Sociobalderdash or Sociobiology? Part III

I want to add a third part to this series, triggered by the kerfluffle over Napoleon Chagnon's new book defending himself against his critics and recapitulating his views and studies of the Yanomami.  The issue about his treatment by the media and his critics is one for the sociology of science, and our objective was, and is, to put some of the scientific issues into perspective.  I tried in Parts I and II to do that.  This third post, however, was triggered by a couple of thoughtful comments made on our previous installments, and to further express what the theoretical context was, based on my experience coming up through graduate school and a post-doc at the time, and in the same group involved in the Yanomami studies.

At the time, in the late '60s and early 70's, there was a flurry of activity in the study of the nature, genetic basis, and/or evolution of social behavior.  Cultural anthropologists often were 'evolutionists' in the sense of trying to work out general principles, or even 'laws', of cultural evolution.  The idea that cultures evolve in a systematic way perhaps analogous to Darwinian biological evolution goes back at least to Herbert Spencer (but even Ibn Khaldun in the Islamic golden era, and the Greeks in the classical era, had relevant ideas).  I studied with Leslie White, who argued that culture evolved as a phenomenon of energy capture, a kind of physics-envy specificity, but others had various more purely sociocultural views (one, for example, that goes back to Marx and others who rejected psychological or Great Man theories; even, for example, Tolstoy's War and Peace, was an attempt to debunk such theories).

We can't go over everything involved here, but by the '60s the eugenic abuses of the Nazi era were fading from memory and it again became possible to challenge the tabula rasa or Freudian theories that propose that we are only what we experience culturally: nothing is built in to our makeup.  Indeed, this was perhaps partly a reaction to some superficial psycho-theories in cultural anthropology and popular 'intellectual' commentary from WWII and thereafter.

Cultural anthropologists rejecting psychological explanations, and seeing evolutionary generalizations in the range or even sequence of human indigenous cultures (Band, Tribe, Chiefdom, State, etc.) argued that humans were uniform slates molded by their culture (a kind of cultural tabula rasa argument).  Relative to cultural change, humans were a biological constant:  After all, no matter what your genes were, if you were (say) born in China you spoke Chinese and ate rice and were Taoist, but if born in Florida you spoke English (or, depending on the time, Cherokee), were Catholic and ate burgers.

Documenting inherent behavioral nature
In the 60s Nikolas Tinbergen, Konrad Lorenz, and others comparably prominent whose names escape me at present, were publishing very interesting studies in 'ethology', which purported to describe the inherent nature of animal behavior for a wide-ranging set of species.  If stereotypical behavior existed from birth (or, in the case of birds, hatching), then mustn't it be genetic?  And if it were genetic--even if we had no ability to identify specific genes at the time--then if it were useful, didn't that mean it had evolved in the classical Darwinian sense of having been forced into the genomes by natural selection--the harsh principles of survival of the fittest in competition among individuals?  What else could there be?

Ethological studies included famous and wonderful ones of lions, elephants, wolves, and so on.   Among the traits being reported were male competition for mates, group defense systems, male dominance hierarchies, and more.  The juicy idea of alpha males having all the fun was reported in one or another way to apply to various species.  This naturally led to a spate of monographs, symposium volumes, and highly popular books some, as now, by professors whose relevant 'expertise' wasn't questioned and who were expert at playing to the popular media.  Indeed, leading anthropologists turned to studies of wild primate populations (as contrasted to individual behavior of caged primates as some psychologists were doing) to relate their ecology to their social behavior, and interpret that in evolutionary deterministic frameworks.  Open country led to one-male harems, forest canopy dwelling to isolated pair-bonding, etc.

Leading anthropologists like Sherry Washburn and Irv DeVore characterized this approach as part of a 'New Physical Anthropology' that went beyond bones and stones: we will learn about human nature more directly, by studying our closest relatives out there in their natural setting.  And we'd do it in a Darwinian framework in which we sought deterministic environmental conditions that correlated with social behavior, accept the analogies of other species, interpret that in selectionist terms, assume it was embedded in the genome, and extrapolate it to human societies.  The idea of alpha males not just bullies but of their reproductive dominance was too much to resist.  This was a theme of the day in biological anthropology.

The degree of sensory overload and publication proliferation was far less in those days than it is now, and as graduate students and post-docs at Michigan where I was, at least, we all devoured everything that was published, book or article, and discussed it all the time.  It naturally affected our work, and some of the major players--including Chagnon and Neel--were right there, and were friends of ours, or were even directly involved in the South American work.

