The Modular Mind

The other day I was walking through the garden when I looked down, saw one of these, leapt back, screamed loudly enough to notify the entire neighborhood:

(The one in my yard was insect free, however.)

After catching my breath, I wondered, “Is that a wasp nest or a beehive?” and crept back for a closer look. Wasp nest. I mentally paged through my knowledge of wasp nests: wasps abandon nests when they fall on the ground. This one was probably empty and safe to step past. I later tossed it onto the compost pile.

The interesting part of this incident wasn’t the nest, but my reaction. I jumped away from the thing before I had even consciously figured out what the nest was. Only once I was safe did I consciously think about the nest.

So I’ve been reading Gazzaniga’s Who’s in Charge? Free Will and the Science of the Brain. (I’m thinking of making this a Book Club pick; debating between this and Kurzweil’s How to Create a Mind: The Secrets of Human thought Revealed, which I have not read, but comes recommended. Feel free to vote for one, the other, or both.)

Gazzaniga discusses a problem faced by brains trying to evolve to be bigger and smarter: how do you get more neurons working without taking up an absurd amount of space connecting each and every neuron to every other neuron?

Imagine a brain with 5 connected neurons: each neuron requires 4 connections to talk to every other neuron. A 5 neuron brain would thus need space for 10 total connections.

The addition of a 6th neuron would require 5 new connections; a 7th neuron requires 6 new connections, etc. A fully connected brain of 100 neurons would require 99 connections per neuron, for a total of 4,950 connections.

The human brain has about 86 billion neurons.

Connecting all of your neurons might work fine if if you’re a sea squirt, with only 230 or so neurons, but it is going to fail hard if you’re trying to hook up 86 billion. The space required to hook up all of these neurons would be massively larger than the space you can actually maintain by eating.

So how does an organism evolving to be smarter deal with the connectivity demands of increasing brain size?

Human social lives suggest an answer: Up on the human scale, one person can, Dunbar estimates, have functional social relationships with about 150 other people, including an understanding of those people’s relationships with each other. 150 people (the “Dunbar number”) is therefore the amount of people who can reliably cooperate or form groups without requiring any top-down organization.

So how do humans survive in groups of a thousand, a million, or a billion (eg, China)? How do we build large-scale infrastructure projects requiring the work of thousands of people and used by millions, like interstate highways? By organization–that is, specialization.

In a small tribe of 150 people, almost everyone in the tribe can do most of the jobs necessary for the tribe’s survival, within the obvious limits of biology. Men and women are both primarily occupied with collecting food. Both prepare clothing and shelter; both can cook. There is some specialization of labor–obviously men can carry heavier loads; women can nurse children–but most people are generally competent at most jobs.

In a modern industrial economy, most people are completely incompetent at most jobs. I have a nice garden, but I don’t even know how to turn on a tractor, much less how to care for a cow. The average person does not know how to knit or sew, much less build a house, wire up the electricity and lay the plumbing. We attend school from 5 to 18 or 22 or 30 and end up less competent at surviving in our own societies than a cave man with no school was in his, not because school is terrible but because modern industrial society requires so much specialized knowledge to keep everything running that no one person can truly master even a tenth of it.

Specialization, not just of people but of organizations and institutions, like hospitals devoted to treating the sick, Walmarts devoted to selling goods, and Microsoft devoted to writing and selling computer software and hardware, lets society function without requiring that everyone learn to be a doctor, merchant, and computer expert.

Source

Similarly, brains expand their competence via specialization, not denser neural connections.

As UPI reports, Intelligence is correlated with fewer neural connections, not more, study finds:

The smartest people may boast more neurons than those of average intelligence, but their brains have fewer neural connections…

Neuroscientists in Germany recruited 259 participants, both men and women, to take IQ tests and have their brains imaged…

The research revealed a strong correlation between the number of dendrites in a person’s cerebral cortex and their intelligence. The smartest participants had fewer neural connections in their cerebral cortex.

Fewer neural connections overall allows different parts of the brain to specialize, increasing local competence.

All things are produced more plentifully and easily and of a better quality when one man does one thing that is natural to him and does it at the right time, and leaves other things. –Plato, The Republic

The brains of mice, as Gazzinga discusses, do not need to be highly specialized, because mice are not very smart and do not do many specialized activities. Human brains, by contrast, are highly specialized, as anyone who has ever had a stroke has discovered. (Henry Harpending of West Hunter, for example, once had a stroke while visiting Germany that knocked out the area of his brain responsible for reading, but since he couldn’t read German in the first place, he didn’t realize anything was wrong until several hours later.)

I read, about a decade ago, that male and female brains have different levels, and patterns, of internal connectivity. (Here and here are articles on the subject.) These differences in connectivity may allow men and women to excel at different skills, and since we humans are a social species that can communicate by talking, this allows us to take cognitive modality beyond the level of a single brain.

So modularity lets us learn (and do) more things, with the downside that sometimes knowledge is highly localized–that is, we have a lot of knowledge that we seem able to access only under specific circumstances, rather than use generally.

For example, I have long wondered at the phenomenon of people who can definitely do complicated math when asked to, but show no practical number sense in everyday life, like the folks from the Yale Philosophy department who are confused about why African Americans are under-represented in their major, even though Yale has an African American Studies department which attracts a disproportionate % of Yale’s African American students. The mathematical certainty that if any major in the whole school that attracts more African American students, then other majors will end up with fewer, has been lost on these otherwise bright minds.

Yalies are not the only folks who struggle to use the things they know. When asked to name a book–any book–ordinary people failed. Surely these people have heard of a book at some point in their lives–the Bible is pretty famous, as is Harry Potter. Even if you don’t like books, they were assigned in school, and your parents probably read The Cat in the Hat and Green Eggs and Ham to you when you were a kid. It is not that they do not have the knowledge as they cannot access it.

Teachers complain all the time that students–even very good ones–can memorize all of the information they need for a test, regurgitate it all perfectly, and then turn around and show no practical understanding of the information at all.

Richard Feynman wrote eloquently of his time teaching future science teachers in Brazil:

In regard to education in Brazil, I had a very interesting experience. I was teaching a group of students who would ultimately become teachers, since at that time there were not many opportunities in Brazil for a highly trained person in science. These students had already had many courses, and this was to be their most advanced course in electricity and magnetism – Maxwell’s equations, and so on. …

I discovered a very strange phenomenon: I could ask a question, which the students would answer immediately. But the next time I would ask the question – the same subject, and the same question, as far as I could tell – they couldn’t answer it at all! For instance, one time I was talking about polarized light, and I gave them all some strips of polaroid.

Polaroid passes only light whose electric vector is in a certain direction, so I explained how you could tell which way the light is polarized from whether the polaroid is dark or light.

We first took two strips of polaroid and rotated them until they let the most light through. From doing that we could tell that the two strips were now admitting light polarized in the same direction – what passed through one piece of polaroid could also pass through the other. But then I asked them how one could tell the absolute direction of polarization, for a single piece of polaroid.

They hadn’t any idea.

I knew this took a certain amount of ingenuity, so I gave them a hint: “Look at the light reflected from the bay outside.”

Nobody said anything.

Then I said, “Have you ever heard of Brewster’s Angle?”

“Yes, sir! Brewster’s Angle is the angle at which light reflected from a medium with an index of refraction is completely polarized.”

“And which way is the light polarized when it’s reflected?”

“The light is polarized perpendicular to the plane of reflection, sir.” Even now, I have to think about it; they knew it cold! They even knew the tangent of the angle equals the index!

I said, “Well?”

Still nothing. They had just told me that light reflected from a medium with an index, such as the bay outside, was polarized; they had even told me which way it was polarized.

I said, “Look at the bay outside, through the polaroid. Now turn the polaroid.”

“Ooh, it’s polarized!” they said.

After a lot of investigation, I finally figured out that the students had memorized everything, but they didn’t know what anything meant. When they heard “light that is reflected from a medium with an index,” they didn’t know that it meant a material such as water. They didn’t know that the “direction of the light” is the direction in which you see something when you’re looking at it, and so on. Everything was entirely memorized, yet nothing had been translated into meaningful words. So if I asked, “What is Brewster’s Angle?” I’m going into the computer with the right keywords. But if I say, “Look at the water,” nothing happens – they don’t have anything under “Look at the water”!

