Running and neurogenesis; the plastic brain

A new paper online in the Journal of Physiology ("Physical exercise increases adult hippocampal neurogenesis in male rats provided it is aerobic and sustained," Nokia et al.), and described here by the NYT, reports that running is good for the brain.  At least the rat brain.

From the paper (emphasis mine):

Adult hippocampal neurogenesis (AHN) is a continuous process through which cells proliferate in the subgranular zone of the dentate gyrus, mature into granule cells, and ultimately become incorporated into hippocampal neuronal networks. In rodents, adult-born hippocampal neurons seem crucial for a variety of adaptive behaviors such as learning, pattern separation, and responses to stress. Aerobic exercise, e.g. running, increases AHN and improves cognitive performance in both male and female adult rodents. The increase in AHN in response to running is reported to be in part due to an increase in the number of surviving neuronal precursor cells (type 2) rather than to the shortening of the cell cycle. There are also studies indicating that running increases the survival and incorporation of newly divided hippocampal cells, born days before commencing training, to increase net neurogenesis. [See the paper for citations for reported findings, which I've removed here for length.]

It has already been well-established that aerobic exercise is associated with an increase in adult hipocampal neurogenesis, the number of neurons in the hippocampus, the region of the brain associated with producing long-term memory among other functions.  But, Nokia et al. wondered if it was only aerobic exercise, or whether other kinds of exercise have the same effect.

So they compared the number of neuronal cells of mice subjected to high-intensity interval training, resistance training and distance running.  They found no increase in the rats who did resistance training compared to sedentary rats, and a smaller than expected increase in rats that did the interval training.  It was only in the brains of the rats who did aerobic exercise that neurogenesis was significantly increased.  The authors hypothesize that this is because running stimulates the production of  brain-derived neurotrophic factor and insulin-like growth factor, which are associated with neurogenesis. The more aerobic exercise the animal does, the more of these the animal produces, and thus the more neurons.

Currently the best advice for preventing dementia in old age is to maintain a social life, quit smoking, and exercise.  And, if this rat study can be applied to humans, this should at least qualify that as aerobic exercise; running or biking, say.  As with all such lifestyle advice, this surely won't work for everyone, but the evidence is increasingly in its favor, at least on a population basis.

But there are deeper implications of this work, I think.  If exercise changes the architecture of the brain in ways that can affect learning, even in adults, and, as has been repeatedly demonstrated, stimulating children by reading to them, using lots of words, playing music to them, and so on, or the reverse, growing up in poverty,  or with disease, or amid famine all can affect brain architecture and thus cognitive ability for better or for worse, why do so many continue to privilege genes and genes alone -- or even more, a single gene -- for the creation of intelligence?

Source: "Effects on brain development leading to cognitive impairment:  A worldwide epidemic," Olness,
Journal of Developmental & Behavioral Pediatrics:
April 2003 - Volume 24 - Issue 2 - pp 120-130

It seems that the brain responds to experience at all ages, but it's possible that there's a 'sensitive period' for cognition.  As just one example, the cognitive abilities of children reared in institutions in Bucharest were compared to that of children never placed in an institution to those whose lives began there but who moved to foster care before age two.  Those who were reared entirely in institutions had much lower cognitive ability than the other two groups; the cognitive abilities of those who were moved to foster care before age two significantly improved.  The authors of this study suggest that there may be a sensitive period for developing cognitive ability, just as there is one for learning language, and many other aspects of brain function.

Of course, as with any trait, genes play a crucial role in the development of the brain.  But they don't do it alone.  E.g., a 2010 paper in Child Development describes the genetic underpinnings of the developing brain, but its plasticity as well.

The foundations of brain architecture are established early in life through a continuous series of dynamic interactions between genetic influences and environmental conditions and experiences (Friederici, 2006; Grossman, 2003; Hensch, 2005; Horn, 2004; Katz & Shatz, 1996; Majdan & Shatz, 2006; Singer, 1995). There is increasing evidence that environmental factors play a crucial role in coordinating the timing and pattern of gene expression, which in turn determines initial brain architecture. Because specific experiences potentiate or inhibit neural connectivity at key developmental stages, these time points are referred to as sensitive periods (Hess, 1973; Knudsen, 2004). Each one of our perceptual, cognitive, and emotional capabilities is built upon the scaffolding provided by early life experiences. Examples can be found in both the visual and auditory systems, where the foundation for later cognitive architecture is laid down during sensitive periods for basic neural circuitry.  

Genetic determinists might acknowledge the plasticity of the brain but then say that how the brain responds to experience is what's genetically determined, and thus that there are children who just aren't genetically equipped to be the next Einstein, or even to learn calculus.  We know this is true at least at one extreme of the distribution of intelligence, because there are many alleles known to be associated with low cognitive ability.  These usually cause syndromic conditions, however, so aren't related only to how quickly synapses are crossed, or memories made, or whatever it is that underlies -- or defines -- intelligence.  As with many other trait distributions, what happens at the extremes doesn't necessarily represent what's going on in the middle, so I think the jury is still out as to the overriding importance of single or even a small number of alleles in the development of normal or above normal intelligence (again, whatever that is -- for the moment, let's call it the ability to score well on IQ tests).  And indeed no genes with large effects on intelligence have yet been identified, despite decades of looking.  That has so far included comparison of the tails of the distribution among individuals without a clear-cut pathology.

So, of course there are genes involved in how quickly people think, or make connections between ideas, or memorize, or invent things, or remember -- how people learn.  But it's not either mainly genes or environment.  It's both, interacting, and molding the reactive brain.  There is enough evidence now to show that the brain is a hungry organ, soaking up and responding to experience at all times, throughout life.  Whether or not we believe that society should be investing in optimizing the environment of every child to maximize their potential is a social and political decision, not a scientific one.

Let's be intelligent about intelligence

A lot of confusion reins over assertions about whether a physical or even behavioral trait is  'genetic'. There are several reasons for this.  One is the difference between mechanism and variation. Every human trait is genetic in the first sense: an organism develops from a fertilized egg because it has genes, and without its genes it could do or even be nothing.  So every trait is 'genetic' in the mechanism sense. But the other meaning of 'genetic' has to do with variation, and that is where the difficulty and often the contention lies.  The assertion that a trait is 'genetic' in this sense means that some people with a trait, or a particular trait measure, have it because of some particular genotype. That is, we all differ in the trait because of causal genetic differences.  Identifying genetic mechanisms or demonstrating that genetic variation is responsible for variation in a trait are genuine challenges.

Searching for genetic mechanisms responsible for, say, heart disease is one of those challenges.  It's difficult scientifically, but unlike with some other traits, the scientific question isn't politically loaded. Many people fervently want to stress the genetic role in intelligence, for example, and it's often for thinly disguised racist or elitist reasons.  A common response to almost any suggestion that an individual's intelligence might not be inborn, due to variants in his/her inherited genotype (meaning built-into the person's DNA sequence), is an accusation that the person is in denial of reality (but see our Dec 14 post about genetics and dialectics).  But who is really denying reality in such cases?  In our view, it is those who misperceive or misuse measures like heritability and have deep, emotional commitment to inborn destiny.

And, again, it's pretty clear that just slightly beneath the surface is often a racist or other discriminatory agenda: "let's identify 'them' and do something about it, to 'improve' them or prevent them from harming everybody else" (Trump's throw the Muslims out campaign, or the reluctance to invest 'our' resources in groups with inferior IQ, or in the worst case, eliminate them). If it's important to understand why people behave as they do (intelligence being just one aspect of behavior; there are of course many others), the argument goes, then one needs to know if it's genetic, that is, built into the genome at conception!  Again, then depending on who such knowledge is important to, individuals in the population can (should, must) be tested.

Of course, it's worth asking carefully whether what's really being looked for are individual differences, or group differences.  Why 'we' (those in power) 'need' (that is, want) to know which of 'their' behaviors are built-in, is unclear, but seems frequently to justify acting in discriminatory ways, favoring some and neglecting others.  In other words, of course intelligence is the result of gene action, but the argument is really about variation rather than mechanism.

