning, it is an essential part of myth-making and religion. The cognitive anthropologist Pascal Boyer has reported on research which suggests that minimally counterintuitive stories are the ones which are most memorable and "sticky" over the long-term. In other words, experimental fiction is just too weird to really make a deep impact, you don't have any common basis for associative memory to operate. In contrast, exceedingly conventional and banal narratives just don't add anything new to the base of data. A boring story is a boring story. But a familiar scenario with just the right amount of spice adds enough twists and turns within the comprehensible base to make it memorable enough to catalog and retrieve later. This explains why most science fiction and fantasy tends to constrain the deviation from normality; you can't relate to a story where most of it is unfamiliar or disorienting. Of course narrative is an essential part of religion. Even "primitive" religions have a robust narrative base; tales of gods & heroes unfettered by abstruse theologies. The story of Jesus as depicted in the Gospels has a power to draw people in and inspire them toward belief & action. In contrast, despite the fact that Christians accept the divine provenance of Deuteronomy, very few believers have ever recounted to me how it inspires them or serves as the ground of their faith. Just as narrative emerges naturally as a byproduct of our overall psychological architecture, it also immediately slots into the overall cultural entity which we label "religion." I suspect the exact same model is applicable to gods; their plausibility precedes their integration into a religious framework and does not derive from direct adaptation. But the universal nature of religious frameworks as well as storytelling implies that these byproduct traits are almost always subject to co-option by cultural systems which are canalized toward a particular configuration. But what is driving that canalization? I suspect there is some functional selection going on. Like many social science generalizations I'm not sure I can be very general here. David Sloan Wilson has collected data which shows that religious fundamentalism is more noticeable in economically depressed regions. Which way does the causality run here? I suspect that it is generally in the direction of economic insecurity to religious fundamentalism. The sociologist of religion Rodney Stark has elucidated a rational choice inspired framework which posits that religious institutions are firms which offer products which satisfy a fragmented market of religious consumers. This model seems highly plausible for the United States, but there are doubts as to its validity in other cultures where religious switching is not as socially acceptable or viable. Similarly, many of Wilson's adaptive arguments for the functional significance of religion are quite likely more relevant in societies which lack the accoutrements of the welfare state so that religious institutions have few competitors or substitutes. In other words, generalizations about the functional significance of religious institutions may not hold across many environments. Nevertheless, though generalizations on higher levels of organization are less impressive when compared to the relatively simplicity and universality of a biopsychological paradigm, I think it is necessary that we analyze the expression of religion outside the bounds of the human mind. After all, though religious ideas are fundamentally mental, they are embedded within a social matrix and have a geopolitical relevance in terms of how they shape human relations and action. We can, for instance, see that over the past few thousand years local tribal religions have ceded ground to the dominance of institutional religions which often have multiple products under the same brand name. The number of supernatural agents seems to be decreasing through a process of competition concurrent with the decrease in polities, languages and ethnic groups. But though institutional religions have gone through a process of consolidation this dynamic has limits; the fragmentation of Christianity during the Reformation or the schisms within the first centuries of Islam attest to this. Though religious institutions far exceed the scale of Dunbar's Number, a One-World-Religion seems as plausible as a One-World-Government. Psychologists have also attempted to move into broader domains of social science. Scott Atran has been at the forefront of attempting to synthesize the cognitivist viewpoint with an analysis of the nature of religious terrorism. Atran emphasizes the power of religious narratives & rituals in cementing group cohesion. The functionalist interpretation on this is pretty obvious; this is a case where heat from one process is quickly being utilized to generate energy through another. To some extent analysis of religious is like the species problem; we should measure the definition against the utility it provides in a particular context. Species define the joints around which nature is carved, and religion is a label for a cluster of integrated characters which we humans imbue with ontological significance. Both species and religion are important to understand, and can serve as frameworks for robust research programs, but a final definition will never be attained so long as scholars in disparate fields have distinct ends. A diversity of ends does not imply that these ends are contradictory, rather, when you have a many dimensional character it is necessary to observe from a variety of angles to obtain the clearest picture. Addendum: I want to add something: theism & religion are very robust phenomena. This is why adaptationist explanations are so compelling. That's why an analogy to misunderstandings due to intuitive physics (e.g., flat earth, variance of acceleration in proportion to mass of an objection) is informative, but only to some extent. Overactive agency detection feeds into something which is far more than the sum of their parts, the falsifiable manifestations of religion such as Young Earth Creationism can resist disconfirmation because of their association with psychological tendencies such as group conformity enforced by common rituals & beliefs. To say religion is a spandrel or exaptation understates its interaction with other aspects of human culture so as to make it inevitable and resistant to suppression. Related: The nature of religion and Breaking the Spell, Modes of religion, Who Dan Dennett think he be foolin'?, An evolutionary anthropology of religion, , God lives, deal with it!, , Belief & belief in belief, Logical consistency is irreligious, God & moralityAre people naturally religious? Yes.... , The round-eyed Buddha, Nerds are nuts, Atheism, Heresy and Hesychasm, The God Delusion - Amongst the unbelievers , Innate atheism & variation across societies, "Hard-wired" for God, Buddhism, a religion or not?, Why do people believe in God?, Is religion an adaptation?, Theological incorrectness - when people behave how they shouldn't....sort of , The gods of the cognitive scientists Labels: Cognitive Science, Evolutionary Psychology, Religion
Thursday, March 27, 2008
As a supplement to my post on Sewall Wright's method of Path Analysis, here is an article on the subject which I just found. I don't agree with all the authors' comments, but the historical background and references are useful.