At that time, in the early '60s, VC Wynne-Edwards wrote a pretentiously pompous, but famous book (Animal Dispersion in Relation to Social Behavior) on the evolution of social behavior.  In a book organized, surely self-consciously, to resemble Darwin's Origin, he proposed a group selection view, quite contrary to Darwin's view of evolution (but less so to Wallace's) that selection was all about competition strictly among individuals.  The gist of Wynn-Edwards' argument for our purposes here was that individual animals have ways of eliminating their reproduction so that, as a group, they avoided serious overpopulation relative to food supplies, and kept their size within what the environment could support.  This could involve male-male competition, including sexual selection by display characteristics as in peacocks, and the exclusion of defeated males from having much of a sex life.  Animal species achieved these self-limiting characteristics in many different ways, involving group displays and so on.

This was a kind of 'voluntary' self-limitation for the good of the group in just what Darwinism argued was contrary to the Hobbesian competition of all against all for reproductive fitness, and for that reason was very controversial.  Isn't it, after all, the individual who reproduces or doesn't? 

At the time many prominent anthropologists, and some of us working in anthropological demography, were interested in how humans limited their populations.  Culturally 'primitive' societies had many ways of doing this, which were being widely reported--a topic du jour.  Male territoriality and hierarchy comprised one.  Infanticide was another.  So were dowries, delayed marriage, abortion and other cultural traits that had been very widely observed.  These practices were culturally imposed, but involved individuals voluntarily abstaining from reproduction or even killing their own newborn infants--but how could such things evolve??

Natural selection and demographic processes
Demographic anthropologists, of which I was one, were interested in the relationship between age-specific birth and death rates in this very context; it was a subject of my PhD dissertation and first book.  How was a given 'type' of culture reflected in the very processes that determined evolutionary fitness?  We didn't know specific genes, but the idea was that the age-specific effects of these practices affected at least the opportunity for natural selection at the genome level.  Demographic genetics was an important component of population genetics theory, worked on by some of its leaders, and prominent in the textbooks, at the time.

In this context interest was high in finding how mating and reproduction were constrained by natural populations both of humans and our close primate relatives.  In this sense, the work by Chagnon and Neel was in tune with the times, a product of the times.  In the enthusiasm for this Darwinian revival, I think the word 'opportunity' slipped subtly out of people's minds and was equated to the 'fact' of selection.

But there were even then, and especially later on, various forms of explicit and implicit opposition:  The idea of 'Man the Hunter' (title of a famous symposium volume) was closely examined, because the widely unquestioned macho image of caveman brutes with hefty clubs could be challenged by those who had studied extant hunter-gatherer societies directly found that they got most of their food by female gathering, and only a small fraction from meat.  Hunter-gatherers were not in a relentless struggle for food but were the 'original affluent society', lazing about most of the day (as Marshall Sahlins' book called them). 

The burgeoning feminist movement included numerous anthropologist primate-watchers trained in the New Physical Anthropology.  Many were women availing themselves of newly opened opportunities in academe, and they refused to see society only through the lens of male competition and control.  The idea of man the manly hunter was challenged as a common mythology.  It wasn't that female primates were important, if delicate, things, but even that they used various selfishly competitive guiles that did not involve violence, but that enhanced their own contributions to evolution.

The idea of self-sacrifice, or altruism, that was in a sense partly behind the Wynne-Edwards and other traits that were being documented, raised a challenge to Darwinism.  Wynne-Edwards' view was vigorously challenged from a classical Darwinist viewpoint, because there were few credible situations in which genes 'for' self-limitation or self-sacrifice for the good of the group could advance in frequency--organisms without the genes could just lay low and wait till the sacrificer had been sacrificed, and then move in on the newly available females!   William Hamilton proposed his inclusive fitness kin selection theory to account for the evolution of altruism:  genetic variation that leads you to sacrifice your own reproduction could advance in frequency if it led to a greater reproductive output of your relatives. Other rationales were also offered, for example, for why people would save drowners  who weren't their relatives, or would be willing to risk their lives by going to war, but in a kindred spirit.   Hamilton's rule ruled in many circles.

Again, strongly committed Darwinists swooned over these explanations, a acceptance of nature as really red in tooth and claw.   EO Wilson coined the term Sociobiology in 1975 in his book of that name, culpably (in my view) adding a final, very badly superficial, chapter on humans, after discussing more legitimate examples like ants, that he knew very well, in the rest of the book.  Like Wynne-Edwards, Wilson's subtitle (The New Synthesis) reached high if not pompously, playing on 'the modern evolutionary synthesis' a self-congratulatory characterization of evolutionary biology in the '40s.