But before we address these issues, it is worth providing a quick description of the core of the 'scientific' basis of the argument, which typically rests on a measure called 'heritability' (denoted here by H but typically written h-squared).

Heritability: simple-sounding word, but a slippery measure
When the genetics of intelligence, or most other behavioral traits for that matter, is considered, the proof that they are genetic is usually that their heritability is high.  Heritability has been known for decades to be a rough indirect indicator of genetic mechanistic cause, but it's a very elusive measure. The usual measure of H is basically the ratio of the amount of variation in genes (G) divided by the amount of variation in genes + variation in environment, G/(G+E), all within a particular sample at a particular time.  This is estimated typically by comparing the trait measure in relatives, since close relatives share specifiable fractions of their respective genetic variants.

This figure schematically shows the scatter of genetic similarities, each dot being values of the measure in an offspring compared to the average of its mother and father.  The figure shows the difference in such correlations if environmental effects are great and genetic variation accounts for only 10% of the similarity (left panel), or small where the environments contribute only 10% (right).

From Wikimedia images, taken from Nature

H in itself measures no specific genes or gene-variants, nor any specific environmental variants.  To avoid some confounding or confusing contributors to the trait, various additional types of sample are often studied or comparisons made, such as between adoptees vs biological children, or dizygous vs monozygous twins. Heritability studies also often try to remove correlations among relatives that are due to shared family environments that could, in the computation, falsely appear as genetic.  While these strategies are not useless, they are well-known to be imperfect.

Since the measure H is a ratio that depends on the particular conditions in your particular sample, if one of the terms (G or E) were to change, even within that same sample, the H value would also change. In other words, let the same population (the exact same set of genotypes) experience changed environments, and H will change. In that sense H is not an absolute measure of how genetic a trait is, but of how relatively important it is.  Let us repeat that--heritability is not a definitive measure of the genetic contribution to a trait.  It is about its context in a particular sample.

Every study of traits like IQ test scores, used as hopeful stand-ins for 'intelligence', shows that there is substantial heritability, though usually far below 1.0.  That means that environmental effects are important, usually predominant, even if genetic variation is contributing as well.  That's about all that H measures show.  'Environment' in this sense tells us nothing in itself about what the specific individual contributing factors might be, because they don't behave the way genetic factors do, thanks to the rules of genetic transmission from parent to offspring; environmental factors don't have theoretically specifiable patterns of clustering among people or even among relatives. The apparent environmental component estimated in H studies can also include things like chance, testing inadequacy, measurement error and so on.

The undeniable bottom line is that variation in traits like intelligence test performance is certainly affected by genetic variation because the trait itself is mechanistically affected by genes. But that is a crude and almost useless fact because the genetic component is generally polygenic, meaning that it is affected by large numbers of varying genomic elements, each making very small individual contributions. Here, we conveniently ignore whether current fad factors such as microbiomic or epigenetic effects are relevant, because each of them is variable, in each population or sample, and over time--even in each individual over time--and could in principle be inherited and hence appear in families as being 'genetic'.

What this means is that even each individual's inborn genetic component will be very different, that is, each of us will have different combinations of variants at tens or hundreds (or more) of contributing gene regions.  The predictability of achieved results from genomes, much less individual variants, will be correspondingly small, practically useless, as we've clearly seen for so many other complex traits (GWAS results, for example, even of IQ test scores). If we could measure environments the way we can measure genomic variation, they would be similarly complex with many individual factors involved, most with individually weak effects.  As with genotypes, the complexity of these environmental factors would mean each person is unique and predictions are weak, and that changing circumstances and imprecision in the risk estimates would have a large potential effect on each person's achieved results.  We've discussed these limitations (and the overselling) of genetic association studies many times here.

But, if one is determined to pry into everyone's inherent worth, here's how to do it properly:
Here's an idea: Let society decide that we want to know the real genetic truth about behaviors, not just the mechanisms but the effect of variation among individuals.  To do that, we must pass legislation to ensure that all environmental factors that contribute to behavior--all of them!--are exactly the same for everyone, from conception onward.  Once that is done, variation in test performance will be entirely due to genes, since the environmental variance, E, would be zero, so that H would be 1.0.  Now we can see how strongly genes in general, or individual genetic variants, determined results.  However, we assert with confidence that the result of individual genetic prediction would still be hopelessly complex in most cases (excepting, for example, clearly pathogenic genetic variants, which we know to be rare, and even they are usually not simple).

But this is of course a fantasy: making environmental effects uniform for everyone is obviously impossible, for at least two reasons.  First, we can't make the climate in Maine like that in Florida or California.  We can't have identical schools everywhere, or the same number of books in every home, or the same number of words spoken to each infant at each developmental stage.  And so on.  So maybe a more realistic idea would be to make the environmental variation the same everywhere, so that in a sense it was a kind of uniformly distributed 'error' term in measuring genetic effects.  Of course that can't be done either, for the same sorts of reason.

Secondly, genes don't work on their own, but interact with 'environments' in almost every imaginable way, and certainly in the development of the brain.  That means that separating G and E (as in G+E) is clearly an oversimplification of something very poorly understood.  Even fixing the same environment everywhere would not have the same effect on every genotype.

The bottom line, in reality, is that arguments, usually by those in privilege, that behaviors (and hence their societal value) are inherent, are almost inevitably working some other form of self-advantaging agenda.  Racism is right beneath the surface in much of this, but so are xenophobia and class differences.  So are hopes of producing babies with some desired property.  That's clear from the history of the subject.

Since it's impossible to think that society could make environments uniform for everyone so all that's left is genetic variation, the next most salubrious thing a society could do would be to provide the best environmental conditions for all of its members to thrive in, not expecting everyone to achieve the same but at least to have safe, satisfactory lives.  More socioeconomic equity by the elimination of poverty and privilege would be a solution if such equity were the real objective. Of course since the beginning of history this has been the stated goal of those who bemoan the unfairness of society (though less so of others who say we're inherently unequal and we ought to reward the privileged).  We gain little by peering into individual genomic 'souls' and condemning those found genetically wanting to fates that we, in the elite, decide is best for them (inevitably making sure we stay at the top).

This doesn't seem too cynical a view of the subject: If what those who assert the deep importance of genetics of behavior really want is for society to be fair, the first thing is to understand the environmental effects that obviously are the predominant causes of behavioral variation, and rectify the inequities.  Let society ensure that everyone has the same conditions: no upper class advantages in schools, ballet lessons, Kaplan prep courses for SATs to get them into Princeton, no jobs to get through family or parents' contacts, same number of books in every house, no corner drug dealers nor rats in the hallways in poor neighborhoods......  Or, how about broader 'intelligence' testing ideas, to include smarts like the ability to read defenses in basketball while flying through the air, or work a fork-lift efficiently, or fix one of today's complicated cars....

H is a complex factor that is misused as much as it is used, because there are too many reasons to interpret its computational subtleties in ways that conveniently favor one's own social agenda. Not everyone interprets these issues in this way, but behaviors like intelligence are too juicy for those with such intentions to resist.  But, yes, let's be scientific, and commit to a concerted effort to make H approach 1.0, so that we can really understand the genetic contributions--that is, to make test-score differences really 'genetic'!  Then we could make sense of 'genetic' causes.  But, would any serious thinker believe it would be very useful?

So...it's not genetic after all! (but who's listening?)

Is it time to predict the gradual out-cycling of a focus on genetic causation and a return of environmental causation, in our mainstream scientific dialog (and funding-pot)?  Such a recycling is bound to happen--even if, say, genetics' claims were correct.  Why?  Because the new generation has to have something to show they're smarter than their elders, and because the abuse of genetic determinism by society is a nearly inevitable consequence of the fervid love-affair we're now having with genomics and its glittering technology.  But maybe there's another reason:  maybe genetics really has been oversold!  Is it possible?