The students here are not dumb, and memorizing things is not bad–memorizing your times tables is very useful–but they have everything lodged in their “memorization module” and nothing in their “practical experience module.” (Note: I am not necessarily suggesting that thee exists a literal, physical spot in the brain where memorized and experienced knowledge reside, but that certain brain structures and networks lodge information in ways that make it easier or harder to access.)

People frequently make arguments that don’t make logical sense when you think them all the way through from start to finish, but do make sense if we assume that people are using specific brain modules for quick reasoning and don’t necessarily cross-check their results with each other. For example, when we are angry because someone has done something bad to us, we tend to snap at people who had nothing to do with it. Our brains are in “fight and punish mode” and latch on to the nearest person as the person who most likely committed the offense, even if we consciously know they weren’t involved.

Political discussions are often marred by folks running what ought to be logical arguments through status signaling, emotional, or tribal modules. The desire to see Bad People punished (a reasonable desire if we all lived in the same physical community with each other) interferes with a discussion of whether said punishment is actually useful, effective, or just. For example, a man who has been incorrectly convicted of the rape of a child will have a difficult time getting anyone to listen sympathetically to his case.

In the case of white South African victims of racially-motivated murder, the notion that their ancestors did wrong and therefore they deserve to be punished often overrides sympathy. As BBC notes, these killings tend to be particularly brutal (they often involve torture) and targeted, but the South African government doesn’t care:

According to one leading political activist, Mandla Nyaqela, this is the after-effect of the huge degree of selfishness and brutality which was shown towards the black population under apartheid. …

Virtually every week the press here report the murders of white farmers, though you will not hear much about it in the media outside South Africa.In South Africa you are twice as likely to be murdered if you are a white farmer than if you are a police officer – and the police here have a particularly dangerous life. The killings of farmers are often particularly brutal. …

Ernst Roets’s organisation has published the names of more than 2,000 people who have died over the last two decades. The government has so far been unwilling to make solving and preventing these murders a priority. …

There used to be 60,000 white farmers in South Africa. In 20 years that number has halved.

The Christian Science Monitor reports on the measures ordinary South Africans have to take in what was once a safe country to not become human shishkabobs, which you should pause and read, but is a bit of a tangent from our present discussion. The article ends with a mind-bending statement about a borrowed dog (dogs are also important for security):

My friends tell me the dog is fine around children, but is skittish around men, especially black men. The people at the dog pound told them it had probably been abused. As we walk past house after house, with barking dog after barking dog, I notice Lampo pays no attention. Instead, he’s watching the stream of housekeepers and gardeners heading home from work. They eye the dog nervously back.

Great, I think, I’m walking a racist dog.

Module one: Boy South Africa has a lot of crime. Better get a dog, cover my house with steel bars, and an extensive security system.

Module two: Associating black people with crime is racist, therefore my dog is racist for being wary of people who look like the person who abused it.

And while some people are obviously sympathetic to the plight of murdered people, “Cry me a river White South African Colonizers” is a very common reaction. (Never mind that the people committing crimes in South Africa today never lived under apartheid; they’ve lived in a black-run country for their entire lives.) Logically, white South Africans did not do anything to deserve being killed, and like the golden goose, killing the people who produce food will just trigger a repeat of Zimbabwe, but the modes of tribalism–“I do not care about these people because they are not mine and I want their stuff”–and punishment–“I read about a horrible thing someone did, so I want to punish everyone who looks like them”–trump logic.

Who dies–and how they die–significantly shapes our engagement with the news. Gun deaths via mass shootings get much more coverage and worry than ordinary homicides, even though ordinary homicides are far more common. homicides get more coverage and worry than suicides, even though suicides are far more common. The majority of gun deaths are actually suicides, but you’d never know that from listening to our national conversation about guns, simply because we are biased to worry far more about other people killng us than about ourselves.

Similarly, the death of one person via volcano receives about the same news coverage as 650 in a flood, 2,000 in a drought, or 40,000 in a famine. As the article notes:

Instead of considering the objective damage caused by natural disasters, networks tend to look for disasters that are “rife with drama”, as one New York Times article put it4—hurricanes, tornadoes, forest fires, earthquakes all make for splashy headlines and captivating visuals. Thanks to this selectivity, less “spectacular” but often times more deadly natural disasters tend to get passed over. Food shortages, for example, result in the most casualties and affect the most people per incident5 but their onset is more gradual than that of a volcanic explosion or sudden earthquake. … This bias for the spectacular is not only unfair and misleading, but also has the potential to misallocate attention and aid.

There are similar biases by continent, with disasters in Africa receiving less attention than disasters in Europe (this correlates with African disasters being more likely to be the slow-motion famines, epidemics and droughts that kill lots of people, and European disasters being splashier, though perhaps we’d consider famines “splashier” if they happened in Paris instead of Ethiopia.)

From Personality and Political Attitudes: “Conservatives are hard-working, organized, closed-minded, and emotionally stable. Liberals are lazy, disorganized, open-minded, and neurotic. Let’s see how the punditocracy spins that one.”

From a neuropolitical perspective, I suspect that patterns such as the Big Five personality traits correlating with particular political positions (“openness” with “liberalism,” for example, or “conscientiousness” with “conservativeness,”) is caused by patterns of brain activity that cause some people to depend more or less on particular brain modules for processing.

For example, conservatives process more of the world through the areas of their brain that are also used for processing disgust, (not one of “the five” but still an important psychological trait) which increases their fear of pathogens, disease vectors, and generally anything new or from the outside. Disgust can go so far as to process other people’s faces or body language as “disgusting” (eg, trans people) even when there is objectively nothing that presents an actual contamination or pathogenic risk involved.

Similarly, people who feel more guilt in one area of their life often feel guilt in others–eg, “White guilt was significantly associated with bulimia nervosa symptomatology.” The arrow of causation is unclear–guilt about eating might spill over into guilt about existing, or guilt about existing might cause guilt about eating, or people who generally feel guilty about everything could have both. Either way, these people are generally not logically reasoning, “Whites have done bad things, therefore I should starve myself.” (Should veganism be classified as a politically motivated eating disorder?)

I could continue forever–

Restrictions on medical research are biased toward preventing mentally salient incidents like thalidomide babies, but against the invisible cost of children who die from diseases that could have been cured had research not been prevented by regulations.

America has a large Somali community but not Congolese, (85,000 Somalis vs. 13,000 Congolese, of whom 10,000 hail from the DRC. Somalia has about 14 million people, the DRC has about 78.7 million people, so it’s not due to there being more Somalis in the world,) for no particular reason I’ve been able to discover, other than President Clinton once disastrously sent a few helicopters to intervene in the eternal Somali civil war and so the government decided that we now have a special obligation to take in Somalis.

–but that’s probably enough.

I have tried here to present a balanced account of different political biases, but I would like to end by noting that modular thinking, while it can lead to stupid decisions, exists for good reasons. If purely logical thinking were superior to modular, we’d probably be better at it. Still, cognitive biases exist and lead to a lot of stupid or sub-optimal results.

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Testosterone metabolization, autism, male brain, and female identity

I began this post intending to write about testosterone metabolization in autism and possible connections with transgender identity, but realized halfway through that I didn’t actually know whether the autist-trans connection was primarily male-to-female or female-to-male. I had assumed that the relevant population is primarily MtF because both autists and trans people are primarily male, but both groups do have female populations that are large enough to contribute significantly. Here’s a sample of the data I’ve found so far:

A study conducted by a team of British scientists in 2012 found that of a pool of individuals not diagnosed on the autism spectrum, female-to-male (FTM) transgender people have higher rates of autistic features than do male-to-female (MTF) transgender people or cisgender males and females. Another study, which looked at children and adolescents admitted to a gender identity clinic in the Netherlands, found that almost 8 percent of subjects were also diagnosed with ASD.

Note that both of these studies are looking at trans people and assessing whether or not they have autism symptoms, not looking at autists and asking if they have trans symptoms. Given the characterization of autism as “extreme male brain” and that autism is diagnosed in males at about 4x the rate of females, the fact that there is some overlap between “women who think they think like men” and “traits associated with male thought patterns” is not surprising.

If the reported connection between autism and trans identity is just “autistic women feel like men,” that’s pretty non-mysterious and I just wasted an afternoon.

Though the data I have found so far still does not look directly at autists and ask how many of them have trans symptoms, the wikipedia page devoted to transgender and transsexual computer programmers lists only MtFs and no FtMs. Whether this is a pattern throughout the wider autism community, it definitely seems to be a thing among programmers. (Relevant discussion.)