All this strong Darwinism was in the eye of the anthropologists: in truth, it was argued that they saw what they wanted to see or had been prepared by their own experiences or by western imperialistic culture to see.  There was, the critics argued, nothing objective about this, and 'laws' of culture were simply reflections of these biases.  Indeed, Darwinism comfortably justified imperialism, male dominance over women, inequality, racism and other similar evils.  Thus went the deconstructionist, post-modern reaction to the 'modernism' of Darwinian 'science' and its attempt to explain, or even justify, the awful state of the world--a view that didn't reflect an objective truth.  It was, whether consciously or not, a kind of controlling 'plot', mainly perpetrated by privileged elites (mainly men).

In many ways this was a continuation of age-old disputes.  Naturally, feelings ran high.  They still do.  I'm oversimplifying all over the place here, for brevity (and, surely, because of my own limited knowledge).  But many of the dogmas, including even Hamilton's rule as well as ideas of group selection, have since on close examination been found to be forced, or wanting, at best, or applicable only under highly restrictive conditions.  But  post-modernist notions that there is no truth out there in the world are also manifestly simplistic.  Ethological findings, and behavioral determinism have been shown in many different ways to be, at best, generic descriptions of what happens in some situations, not what is genetically prescribed.

There is no wonder that, while the ideas when first proposed by Changon and Neel and many others in their time had wide societal purchase, there was a backlash.  The many other factors, including the anti-imperialistic defense of indigenous populations, that were simmering widely in the social sciences during and after the Viet Nam war era, naturally were sent nuclear in and by Patrick Tierney's often wildly irresponsible attacks on the Yanomami studies.  Legitimate questions of anthropological ethics that may be raised by those studies are buried under the storm-surge of contention, polemic demagoguery, and the like.

Natural selection and the "Truth"
My own predilection is that natural selection, especially for complex behavioral traits, is far weaker and more diffuse than the sociobiological view -- or, perhaps more accurately, assumptions -- would have it.  I think the genetic arguments about the role of the candidate behaviors (like Headman dominance) are weak, at best.  I also think that our behavioral repertoire and intelligence, which we know were on the rise long before humans came on the scene, are manifestly more about abilities to sense and respond to complex social situations than it is prescriptive.  I think rigid behavioral programming would be strongly selected against, because circumstances can vary greatly in a species like ours.

To me, the wide array of cultures shows this very clearly, and even ethological studies have shown that some of the classical case studies were not correctly interpreted (e.g., things assumed to be inherent were shown to have environmental causation, even including pre-hatching effects on chick behaviors shown in work by Gil Gottlieb and others).  That is why in my previous posts in this series, I have argued that however accurate Nap's characterization of the Yanomami as he saw them when he was there were, those traits are neither necessary nor universal even in South American indigenes, but further, are irrelevant to what is generally 'human' or how prescriptive that may be, or how or even what has 'evolved' in the Darwinian sense.

But of course my view is just one and just as I am sincere in holding them, we shouldn't question the sincerity of those with other views who in their own way understand genetics and evolution, often not including the chatterati on this topic in the public and even professional media, who don't really understand genetics or evolution, or perhaps even ethnology, yet who are not inhibited to opine on the subject.  There are intelligent thinkers with different points of view.  They don't advocate it any more strongly or irresponsibly then do their (knowledgeably qualified) opposition.

I happen to think the Darwinian case is greatly overstated and I think there is plenty of evidence to that effect (and commenters on  our previous posts have pointed to some of that evidence).  But the food-fights that treat people like Nap either as totally unaware of reality, or as having a throat-hold on the truth, are not constructive if we really do want to know what that truth might be.

Sociobalderdash, and the Yanomami? Part I

Napoleon Chagnon's new book, Noble Savages, being widely reviewed and promoted, is great grist for the academic controversy mill.  Every pop-sci author, everyone with media-assigned expertise (including some prominent university professors automatically credited with relevant insight because of some book they've written) is in on the act.

Nap -- we've known each other since we were in the Human Genetics Department at Michigan, working with Jim Neel, the leader of the biomedical studies of the Yanoami -- is not the most relaxed personality you'll ever meet.  He's fiery and he's got very strong ideas that, even as graduate students, we wondered if didn't make him unsuitable as an objective observer of other cultures.

But we need not be post-modernists to recognize not only that Nap was for decades the most prominent cultural anthropologist in the post-Margaret Mead era, and he made the Yanomami one of the two most prominent 'primitive' (i.e., culturally non-technical relative to us) people in public and even professional awareness.  The Yanomami were #1 by far, I think, but the Kalahari San ('bushmen') of Africa were #2, after the prior era's more numerously prominent, but less publicly, well-known tribal populations having been visited by anthropologists in the colonial era.