Bees and societal (in)determination
Honey bee harvesting is a social phenomenon and experiments by various authors have found that only a fraction (in some studies, 20%) of the workers actually do most of the work.  But a recent controlled study reported in the journal Animal Behavior by Tenczar et al (vol. 95, pp41-48, 2014, but paywalled) found that if those 'busy-bees' are removed, others step in to fill the work gap.  The gist of the evidence seems to be that among the gatherer work force (and presumably other castes as well, though that's not reported), there is a spectrum of contribution and it's condition or context-dependent.  As the paper says:

These bees resembled ‘elite workers’ reported in a number of other species. However, our results also show that honeybee foraging activity level is flexibly adjusted during a bee's lifetime, suggesting that in honeybees, elitism does not involve a distinct subcaste of foragers but rather stems from an extreme of a range of individual activity levels that are continuously adjusted and may be influenced by environmental cues.  . . . these results support the view that individual workers continuously adjust their activity level to ensure that the colony's nutritional needs are being adequately and efficiently met, and that the net activity of the whole foraging population is likely to be one of the factors that influences this decision. 

The authors discuss the fact that these patterns have not been studied, with varying levels of rigor, in many species of social insects.  While it is not clear that genetic differences are never partly responsible, the evidence is that social roles are not rigidly pre-programmed.  This study was presented by the NYTimes with a captivating video from the authors, but while that was nice and led us to the research story itself, the Times characterized this as a system allowing upward social mobility.  That's a bit pandering to middle-class readership, and didn't really critique this work in the context of today's prevailing genetic-deterministic viewpoint. However, the idea of context-dependent roles, based on the needs and opportunities in society at large, is noteworthy and of course is something that also happens in humans.

Honeybee; Wikimedia Commons

This of course raises the question of how the bees perceive the needs or different roles, or if the role pattern is a spectrum of activity of each bee, then how does it know when and what to do.  This would relate to the bees' brains' ability to digest quite complex information and make decisions, something very interesting to try to understand, and something we wrote about here not long ago.

Intelligence
A new paper in PNAS reports the results of a large study of the genetics of IQ.  Essentially, they found three genes with very small effect and unknown functional association with cognition.  Indeed, one of the genes may not even be a gene. To sort this all out, of course, they say they would need a sample of a million people.  One of the authors faced with this mountain of chaff is quoted this way in the story:

Benjamin says that he and his colleagues knew from the outset that their efforts might come up empty handed. But the discovery that traits such as intelligence are influenced by many genes, each having a very small effect, should help to guide future studies and also temper expectations of what they will deliver. “We haven’t found nothing,” he says.

Nice try!  But the truth is that that is just what they have found: nothing.  Or, at least, nothing new, that is, no thing.  We knew very well that this was the most likely sort of finding.  We have countless precedents, including the results of countless earlier searches for genes for intelligence (and, for that matter, similar findings for most psychological/behavioral traits).  Like other traits from normal ones like stature and IQ, to body weight and major diseases of all sorts, we find polygenic control--countless contributing genetic factors with individually minimal effect. This even though usually the heritability of the trait is substantial, meaning that variation in genes together accounts for a non-trivial fraction of the overall variation in the trait (the environment and other factors contribute the rest, usually around 60-70%).  

But heritability is a persistently subtle and misunderstood (or ignored) measure. Even with nontrivial overall heritability, the aggregate nature of the measure means we cannot say in any given individual whether his/her IQ is based on this or that particular genes, or is some specifiable percent due to genes (that is itself difficult to make sense of when referring to an individual).  And heritability is often measured after taking out, or controlling for the major real causal factors, such as age and sex.  Arguing for a sample for a million, if allowed and funded, is a huge fool's errand and a corrupt way to spend money (because it's mainly to keep professors off the street of unemployment).

Yet the issues in these cases are subtle, because we also know of many different individual genes that, when seriously mutated, cause direct, major, usually congenital damage to traits like intelligence.  Yet few if any of these genes show up in these mega-mapping studies.  It is this sort of landscape of elusive complexity that we need to address, rather than just building expensive Big Data resources that will largely be obsolete before the DNA sequence is even analyzed, based on the daydream that we are not, knowingly, chasing rainbows.

The primary question one thinks to ask is whether 'intelligence' is a biologically meaningful trait.  If not, even if it can be measured and be affected by genes, it isn't really an 'it' and one can't be surprised that no strong genetic influences are found even if the measure is stable and heritable.  Asking about the genetic basis of intelligence under such circumstances is not asking a well-posed question.

Baby stories
The other day we posted about the recent Science issue on non-genetic influences on parenting,  environmental effects on traits and how long-term and subtle they can be, and how they are not Genetic in the sense of the G-rush we are currently experiencing.  The stories are many and diverse and tell the same tale.  

Here the fascinating question is how the various environmental factors could influence a fetus in factor-specific manners that even relate to the factor itself (e.g., maternal diet affecting the future baby's obesity level, or the effect of the mother eating garlic or being exposed to odors on taste preference or specific odor-related behavior in the child).  To answer such questions we have to know more than just about a gene or two.

So, why aren't these findings grabbing headlines?
The bee story made the front-page of the NYTimes, but mainly because of the video and not because it is a counter to the strong genomic hard-wiring ethos so often promoted by scientists these days.  Likewise, the baby influences made the cover of Science, but we didn't see a Hot-News blare announcing that genetics isn't, after all, everything.  And of course the IQ story didn't make that clear either, given that the author said he wanted studies of a million to find the real genetic causes of IQ.  And, determinists say this isn't going to change their mind about the genetics of intelligence, because it's definitely genetic.  

Will we, or when will we, see people begin to back off their claims of strong genetic determinism, and begin addressing the really hard questions concerning how complex genomes interact with complex environments to produce what we are clearly observing?  In my opinion, these questions cannot be addressed from a genetic, or from an environmental, or from a simple Gene + Environment point of view.

Smart as can bee; leafcutter bees, another example

A week or so ago we blogged about a paper on bee navigation and other aspects of animal behavior, and whether such behavior can be said to be evidence of 'intelligence'.  We mused about the word, and whether ideas about whether animals other than ourselves are 'intelligent' or 'sentient' or--the real big Prize, 'conscious'.  That post generated quite a lot of interest.

It's perhaps a definitional issue, beautifully suited to endless debate and a guarantee of no solution.  But one thing is for sure, we think:  what the little old bee-brain guys are doing is quite complex.

In the interim, we read this beautiful and fascinating post by Hollis Marriot on her blog, "In The Company of Plants and Rocks."  Hollis is, we think it's right to say, truly a naturalist (though a professional botanist) who lives and works in Wyoming and blogs about botany, geology, nature, her travels, and more.  She's a beautiful writer, photographer and observer of the world.  The question this particular post raises is similar to ours about bee navigation or the problem-solving talents of crows.  In this case, she describes how solitary leaf-cutter bees cut a disk from nearby leaves, curl it up, tuck it under their legs like an architect carrying building blue-prints, and hie back home.  Home to a leaf-cutter bee is likely to be a crevice in an old piece of wood.  They build a dozen or so cells inside their crevice, lay an egg in each one and seal it with one of the leafy disks they've harvested a short distance away.

Leafcutter bee: Wikipedia

Now just think about any of these acts this behavior requires: finding an appropriate leaf (is it by some taste-test as well as size and so on?), then knowing how to cut a circular disk (without using a compass to inscribe it first!), then how to roll it up and tuck it between (well, among) their legs, and so on.  This is complex behavior and cannot entirely be pre-programmed.  That's because no a priori program can know where the tasty, cushiony leaves will be, nor how to fold them up, and so on.  It must look, smell, hear or whatever around its environment, resolve various images such as the trees and leaves, often when both it and they are moving, assess them, know how to work directed aeronautics of its wings and halteres to get there, and its many appendages to land its complex mouth and jaws to carve.  And then how to do the apparently simple thing of tucking it in amongst six (count 'em!) legs, then adjust its aeronautics so it can still fly properly back home.