Monday, March 24, 2008
Via Over Coming Bias, The science of religion - Where angels no longer fear to tread:
It is an ambitious shopping list. Fortunately, other researchers have blazed a trail. Patrick McNamara, for example, is the head of the Evolutionary Neurobehaviour Laboratory at Boston University's School of Medicine. He works with people who suffer from Parkinson's disease. This illness is caused by low levels of a messenger molecule called dopamine in certain parts of the brain. In a preliminary study, Dr McNamara discovered that those with Parkinson's had lower levels of religiosity than healthy individuals, and that the difference seemed to correlate with the disease's severity. He therefore suspects a link with dopamine levels and is now conducting a follow-up involving some patients who are taking dopamine-boosting medicine and some of whom are not. Any bets on what's causing this? I suspect low dopamine individuals are less likely to be socially conforming, so the effect on religiosity might be weaker in a society where religion is less important than the United States. But nice to see some neurochemical work on this. In the future perhaps neuroscientists will be able to advise parents on the optimal mixture of the "soup" in their offsprings' brains to increase the chances of religiosity, or decrease it? (Randall Parker has been talking about this for years) But probably the most interesting reported research in the piece has to do with group selection & functionalism: To test whether religion might have emerged as a way of improving group co-operation while reducing the need to keep an eye out for free-riders, Dr Sosis drew on a catalogue of 19th-century American communes published in 1988 by Yaacov Oved of Tel Aviv University. Dr Sosis picked 200 of these for his analysis; 88 were religious and 112 were secular. Dr Oved's data include the span of each commune's existence and Dr Sosis found that communes whose ideology was secular were up to four times as likely as religious ones to dissolve in any given year. These sorts of data are relatively persuave to me about the functional power of religious institutions and social dynamics. Of course, apparent deviations from the trendline will be important to examine too. This is the closest thing to a website I could find for the Explaining Religion Project. Labels: Religion
Friday, March 21, 2008
Over at my other blog I flogged Jamie Kirchick somewhat for what seemed to me a pretty obvious misrepresentation of basic facts. You might think these "gotchas" are picayune, but I don't think they are at all. Do you remember back in 2002 when Colin Powell misspoke about the "Sunni majority" of Iraq? These are not easy slip ups to make if you have a good model in your head for the situation on the ground in far off lands, rather, they indicate a thin network of contingent data. Scratching below the surface of the CIA Factbook is important. Knowing that 40% of Yemenis are Shia is an important fact, but knowing that most of these 40% are Zaidis, stereotypically the "most Sunni" of the modern Shia adds more nuance. Many of the rest are Ismaili, who are the "least Sunni." The smallest of the Shia groups are Twelver Shias. This is the largest of the Shia sects, and probably the most typical one in terms of compromising between Ismaili distinctiveness and Zaidi banality. It is the group dominant in Iran, the Gulf and Lebanon. Does this matter? If you think geopolitically in terms of the Shia Crescent, it does. Does thinking geo-politically matter? I'll leave that up to you.