Nap's interpretation of the Yanomami were a reflection of his time.  Animal behavior was being studied widely, and interpreted in the Darwinian context of attempts to explain the behavior in survival-of-the-fittest (SOTF) terms--that is, the traits we see today were assumed to be due to past natural selection essentially for the trait per se.  The term 'sociobiology' was coined by EO Wilson some years later, but the idea was already rampant.

The question being studied involved many different components, one of which was a genetic question related to issues of the amount of harmful genetic variation that our primitive ancestors carried in their populations (related, at the time, to what chemical and nuclear fallout might be doing to our much larger and more socially complex populations).  Looking at (or, perhaps more accurately, for) cultures today that were frozen replicates of our past was an objective of the evolutionary perspective of anthropology in the '60s and for a while thereafter.

Anthropological views and strategies on behavioral evolution
Rather than laboratory experiments, a prominent idea in anthropology at the time was that primates studied in the wild could show us how population structure evolved--how open vs forest environments led to selection for this or that kind of population size, territoriality, male dominance hierarchies, and the like.  Books reporting fascinating field studies, and opining captivatingly simple Darwinian explanations were rife.

Male dominance hierarchies suited the Hobbesian, Darwinian SOTF terms.  One tough guy (or alpha chimp, baboon, or whatever else that swimmeth in the sea or creepeth on the face of the earth), intimidated all the other guys and did all the rutting.  This very effectively spread tough-guy genes, leading us to be the way we are today.

Unfortunately how we really are can't be seen in modern complex societies.  Too many ways to reduce one guy's reproductive success, too many hospitals to take care of the weak, or soup kitchens for the needy.  So, to see how we really are we needed the frozen cultural fossils of our ancestry.  They could only be found in the most remote of places.

Neel seeking to understand the biomedical implications of the Big Man theory, and Chagnon to understand it culturally, made a very successful team.  I'll talk about what they actually did, found, or argued tomorrow, but here I want to go over just a bit of the reaction to Nap's book.

Flying fruit: anthropological food-fighting
I haven't read the book.  But, it's clear from reviews and stories in major media that, in essence, Nap is ranting about the way his work has been treated in recent years.  Anthropological opponents, who don't like Nap's aggressive personality or who don't like the idea that people might fight over resources or who don't like anthropologists' mucking about and stirring up the natives, accused him of seriously damaging the Yanomami, in many ways with lethal if inadvertent--but avoidable and predictable--effects, accused him of nefarious practice.

Nap responds that his opponents tried to vilify him within his profession, cowed a main professional organization into buying the accusations, and have done him dirty.  What really happened to the Yanomami and Nap's role in it (as alleged in Patrick Tierney's book Darkness in El Dorado roughly a decade ago), is disputed.  The biomedical accusations, such as giving measles to the Indians to see how they, not previously exposed, were manifestly false, as I know personally from discussions with and seeing field notes of,  Neel and one of his main field companions.

But if Chagnon has his enemies, he also has his supporters in what has become an archetype of a professional food-fight gone viral.  He was, at an advanced age and far after his work itself was done, elected into the National Academy of Sciences last year.  This must have a political symbolic nature, especially perhaps as the current NAS anthropology membership rather predominantly favors the Darwinian viewpoint of behavior and Nap's election (which would have been fully appropriate decades ago, without a political aroma) has to be seen as a gesture in the context of his recent fights within Anthropology.   This gives a joyful finger in the eye to Nap's opponents--and many would argue it's a well-deserved symbolic finger-gesture at their demagogic treatment of him.  And this new book is his attempt to revive his reputation.  Based on the reviews and articles about it, nobody will mistake it for an objective factual treatise. He is as feisty as ever.

A major explanation for the criticism to which he's been subjected, and a major element of his defense, is the fact that many anthropologists just can't buy sociobiological theorizing about human culture, nor his using the Yanomami as a valid, even archetypal 'primitive' people.  He argues that his antagonists simply can't abide the idea that Darwinian evolution has made us culturally and behaviorally, as well as physically the way we are.  That's true, whether one gives credence to the critics' viewpoint or not.

So regardless of whether his work directly or indirectly harmed the Yanomami, questions which involve legitimate ethical issues, the heat of the attacks have always been, I think, aimed at his justification of violence and inequality as being inherent in our nature, for reasons that he claims his studies of the Yanomami show.

Tomorrow, we'll look at some of those issues themselves.

The microbiome: competition or cooperation, adaptation or adaptability?