To me, this is mental behavior, and whether or not you want to say it involves 'thinking' is basically a semantic question.  I personally would call it intelligent, far less robotic than, say, how amoebas mechanically and purely biochemically flow pseudopods towards food or respond to light.  It involves neurons, sensory systems, limbs and so on that use many of the same genes we use for the same systems.  Just because it's not doing full-blown trigonometry, what it is doing is still complex.

This is what leads me to think those who are being too restrictive about what counts as intelligence, as we discussed last week, are minimizing a very important, and fascinating question:  How can DNA and its coded products possibly achieve such feats?  This is not a mystical question, nor any invocation of mind-matter dualism immaterialism.  It's simply a willingness to acknowledge that our understanding of brain function, and the translation of linear codes to 4-dimensional actions, is at present elaborate in data-detail and paltry in substance.

From this point of view, none of us should be making pronouncements about what is 'genetic' and what 'must be' programmed and what 'environmental'.   This is another illustration of clear knowledge that should make us much more humble about what we claim to be knowledge--about bees, much less human behavior.

Are bees intelligent?

The other day, Ken and I had coffee with a couple of philosophers who spend their time thinking about philosophy of the mind.  What is consciousness?  Do non-human organisms have consciousness?  What is intelligence?  How do we make decisions?  What about ants?  These are hard questions to answer, perhaps even unanswerable, but they are fascinating to think about.

Our meeting was occasioned by the recent paper in PNAS about the mental map of bees ("Way-finding in displaced clock-shifted bees proves bees use a cognitive map", Cheeseman et al.).  Cognitive maps are mental representations of physical places, which mammals use to navigate their surroundings.  Insects clearly have ways to do the same; whether or not they do it with cognitive maps is the question.

Honeybee: Wikipedia

The "computational theory of mind" is the predominant theory of how mammals think -- the brain is posited to be an information processing system, and thinking is the brain computing, or processing information (though, whether this is 'truth' or primarily a reflection of the computer age isn't clear, at least to us).  In vertebrates some at least of this takes place in the section called the hippocampus, or in non-vertebrates in some neurological  homologs.  But, what do insects do?  

Previous work has shown that captured insects, once released, often fly off in the compass direction in which they were headed when they were caught, even if they were moved during capture and the direction is no longer appropriate.  But, they then can correct themselves, and then have no problem locating their hives. That indicates that they've got some kind of an "integrated metric map" of their environment.

Some theories have held that they mark the location of the sun relative to the direction they take and then later calculate 'home' based on a computation of time and the motion of the sun.  This by itself would be a lot of sophisticated computing, or thinking....and why not 'intelligence'?

Cheeseman et al. asked whether instead what they are relying on is a series of snapshots of their environment, which enables them to recognize different landmarks, one after the other as they come into view, rather than a completely integrated mental map.  They experimented with anesthetizing bees and shifting their sense of time, so that they couldn't rely on the sun to get them home.  It took some flying for the bees to recognize that they were off-course, but they always were able to re-orient themselves and get back to the hive.

Cheeseman et al. conclude that that because bees don't rely entirely on a sun-compass for their sense of direction, they must have the apian equivalent of a cognitive map.  That is, they collect relevant spatial information from the environment with which they navigate, and use it to make decisions about how to get where they are going. That is, they take and file away snapshots; remember that insect eyes are complex, including two compound eyes and in most species three forehead-located small, simpler ocelli so this is synthesizing a many-camera pixellation and differently sensitive integration of the light-world. Then, they use a sequence of these frames, later, from a different position from that at which the photos were taken so not all landmarks might even be visible, and at a different time, which can affect shadows, colors, and so on.  Then, tiling these lined up in reverse order in mirror left-right flipped order somehow, and adjusting their angles of perspective and so on, also perhaps sound, wind direction, and even perhaps monitoring the olfactory trail (also in reverse relative position) like Hansel and Gretel's bread crumbs, they head home for dinner.

Two big compound eyes, and 3 simpler central ocelli. From http://169.237.77.3/news/valleycarpenterbees.html

To us, this is a remarkable feat for their small brains!  For some of us, even with a human brain, finding one's way home without a GPS is no easy task, and deserves a nice cold drink when done successfully.  However, the philosophers we were chatting about this with did not think what Cheeseman et al. believe they discovered about bees should be called a cognitive map because, and we think we've got this right, they haven't got a mental image of the entire lay of the land.  Instead it's as though they are connecting the dots; they recognize landmarks and go from one mental snapshot with a familiar landmark to the next. So what kind of 'intelligence' this is becomes a definitional question perhaps.  Call it mechanical or whatever you want, we would call this 'intelligent' behavior.

We don't know enough about philosophy (or the biology) of the mind to know how significantly these two models differ, or whether 'consciousness' is subtly underlying how these judgments about cognition are made, but in any case, that's not what interested us about the bee story.  What is the experience of being a bee?  Whichever kind of imaging and processing they do to navigate, how do they turn the locational information into action?  It's one thing to know that your hive is east (or the apian equivalent) of the pine tree, but getting there requires "knowing" that after you've collected the nectar, you then want to bring it home, and that means you have to find your way there.  Your mental map, whatever it consists of, must be made operational.  How does that happen, in a brain the size of a bee's? Or an ant's?




Or bird brains?  Crows, corvids, are considered among the smartest of birds.  Their problem solving skills have been documented by a number of researchers, but crows have fascinated many non-scientists as well, including our son, who sent this observation from Lake Thun in Switzerland.

Crow found a little paper cup with some dried out dregs of leftover ketchup in the bottom. This is the sort of little paper condiment cup that would come with some french fries. We watched the crow try a couple of times to scrape some ketchup out with his beak, holding the cup down with his foot. It apparently wasn't working enough to his satisfaction, so he flew with the cup to the edge of the water (we were at the lake). He wanted to get the ketchup wet to "hydrate" it, to make it easier to scoop out. That was impressive enough, but what he did next was even more. There were little waves lapping on the "shore" (this was actually in a harbour and the shore was concrete) and each time threatening to carry away his cup. So he picked up the cup and carried it along up and down the shore until he found a little crevasse in the concrete that he could secure the cup, and let the water wash over it without taking it away. Clever.

If that's not intelligence, it's hard to know what it is, then.

One view of intelligence is that it's what's measured by IQ tests.  Or, at least, what humans think 'thinking' is all about.  But this is perhaps a very parochial view.  We tend to dismiss the kind of intricate brainwork that is required by nonverbal activities, or by athletes, or artists, or artisans.  We tend to equate intelligence with verbal kinds of skills measured on tests devised by the literate segments of society who are using the results to screen for various kinds of western-culture activities, suitability for school, and the like. There's no reason to suggest that those aspects of brainware are not relevant to society, but it is our culturally chosen sort of definition.

Philosophers and perhaps most psychologists might not want to credit the crow with 'intelligence', or they may use the word but exclude concepts of perceptual consciousness--though whether there are adequate grounds for that that are not entirely based on our own experience as the defining one, isn't clear (to us, at least).  In any case, wiring and behavior are empirically observable, but experience much less so, and consciousness as a component of brain activity, and perhaps of intelligence, remains elusive because it's a subjective experience while science is a method for exploring the empirical, and in that sense objective world.

If bees and, indeed, very tiny insects can navigate around searching the environment, having ideas about 'home', finding mates, recognizing food and dangers, and they can do it with thousands rather than billions of neurons, at present we haven't enough understanding of what 'thinking' is, much less 'intelligence', to know what goes through a bee's or a crow's mind when they're exploring their world....

The fluidity of fluid intelligence

If IQ is a measure of some aspects of intelligence, and intelligence is the product of a gene or genes, then it should follow that IQ is a stable trait during an individual's lifetime. So I was interested to hear on a recent episode of the BBC radio program, Analysis, that IQ can change even over the course of participation in a brief psychological study.