 When we're talking about science there's a lot of precise and fixed background information we're working with. Not only are there facts, there are strong theoretical frameworks which give you "free information" and that you can use in your heuristics. Unfortunately there aren't that many robust theoretical frameworks on the scale of area studies. Facts matter because they're the only guides you have in making proximate decisions. Conclusions will differ between people because of different interests and alternative normative frames, but an agreemant on known background facts is essential for elevating the level of discussion above that of two blind people discussing the merits of Monet vs. Picasso (no offense to the blind readers of this weblog!). I don't really mind differences of conclusion based on varied norms or self-interest; but the casual pig-ignorance of very smart people on topics which they feel qualified to offer an opinion on irritates me because mitigation of a dearth of facts is relatively easy if you have the marginal time. My own experience is that the denser the network of facts the easier retention becomes. At a particular density threshold I suspect there is an increase of the marginal value of the fact in terms of discerning patterns and trends, though diminishing returns kicks in once we've attained all the perceptual power the human mind can expect.Many times I've criticized people for using a very weak analogy, or relying on fallacious background facts. These are critiques of process, and I can tell people get frustrated by this, they want to get to the conclusions and argue over the ends instead of the means. I think this is totally wrong-headed; imagine if someone wanted to discuss particle physics without taking the prerequisite mathematical & science courses (you encounter such retards regularly actually). Personally I would much rather listen to a well argued case or position at variance with my own than a weak case which buttressed a personally held opinion (my favorite form of masturbation is sexual). It is ultimately a game where we need to look beyond individual battles, and focus on the war. The long forever war to understand the world around us predicated on good faith and particular principles which keep the ecology relatively clean. For an appropriate equilibrium to be maintained cheaters must be punished lest they invade the ecosystem. Labels: Razib Guru
New PLOS paper, Geographic Patterns of Genome Admixture in Latin American Mestizos. Nothing new, but pushing the ball forward....
 A = autosomal X = X chromosomal
Thursday, March 20, 2008
If you are a male, and someone says your mother is a slut, how do you respond? I think most non-autistic individuals, even if they are reflexive pussies as many civilized American men raised in urban areas and suburbs tend to be, will feel an urge to react violently. I think we can agree that someone calling your mother a slut does not have obvious material consequences; it isn't inimical to your economic interests, especially if the exchange occurs in a bar and your interlocutor and yourself are drunk. I won't rehash evolutionary psychological arguments for why there's a tendency for most males to react viscerally with rage when someone insults the sexual character of their mother; I simply want to use it to illustrate the power of words and concepts which have no material consequence, and might not even be rooted in fact. A stranger who throws this insult at you usually doesn't even believe in its accuracy, his usage of the phrase is calculated to offend and elicit a reaction. There are certain things which are sacred, certain lines you don't cross. Sometimes these are strongly biased by biological parameters (e.g., I suspect near-family incest taboos is one of these), and sometimes they are not. It is the latter case I was thinking about a few months ago when I read Rome & Jerusalem: A Clash of Ancient Civilizations and God's Rule - Government and Islam.
You see, the ancient Romans and Muslims did not have kings. Kings were tyrants, and the early Roman and Islamic polities rejected such tyranny on principle. So of course, instead of kings, the Roman Empire was headed by an emperor, while the Muslims had caliphs.1 Get it? When Augustus defeated Mark Antony and Cleopatra the official narrative was that the doughty republican traditions of Rome had bested once more the oriental despotism of the Hellenistic world, with their Greek kings and queens. Similarly, the righteous Abbasids overthrew the despotic Arab Kingdom, the Umayyads. In its place they established a genuine Islamic state which was guided by the traditions of the community as opposed to profane naked autocracy. Right.... As you can see here, the extent of the self-deception and semantic delusion is really humorous. Now, it is true that the early emperors of Rome tended to keep up the illusion that they were simply stewards of the Roman Republic with some verisimilitude.2 Augustus' shtick was that his was a restorationist project; he was no dictator or king, just the First Citizen. Similarly, the early Abbasids were ostensibly bringing the vision of the Islamic community to its true fulfillment (especially the Shia party), whereas the Umayyads had been worldly Arab tribalists more in keeping with the values of the jahiliya. But the reality is that Augustus' Rome was as republican as Constantinople in 1453 was the capital of the Roman Empire. Similarly, the Abbasids resurrected the values of the primitive ummah by way of formulating a more ideologically coherent oriental despotism than the barracks state of the Umayyads. Despite their more effective propaganda the Abbasid