We're just now getting around to blogging about a Perspectives piece in the Oct 12 Science called "Animal Behavior and the Microbiome" by Vanessa Ezenwa et al. It's an overview of current thinking about the role microorganisms play in animal behavior.  The Human Microbiome Project documenting the extent of such organisms in humans, and the essential role these guys play in human health and disease, has found that the genes in the trillions of microorganisms with which we share our bodies outnumber ours by 100 to 1.

Since at least some of these are necessary for life, one offshoot of learning about this is to ask what 'the' human genome really is.  Most bacteria we know of, like the ones in our gut, have to do with rather prosaic, if vital, physiology such as digestion.  These are interesting and important, but they don't involve more sensitive issues such as our personal identity -- our behavior.  The role of microbes in animal behavior is just beginning to be understood, and it may be more profound than had been thought. 

Kudzu bug; Wikipedia

For example, as described in the paper, "the Kudzu bug (Megacopta cribraria), an agricultural pest, is born without any symbionts (species with which both have a mutually necessary affiliation for survival). After birth it acquires a specific symbiont from bacterial capsules left by its mother. If these capsules are removed, the bugs show dramatic wandering behaviors, presumably to search for symbiont capsules left with nearby eggs."

Or, bumble bees acquire gut microbiota either through contact with nest mates or by feeding on feces containing the microbiota required by the gut. Bees without these microbiota were more susceptible to a bumble bee parasite, Crithidia bombi. Fruit flies that share the same diet-acquired microbiota are much more likely to mate with each other than with those that don't.  And then there's the zombie ant, infected by killer fungi, and the rats -- and cat ladies -- infected by Toxoplasma gondii, both of which we described here.  The examples go on and on.

But what does the recognition that we don't go through life alone mean for the usual understanding of social context, ecosystems and the evolution of behavior?  It's tempting to suggest that these are examples of exquisitely fine-tuned co-evolution, and the usual darwinian interpretation would be that every organism is out for itself, selfishly hijacking another's gut, brain, feces, nasal passages, skin, eyes, now manipulating their behavior -- any and everything -- to make a living.  And needing to out-compete all the other microbes fighting for the same territory.  But don't get too greedy or you'll kill your host and then you're in trouble too.  (Reminiscent of how humans feel about climate change -- we have to save the planet so we can continue to exploit it ourselves.) 

But this is rather a stretch, really, and depends on fitting the facts to a preconceived view of the purpose of organismal interactions (apply our take on why people believe microbes will be found on Mars here).  And that preconceived view is that life is all about selfishness, exploitation and competition.

But there's an alternative view, and that is that what this represents is cooperation, one of the fundamental principles of life that we've often written about here and in our book MT.  It's a principle that requires abandoning the long-held belief in the primacy of "survival of the fittest" because that very rarely happens.  A better description would be "failure of the frail" -- it's only the weakest organisms that can't reproduce; most everyone else does just fine.  Plus, much of survival depends to a large degree on luck and has nothing to do with genes or competition or your ability to outwit your neighbor.

So, this Russian doll kind of life-within-life-within-life that's being catalogued is an ongoing documentation of the centrality of cooperation in life.  There's surely some adaptation going on -- the bumble bee is better off without Crithidia bombi than with, but 10-20% of worker bees in hives in the field have been shown to be infected and bees have carried on; it's only now that they're bombarded with infection with multiple parasites and more that it's a problem.  But the bee did not evolve to be infected with gut microbiota to fight off C. bombi, the bee evolved with the ability to host gut microbiota and to fight off the parasite, however that happens. 

Further, some infection was survivable, and the parasite didn't need the bumble bee because it's an equal opportunity infector, infecting other insects.  This brings up another fundamental principle of life, and that's adaptability.  Because it's ubiquitous, we believe adaptability is a characteristic of life that was present very early in evolution. So, humans can't live without a gut full of microbiota, but the species that we host are widely variable, they change when we're ill or pregnant, we can kill them off in great numbers with antibiotics, can add more with probiotics or natural exposures, and we're fine.  The same has to be true for other organisms.

One can say that what's here has to work, or at least to have worked successfully enough in the past to be here today.  But that's only a part of the biology, and there has been a tendency to focus more on how that evolved via competition, than on the interactions themselves.  How cooperation works is turning out to be an elegant but complex business.  Even if Darwinian explanations are 100% correct -- and there are reasons to temper such a view -- understanding how such things work today is in itself a challenge, and a very interesting one at that.  Though, perhaps our very interest in it is because of some microbe in our brains, that makes us sympathetic to the lives of microbes...