Princeton professor of psychology and public affairs, Eldar Shafir, co-author of the book, with economist Sendhil Mullainathan, "Scarcity: Why Having Too Little Means So Much", was interviewed  on the program about how having too little time or money influences our lives.  Mullainathan and Shafir believe that experiencing scarcity changes the way we think, and makes a bad situation even worse; poverty creates a "scarcity mind-set" and causes poor people to make bad decisions, which perpetuates their poverty.

To test this, they interviewed people shopping in a mall in New Jersey, determined their financial status, presented them with various financial scenarios and then asked them to play computer games that measured their 'fluid intelligence', a component of IQ that indicates things like the ability to think logically, to reason, or to handle novel situations.

When the scenario is manageable, if for example they are asked what they would do if their car breaks down but it won't cost much to fix, poor and rich people perform equally well on the tests.  But if the scenario is challenging, say fixing the car costs $1500, rich people did as well on the intelligence tests as they did before, but poor people did significantly worse.

Mullainathan and Shafir contribute this to scarcity of what they call 'bandwidth', or the amount of mental capacity that is used to make decisions.  They found that IQ fell by 13 points in their poor study subjects given a challenging scenario.  This, Shafir said, can be equivalent to a drop from borderline gifted to average, or average to borderline deficient.  Shafir contrasted this with a night without sleep, which leads the IQ of the sleep-deprived to be 10 points lower than usual.

Scarcity has other effects as well, according to Mullainathan and Shafir, leading people into a cognitive 'tunnel' so that they can't think broadly about how to solve a problem.  Shafir describes it this way in an interview with the the American Psychological Association:

Every psychologist understands that we have very limited cognitive space and bandwidth. When you focus heavily on one thing, there is just less mind to devote to other things. We call it tunneling — as you devote more and more to dealing with scarcity you have less and less for other things in your life, some of which are very important for dealing with scarcity. There's a lot of literature showing that poor people don't do as well in many areas of their lives. They are often less attentive parents than those who have more money, they're worse at adhering to their medication than the rich, and even poor farmers weed their fields less well than those who are less poor.

Clearly this can become politically volatile very quickly; right-wingers might interpret these results as indicating that poor people doom themselves to poverty, while left-wingers interpret them to show that poverty begets poverty.

But it's the effect on IQ that interests me, and yes, this is another subject that gets volatile very fast. How can this thing, that so many believe is genetic and therefore relatively fixed, change so readily, and in fact predictably?  This is not the first time that fluid intelligence has been shown to be, well, fluid.  A 2007 paper in PNAS showed that it is trainable, and can be significantly improved, e.g., and methods for improving intelligence, something previously thought to be impossible, are now rife.

If true, this doesn't mean that genes have nothing to do with intelligence -- whatever that is -- though it does mean intelligence isn't fixed.  Perhaps intelligence can be thought of as analogous to blood lipid levels, say; we may be genetically predisposed to high or low cholesterol, but we can raise or lower our levels with diet, exercise, or medication.  That is, as every trait, it has a genetic scaffolding, but it is also influenced by experience.  And, as with intelligence, some people have extreme cholesterol levels, generally due to single or few genes.  However, generally, these are genes that don't influence cholesterol levels in people between the extremes.

This is of course one implication of the clear fact that the 'heritability' of intelligence is well below 1.0, meaning that environmental factors are important as well as genetic ones.  The volatility of the measure is, however, an indicator that even the trait itself may not be very stable and that 'environment' may not refer just to random non-genetic factors but ones that systematically affect the measure.  In this case, the environmental factor could suggest that people in poverty are poor because of low-IQ genotypes, but Mullainathan and Shafir believe it's more complicated than that, that poverty creates a mindset that perpetuates poverty.

Similar kinds of issues apply to most complex traits.  Heritability can vary with age as well as many other factors, because the impact of environmental factors can change, and perhaps for genetic reasons as well.  Some genetic factors may be expressed differently at different ages.  A major issue in general in regard to complex traits would be if the genetic component doesn't just fix a certain fraction of the trait value, but is volatile.  Then the time and way of measurement could generate values that are taken as more inherent and permanent, but in fact are more widely variable.  The variation could be such that the genetic component is far less relevant than is often thought.  Of course it could be the other way round.  In each trait if we are determined to identify how much is inborn and how much acquired, it may be that we need to be much more knowledgeable about the determinants, and more careful in how we measure traits -- or how we 'label' individuals.

"Roots": the saga of (plant) families caring for each other

We did a post a few weeks ago about plant intelligence.  We wrote primarily about a recent Michael Pollan piece in The New Yorker that discussed the issue at length, we thought in a nicely thought-provoking way.  A piece in The Scientist, "Plant Talk" by Dan Cossins, pushes the issue a bit further.



Cossins describes an experiment that demonstrates that plants communicate through their root systems.  They send warning signals about insect infestations, and share nutrients.  A PhD student in Scotland, Zdenka Babikova, tested the role of mycorrhizal fungi in this communication system, and published the results in Ecology Letters in July.  She planted 5 bean plants in 8 different pots; one was a 'donor' plant, and the other four were 'receiver' plants.  One formed root and mycorrhizal contact with the donor, another only mycorrhizal contact, and two had neither.  Cossins writes:

Once the mycorrhizal networks were well established, Babikova infested the donor plants with aphids and sealed each plant in a separate plastic bag that allowed for the passage of carbon dioxide, water, and water vapor but blocked larger molecules, such as the VOCs [volatile organic compounds] used for airborne communication.

Four days later, Babikova placed individual aphids or parasitoid wasps in spherical choice chambers to see how they reacted to the VOC bouquets collected from receiver plants. Sure enough, only plants that had mycorrhizal connections to the infested plant were repellent to aphids and attractive to wasps, an indication that the plants were in fact using their fungal symbionts to send warnings.

Figure 1. Experimental mesocosm (30 cm diameter; n = 8) showing the donor plant, which was colonised by aphids, and four aphid-free receiver plants. All plants were grown in the mycorrhizal condition but one plant was prevented from forming mycelial connections to donor plants (0.5 μm mesh), another was allowed to form connections initially but the connections were snapped after additions of aphids to the donor (rotated 40 μm mesh), and two other plants were allowed to form shared mycorrhizal fungal networks (non-rotated 40 μm mesh allowing fungal contact only; no barrier allowing fungal and root contact) with the donor plant for the duration of the experiment. Ecology Letters, Babikova et al., 2013

Cossins adds, with respect to plant communication, "Moreover, plants can “talk” in several different ways: via airborne chemicals, soluble compounds exchanged by roots and networks of threadlike fungi, and perhaps even ultrasonic sounds. Plants, it seems, have a social life that scientists are just beginning to understand."

A lot of the work on communication between plants was dismissed by most botanists until recently. Now botanists acknowledge that there may well be signaling going on, but some still are not willing to consider plants to be social organisms, or altruistic, and see all this signaling as an offshoot of a plant's ability to alert healthy cells of insect attack from damaged cells, or of a plant's response to drought, and so forth.  Is that just a bias because plants don't do it the same way we do?

Plus, the inter-plant communication doesn't seem to do the sender of the signal any good, so some wonder how this could have evolved.  The same debate has been going on with respect to animals for a very long time, and the same kinds of answers are coming up -- plants seem to most effectively receive signals from related plants, so they may be protecting copies of their own genes when they signal to neighboring plants, because related plants share many of their genotypes.  Kin selection is controversial especially if it involves risk to the helping organism, such as a plant when it helps another.

This is all interesting for its own sake.  But there are possible important applications.  For example, Babikova et al. note that it has been found that some commercially bred maize no longer produces the VOCs induced by insect infestation. That is, a natural early warning system may be being bred out of crop plants, and thus increasing the need for pesticides. As Babikova et al. say, "...our data suggest a pressing need to determine the extent to which manipulation of common mycorrhizal mycelial networks can provide sustainable solutions to manage insect pests. The role of mycorrhizal fungi in mediating multitrophic interactions in agricultural ecosystems has largely been overlooked, but our findings suggest that there may be potential to develop fungal treatments to enhance crop protection." So indeed learning about inter-plant communication is of more than whimsical interest. 