So, returning to the original post:

Autism contains an amusing contradiction: on the one hand, autism is sometimes characterized as “extreme male brain,” and on the other hand, (some) autists (may be) more likely than neurotypicals to self-identify as transwomen–that is, biological men who see themselves as women. This seems contradictory: if autists are more masculine, mentally, than the average male, why don’t they identify as football players, army rangers, or something else equally masculine? For that matter, why isn’t a group with “extreme male brains” regarded as more, well, masculine?

(And if autists have extreme male brains, does that mean football players don’t? Do football players have more feminine brains than autists? Do colorless green ideas sleep furiously? DO WORDS MEAN?)

*Ahem*

In favor of the “extreme male brain” hypothesis, we have evidence that testosterone is important for certain brain functions, like spacial recognition, we have articles like this one: Testosterone and the brain:

Gender differences in spatial recognition, and age-related declines in cognition and mood, point towards testosterone as an important modulator of cerebral functions. Testosterone appears to activate a distributed cortical network, the ventral processing stream, during spatial cognition tasks, and addition of testosterone improves spatial cognition in younger and older hypogonadal men. In addition, reduced testosterone is associated with depressive disorders.

(Note that women also suffer depression at higher rates than men.)

So people with more testosterone are better at spacial cognition and other tasks that “autistic” brains typically excel at, and brains with less testosterone tend to be moody and depressed.

But hormones are tricky things. Where do they come from? Where do they go? How do we use them?

According to Wikipedia:

During the second trimester [of pregnancy], androgen level is associated with gender formation.[13] This period affects the femininization or masculinization of the fetus and can be a better predictor of feminine or masculine behaviours such as sex typed behaviour than an adult’s own levels. A mother’s testosterone level during pregnancy is correlated with her daughter’s sex-typical behavior as an adult, and the correlation is even stronger than with the daughter’s own adult testosterone level.[14]

… Early infancy androgen effects are the least understood. In the first weeks of life for male infants, testosterone levels rise. The levels remain in a pubertal range for a few months, but usually reach the barely detectable levels of childhood by 4–6 months of age.[15][16] The function of this rise in humans is unknown. It has been theorized that brain masculinization is occurring since no significant changes have been identified in other parts of the body.[17] The male brain is masculinized by the aromatization of testosterone into estrogen, which crosses the blood–brain barrier and enters the male brain, whereas female fetuses have α-fetoprotein, which binds the estrogen so that female brains are not affected.[18]

(Bold mine.)

Let’s re-read that: the male brain is masculinized by the aromatization of testosterone into estrogen.

If that’s not a weird sentence, I don’t know what is.

Let’s hop over to the scientific literature, eg, Estrogen Actions in the Brain and the Basis for Differential Action in Men and Women: A Case for Sex-Specific Medicines:

Burgeoning evidence now documents profound effects of estrogens on learning, memory, and mood as well as neurodevelopmental and neurodegenerative processes. Most data derive from studies in females, but there is mounting recognition that estrogens play important roles in the male brain, where they can be generated from circulating testosterone by local aromatase enzymes or synthesized de novo by neurons and glia. Estrogen-based therapy therefore holds considerable promise for brain disorders that affect both men and women. However, as investigations are beginning to consider the role of estrogens in the male brain more carefully, it emerges that they have different, even opposite, effects as well as similar effects in male and female brains. This review focuses on these differences, including sex dimorphisms in the ability of estradiol to influence synaptic plasticity, neurotransmission, neurodegeneration, and cognition, which, we argue, are due in a large part to sex differences in the organization of the underlying circuitry.

Hypothesis: the way testosterone works in the brain (where we both do math and “feel” male or female) and the way it works in the muscles might be very different.

Do autists actually differ from other people in testosterone (or other hormone) levels?

In Elevated rates of testosterone-related disorders in women with autism spectrum conditions, researchers surveyed autistic women and mothers of autistic children about various testosterone-related medical conditions:

Compared to controls, significantly more women with ASC [Autism Spectrum Conditions] reported (a) hirsutism, (b) bisexuality or asexuality, (c) irregular menstrual cycle, (d) dysmenorrhea, (e) polycystic ovary syndrome, (f) severe acne, (g) epilepsy, (h) tomboyism, and (i) family history of ovarian, uterine, and prostate cancers, tumors, or growths. Compared to controls, significantly more mothers of ASC children reported (a) severe acne, (b) breast and uterine cancers, tumors, or growths, and (c) family history of ovarian and uterine cancers, tumors, or growths.

Androgenic Activity in Autism has an unfortunately low number of subjects (N=9) but their results are nonetheless intriguing:

Three of the children had exhibited explosive aggression against others (anger, broken objects, violence toward others). Three engaged in self-mutilations, and three demonstrated no aggression and were in a severe state of autistic withdrawal. The appearance of aggression against others was associated with having fewer of the main symptoms of autism (autistic withdrawal, stereotypies, language dysfunctions).

Three of their subjects (they don’t say which, but presumably from the first group,) had abnormally high testosterone levels (including one of the girls in the study.) The other six subjects had normal androgen levels.

This is the first report of an association between abnormally high androgenic activity and aggression in subjects with autism. Although a previously reported study did not find group mean elevations in plasma testosterone in prepubertal autistic subjects (4), it appears here that in certain autistic individuals, especially those in puberty, hyperandrogeny may play a role in aggressive behaviors. Also, there appear to be distinct clinical forms of autism that are based on aggressive behaviors and are not classified in DSM-IV. Our preliminary findings suggest that abnormally high plasma testosterone concentration is associated with aggression against others and having fewer of the main autistic symptoms.

So, some autists have do have abnormally high testosterone levels, but those same autists are less autistic, overall, than other autists. More autistic behavior, aggression aside, is associated with normal hormone levels. Probably.

But of course that’s not fetal or early infancy testosterone levels. Unfortunately, it’s rather difficult to study fetal testosterone levels in autists, as few autists were diagnosed as fetuses. However, Foetal testosterone and autistic traits in 18 to 24-month-old children comes close:

Levels of FT [Fetal Testosterone] were analysed in amniotic fluid and compared with autistic traits, measured using the Quantitative Checklist for Autism in Toddlers (Q-CHAT) in 129 typically developing toddlers aged between 18 and 24 months (mean ± SD 19.25 ± 1.52 months). …

Sex differences were observed in Q-CHAT scores, with boys scoring significantly higher (indicating more autistic traits) than girls. In addition, we confirmed a significant positive relationship between FT levels and autistic traits.

I feel like this is veering into “we found that boys score higher on a test of male traits than girls did” territory, though.

In Polymorphisms in Genes Involved in Testosterone Metabolism in Slovak Autistic Boys, researchers found:

The present study evaluates androgen and estrogen levels in saliva as well as polymorphisms in genes for androgen receptor (AR), 5-alpha reductase (SRD5A2), and estrogen receptor alpha (ESR1) in the Slovak population of prepubertal (under 10 years) and pubertal (over 10 years) children with autism spectrum disorders. The examined prepubertal patients with autism, pubertal patients with autism, and prepubertal patients with Asperger syndrome had significantly increased levels of salivary testosterone (P < 0.05, P < 0.01, and P < 0.05, respectively) in comparison with control subjects. We found a lower number of (CAG)n repeats in the AR gene in boys with Asperger syndrome (P < 0.001). Autistic boys had an increased frequency of the T allele in the SRD5A2 gene in comparison with the control group. The frequencies of T and C alleles in ESR1 gene were comparable in all assessed groups.

What’s the significance of CAG repeats in the AR gene? Apparently they vary inversely with sensitivity to androgens:

Individuals with a lower number of CAG repeats exhibit higher AR gene expression levels and generate more functional AR receptors increasing their sensitivity to testosterone…

Fewer repeats, more sensitivity to androgens. The SRD5A2 gene is also involved in testosterone metabolization, though I’m not sure exactly what the T allele does relative to the other variants.

But just because there’s a lot of something in the blood (or saliva) doesn’t mean the body is using it. Diabetics can have high blood sugar because their bodies lack the necessary insulin to move the sugar from the blood, into their cells. Fewer androgen receptors could mean the body is metabolizing testosterone less effectively, which in turn leaves more of it floating in the blood… Biology is complicated.