The true meaning of "candidate" genes revealed

The biology of behavior
I take a deep breath.  If you were here with me you'd have noticed that it was breath signifying annoyance, annoyance over something I've just read.  The annoyance triggered my brain to trigger my diaphragm to contract and elevate my lower ribs and expand my thoracic cavity vertically, while at the same time my external intercostal muscles and interchondral muscles have elevated my upper rib cage to expand the width of my thoracic cavity to allow the intake of air.  The process is reversed as I breathe out. It's a biological thing.  My annoyance also surely triggered hormonal releases of some sort as well, and other downstream reactions that may or may not catch up with me someday in the form of "stress-related illness."

But ok, that deep breath out of the way now, I start to type.  My brain has begun to formulate sentences in response to what I've just read, and now transferring those sentences to the screen requires a complex interplay between the parts of my brain that think (clearly or not) and the muscles that govern my fingers on the keyboard.

More biology.  Genes are firing all over the place, creating and controlling the complex interactions that make all this, and more, happen simultaneously without me making it happen or even being aware of what's going on.  That's because in many senses I'm nothing but an automaton controlled by my genetic makeup to respond to my environment with biological impulses. 

But I'm also eating a pear as I type.  My hunger is a biological drive -- a genetic predisposition, even -- to which I'm responding.  I have to eat or I can't fulfill my darwinian destiny to survive and reproduce.

But why am I eating a pear and not a durian fruit?  Or a betel nut?  Or a peanut butter and jelly sandwich on Wonder Bread?  Because durians and betel nuts aren't sold at my local grocery stores, or even my local farmers' markets, and I don't like Wonder Bread.  (Have you tried peanut butter and pickle sandwiches though?  My mother's favorite lunch, a taste passed down to me.)  So my clearly biological drive has to be satisfied in culturally specific ways, and based on my own personal taste.  In part taught to me by my mother. 

Let's go back to the source of my annoyance.  It's a commentary in this week's Nature: "Biology and ideology: the anatomy of politics," about how biology shapes our politics.

An increasing number of studies suggest that biology can exert a significant influence on political beliefs and behaviours. Biological factors including genes, hormone levels and neurotransmitter systems may partly shape people's attitudes on political issues such as welfare, immigration, same-sex marriage and war. And shrewd politicians might be able to take advantage of those biological levers through clever advertisements aimed at voters' primal emotions.

Many of the studies linking biology to politics remain controversial and unreplicated. But the overall body of evidence is growing and might alter how people think about their own and others' political attitudes.

Of course biology affects our beliefs and behaviors, in much the same ways that it affects what we choose to eat or our responses to things that annoy us, which in turn have been affected by our culture and upbringing.  The work described in this commentary annoys me but it might strike you as perfectly fine.  We are biological beings, and everything we do and are is affected by genes and hormones and neurotransmitters.  But that is not the same as saying that everything we do is determined by our biology.  I eat a pear but not a durian fruit, if I'm a southerner I voted Democratic in my youth and Republican now.

Genes 'for' 
Genetics is now becoming deeply entrenched in the social sciences; economists, psychologists, sociologists, political scientists are being seduced by the appeal of genetics and Darwin as they try to explain why humans do what they do.  Hell, evolutionary theory is even used to explain why characters in classic novels behave the way they do.

But this shows how little social scientists understand what genetics can actually tell us about complex traits like, well, like all the traits of interest to these disciplines.  We can't even find genes 'for' truly biological traits like type 1 diabetes or clinical depression, even if the commentary assumes we have:

The past few decades have seen a wave of research connecting genes to disorders such as schizophrenia, depression and alcoholism, and to complex outcomes such as sexual orientation and how far people progress in education.

Well, but we have made very little progress in geneticizing such things, and where we've found genetic variants that affect such traits, they usually have very little, and inconsistent, effect.  Indeed, when we throw in the effects of culture and learning, not to mention neuroplasticity of the brain, almost all bets are off in terms of identifying biological forces that shape what we believe or how we behave.

And then there's the question of just what phenotype is being measured anyway.  This is hard enough for biological traits -- what constitutes 'high' blood pressure, obesity, or autism?  Very large studies to find genes for obesity find essentially entirely different candidates depending on the measure being used (e.g., body mass index, waist-hip ratio), or the obesity-related traits like diabetes, hypertension, or Alzheimer's disease.  So how on Earth do you measure political belief in such a way that it is a proxy for some protein coded for by some gene?  

Eugenics
What about this sentence, that you might have just glided over above:

...shrewd politicians might be able to take advantage of those biological levers through clever advertisements aimed at voters' primal emotions.

We've been down this road before.