As for how apparent altruism could have evolved in plants, or whether these communication mechanisms are helpful to other plants purely by accident, this is only a problem when the assumption is that evolution is about competition rather than cooperation.  The argument can be made -- we made it in our book "The Mermaid's Tale" and elsewhere, but more and more evolutionary biologists are making the argument as well -- that cooperation is more fundamental to life and to evolution than competition.

This is a serious problem if one individual makes a big reproductive sacrifice that serves to help another's reproduction.  It is that aspect of altruism that has attracted so much theoretical attention over the years (in animals).  But, again, it is a serious problem mainly if one views each organism as an independent actor, ignores mutuality and things like recombination and population change over time, and ignores the almost automatic kinship among nearby individuals in many species.

Whether human culture-derived words like kin or altruism should be applied to plants in a way that skirts so close to anthropomorphizing, this depends, we think, on whether you think of humans as exceptions, or more representative of the rest of nature than we generally like to accept. Or if you think that our kind of wet-ware (neurons and interconnections that form our unitary sense of existence) is the only one that counts.  But that's somewhat like saying trains or planes are not vehicles, because they don't work like cars do.  The same sorts of questions can be asked of consciousness -- are we really the only organisms that have self-awareness?

Smarten up....but do it quickly!

To what extent is  'intelligence' genetic?  That is, to what extent is your intellectual ability a native ability rather than something learned or developed?  This has long been a very heated 'discussion', not because it's about individuals with truly impaired intellectual abilities, which can often be due to known genetic mutations.  Instead it's largely been about groups, that is, 'races', and it's therefore inextricably related to society at large.

One argument that IQ (here, we let that stand for whatever is measured, without making any supportive judgments that, or when and where it is an appropriate measure of something).   Heritability of IQ is not-trivial, generally estimated to be around 80%.  The remaining 20% is 'environment', and measurement error and the like.

xkcd: Idiocracy

Previous studies had shown the tremendous advantage that early exposure to language and complex concepts has on later development, and that means later school success, and that means higher IQ test achievement.  Prior work showed that by age 3, children from privileged professional families had heard millions more words spoken than children from unpriviliged families.  They also had heard many different words spoken and learned their use.  Now, the NY Times reports that this difference can be detected even by or before age 2.  Samples were small but the study reinforces the idea that very early experience is telling throughout later life.

So what?
Those who see important group differences in IQ are going to defend their viewpoint by saying that they know very well about environmental variation and take that into account but that early experiences cannot obscure the entire group difference.  We don't happen to agree, and this is clearly a matter of personal politics all round, but there are a couple of questions that are fair to ask.

First, is it possible that the actual heritability of the measure is much lower than its estimates?  If social class is correlated in families, say by neighborhood, race, or education etc., then this can inflate heritability estimates, showing similar values for similar reasons, in professional as well as lower SES families.  This is why adoption studies are often used to show the true heritability, but even there there has been evidence of SES correlation in adoptions.

Secondly, if SES inequality were removed from the picture, the overall heritability might stay the same but there would be no difference of the average and far less variance (variation among individuals) among what were previously very different SES groups.

Third, education policy strives and presumably would strive even harder, to standardize what children are taught from birth on up.  They'd be taught or exposed to what our society values, be it vocabulary or mathematics or music or sports.  IQ test scores could increase steadily, as they have done for the past several decades, by making the most of everyone's inherited abilities.

There will always be those who are unusual on this or any other kind of value-score system.  There will be those who are seriously impaired or seriously gifted, however the neural mechanism works.  But the issues of group differences would largely if not entirely disappear; there will always be some average difference between any two groups that are compared on almost any measure of attributes, but that doesn't make the difference 'important', which is a social judgment.

The current study doesn't take us all the way back to Freudian ideas that the first glimpse an infant has of the world is hugely transformative, though who knows what further studies might find.  In any case, the important fact is not about the IQ controversy, because there is no reason to doubt that an enriched environment throughout life is an enriching fact of life.

Let's put this subject to bed...

Our Monday post raised quite a stir.  It was triggered by a Science paper about a large mega-study on the genomics of educational achievement, and a subsequent blog post by geneticist Dan Graur.  An issue that we suggested would come up was what we felt was an inevitable interest in using this GWAS result specifically to look for group differences (i.e., especially including 'race' differences) in intelligence.  Even such super-minimal results as reported in the Science paper--trivial genetic contributions to the chosen outcome, educational attainment--can be easily used to justify such purposes.

Our 'policy' on vitriol
Sure enough, we got a few comments expounding upon exactly that point of view, some rather virulently.  You won't see these here, because, for one thing, we didn't want to let that thread get started.  And we don't publish comments that attack individuals in ad hominem ways, nor take blatantly racist stances.  While we don't block disagreement, we do exercise what does amount to a form of censorship.  Those views have plenty of other places to be aired, but not here. 

It is fair enough to disagree, and the blogosphere is a place for opinions to be aired and discussed.  There are few other venues with so wide and fast a reach, a wonderful thing.  Indeed, we use much of our post-space to critique areas in which we feel evolutionary concepts, or genetics and related topics could be differently considered.  We try to do it in the context of the science itself, pointing out issues as we see them.

Of course each study is done by people, and we criticize the 'system' for the various vested interests that drive it.  But we rarely if ever knowingly aim this directly at individual authors in a personalized sense, even if we can and will say when we think someone should know better than to say what he or she said.  We're all human and fallible, however, so it is the issues that are important, not the individuals in our context.

Racism and 'IQ' (here used to represent the panoply of intellectual achievement measures and concepts) have a nasty history.  Polarization is deep and the issues--for those who want to take science seriously--are complex, and the science can and will be used by both those who believe that inequality is justified, and those who believe it's not.

Taking the science seriously
What about intelligence differences, for example?  Are they real, or are they only social constructs by right-wingers?   From a genetic and evolutionary point of view, if you do an IQ study comparing any two individuals, or two groups (say, the left and right sides of a class, two random individuals, two populations you choose to sample--even identical twins) and you find no difference between them, then there is something wrong with your study!  Because of existing variation and new mutational variation, every pair of individuals, and hence every set of indigenous, geographically separate populations that you sample, will differ genetically, and differences will be found across the genome.  Even identical twins are not genomically identical, because every cell division during each twin's life involves the occurrence of some new mutation.

At the moment, we're not considering the manifestly important 'environmental' effects.  But a reductio ad absurdem is that if you don't go to school or can't read you can't score high on a school IQ test.  So, because evolution is the process that got us where we are and is a population process of sorting through variation, you cannot expect exact identity between any two people.  So a study that finds nothing is not done right, uses inaccurate methods of testing for differences, etc.

GWAS knowingly bury genome sites whose differences between cases and controls, for example, are not statistically 'significant', reporting only what passes a specified statistical test.  This is essentially what must be done if one takes a sampling and statistical approach to the subject, as is current standard practice.  We think it's not good science, but that's beside the point.  The point is that when only a few small effects are reported, this does not mean there are no other genomic effects even in that study's data.  Indeed, the idea that most of the heritability--the aggregate genetic effects we find by using trait comparisons in relatives, for example--is 'hidden', really refers to the problem of statistical testing and the intentional ignoring of effects that must be there but don't individually pass a statistical significance test.

To do the science right, or at least in a better way, is a difficult challenge.  Serious issues that may not be compatible with a steady stream of hypothesis-free mega Big Data projects, studies too large and too costly to terminate so the funds can go more productively elsewhere, should be but too often aren't addressed.  But the issues are known, and they are subtle.  These facts are not secret, known only to science critics.  Everyone who cares to think about them, can know them.