What about estrogen and the autistic brain? That gets really complicated. According to Sex Hormones in Autism: Androgens and Estrogens Differentially and Reciprocally Regulate RORA, a Novel Candidate Gene for Autism:

Here, we show that male and female hormones differentially regulate the expression of a novel autism candidate gene, retinoic acid-related orphan receptor-alpha (RORA) in a neuronal cell line, SH-SY5Y. In addition, we demonstrate that RORA transcriptionally regulates aromatase, an enzyme that converts testosterone to estrogen. We further show that aromatase protein is significantly reduced in the frontal cortex of autistic subjects relative to sex- and age-matched controls, and is strongly correlated with RORA protein levels in the brain.

If autists are bad at converting testosterone to estrogen, this could leave extra testosterone floating around in their blood… but doens’t explain their supposed “extreme male brain.” Here’s another study on the same subject, since it’s confusing:

Comparing the brains of 13 children with and 13 children without autism spectrum disorder, the researchers found a 35 percent decrease in estrogen receptor beta expression as well as a 38 percent reduction in the amount of aromatase, the enzyme that converts testosterone to estrogen.

Levels of estrogen receptor beta proteins, the active molecules that result from gene expression and enable functions like brain protection, were similarly low. There was no discernable change in expression levels of estrogen receptor alpha, which mediates sexual behavior.

I don’t know if anyone has tried injecting RORA-deficient mice with estrogen, but here is a study about the effects of injecting reelin-deficient mice with estrogen:

The animals in the new studies, called ‘reeler’ mice, have one defective copy of the reelin gene and make about half the amount of reelin compared with controls. …

Reeler mice with one faulty copy serve as a model of one of the most well-established neuro-anatomical abnormalities in autism. Since the mid-1980s, scientists have known that people with autism have fewer Purkinje cells in the cerebellum than normal. These cells integrate information from throughout the cerebellum and relay it to other parts of the brain, particularly the cerebral cortex.

But there’s a twist: both male and female reeler mice have less reelin than control mice, but only the males lose Purkinje cells. …

In one of the studies, the researchers found that five days after birth, reeler mice have higher levels of testosterone in the cerebellum compared with genetically normal males3.

Keller’s team then injected estradiol — a form of the female sex hormone estrogen — into the brains of 5-day-old mice. In the male reeler mice, this treatment increases reelin levels in the cerebellum and partially blocks Purkinje cell loss. Giving more estrogen to female reeler mice has no effect — but females injected with tamoxifen, an estrogen blocker, lose Purkinje cells. …

In another study, the researchers investigated the effects of reelin deficiency and estrogen treatment on cognitive flexibility — the ability to switch strategies to solve a problem4. …

“And we saw indeed that the reeler mice are slower to switch. They tend to persevere in the old strategy,” Keller says. However, male reeler mice treated with estrogen at 5 days old show improved cognitive flexibility as adults, suggesting that the estrogen has a long-term effect.

This still doesn’t explain why autists would self-identify as transgender women (mtf) at higher rates than average, but it does suggest that any who do start hormone therapy might receive benefits completely independent of gender identity.

Let’s stop and step back a moment.

Autism is, unfortunately, badly defined. As the saying goes, if you’ve met one autist, you’ve met one autist. There are probably a variety of different, complicated things going on in the brains of different autists simply because a variety of different, complicated conditions are all being lumped together under a single label. Any mental disability that can include both non-verbal people who can barely dress and feed themselves and require lifetime care and billionaires like Bill Gates is a very badly defined condition.

(Unfortunately, people diagnose autism with questionnaires that include questions like “Is the child pedantic?” which could be equally true of both an autistic child and a child who is merely very smart and has learned more about a particular subject than their peers and so is responding in more detail than the adult is used to.)

The average autistic person is not a programmer. Autism is a disability, and the average diagnosed autist is pretty darn disabled. Among the people who have jobs and friends but nonetheless share some symptoms with formally diagnosed autists, though, programmer and the like appear to be pretty popular professions.

Back in my day, we just called these folks nerds.

Here’s a theory from a completely different direction: People feel the differences between themselves and a group they are supposed to fit into and associate with a lot more strongly than the differences between themselves and a distant group. Growing up, you probably got into more conflicts with your siblings and parents than with random strangers, even though–or perhaps because–your family is nearly identical to you genetically, culturally, and environmentally. “I am nothing like my brother!” a man declares, while simultaneously affirming that there is a great deal in common between himself and members of a race and culture from the other side of the planet. Your  coworker, someone specifically selected for the fact that they have similar mental and technical aptitudes and training as yourself, has a distinct list of traits that drive you nuts, from the way he staples papers to the way he pronounces his Ts, while the women of an obscure Afghan tribe of goat herders simply don’t enter your consciousness.

Nerds, somewhat by definition, don’t fit in. You don’t worry much about fitting into a group you’re not part of in the fist place–you probably don’t worry much about whether or not you fit in with Melanesian fishermen–but most people work hard at fitting in with their own group.

So if you’re male, but you don’t fit in with other males (say, because you’re a nerd,) and you’re down at the bottom of the highschool totem pole and feel like all of the women you’d like to date are judging you negatively next to the football players, then you might feel, rather strongly, the differences between you and other males. Other males are aggressive, they call you a faggot, they push you out of their spaces and threaten you with violence, and there’s very little you can do to respond besides retreat into your “nerd games.”

By contrast, women are polite to you, not aggressive, and don’t aggressively push you out of their spaces. Your differences with them are much less problematic, so you feel like you “fit in” with them.

(There is probably a similar dynamic at play with American men who are obsessed with anime. It’s not so much that they are truly into Japanese culture–which is mostly about quietly working hard–as they don’t fit in very well with their own culture.) (Note: not intended as a knock on anime, which certainly has some good works.)

And here’s another theory: autists have some interesting difficulties with constructing categories and making inferences from data. They also have trouble going along with the crowd, and may have fewer “mirror neurons” than normal people. So maybe autists just process the categories of “male” and “female” a little differently than everyone else, and in a small subset of autists, this results in trans identity.*

And another: maybe there are certain intersex disorders which result in differences in brain wiring/organization. (Yes, there are real interesx disorders, like Klinefelter’s, in which people have XXY chromosomes instead of XX or XY.) In a small set of cases, these unusually wired brains may be extremely good at doing certain tasks (like programming) resulting people who are both “autism spectrum” and “trans”. This is actually the theory I’ve been running with for years, though it is not incompatible with the hormonal theories discussed above.

But we are talking small: trans people of any sort are extremely rare, probably on the order of <1/1000. Even if autists were trans at 8 times the rates of non-autists, that’s still only 8/1000 or 1/125. Autists themselves are pretty rare (estimates vary, but the vast majority of people are not autistic at all,) so we are talking about a very small subset of a very small population in the first place. We only notice these correlations at all because the total population has gotten so huge.

Sometimes, extremely rare things are random chance.

Anthropology Friday: Numbers and the Making of Us, part 2

Welcome to part 2 of my review of Caleb Everett’s Numbers and the Making of Us: Counting and the Course of Human Cultures.

I was really excited about this book when I picked it up at the library. It has the word “numbers” on the cover and a subtitle that implies a story about human cultural and cognitive evolution.

Regrettably, what could have been a great books has turned out to be kind of annoying. There’s some fascinating information in here–for example, there’s a really interesting part on pages 249-252–but you have to get through pages 1-248 to get there. (Unfortunately, sometimes authors put their most interesting bits at the end so that people looking to make trouble have gotten bored and wandered off by then.)

I shall try to discuss/quote some of the book’s more interesting bits, and leave aside my differences with the author (who keeps reiterating his position that mathematical ability is entirely dependent on the culture you’re raised in.) Everett nonetheless has a fascinating perspective, having actually spent much of his childhood in a remote Amazonian village belonging to the Piraha, who have no real words for numbers. (His parents were missionaries.)

Which languages contain number words? Which don’t? Everett gives a broad survey:

“…we can reach a few broad conclusions about numbers in speech. First, they are common to nearly all of the world’s languages. … this discussion has shown that number words, across unrelated language, tend to exhibit striking parallels, since most languages employ a biologically based body-part model evident in their number bases.”

That is, many languages have words that translate essentially to “One, Two, Three, Four, Hand, … Two hands, (10)… Two Feet, (20),” etc., and reflect this in their higher counting systems, which can end up containing a mix of base five, 10, and 20. (The Romans, for example, used both base five and ten in their written system.)

“Third, the linguistic evidence suggests not only that this body-part model has motivated the innovation of numebers throughout the world, but also that this body-part basis of number words stretches back historically as far as the linguistic data can take us. It is evident in reconstruction of ancestral languages, including Proto-Sino-Tibetan, Proto-Niger-Congo, Proto-Autronesian, and Proto-Indo-European, the languages whose descendant tongues are best represented in the world today.”