Once Darwin gave people, especially the noble science class, the idea that Nature not God made people what they were, and that through their insight they the scientists rather than clergy, could divine what was good and bad, they (like clergy) are the ones who should evaluate who was naughty and who was nice, and indeed could help Nature out by doing something about the offenders.  Of course it was all for the good.  Just like clergy helping to save souls, scientists would help save society.  And since Darwin showed that our essence was not our soul, but our biology, which within decades became  genes, their term for their wise engineering was not absolution, but eugenics.

The temptation was of course to believe that they, through their science, could find out people's true essence, and recommend what to do about it.  All for the protection of society.  Does it sound a lot like the inquisition, where clergy decided how to test, and judge, and engineer (get rid of) those who polluted the true and faithful?

Eugenics in its early form, which crept in on little cat's feet, led by the biomedical research establishment, was all for human good, of course.  But of course power corrupts and demagogues are always ready to use it, and scientists as we know very well from the past -- and today -- are easily co-opted by the hands that feed them.  And of course that kind of thinking, in its various guises, led to the Nazi exterminations (and, here and elsewhere, incarcerations, involuntary sterilizations, and the like).  It also led to the abuses of the Stalinist era called Lysenkoism, which was the inverse of Darwinism out of control.

Well, you might say, that was then and this is now.  Yes, the early eugenicists were the well-respected scientists and physicians, but they were misguided.  Now, we know better, and our scientists have only everybody (else's) good at heart, don't they?  Intrusive abuses couldn't happen any more, could they?

The DNA methylation buzz

Cells differentiate and specialize within organisms by expressing different genes as they develop, so that one stem cell becomes part of a thigh muscle and another part of the thymus gland.  But what makes organisms like bees specialize?  Some are foragers and some are nurses, and most switch their specialties during their lifetime, sometimes a forager, sometimes a nurse.  Queens are committed for life, and it has long been known that royal jelly makes a queen, but how does a bee become a nurse and then a forager?  And why are these roles reversible?

A paper published online in Nature Neuroscience September 16 by Herb et al., and reported on the BBC here, says that these behaviors are the result of epigenetic signaling.  That is, it's not heritable DNA sequence differences that create castes, but chemical alterations to DNA within the bee's lifetime through the process of DNA methylation.

DNA methylation affects gene expression rather than DNA sequence, but since it affects gene usage it is certainly valid to consider it 'genetic' in the functional sense of the world.  But many people use the word 'genetic' to refer to heritable variation, passed from parent to offspring.  One key thing that is being demonstrated in many ways is that the methylation patterns themselves can be inherited.  Effects of genetic modification of this kind can affect traits--like disease susceptibility among many others--and be 'remembered' by the person who inherited a particular genomewide methylation pattern, and that pattern then transmitted to the offspring.  A recent study in experimental flatworms is that this can happen for many generations.  That, in a sense, is the deeper importance of DNA methylation.  Whether or not that's happening with bees is another question.

Herb et al. analyzed methylation patterns in tissue from the brains of honeybee queens and workers, but found no significant differential methylation rates (DMRs) between them.  Most workers start life as nurses, caring for the queen and larvae for 2 to 3 weeks, at which time they transition to foraging. Comparison of DRMs between worker subcastes revealed 155 DRMs between nurses and age-matched foragers.

These differences might have been due to the caste transition itself rather than the state of being a forager, but the authors tricked foraging honeybees into transitioning back into nursing the queen and larvae, and determined that the DMRs are linked to the phenotype, not the transition.  They replicated their experiment to demonstrate consistency of results, and determined that reversion from nurse to forager reliably re-establishes methylation of many of the same genes, including one associated with learning and axon migration in fruit flies.

They also found evidence of a high frequency of alternative splicing in DMRs, that is, changes in gene expression that come about by the same genes being transcribed differently, probably in response to methylation.

This is all interesting in its own right, but as we often say here, it's further evidence that as we understand more about biology it becomes more complex, not less.  DNA methylation assays are hot right now, but it has been clear for a long time that there aren't going to be genes 'for' most traits and behaviors, that something else, or numerous other things will be involved.  Methylation may be a part of that repertoire, but like single genes, or single nucleotide polymorphisms, it won't explain everything.

Some ants are more equal than others

Individually coded ants (photo from JEB).

A study published in the September 15 issue of the Journal of Experimental Biology (and reported on the BBC web site) concludes that ants recognize the decision-makers in their midst.