An example we mentioned in a response to a comment on Monday's post is this.  In its effort not to be flooded with false positive test results, GWAS buries small, non-statistically significant effects.  The larger the study (assuming properly informed design) the smaller will the undetected effects be, even if they are there in aggregate and indeed are the bulk of the causal variation.  But GWAS and similar findings are widely presented as being far more definitive than they usually are.  For example, not only do genomewide association types of study bury, for practical reasons, the bulk (usually the vast bulk) of genomic effects, but typically many or most or even all clear, previously documented effects are not found in even huge GWAS reports.  How can that be, if the study is so huge?  For example, there are, as we noted on Monday, tens or even hundreds of rather clear-cut genes that when mutated in some ways cause serious IQ impairment.  Yet virtually none of them were found in the large educational achievement study.  Were previous studies wrong?  Are these genes not involved after all?

One answer is that causal mutations simply were not present in those genes in the  specific study sample.  They do exist, at low frequency, in the population, but not in the sampled 'normal' part of the population going to regular schools. The point is that even such huge studies do not represent genomic effects on a trait, nor even those in the population, in a very clear way.  Other samples, in other populations, will (as we know and should expect from what we understand about evolution) typically find other 'hits'.  And this without considering environment.  This is poor epistemology for understanding traits, and it's poor science; or at least, we should be thinking hard about better conceptual ways to understand what genomes do.

Why it's so hard to put this subject to bed!
Well, what about environment?  Reflecting the obvious, if not even perhaps rather ridiculous, state of things, the BBC posted a story yesterday on the major effects on education achievement of going to bed late.  This study was a mere 11,000 strong (compare to the genome mapping study's mega design), yet it easily found substantial achievement effects--far bigger in that sense than the Big Data study.  And it was also clear that they were partly reflective of socieoeconomic status.

Now since most genes--80%, according to gene expression results from the Allen Brain Atlas--are known to be expressed in the brain at some point, they all become potential candidates, and many or most are affected by various environmental conditions (including bedtime, or breast feeding as we described on Monday?).  This means that in any given study only some few genes have statistically detectable effect, and that means the study only reflects its particular sub-sample of the population.  It misses the effects, genuine and present, of countless other gene regions.  At best, it means that such genes did not vary in relevant ways in one's sample, but that does not mean the gene isn't contributing to the trait, just not to its variation in the sample. 

One of the legitimate problems, as well as keep-funding-me rationales for Big Data studies, is that after collecting the gobs of proposed data, later one inevitably learns of things that weren't measured or flaws in the measurement methods.  The investigators then say they 'must' go back and re-contact, re-interview, or re-test all the subjects to add this bit of new vital information.  It is not entirely unrelated that  this is a justification for further funding, and this suggestion is reflected in the fact that rarely (if ever) does the investigator say they need no further work or funds.

So, if breast feeding and bedtimes weren't measured in the current study we've been discussing, and yet they've been demonstrated by other studies to have effects on educational attainment, the results are almost literally worthless.  One might assume that breast feeding could be interacting with the few minor hits that were found, and taking that into account might un-hit those genome sites (and just as likely up the test score for others).  The point is easy to see and is a very serious one.

Beyond the principles, of course you can't practicably recontact everyone in a mega-study (many original subjects will have died and new potential subjects born since the first data acquisition--so the routine ploy is to say we 'need' to study the next generation, etc.).  And environments we live in are very rapidly changing, in literally unpredictable ways and amounts, as lifestyle and medication (and education) fads and fashions come and go faster than a video game.  It's a moving target and this is one reason we think that such massive can't-be-terminated database or survey studies are often not a good way to spend huge amounts of public funds.  They entrench diminishing returns.  There are many such studies that are decades old, well past their proper sell-by dates.

The issues as well as the very ways they are studied, are not being given their due consideration, and in this case interpretation, even by scientists who don't think about these issues very carefully in the rush to do more and larger studies and the like.  We are not working with well-posed questions.  When that is the case, then our epistemology--theory, study designs, and inference--is ripe for questioning.

Science as politics
The key issues here are the epistemic ones of how to identify or even just to define causation, how causation works, and what causal effects are important.  These are fundamental questions in science generally, not just with respect to the study of intelligence.  These aspects of science are inherently subjective.  We have to make judgments about them, no matter how causation really works.  When we make judgments, and the work that leads to them, or follow-up work, or implications of the work involve public policy and the like, then the science is necessarily political.

To accuse a scientist of being just political because of his/her views on a subject--like looking for genomic effects on IQ--is to misunderstand the very nature of the enterprise.  To act as if history provides no guide to understanding the nature or use of science is naive, if not downright societally dangerous.  But often, the right and left wings of our political spectrum accuse science they don't like of being 'just political' and thus dismiss it. Think of 'evolution' or 'climate change'--or IQ.

The truth is that today much of science today is political in this unavoidable sense.  We all pay for it, and what is studied and what is done with the results affect us.  It is, and it should be political.  This is not to say (as some science-studies critiques seem to) that the real world is all imagined and doesn't exist and is a plot by the intellectual elite.  The point is that the real world exists, but how we respond to it, or what we choose to study, as a society are affected by considerations other than scientific study design or analytical methods and other related decisions and techniques.  And we also affect what we learn by how we choose to study it.  Objectivity is our stated goal but is often quite elusive and subtle to achieve.  But nobody seems to want to think about this seriously.  Leave us alone, trust us: we'll do the science right.

The societal decisions we make and what we fund are not just how to respond to curiosity about the world, but to decide which subjects are important enough to us to invest in, or how much to invest.  These are not easy, and we freely express our views here on this blog.  They are subjects that should be taken seriously. It is perfectly legitimate to say that this or that kind of investigation are not in society's interests to support, or even to allow (we don't allow torturing of prisoners for research purposes, for example, and institutional review boards are charged with making decisions about whether other less obviously egregious but potentially problematic studies should be allowed).

So we certainly do color our own MT blog posts with considerations that we think are relevant in this respect.  These considerations, such as where funds should be spent, are openly, not deceptively, political.  Obviously, vested interests, cultural practices, professional needs, careerism, desire to improve society, and genuine quest for knowledge are all at work.  Rather than energetic but reflexive reactions, much less vitriolic responses, what we try to urge is that we take nature more seriously in our attempt to understand how she works.  That's a lot harder than just business as usual.

Inherit the wind?

The famous 1955 play about the Scopes trial, Inherit the Wind, is based on a quote from the Bible that warns that if you make trouble in your own house all you'll inherit will be the wind -- "He who brings trouble on his family will inherit only wind, and the fool will be servant to the wise."

The Scopes trial was nominally about teaching evolution in schools, but it's not well understood that a main part of the underlying issues was not just stupid biblical literalism or bigotry, but objection (yes, by the prosecuting attorney -- and biblical literalist -- William Jennings Bryan) to the justification based on notions of genetic determinism for racism and inequality.  I've discussed this elsewhere.

One of the most delicate issues in genetics has for more than a century had to do with intelligence.  There are two camps, those who think IQ (whatever it is, something we need not debate here!) is largely 'genetic' and unchangeable, and those who think it is malleable and responsive to environments.  As usual, the argument is largely political (for good reasons) but also ideological rather than scientific.

The brain is a complex organ that develops rapidly as countless genes are expressed in different tissues, in a highly orchestrated dance of interactions.  So IQ, if it's any sort of brain function, must be 'genetic' in the sense that the brain is a product of genetic interactions.  More socially important is that all these countless genes and their regulatory DNA sequences are subject to variation among individuals, and that must have some effects on the resulting IQ (again, let's not quibble here about whether experts actually know how to define or measure IQ).  Family correlations show evidence of this genetic variation, whether or not the amount of heritability is being correctly estimated, and whether or not the genetic effects do or don't determine the person's achieved IQ (e.g., depending on environment, schooling, etc.).

The most fiery aspect of the debate is whether specific genes can be identified that cause or predict IQ.  It's bad enough to assume that certain people or groups of people we might not like have low IQ and nothing can be done about it, but even worse if one can identify the responsible genes, because then something can be done about it, and the eugenics era proved that that something was dreadful.  There was a lot of pain but all our society inherited from it was wind, nothing of substance.