Note, though, that linguistics does not actually give us a very long time horizon. Proto-Indo-European was spoken about 4-6,000 years ago. Proto-Sino-Tibetan is not as well studied yet as PIE, but also appears to be at most 6,000 years old. Proto-Niger-Congo is probably about 5-6,000 years old. Proto-Austronesian (which, despite its name, is not associated with Australia,) is about 5,000 years old.

These ranges are not a coincidence: languages change as they age, and once they have changed too much, they become impossible to classify into language families. Older languages, like Basque or Ainu, are often simply described as isolates, because we can’t link them to their relatives. Since humanity itself is 200,000-300,000 years old, comparative linguistics only opens a very short window into the past. Various groups–like the Amazonian tribes Everett studies–split off from other groups of humans thousands 0r hundreds of thousands of years before anyone started speaking Proto-Indo-European. Even agriculture, which began about 10,000-15,000 years ago, is older than these proto-languages (and agriculture seems to have prompted the real development of math.)

I also note these language families are the world’s biggest because they successfully conquered speakers of the world’s other languages. Spanish, Portuguese, and English are now widely spoken in the Americas instead of Cherokee, Mayan, and Nheengatu because Indo-European language speakers conquered the speakers of those languages.

The guy with the better numbers doesn’t always conquer the guy with the worse numbers–the Mongol conquest of China is an obvious counter. But in these cases, the superior number system sticks around, because no one wants to replace good numbers with bad ones.

In general, though, better tech–which requires numbers–tends to conquer worse tech.

Which means that even though our most successful language families all have number words that appear to be about 4-6,000 years old, we shouldn’t assume this was the norm for most people throughout most of history. Current human numeracy may be a very recent phenomenon.

“The invention of number is attainable by the human mind but is attained through our fingers. Linguistic data, both historical and current, suggest that numbers in disparate cultures have arisen independently, on an indeterminate range of occasions, through the realization that hands can be used to name quantities like 5 and 10. … Words, our ultimate implements for abstract symbolization, can thankfully be enlisted to denote quantities. But they are usually enlisted only after people establish a more concrete embodied correspondence between their finger sand quantities.”

Some more on numbers in different languages:

“Rare number bases have been observed, for instance, in the quaternary (base-4) systems of Lainana languages of California, or in the senary (base-6) systems that are found in southern New Guinea. …

Several languages in Melanesia and Polynesia have or once had number system that vary in accordance with the type of object being counted. In the case of Old High Fijian, for instance, the word for 100 was Bola when people were counting canoes, but Kora when they were counting coconuts. …

some languages in northwest Amazonia base their numbers on kinship relationships. This is true of Daw and Hup two related language in the region. Speakers of the former languages use fingers complemented with words when counting from 4 to 10. The fingers signify the quantity of items being counted, but words are used to denote whether the quantity is odd or even. If the quantity is even, speakers say it “has a brother,” if it is odd they state it “has no brother.”

What about languages with no or very few words for numbers?

In one recent survey of limited number system, it was found that more than a dozen languages lack bases altogether, and several do not have words for exact quantities beyond 2 and, in some cases, beyond 1. Of course, such cases represent a miniscule fraction of the world’s languages, the bulk of which have number bases reflecting the body-part model. Furthermore, most of the extreme cases in question are restricted geographically to Amazonia. …

All of the extremely restricted languages, I believe, are used by people who are hunter-gatherers or horticulturalists, eg, the Munduruku. Hunter gatherers typically don’t have a lot of goods to keep track of or trade, fields to measure or taxes to pay, and so don’t need to use a lot of numbers. (Note, however, that the Inuit/Eskimo have a perfectly normal base-20 counting system. Their particularly harsh environment appears to have inspired both technological and cultural adaptations.) But why are Amazonian languages even less numeric than those of other hunter-gatherers from similar environments, like central African?

Famously, most of the languages of Australia have somewhat limited number system, and some linguists previously claimed that most Australian language slack precise terms for quantities beyond 2…. [however] many languages on that continent actually have native means of describing various quantities in precise ways, and their number words for small quantities can sometimes be combined to represent larger quantities via the additive and even multiplicative usage of bases. …

Of the nearly 200 Australian languages considered in the survey, all have words to denote 1 and 2. In about three-quarters of the languages, however, the highest number is 3 or 4. Still, may of the languages use a word for “two” as a base for other numbers. Several of the languages use a word for “five” as a base, an eight of the languages top out at a word for “ten.”

Everett then digresses into what initially seems like a tangent about grammatical number, but luckily I enjoy comparative linguistics.

In an incredibly comprehensive survey of 1,066 languages, linguist Matthew Dryer recently found that 98 of them are like Karitiana and lack a grammatical means of marking nouns of being plural. So it is not particularly rare to find languages in which numbers do not show plurality. … about 90% of them, have a grammatical means through which speakers can convey whether they are talking about one or more than one thing.

Mandarin is a major language that has limited expression of plurals. According to Wikipedia:

The grammar of Standard Chinese shares many features with other varieties of Chinese. The language almost entirely lacks inflection, so that words typically have only one grammatical form. Categories such as number (singular or plural) and verb tense are frequently not expressed by any grammatical means, although there are several particles that serve to express verbal aspect, and to some extent mood.

Some languages, such as modern Arabic and Proto-Indo-European also have a “dual” category distinct from singular or plural; an extremely small set of languages have a trial category.

Many languages also change their verbs depending on how many nouns are involved; in English we say “He runs; they run;” languages like Latin or Spanish have far more extensive systems.

In sum: the vast majority of languages distinguish between 1 and more than one; a few distinguish between one, two, and many, and a very few distinguish between one, two, three, and many.

From the endnotes:

… some controversial claims of quadral markers, used in restricted contexts, have been made for the Austronesian languages Tangga, Marshallese, and Sursurunga. .. As Corbett notes in his comprehensive survey, the forms are probably best considered quadral markers. In fact, his impressive survey did not uncover any cases of quadral marking in the world’s languages.

Everett tends to bury his point; his intention in this chapter is to marshal support for the idea that humans have an “innate number sense” that allows them to pretty much instantly realize if they are looking at 1, 2, or 3 objects, but does not allow for instant recognition of larger numbers, like 4. He posits a second, much vaguer number sense that lets us distinguish between “big” and “small” amounts of things, eg, 10 looks smaller than 100, even if you can’t count.

He does cite actual neuroscience on this point–he’s not just making it up. Even newborn humans appear to be able to distinguish between 1, 2, and 3 of something, but not larger numbers. They also seem to distinguish between some and a bunch of something. Anumeric peoples, like the Piraha, also appear to only distinguish between 1, 2, and 3 items with good accuracy, though they can tell “a little” “some” and “a lot” apart. Everett also cites data from animal studies that find, similarly, that animals can distinguish 1, 2, and 3, as well as “a little” and “a lot”. (I had been hoping for a discussion of cephalopod intelligence, but unfortunately, no.)

How then, Everett asks, do we wed our specific number sense (1, 2, and 3) with our general number sense (“some” vs “a lot”) to produce ideas like 6, 7, and a googol? He proposes that we have no innate idea of 6, nor ability to count to 10. Rather, we can count because we were taught to (just as some highly trained parrots and chimps can.) It is only the presence of number words in our languages that allows us to count past 3–after all, anumeric people cannot.

But I feel like Everett is railroading us to a particular conclusion. For example, he sites neurology studies that found one part of the brain does math–the intraparietal suclus (IPS)–but only one part? Surely there’s more than one part of the brain involved in math.

About 5 seconds of Googling got me “Neural Basis of Mathematical Cognition,” which states that:

The IPS turns out to be part of the extensive network of brain areas that support human arithmetic (Figure 1). Like all networks it is distributed, and it is clear that numerical cognition engages perceptual, motor, spatial and mnemonic functions, but the hub areas are the parietal lobes …

(By contrast, I’ve spent over half an hour searching and failing to figure out how high octopuses can count.)