caliphs integrated pre-Islamic Sassanid motifs into their court far more than the Umayyads ever had. But this sort of pro forma packaging mattered a great deal. Muslim soldiers were enraged and shocked when the conqueror of Spain allowed his Visigothic wife to convince him to don a crown and so indicate kingship; they accused him of becoming a Christian. This despite their own fealty to an Umayyad regime which was excoriated later in history by mainstream Muslims as a semi-pagan autocracy! These sorts of issues tie in to events and dynamics we see in the modern world. Muslims, for example, wish to criminalize blasphemous criticism of their prophet, desecration of their holy bookm and disrespect of their religion generally. Obviously they're met with skepticism from non-Muslims, but a number of them analogize their position to that of Europeans who ban Holocaust Denial. Dismissing the details of the analogy and my personal rejection of these Holocaust Denial laws, it is important to state that I think it trivializes the extermination of millions of human men, women and children on an industrial scale to compare this to an insult to an idea, or the desecration of a configuration of ink, paper and binding which results in a Koran. My own perspective is pretty obviously conditioned by the fact that I accept that human beings were tortured and killed en masse 60-70 years ago, while I don't think that the Muslim religion is anything more than a belief system rooted in made up stuff. The only damage is done to feelings, not a One True God. That being said, a billion people have invested a lot of psychological import into these beliefs and they just go insane when you insult those beliefs. Billions of others can empathize on some level because they have other beliefs which are cognate in the broad outlines. In the West, what I like to think of as the civilized world, there has emerged a consensus that constrains, and almost devalues, sacred lines and the right to take offense. Feelings rooted in immaterial beliefs still matter; if one makes a religious objection to a public norm one is accorded more credibility than if one makes an areligious objection (e.g., prisoners who need a special diet due to religious restrictions vs. those who really hate the taste of the cuisine). But to a large extent the power of religion to defend itself from blasphemy through the arm of state power has been abolished, even if there are blasphemy laws on the books in many jurisdictions. The transgressive assertions of men such as Denis Diderot in the 18th century broke down those barriers, and the reality of religious pluralism in the United States meant that reciprocal blasphemies between Protestants and Catholics occurred which did not elicit the intervention of the state as in the past lest it enflame the conflict furthermore. In any case, the attempt by Muslims to resurrect in the West the enforcement of pietas by governmental fiat has changed my own opinion as an atheist about the value of religious pluralism. Because I believe that religious sentiment and feeling is normal, and will be dominant in our species barring a reprogramming of the software, I think that one religious tradition is probably easier to manage in terms of negotiating the terms of relating state, religion and the role of the ontologically blasphemous irreligious minority within a society (by ontologically I mean that by the very nature of my atheism & apostasy I offend against Islam, for example). Since the militant secular party is by definition a negative one, objecting to the prescribed social pieties, it is much simpler when one has to face-off with a unified front and one dimensionality of supernaturalism. With the rise of a polycentric supernatural marketplace the act of negation multiplies in complexity as the permutations of absurdity increase ever upward. Diversity has costs, the common norms are essential so that even transgression of those norms can be regularized and tolerated reasonably. Addendum: I want to add that I was in rural Bangladesh during the Rushdie Affair. I was called on to translate some photocopies of English pamphlets which in hindsight totally misrepresented the The Satanic Verses (long story short, they made it sound like Muhammad's wives were starring in a novelization of EuroGangBang #69, and it was kind of awkward for me since I didn't know the appropriate words in Bengali for a lot of the stuff). But it was notable that many of the young Muslim men were enraged about something that they barely even comprehended in its accurate details. Feelings.... 1 - Minor note before David Ross points this out, but the term imperator did not come to be regularly used by the emperors until the Flavians. Before that they had been only the princips. 2 - The transition from First Citizens of the Julio-Claudian period to the autocrats (of the Byzantine Empire was a gradual one. The Flavians in the late 1st century reiterated the hereditary principle and banished any delusion that a senatorial resurrection was in the offing. Septimius Severus in the early 3rd century crystallized the idea that the law was an expression of imperial will as opposed to senatorial consensus. Diocletian in the early 4th century introduced the proto-medieval regalia which typified Byzantine autocrats, an oriental court and diademed crown. Labels: History
Tuesday, March 18, 2008
It's hard to have a recessive lethal hang around for a long time without some kind of heterozygote advantage: selection reduces its frequency. If the population is even moderately large, more than a few thousand, changes in allele frequency over time are very predictable: deterministic.