Coordination of biological processes in groups that lack the ability to communicate globally among themselves, such as insect societies, has long been thought to be due to self-organization. That there is division of labor in these societies has long been known, but it has been thought that within strata, every individual must know the same rules, and be equally able to follow them.  And the general assumption has been that they are basically chemical automata in this respect--all molecular recognition rather than open cognition.  Indeed, human exceptionalism is so widespread in science that one often sees it viewed as surprising that any other species can think (much less has 'mind').  So, this experiment, while quite basic, is interesting.

It's starting to look as though ants not only learn, but recognize that some of their peers may have more knowledge than others.  That is, some may play more influential roles in key behaviors, including decision-making.  Stroeymeyt et al., at the University of Bristol, looked at this question in the house-hunting ant, Temnothorax albipennis.  These ants live in precarious places such as under tree bark or in rock crevices, and their homes are frequently destroyed, and they thus need to rebuild at a new site.

When it's time to move, scouts go out from the nest, or hive in the case of bees, to find new sites.  Behavior was always focused on the colony previously, not the individual, so it has always been thought that every scout had an equal chance of happening upon the best new site, and thus being followed by the rest of the group.  But Stroeymeyt et al. have discovered that Temnothorax ants seem to acknowledge that some scouts are more experienced than others, and thus should be allowed to make the decision as to where to move.

Temnothorax ants investigate their environment preemptively, collecting information about potential nest sites before they must move, which apparently increases their chances of choosing a good site (though it does sound as though none of their choices are all that good, or they wouldn't have to be moving all the time!).

Information about suitable sites is initially gathered by the workers that discover and explore the sites. It could then potentially be stored in two, non-exclusive forms: in a common repository of information, such as pheromones (social information) marking the nest itself or leading to it, or in the memories of informed workers and/or individual-specific chemical marking (private information), frequently used by Temnothorax ants. In the latter case, informed individuals accessing this information could play a key role during later emigrations.

To look at the role individuals play in this decision,  Stroeymeyt et al. painted tiny uniquely colored dots on the backs of all the workers in colonies they brought into the lab.  The idea was to determine "the role of specific individuals and the relative importance of private versus social information".

They brought 30 colonies into their lab, and moved them into nests consisting of 5 interconnected Petri dishes.  They were given a week to explore the area.  Their nest was then destroyed, inducing them to relocate.  They had the choice of a nest just like the one that had been destroyed, that some of their number had previously investigated, and an identical one none of them had ever seen before.  A new nest was considered chosen if all brood items were moved to that site, but not if items were split between two nests.

Exploration throughout the week was captured on webcams, so that it was known which individuals explored, and thus collected 'private' information about new nest sites.  These were considered 'informed' workers.  More informed workers were those that visited the site most, naive workers never visited it.

They also investigated "the relative importance of navigational memory and individual-specific chemical trails in the early discoveries of the familiar nest by informed workers".  They did this by laying sheets of acetate between two nests, then rotating them, thus changing the location of previously laid chemical trails. The idea was to test the relative importance of chemical versus visual orientation clues.

As it turned out, familiar nests were discovered first, and seemed to be preferred over unfamiliar nests.  Naive workers were as likely to find the unfamiliar nest as experienced workers, and took an equal amount of time to find either.  Informed workers, however, were much more likely to find the familiar nest quickly.  So, the researchers conclude that information collected by individual ants -- private information -- is important in leading them to new sites.

And they discovered that the ants do seem to follow chemical clues, since colonies emigrated significantly faster when the acetate under them, containing their chemical trail, was not moved, although they still preferred the familiar nest site over the unfamiliar, indicating that they were in fact following ants with private personal knowledge, which seems to include visual cues.  And, the existence of private knowledge seems to be recognized by other ants in the colony, which speeds emigration to the site preferred by the experienced workers.

So, yes, the choice of a new site seems to be a collective decision, but some individuals have more influence over that decision than do others.  We've blogged before about ants, and whether they think (we concluded that they do).  We noted then what Darwin said in Descent of Man (1871) about ants, and it's worth repeating:

...the wonderfully diversified instincts, mental powers, and affections of ants are notorious, yet their cerebral ganglia are not so large as the quarter of a pin's head. Under this view, the brain of an ant is one of the most marvelous atoms of matter in the world, perhaps more so than the brain of man.

The general idea about  cognition and consciousness (often implicitly equated) is that it's a phenomenon of large-scale interactions among synapsed neurons: you need zillions of these to have 'thoughts' or make cognitive, evaluative judgments that go beyond mecahnical responses to, say, odorant detection.  But if the pinheads of ants can do this, perhaps our ideas about what makes this possible has been too closely associated with our own high encephalization (big heads relative to body size) and egotism.  Maybe quality rather than quantity in neuronal function is more important than we've thought, or in ways we yet haven't thought of.