Intelligence and its genetics are involved in all sorts of social science discussions because they affect many aspects of society including investments to address systematic inequality and so on.  Some argue that we should not waste money on those with low-IQ genes, others that at least we should help those people raise their achieved-intelligence.

These are social and political issues, and yesterday we discussed the problems with the social sciences, so self-described, in terms of whether or how they are actually 'scientific,' or have failed to produce useful results, or whether the experts in this field know more than anybody else -- or can predict the future better than a chimp (untrained at that).  We criticized the persistent funding of go-hardlyanywhere research in those fields, as we've done for genetics, our own field.

A recent paper by Douglas Wahlsten sheds light on these issues.  This is a paper showing from the actual scientific literature how clearly and substantially we have so far failed to identify genes with useful contribution to normal behavior.  Nobody doubts the clear evidence for major mutations in genes that can cause serious, clinically relevant behavior problems, and many of these involve mental impairment.  However, even the understanding of many serious psychiatric disorders has eluded serious advancement based on genetics, genome mapping and the like.  Schizophrenia and autism are two cases Wahlsten mentions.  These traits are clearly familial and seem 'genetic' but GWAS have basically identified a plethora of different genes that make individually minor contributions, and no blockbuster single-genes.  Even MZ (genetically identical, monozygotic) twins do not have dramatically high concordance.

These are apparently polygenic traits, affected by genes to be sure, but generally not by major, common genetic variants.  Among the best indicators of this are the paucity of really replicable gene-specific findings for these traits.  That means the original finding could be false, or the effect so weak or low in frequency that it simply doesn't recur in different samples.

Wahlsten specifically goes after IQ genetic arguments.  In essence he shows from the data that even huge samples would identify genes whose effects are less, or much less, than 1 point on the IQ scale (which is scaled to have mean of 100).  And these are elusive if they exist--most effects may be even smaller.  More than that, the effect seems almost inevitably not to be an inherent one but depends on the variation in genes elsewhere in each individual's genome.  Even the total of things found by some of these tests would not account for even 1% of the variation in IQ among the subjects.

Yet the hunt for genes for intelligence goes on, in the face of these clear patterns.  Even though intelligence is essentially and clearly polygenic.  There are few if any smoking gun genes, for the normal range.  Even the genes whose variation is known to cause clinically serious impairment typically do not show up as 'hits' in genomewide mapping studies.  Predictive power based on genotype is thus very weak indeed.

Yet behavioral genetics motors on, with the implicit or explicit promise of prediction based on genotype, a potentially dangerous kind of determinism that history has shown can be badly abused by powers that be.  We keep pouring funds into this, as well.

We are not arguing that IQ whatever its reality is not 'genetic', but that it is generally not useful to evaluate people based on the geneIQ but on their actual performance.  And because the more that is learned about the development and workings of the brain the more is learned about its plasticity, it's clear that intelligence can't be understood without due attention to the considerable environmental influences on the trait.

Pulling the plug on this kind of fruitless genomics, which is growing despite these kinds of facts basically across the board, would save resources for things where that kind of science can really make a difference, and be less potentially contentious.  What to do as a society about variation in intelligence is a thorny problem, and we don't have any answers.  Sadly, as we discussed yesterday, the experts don't have any answers either.  But if they stir the pot of our society, hopefully all they'll inherit will be the wind of their pronouncements.

Brains are like jelly....and they're fluid, too.

Intelligence is malleable?
Two pieces in the April 22 New York Times Sunday Magazine suggest that the idea that intelligence is fixed at birth has been greatly exaggerated.  We can get smarter if we work at it.  According to one piece, we have to exercise our fluid intelligence, and in the other, we have to exercise our bodies.

Fluid intelligence lifting weights
In 2008, two psychologists, Susanne Jaeggi and Martin Buschkuehl, published a paper in which they reported that young adults who play a challenging game requiring concentration can improve their "fluid intelligence", which the NYT article defines as "the capacity to solve novel problems, to learn, to reason, to see connections and to get to the bottom of things."

Psychologists have long regarded intelligence as coming in two flavors: crystallized intelligence, the treasure trove of stored-up information and how-to knowledge (the sort of thing tested on “Jeopardy!” or put to use when you ride a bicycle); and fluid intelligence. Crystallized intelligence grows as you age; fluid intelligence has long been known to peak in early adulthood, around college age, and then to decline gradually. And unlike physical conditioning, which can transform 98-pound weaklings into hunks, fluid intelligence has always been considered impervious to training.

The inflexibility of fluid intelligence has been the explanation for why we can't do better on I.Q. tests over our lifetimes.  Though, the pesky little problem of the Flynn effect, the sustained increase in I.Q. scores over decades in much of the world, has been a thorn in the side of those who hold that I.Q. is fixed.  And, even if people have never actually settled on what intelligence actually is, the idea that at least we know it's fixed, and that most studies show a considerable amount of heritability, has lead many to believe there must basically be due to the genotypes we're each born with.

Raven Matrix component of IQ test: fill in the blank square
Wikimedia Commons

So, if Jaeggi and Buschkuehl are correct that fluid intelligence can be improved with practice, a result they continue to demonstrate, this is a challenge to the idea that we're blessed or cursed with innate intelligence.  The idea is that intelligence must be similar to other highly heritable traits, like height, which is also susceptible to environmental effects -- even if within each individual's genetic or other constraints.

Mice lifting weights
The second intelligence story in the Sunday magazine comes at the issue from a different angle.  Mice given the chance to exercise get smarter.  Researchers determined this by giving them before and after cognitive tests, as well as before and after assessments of the structure of their brains.  And, as it happens, people who exercise get smarter, too.  Or at least their brains don't shrink nearly as much as they age as do the brains of sedentary people.

For more than a decade, neuroscientists and physiologists have been gathering evidence of the beneficial relationship between exercise and brainpower. But the newest findings make it clear that this isn’t just a relationship; it is the relationship. Using sophisticated technologies to examine the workings of individual neurons — and the makeup of brain matter itself — scientists in just the past few months have discovered that exercise appears to build a brain that resists physical shrinkage and enhance cognitive flexibility. Exercise, the latest neuroscience suggests, does more to bolster thinking than thinking does.

So, forget personalized genomic medicine, to get smart, just bike (or run) to work, thinking about something profound all the way.

Can this really be true?
Of course, Jaeggi and Buschkuehl have their critics.  Some simply don't believe that fluid intelligence is mutable, and studies continue to confirm this view. But J and B aren't the only psychologists who are beginning to find mutability and as a result, other psychologists are starting to believe their work. But, it's an interesting thing when expert assessment of scientific results depends on belief.  And the word is laced throughout the NYT piece.

Indeed, you're more likely to buy their work if you're not predisposed to think that I.Q. is genetically determined.  Well, and if you think I.Q. is real, measurable, not culturally determined and so on.  And where you come down on these issues seems to be correlated with your politics, at least to some extent.  Rather like where you come down on climate change, or evolution, or the genetics of how people vote.

But let's step away from the politics for the moment, and think about what our particular view of evolution might have to offer here.  Specifically, the idea that seems fairly obvious, that evolution has been consistently good at producing adaptability.  Over and over and over again, so much so that it seems to us to be a fundamental principle of life, organisms have been imbued with the ability to detect, evaluate, and adapt to changing circumstances.  So, to us, it's no surprise that our brains, too, can respond to changing circumstances, can respond to environmental challenges by, say, building new neuronal synapses.  It would be more surprising if it couldn't.  And changes in the brain can involve non-cognitive as well as cognitive intelligence -- that is, it need not involve consciousness as it often does in humans and presumably other animals.

Brains and central nervous systems are, after all, centers of evaluation.  Sensory inputs go there, and are sorted through and evaluated, and decisions made on how to respond to them.  The idea, no pun intended, is that the brain is not a pre-programmed, hard-wired automoton, but allows each unique moment to be sifted and judged, and even more, each moment can leave its mark.  Someone whose cognition is too rigid might be much more likely to be a former someone.

Brains have the texture of jello, but they're fluid as well -- food for thought at least.