That also means that one can calculate past frequencies, as long as as these assumptions hold (i.e. as long as there was no tight bottleneck & selection coefficients were the same). Going forward in time , the frequency of a recessive lethal with no het advantage declines more and more slowly, since the ratio of homozygotes to heterozygotes declines as the allele frequency declines. But if you go backward in time, the frequency grows, and it grows more and more rapidly as you go further and further back in time. This doesn't continue indefinitely: the frequency can't go above 100%. Project the frequency of such a recessive lethal back in time and you hit a singularity. Today, lethal cystic fibrosis alleles have a frequency of 2% in northern Europeans. Unless I'm wrong, it takes 50 generations for a recessive lethal to go from almost 100% to 2%, and another 50 to go from 2% to 1%, assuming no reproductive compensation. 'Reproductive compensation' means that parents have another kid when one dies young and thus end up with the same number of children raised to adulthood. This effect weakens, but does not eliminate, selection against lethal recessives. With full reproductive compensation, it takes 80 generations for a recessive lethal to go from 99.5% to 2%, and another 75 to go from 2% to 1%. If the frequency of lethal CF alleles is 2% today, there must have either been a selective advantage in heterogygotes over most the of the past two thousand years, or the population of northern Europe must have crashed down to a few hundred or less sometime during that period. There was no such crash, which would have been worse than a nuclear war. Indeed, there was no bottleneck of any kind in that time period: we know this from the historical record. Events like the Black Death do not a bottleneck make: you need to get the population down into the low thousands or less. The Black Death left tens of millions. So lethal CF mutants had some kind of selective advantage, or were closely linked to some allele that did.
I was talking the other day with a friend about why economists think they're so smart to the point of ignoring easily accessible data from other fields. Will points me to this Greg Clark review of a new book from the field of economic sociology, Adam Smith in Beijing. Clark doesn't think much of the reasoning, and my own first reaction was shock at what seemed to be a childishly naive argument worthy of a simpleton if the summary is accurate. Whatever the merits of the book, the arrogance of economists made a lot more sense if these were their adjacent fields whose scholarship they were aware of. Especially considering the relatively large number of economists who switched from physics or mathematics. Here are average GRE scores by intended major for graduate school.
Monday, March 17, 2008
 Pursuing a hunch inspired by a post on breast size and getting married by Irina, I managed to hunt down a study that shows the characteristics of the Boobman, Assman, and Legman. First though, I could not find any studies that investigated what non-obvious correlates there may be of breast size, rump size, or leg length. So I can't back up Irina's observation that larger breasts, as opposed to say a rounder butt, make a woman more likely to get married.The idea is not ridiculous: females vary in their reproductive strategies, some specializing in shorter-term and some in longer-term relationships, for example. And like many strategic choices, there is likely a trade-off: to wit, between investing a finite amount of body fat more in the upper or more in the lower region. Larger breasts could reflect pleiotropic effects of genes that also contribute to being more focused on stability and the long-term in mate choice. Or perhaps men who are more of the "good dad" type have a bias toward larger breasts, so that these are a response to the preferences of guys who will stick around. Moving on to what I do have data for, let's see what Wiggins et al. (1968) have to say about what men with different physical tastes are like. They asked 95 male college students which silhouette drawings they preferred, and these independently varied the size of the breasts, butt, and legs: each appeared in a "normal" size, somewhat large, large, somewhat small, and small. They completed personality questionnaires and provided demographic background info. Men who preferred the "large" figure -- large breasts, large butt, and large legs -- were characterized by "a need for achievement." Those who preferred the "standard" figure -- normal size for all parts -- were characterized by "a tendency to be disorganized in personal habits." And as for the small figure -- small size for all parts -- Those who preferred the small figure tend to persevere in their work. They are not cynical about authority and reported coming from an upper-class background. Although the small figure was generally disliked by the present group of subjects (Table 1), it very well may be a preferred type among members of the upper class (Moore, Stunkard, & Srole, 1962) as suggested by the present data. I don't think there's any deep evolutionary strategy going on with upper-class people preferring petite females. It could just be a fashion statement. Men who like large breasts: Also characterizing large-breast preference was a tendency to date frequently, to have masculine interests, and to read sports magazines. Further, large-breast preference was related to a need for heterosexual contact and for exhibitionism (saying witty things and being the center of attention). In social relations, men who preferred the large breasts tend to be non-nurturant and independent. This latter result gives support to Scodel's (1957) finding of a lack of fantasy dependence among college men who preferred large-breasted figures. In the present study, preference for large breasts was positively correlated with smoking and negatively correlated with endurance (perseverance in work habits). Sounds like the Boobman is a gregarious "guy's guy." Men who prefer boobs that are friendly and unpretentious:
Men who prefer large buttocks (that is, men who are not homosexuals):
Sounds like the Type A businessman or political leader. (I would say "alpha-male," but that wouldn't be very self-abasing, would it?) Quoth bodybuilder, badass actor, and governator of California Arnold Schwarzenegger (watch from 1:35 - 2:25 in this clip): "I can absolutely understand why Brazil is devoted to my favorite body part - the ass." Men who like small buttocks: Unlike those who preferred large buttocks, those who preferred small buttocks tend not to be self-abasing. They tend to persevere in the completion of their work and do not feel the need to be the center of attention. As a group they tend not to be education majors and their reading interests do not include sports magazines. Men who like large legs: The most substantial correlate of large-leg preference is an abstinence from alcoholic beverages as indicated by the negative correlation with both drinking and amount of drinking. Those who preferred large legs are nonaggressive and self-abasing (guilty, self-blaming). They tend to be psychologically minded (intraceptive) and are characterized by a slow personal tempo. . . Subjects who preferred large legs indicated that they are not business majors and that they would choose their mother over their father if they had to make a choice. The personality pattern suggested by these correlates is one of inhibition and restraint in social situations. Men who like small legs: [P]reference for small legs is characterized by a strong need for social participation. Those who preferred small legs are characterized by needs for nurturance, affiliation, and exhibitionism. That is, they are helpful to others, feel a need for social participation, and like to be the center of attention in social situations. They are also socially dependent and tend not to stick at a task until completed. So, men who like the "large" figure (the one who's tall and has t&a) are the more ambitious ones, the Boobman sounds like a social guy's guy, and the Assman sounds like a Type A businessman. It's possible to interpret this pattern as showing that the Boobman is more likely to settle down with one woman, while the Assman would be the polygynous executive type. Admittedly, the data aren't very clear; they certainly don't contain any direct information about willingness to marry, thoughts on monogamy, and so on. It has been 40 years since this study was done, but in my search I could not find any follow-up studies -- you have to admit that it's not exactly a major research concern. If any readers know of similar studies, or especially of studies on the non-obvious correlates of female breast, butt, and leg size, please say so in the comments. * I believe "not psychologically minded" in this case means they tend to think of people in simple stereotypes rather than using complex and varied concepts. Terms like "psychologically minded" and "intraceptive" are fossilized jargon from 40 years ago, and it's not totally clear what is meant. Reference: Wiggins, J.S., J. Wiggins, & J.C. Conger (1968). Correlates of heterosexual somatic preference. J Pers Soc Psych, 10(1): 82-90. Labels: babes and hunks, Personality
Sunday, March 16, 2008
Finnish Parliament debates proposal for "love vacations":
A proposal by MP Tommy Tabermann (SDP) to grant all employees a paid 7-day "love vacation" once a year led to an exceptionally colourful debate in Parliament on Thursday evening. Tommy Tabermann is a poet, but I don't think he's working on a follow up to the Kalevala. Labels: Finn baiting
Saturday, March 15, 2008
During the height of the Roman Empire there was a NW-SE (of course mostly west to east) gradient in per capita income. This is well known. One of the reasons given for the collapse of the Western Empire in the 5h century in contrast to the persistence of the Eastern Empire is that the provinces of the latter were wealthier and so could afford initiatives such as bribing barbarian tribes to move on toward the west. In Contours of the World Economy 1-2030 AD Angus Maddison confirms this (table below the fold). Additionally, in Peter Heather's The Fall of the Roman Empire the argument is also made that expansion beyond the Rhine did not occur mostly because of the poverty of the lands; the lack of tax base meaning that the conquest wouldn't have been self-supporting. So as you go north there is an inversion of the east-west wealth gradient. The main exception to this clinal geographic distribution of wealth is Italy, for obvious reasons. But there are a few other data which Maddison alludes to which interest me in relation to per capita income. He confirms that Germans were larger and more physically robust because they had more meat and milk in their diet (better sources of protein). Maddison also notes that Roman culinary science which reflected the needs and interests of the elites had a strong focus on condiments and sauces because even imported foods tended to go bad. I know that the Dutch became wealthy in the early modern period in part by exporting salted herring, but these data seem to imply that the Roman trade in food was mostly in grain. Unless curred or salted it seems that vegetables and meats wouldn't make it. If there had been magic preservatives perhaps those in the wealthier provinces would have purchased milk & meat to shore up their nutritional intake? But decomposition constrained the possibilities for trade across long distances in such perishable food stuffs.