Moreover, I question the idea that the specific and general number senses are actually separate. Rather, I suspect there is only one sense, but it is essentially logarithmic. For example, hearing is logarithmic (or perhaps exponential,) which is why decibels are also logarithmic. Vision is also logarithmic:

The eye senses brightness approximately logarithmically over a moderate range (but more like a power law over a wider range), and stellar magnitude is measured on a logarithmic scale.[14] This magnitude scale was invented by the ancient Greek astronomer Hipparchus in about 150 B.C. He ranked the stars he could see in terms of their brightness, with 1 representing the brightest down to 6 representing the faintest, though now the scale has been extended beyond these limits; an increase in 5 magnitudes corresponds to a decrease in brightness by a factor of 100.[14] Modern researchers have attempted to incorporate such perceptual effects into mathematical models of vision.[15][16]

So many experiments have revealed logarithmic responses to stimuli that someone has formulated a mathematical “law” on the matter:

Fechner’s law states that the subjective sensation is proportional to the logarithm of the stimulus intensity. According to this law, human perceptions of sight and sound work as follows: Perceived loudness/brightness is proportional to logarithm of the actual intensity measured with an accurate nonhuman instrument.[3]

p = k ln ⁡ S S 0 {\displaystyle p=k\ln {\frac {S}{S_{0}}}\,\!}

The relationship between stimulus and perception is logarithmic. This logarithmic relationship means that if a stimulus varies as a geometric progression (i.e., multiplied by a fixed factor), the corresponding perception is altered in an arithmetic progression (i.e., in additive constant amounts). For example, if a stimulus is tripled in strength (i.e., 3 x 1), the corresponding perception may be two times as strong as its original value (i.e., 1 + 1). If the stimulus is again tripled in strength (i.e., 3 x 3 x 3), the corresponding perception will be three times as strong as its original value (i.e., 1 + 1 + 1). Hence, for multiplications in stimulus strength, the strength of perception only adds. The mathematical derivations of the torques on a simple beam balance produce a description that is strictly compatible with Weber’s law.[6][7]

In any logarithmic scale, small quantities–like 1, 2, and 3–are easy to distinguish, while medium quantities–like 101, 102, and 103–get lumped together as “approximately the same.”

Of course, this still doesn’t answer the question of how people develop the ability to count past 3, but this is getting long, so we’ll continue our discussion next week.

Weight, Taste, and Politics: A Theory of Republican Over-Indulgence

So I was thinking about taste (flavor) and disgust (emotion.)

As I mentioned about a month ago, 25% of people are “supertasters,” that is, better at tasting than the other 75% of people. Supertasters experience flavors more intensely than ordinary tasters, resulting in a preference for “bland” food (food with too much flavor is “overwhelming” to them.) They also have a more difficult time getting used to new foods.

One of my work acquaintances of many years –we’ll call her Echo–is obese, constantly on a diet, and constantly eats sweets. She knows she should eat vegetables and tries to do so, but finds them bitter and unpleasant, and so the general outcome is as you expect: she doesn’t eat them.

Since I find most vegetables quite tasty, I find this attitude very strange–but I am willing to admit that I may be the one with unusual attitudes toward food.

Echo is also quite conservative.

This got me thinking about vegetarians vs. people who think vegetarians are crazy. Why (aside from novelty of the idea) should vegetarians be liberals? Why aren’t vegetarians just people who happen to really like vegetables?

What if there were something in preference for vegetables themselves that correlated with political ideology?

Certainly we can theorize that “supertaster” => “vegetables taste bitter” => “dislike of vegetables” => “thinks vegetarians are crazy.” (Some supertasters might think meat tastes bad, but anecdotal evidence doesn’t support this; see also Wikipedia, where supertasting is clearly associated with responses to plants:

Any evolutionary advantage to supertasting is unclear. In some environments, heightened taste response, particularly to bitterness, would represent an important advantage in avoiding potentially toxic plant alkaloids. In other environments, increased response to bitterness may have limited the range of palatable foods. …

Although individual food preference for supertasters cannot be typified, documented examples for either lessened preference or consumption include:

Mushrooms? Echo was just complaining about mushrooms.

Let’s talk about disgust. Disgust is an important reaction to things that might infect or poison you, triggering reactions from scrunching up your face to vomiting (ie, expelling the poison.) We process disgust in our amygdalas, and some people appear to have bigger or smaller amygdalas than others, with the result that the folks with more amygdalas feel more disgust.

Humans also route a variety of social situations through their amygdalas, resulting in the feeling of “disgust” in response to things that are not rotten food, like other people’s sexual behaviors, criminals, or particularly unattractive people. People with larger amygdalas also tend to find more human behaviors disgusting, and this disgust correlates with social conservatism.

To what extent are “taste” and “disgust” independent of each other? I don’t know; perhaps they are intimately linked into a single feedback system, where disgust and taste sensitivity cause each other, or perhaps they are relatively independent, so that a few unlucky people are both super-sensitive to taste and easily disgusted.

People who find other people’s behavior disgusting and off-putting may also be people who find flavors overwhelming, prefer bland or sweet foods over bitter ones, think vegetables are icky, vegetarians are crazy, and struggle to stay on diets.

What’s that, you say, I’ve just constructed a just-so story?

Well, this is the part where I go looking for evidence. It turns out that obesity and political orientation do correlate:

Michael Shin and William McCarthy, researchers from UCLA, have found an association between counties with higher levels of support for the 2012 Republican presidential candidate and higher levels of obesity in those counties.

Shin and McCarthy's map of obesity vs. political orientation
Shin and McCarthy’s map of obesity vs. political orientation

Looks like the Mormons and Southern blacks are outliers.

(I don’t really like maps like this for displaying data; I would much prefer a simple graph showing orientation on one axis and obesity on the other, with each county as a datapoint.)

(Unsurprisingly, the first 49 hits I got when searching for correlations between political orientation and obesity were almost all about what other people think of fat people, not what fat people think. This is probably because researchers tend to be skinny people who want to fight “fat phobia” but aren’t actually interested in the opinions of fat people.)

The 15 most caffeinated cities, from I love Coffee
The 15 most caffeinated cities, from I love Coffee–note that Phoenix is #7, not #1.

Disgust also correlates with political belief, but we already knew that.

A not entirely scientific survey also indicates that liberals seem to like vegetables better than conservatives:

  • Liberals are 28 percent more likely than conservatives to eat fresh fruit daily, and 17 percent more likely to eat toast or a bagel in the morning, while conservatives are 20 percent more likely to skip breakfast.
  • Ten percent of liberals surveyed indicated they are vegetarians, compared with 3 percent of conservatives.
  • Liberals are 28 percent more likely than conservatives to enjoy beer, with 60 percent of liberals indicating they like beer.

(See above where Wikipedia noted that supertasters dislike beer.) I will also note that coffee, which supertasters tend to dislike because it is too bitter, is very popular in the ultra-liberal cities of Portland and Seattle, whereas heavily sweetened iced tea is practically the official beverage of the South.

The only remaining question is if supertasters are conservative. That may take some research.

Update: I have not found, to my disappointment, a simple study that just looks at correlation between ideology and supertasting (or nontasting.) However, I have found a couple of useful items.

In Verbal priming and taste sensitivity make moral transgressions gross, Herz writes:

Standard tests of disgust sensitivity, a questionnaire developed for this research assessing different types of moral transgressions (nonvisceral, implied-visceral, visceral) with the terms “angry” and “grossed-out,” and a taste sensitivity test of 6-n-propylthiouracil (PROP) were administered to 102 participants. [PROP is commonly used to test for “supertasters.”] Results confirmed past findings that the more sensitive to PROP a participant was the more disgusted they were by visceral, but not moral, disgust elicitors. Importantly, the findings newly revealed that taste sensitivity had no bearing on evaluations of moral transgressions, regardless of their visceral nature, when “angry” was the emotion primed. However, when “grossed-out” was primed for evaluating moral violations, the more intense PROP tasted to a participant the more “grossed-out” they were by all transgressions. Women were generally more disgust sensitive and morally condemning than men, … The present findings support the proposition that moral and visceral disgust do not share a common oral origin, but show that linguistic priming can transform a moral transgression into a viscerally repulsive event and that susceptibility to this priming varies as a function of an individual’s sensitivity to the origins of visceral disgust—bitter taste. [bold mine.]

In other words, supertasters are more easily disgusted, and with verbal priming will transfer that disgust to moral transgressions. (And easily disgusted people tend to be conservatives.)

The Effect of Calorie Information on Consumers’ Food Choice: Sources of Observed Gender Heterogeneity, by Heiman and Lowengart, states:

While previous studies found that inherited taste-blindness to bitter compounds such
as PROP may be a risk factor for obesity, this literature has been hotly disputed
(Keller et al. 2010).