I bring this up because in Farewell to Alms Greg Clark used the distribution of lactose tolerance to imply that northern Europe had always been very wealthy, since after all milk was produced from cows which indicated a relatively high standard of living where land could be given over to husbandry. Now, Clark is obviously a smart guy, smart enough that Brad DeLong seems to have creamed himself with praise over his book, but that sort of assertion seemed really dumb and reinforces the perception that economists don't know jack. After all, we have a good idea of the distribution of lactose tolerance and the nature of its evolution, and it seems that ecological constraints and possibly path dependence is very critical in conditioning whether this trait will emerge. In fact, as I note above scholars of the Roman period assume that the lands of Germany were relatively sparsely populated and poor if material data are any evidence (Hitler was irritated with Himmler for funding archaeological digs in Germany and Scandinavia because he felt it just made the ancestors look primitive). Gaul was wealthier and more densely populated. That serves to explain why it remained occupied after being gutted for the glory of Julius Caesar, while the campaigns of Germanicus served mainly to buttress the popularity of his insane son the emperor Gaius (Caligula). Reading economic history I notice all sorts of glosses and oversimplifications when it comes to cultural details. I don't mind that too much; I don't read Maddison's work for his analysis or even his often tenuous causal claims, but rather for his copious data sets. Nevertheless, when it comes to something like inferring economic conditions from biological data one can work out objections from the armchair without reading historical works. The extrapolation does though require taking non-economic dynamics and conditions seriously, which Clark presumably does. Note: The estimates below are for 14 AD.   Labels: History
A long time ago I said I was planning a series of posts on the work of Sewall Wright. I am finally getting round to it. I originally planned to write notes on the following topics: 1. The measurement of kinship. 2. Inbreeding and the decline of genetic variance. 3. Population size and migration. 4. The adaptive landscape. 5. The shifting balance theory of evolution. I still hope to cover these topics, but I will begin with a few notes on Wright's method of Path Analysis..... Path Analysis is Wright's main contribution to statistical theory. It is one of several methods of multivariate analysis developed between 1900 and 1930, after the basic theory of multivariate correlation and regression had been established by Karl Pearson and others in the 1890s. Other types of multivariate analysis include Factor Analysis, pioneered by the psychologist Charles Spearman in 1904; Principal Component Analysis, developed by H. Hotelling in the 1920s but foreshadowed by Karl Pearson in 1901; and Analysis of Variance, due mainly to R. A. Fisher from 1918 onwards. A bibliography of Wright's main work on Path Analysis is available here. The three most useful items are: 1. Correlation and causation (1921) 2. The theory of path coefficients: reply to Niles's criticism (1922) 3. The method of path coefficients (1934) Items 1 and 3 are available as pdf downloads linked to the online bibliography. Item 2 is not, but it is available here. As I mentioned in a previous post, a page is missing from the pdf file of item 1, but fortunately the most important part of the missing page (the definition of path coefficients) is quoted verbatim in item 2. The distinctive feature of Wright's path analysis is that it introduces questions of causation into the treatment of correlation and regression between variables. Every statistics textbook makes a ritual statement that 'correlation does not imply causation', but in practice there very often is a causal relationship between correlated variables. Path Analysis provides a systematic means of investigating such relationships. As Wright several times emphasised, it does not provide a method of discovering or proving causal relationships, but if these are known or hypothesised to exist on other grounds, Path Analysis can (in principle) help quantify their relative importance. The following comments are in no way intended as a substitute for reading Wright's own studies, which are essential. I am only aiming to provide supplementary explanations on points which Wright deals with very briefly, and sometimes obscurely. In particular, I want to clarify the relationship between Path Analysis and multivariate correlation and regression. Wright's own attitude on this seems to have changed over time. It seems that initially he was dissatisfied with what he thought of as paradoxes in the existing methods, and wanted to provide a substantially different approach. But in the course of his work he discovered that his own system was more closely related to conventional multiple regression than he had realised, and increasingly he emphasised this relationship. In Path Analysis the investigator first devises a model, shown in a path diagram, representing the assumed direction of causal relationships among a number of variables. There will be one or more dependent variables, and one or more independent variables which are assumed to influence the former. Some variables may be intermediate links in a chain of causation. The independent variables may be either correlated or uncorrelated with each other. Each segment of a path in the diagram is assigned a path coefficient which quantitatively measures the strength of the causal influence along that segment. The fundamental problems in understanding Path Analysis are: what exactly are these path coefficients? And how are they to be quantified? I will return to these questions shortly. Assuming for the moment that all the path coefficients are known, the correlations between the variables can be derived from the path coefficients by a few simple rules. Briefly, the correlation between any two variables is the sum of the products of the path coefficients along each distinct path (or chain of paths) joining the two variables. For this purpose a correlation between two independent variables can