(Always remember, of course, that a great many social-science studies ultimately do not replicate.)

I’ll let you know if I find anything else.

Southpaw Genetics

Warning: Totally speculative

This is an attempt at a coherent explanation for why left-handedness (and right-handedness) exist in the distributions that they do.

Handedness is a rather exceptional human trait. Most animals don’t have a dominant hand (or foot.) Horses have no dominant hooves; anteaters dig equally well with both paws; dolphins don’t favor one flipper over the other; monkeys don’t fall out of trees if they try to grab a branch with their left hands. Only humans have a really distinct tendency to use one side of their bodies over the other.

And about 90% of us use our right hands, and about 10% of us use our left hands, (Wikipedia claims 10%, but The Lopsided Ape reports 12%.) an observation that appears to hold pretty consistently throughout both time and culture, so long as we aren’t dealing with a culture where lefties are forced to write with their right hands.

A simple Mendel-square two-gene explanation for handedness–a dominant allele for right-handedness and a recessive one for left-handedness, with equal proportions of alleles in society, would result in a 75% righties to 25% lefties. Even if the proportions weren’t equal, the offspring of two lefties ought to be 100% left-handed. This is not, however, what we see. The children of two lefties have only a 25% chance or so of being left-handed themselves.

So let’s try a more complicated model.

Let’s assume that there are two alleles that code for right-handedness. (Hereafter “R”) You get one from your mom and one from your dad.

Each of these alleles is accompanied by a second allele that codes for either nothing (hereafter “O”) or potentially switches the expression of your handedness (hereafter “S”)

Everybody in the world gets two identical R alleles, one from mom and one from dad.

Everyone also gets two S or O alleles, one from mom and one from dad. One of these S or O alleles affects one of your Rs, and the other affects the other R.

Your potential pairs, then, are:

RO/RO, RO/RS, RS/RO, or RS/RS

RO=right handed allele.

RS=50% chance of expressing for right or left dominance; RS/RS thus => 25% chance of both alleles coming out lefty.

So RO/RO, RO/RS, and RS/RO = righties, (but the RO/ROs may have especially dominant right hands; half of the RO/RS guys may have weakly dominant right hands.)

Only RS/RS produces lefties, and of those, only 25% defeat the dominance odds.

This gets us our observed correlation of only 25% of children of left-handed couples being left-handed themselves.

(Please note that this is still a very simplified model; Wikipedia claims that there may be more than 40 alleles involved.)

What of the general population as a whole?

Assuming random mating in a population with equal quantities of RO/RO, RO/RS, RS/RO and RS/RS, we’d end up with 25% of children RS/RS. But if only 25% of RS/RS turn out lefties, only 6.25% of children would be lefties. We’re still missing 4-6% of the population.

This implies that either: A. Wikipedia has the wrong #s for % of children of lefties who are left-handed; B. about half of lefties are RO/RS (about 1/8th of the RO/RS population); C. RS is found in twice the proportion as RO in the population; or D. my model is wrong.

According to Anything Left-Handed:

Dr Chris McManus reported in his book Right Hand, Left Hand on a study he had done based on a review of scientific literature which showed parent handedness for 70,000 children. On average, the chances of two right-handed parents having a left-handed child were around 9% left-handed children, two left-handed parents around 26% and one left and one right-handed parent around 19%. …
More than 50% of left-handers do not know of any other left-hander anywhere in their living family.

This implies B, that about half of lefties are RO/RS. Having one RS combination gives you a 12.5% chance of being left-handed; having two RS combinations gives you a 25% chance.

And that… I think that works. And it means we can refine our theory–we don’t need two R alleles; we only need one. (Obviously it is more likely a whole bunch of alleles that code for a whole system, but since they act together, we can model them as one.) The R allele is then modified by a pair of alleles that comes in either O (do nothing,) or S (switch.)

One S allele gives you a 12.5% chance of being a lefty; two doubles your chances to 25%.

Interestingly, this model suggests that not only does no gene for “left handedness” exist, but that “left handedness” might not even be the allele’s goal. Despite the rarity of lefties, the S allele is found in 75% of the population (an equal % as the O allele.) My suspicion is that the S allele is doing something else valuable, like making sure we don’t become too lopsided in our abilities or try to shunt all of our mental functions to one side of our brain.

Is there a correlation between intelligence and taste?

(I am annoyed by the lack of bands between 1200 and 1350)
(source)

De gustibus non disputandum est. — Confucius

We’re talking about foods, not whether you prefer Beethoven or Lil’ Wayne.

Certainly there are broad correlations between the foods people enjoy and their ethnicity/social class. If you know whether I chose fried okra, chicken feet, gefilte fish, escargot, or grasshoppers for dinner, you can make a pretty good guess about my background. (Actually, I have eaten all of these things. The grasshoppers were over-salted, but otherwise fine.) The world’s plethora of tasty (and not-so-tasty) cuisines is due primarily to regional variations in what grows well where (not a lot of chili peppers growing up in Nunavut, Canada,) and cost (the rich can always afford fancier fare than the poor,) with a side dish of seemingly random cultural taboos like “don’t eat pork” or “don’t eat cows” or “don’t eat grasshoppers.”

But do people vary in their experience of taste? Does intelligence influence how you perceive your meal, driving smarter (or less-smart) people to seek out particular flavor profiles or combinations? Or could there be other psychological or neurological factors at play n people’s eating decisions?

This post was inspired by a meal my husband, an older relative and I shared recently at McDonald’s. It had been a while since we’d last patronized McDonald’s, but older relative likes their burgers, so we went and ordered some new-to-us variety of meat-on-a-bun. As my husband and I sat there, deconstructing the novel taste experience and comparing it to other burgers, the older relative gave us this look of “Jeez, the idiots are discussing the flavor of a burger! Just eat it already!”

As we dined later that evening at my nemesis, Olive Garden, I began wondering whether we actually experienced the food the same way. Perhaps there is something in people that makes them prefer bland, predictable food. Perhaps some people are better at discerning different flavors, and the people who cannot discern them end up with worse food because they can’t tell?

Unfortunately, it appears that not a lot of people have studied whether there is any sort of correlation between IQ and taste (or smell.) There’s a fair amount of research on taste (and smell,) like “do relatives of schizophrenics have impaired senses of smell?” (More on Schizophrenics and their decreased ability to smell) or “can we get fat kids to eat more vegetables?” Oh, and apparently the nature of auditory hallucinations in epileptics varies with IQ (IIRC.) But not much that directly addresses the question.

I did find two references that, somewhat in passing, noted that they found no relationship between taste and IQ, but these weren’t studies designed to test for that. For example, in A Food Study of Monotony, published in 1958 (you know I am really looking for sources when I have to go back to 1958,) researchers restricted the diets of military personnel employed at an army hospital to only 4 menus to see how quickly and badly they’d get bored of the food. They found no correlation between boredom and IQ, but people employed at an army hospital are probably pre-selected for being pretty bright (and having certain personality traits in common, including ability to stand army food.)

Interestingly, three traits did correlate with (or against) boredom:

Fatter people got bored fastest (the authors speculate that they care the most about their food,) while depressed and feminine men (all subjects in the study were men) got bored the least. Depressed people are already disinterested in food, so it is hard to get less-interested, but no explanation was given of what they meant by “femininity” or how this might affect food preferences. (Also, the hypochondriacs got bored quickly.)

Some foods inspire boredom (or even disgust) quickly, while others are virtually immune. Milk and bread, for example, can be eaten every day without complaint (though you might get bored if bread were your only food.) Potted meat, by contrast, gets old fast.

Likewise, Personality Traits and Eating Habits (warning PDF) notes that:

Although self-reported eating practices were not associated with educational level, intelligence, nor various indices of psychopathology, they were related to the demographic variables of gender and age: older participants reported eating more fiber in their diets than did younger ones, and women reported more avoidance of fats from meats than did men.

Self-reported eating habits may not be all that reliable, though.

Autistic children do seem to be worse at distinguishing flavors (and smells) than non-autistic children, eg Olfaction and Taste Processing in Autism:

Participants with autism were significantly less accurate than control participants in identifying sour tastes and marginally less accurate for bitter tastes, but they were not different in identifying sweet and salty stimuli. … Olfactory identification was significantly worse among participants with autism. … True differences exist in taste and olfactory identification in autism. Impairment in taste identification with normal detection thresholds suggests cortical, rather than brainstem dysfunction.