be counted as a path between them. The relative importance of the causal influence of an independent variable on any given dependent variable can be measured by the square of the path coefficient between them, which Wright calls a 'coefficient of determination' (possibly the first use of this term). The rules for operating with path coefficients are explained by Wright reasonably clearly in 'Correlation and causation' and later papers. [Note 1] The real difficulty is to understand the nature of the path coefficients themselves. Wright's verbal explanation is that 'the direct influence along a given path can be measured by the standard deviation remaining in the effect after all other possible paths of influence are eliminated, while variation of the causes back of the given path is kept as great as ever, regardless of their relations to the other variables which have been made constant.' This is defined as 'the standard deviation due to' the independent variable in question. The path coefficient itself is then defined as the ratio of this standard deviation to the total standard deviation of the dependent variable. This definition is not ideally clear, especially for cases where the independent variables are correlated with each other. Various objections were made in a critique of Wright's theory by Henry Niles. In his 'Reply to Niles' Wright admits that 'the operations suggested by the verbal definitions could not be literally carried out in extreme cases, and the definition is therefore imperfect'. Wright points out, however, that the path coefficient can always be calculated by the methods described in his 1921 paper. In the later paper on 'The method of path coefficients' Wright offers a variant on his original definition which is perhaps a little clearer: 'Each [path coefficient] obviously measures the fraction of the standard deviation of the dependent variable (with the appropriate sign) for which the designated factor is directly responsible, in the sense of the fraction which would be found if this factor varies to the same extent as in the observed data while all others .... are constant'. The problem with both formulations, as Wright was aware, is that in the case of correlated independent variables they seem to require a counterfactual assumption. If all variables other than the dependent and independent variables of interest are held constant, but one or more of those other variables are correlated with both of the variables of interest, then both of the latter variables will have their variability reduced. By insisting that the causative variable of interest retains its full variability, Wright is therefore assuming a counterfactual condition. In order to keep the variability of the causative variable unchanged, Wright says 'the definition of [the standard deviation in X due to M] implies that not only is [the other independent variable] made constant but that there is such a readjustment among the more remote causes .... that [the standard deviation of M] is unchanged ('Correlation and Causation', p.566). What Wright meant by 'readjustment' is unclear to me and, so far as I know, Wright never attempted to explain it. The causal relationships are what they are, and any 'readjustment' sounds like an artificial if not improper procedure. Rather than make further efforts to decipher Wright's formulations, I think it will be more useful to approach the problem from first principles, drawing on the general theory of correlation and regression as set out in my Notes on Correlation, Parts 1, 2, and 3. I hope to show that Wright's path coefficients can in fact be derived in a way which avoids the problems of his verbal formulations. I will assume linearity of all relationships. (Wright also in general assumes linearity, but does briefly consider the effects of departures from linearity.) It is presupposed, of course, that items represented by one variable are associated in some way with the items represented by the other variables, e.g. that the height of fathers is associated with the height of sons. The general idea behind Wright's definition is that variation in one (independent) variable has an effect in producing variation in another (dependent) variable. Since we are assuming linearity, the size of the effect should be simply proportional to the size of the cause. This naturally suggests a connection with statistical regression. The regression of one variable on another measures the average size of the deviation in the dependent variable as a proportion of the associated deviation in the independent variable. In the case of a causal influence, it is therefore reasonable to say that a certain amount of variation in one variable is caused by or 'due to' its regression on the other. The effects caused in this way will have a calculable standard deviation, which can be taken as a measure of the total size of the causal influence. Case 1 Let us begin with the simplest possible case. Suppose there is one dependent variable, X, and one independent variable, Y. I assume, as usual, that the variables are measured as deviations from their means, in appropriate units (not necessarily the same for both variables). Let the regression coefficient of X on Y be designated bxy. We are assuming that each unit of variation in the items of Y has a simple proportional effect on the corresponding items in X. The proportion must then be equal to bxy, since this is a measure of the proportional mean deviation in X associated with a given deviation in Y. For example, if bxy = .6, then for each deviation of 1 unit in Y there will on average be a deviation of .6 units in X. In general this need not be a causal relationship, but in the present case we are assuming that it is, and that the deviation in X is an effect 'due to' the deviation in Y. The total amount of variation in X that is due to variation in Y will of course depend on the total amount of variation in Y as well as on the regression coefficient. If we designate the standard deviation of Y as sy, the standard deviation in X that can be attributed to the causal influence of Y will be bxy.sy. [Note 2] If the total standard deviation of X is sx, the proportion of the standard deviation of X that is due to Y will therefore be bxy.s |