(Another study of the eating habits of autistic kids found that the pickier ones were rated by their parents as more severely impaired than the less picky ones, but then severe food aversions are a form of life impairment. By the way, do not tell the parents of an autistic kid, “oh, he’ll eat when he’s hungry.” They will probably respond politely, but mentally they are stabbing you.)

On brainstem vs. cortical function–it appears that we do some of our basic flavor identification way down in the most instinctual part of the brain, as Facial Expressions in Response to Taste and Smell Stimulation explores. The authors found that pretty much everyone makes the same faces in response to sweet, sour, and bitter flavors–whites and blacks, old people and newborns, retarded people and blind people, even premature infants, blind infants, and infants born missing most of their brains. All of which is another point in favor of my theory that disgust is real. (And if that is not enough science of taste for you, I recommend Place and Taste Aversion Learning, in which animals with brain lesions lost their fear of new foods.)

Genetics obviously plays a role in taste. If you are one of the 14% or so of people who think cilantro tastes like soap (and I sympathize, because cilantro definitely tastes like soap,) then you’ve already discovered this in a very practical way. Genetics also obviously determine whether you continue producing the enzyme for milk digestion after infancy (lactase persistence). According to Why are you a picky eater? Blame genes, brains, and breastmilk:

In many cases, mom and dad have only themselves to blame for unwittingly passing on the genes that can govern finicky tastes. Studies show that genes play a major role in determining who becomes a picky eater, including recent research on a group of 4- to 7-year-old twins. Part of the pickiness can be attributed to specific genes that govern taste. Variants of the TAS2R38 gene, for example, have been found to encode for taste receptors that determine how strongly someone tastes bitter flavors.

Researchers at Philadelphia’s Monell Chemical Senses Center, a scientific institute dedicated to the study of smell and taste, have found that this same gene also predicts the strength of sweet-tooth cravings among children. Kids who were more sensitive to bitterness preferred sugary foods and drinks. However, adults with the bitter receptor genes remained picky about bitter foods but did not prefer more sweets, the Monell study found. This suggests that sometimes age and experience can override genetics.

I suspect that there is actually a sound biological, evolutionary reason why kids crave sweets more than grownups, and this desire for sweets is somewhat “turned off” as we age.

Picture 10

From a review of Why some like it hot: Food, Genetics, and Cultural Diversity:

Ethnobotanist Gary Paul Nabhan suggests that diet had a key role in human evolution, specifically, that human genetic diversity is predominately a product of regional differences in ancestral diets. Chemical compounds found within animals and plants varied depending on climate. These compounds induced changes in gene expression, which can vary depending on the amount within the particular food and its availability. The Agricultural Age led to further diet-based genetic diversity. Cultivation of foods led to the development of novel plants and animals that were not available in the ancestral environment. …

There are other fascinating examples of gene-diet interaction. Culturally specific recipes, semi-quantitative blending of locally available foods and herbs, and cooking directions needed in order to reduce toxins present in plants, emerged over time through a process of trial-and error and were transmitted through the ages. The effects on genes by foods can be extremely complex given the range of plant-derived compounds available within a given region. The advent of agriculture is suggested to have overridden natural selection by random changes in the environment. The results of human-driven selection can be highly unexpected. …

In sedentary herding societies, drinking water was frequently contaminated by livestock waste. The author suggests in order to avoid contaminated water, beverages made with fermented grains or fruit were drunk instead. Thus, alcohol resistance was selected for in populations that herded animals, such as Europeans. By contrast, those groups which did not practice herding, such as East Asians and Native Americans, did not need to utilize alcohol as a water substitute and are highly sensitive to the effects of alcohol.

Speaking of genetics:

(source?)
From Eating Green could be in your Genes

Indians and Africans are much more likely than Europeans and native South Americans to have an allele that lets them eat a vegetarian diet:

The vegetarian allele evolved in populations that have eaten a plant-based diet over hundreds of generations. The adaptation allows these people to efficiently process omega-3 and omega-6 fatty acids and convert them into compounds essential for early brain development and controlling inflammation. In populations that live on plant-based diets, this genetic variation provided an advantage and was positively selected in those groups.

In Inuit populations of Greenland, the researchers uncovered that a previously identified adaptation is opposite to the one found in long-standing vegetarian populations: While the vegetarian allele has an insertion of 22 bases (a base is a building block of DNA) within the gene, this insertion was found to be deleted in the seafood allele.

Of course, this sort of thing inspires a wealth of pop-psych investigations like Dr. Hirsch’s What Flavor is your Personality?  (from a review:

Dr. Hirsh, neurological director of the Smell and Taste Research and Treatment Foundation in Chicago, stands by his book that is based on over 24 years of scientific study and tests on more than 18,000 people’s food choices and personalities.)

that nonetheless may have some basis in fact, eg: Personality may predict if you like spicy foods:

Byrnes assessed the group using the Arnett Inventory of Sensation Seeking (AISS), a test for the personality trait of sensation-seeking, defined as desiring novel and intense stimulation and presumed to contribute to risk preferences. Those in the group who score above the mean AISS score are considered more open to risks and new experiences, while those scoring below the mean are considered less open to those things.

The subjects were given 25 micrometers of capsaicin, the active component of chili peppers, and asked to rate how much they liked a spicy meal as the burn from the capsaicin increased in intensity. Those in the group who fell below the mean AISS rapidly disliked the meal as the burn increased. People who were above the mean AISS had a consistently high liking of the meal even as the burn increased. Those in the mean group liked the meal less as the burn increased, but not nearly as rapidly as those below the mean.

And then there are the roughly 25% of us who are “supertasters“:

A supertaster is a person who experiences the sense of taste with far greater intensity than average. Women are more likely to be supertasters, as are those from Asia, South America and Africa.[1] The cause of this heightened response is unknown, although it is thought to be related to the presence of the TAS2R38 gene, the ability to taste PROP and PTC, and at least in part, due to an increased number of fungiform papillae.[2]

Perhaps the global distribution of supertasters is related to the distribution of vegetarian-friendly alleles. It’s not surprising that women are more likely to be supertasters, as they have a better sense of smell than men. What may be surprising is that supertasters tend not to be foodies who delight in flavoring their foods with all sorts of new spices, but instead tend toward more restricted, bland diets. Because their sense of taste is essentially on overdrive, flavors that taste “mild” to most people taste “overwhelming” on their tongues. As a result, they tend to prefer a much more subdued palette–which is, of course, perfectly tasty to them.

Picture 8A French study, Changes in Food Preferences and Food Neophobia during a Weight Reduction Session, measured kids’ ability to taste flavors, then the rate at which they became accustomed to new foods. The more sensitive the kids were to flavors, the less likely they were to adopt a new food; the less adept they were at tasting flavors, the more likely they were to start eating vegetables.

Speaking of pickiness again:

“During research back in the 1980s, we discovered that people are more reluctant to try new foods of animal origin than those of plant origin,” Pelchat says. “That’s ironic in two ways. As far as taste is concerned, the range of flavors in animal meat isn’t that large compared to plants, so there isn’t as much of a difference. And, of course, people are much more likely to be poisoned by eating plants than by animals, as long as the meat is properly cooked.” …

It’s also possible that reward mechanisms in our brain can drive changes in taste. Pelchat’s team once had test subjects sample tiny bits of unfamiliar food with no substantial nutritional value, and accompanied them with pills that contained either nothing or a potent cocktail of caloric sugar and fat. Subjects had no idea what was in the pills they swallowed. They learned to like the unfamiliar flavors more quickly when they were paired with a big caloric impact—suggesting that body and brain combined can alter tastes more easily when unappetizing foods deliver big benefits.

So trying to get people to adopt new foods while losing weight may not be the best idea.

(For all that people complain about kids’ pickiness, parents are much pickier. Kids will happily eat playdoh and crayons, but one stray chicken heart in your parents’ soup and suddenly it’s “no more eating at your house.”)

Of course, you can’t talk about food without encountering meddlers who are convinced that people should eat whatever they’re convinced is the perfect diet, like these probably well-meaning folks trying to get Latinos to eat fewer snacks:

Latinos are the largest racial and ethnic minority group in the United States and bear a disproportionate burden of obesity related chronic disease. Despite national efforts to improve dietary habits and prevent obesity among Latinos, obesity rates remain high. …

there is a need for more targeted health promotion and nutrition education efforts on the risks associated with soda and energy-dense food consumption to help improve dietary habits and obesity levels in low-income Latino communities.

Never mind that Latinos are one of the healthiest groups in the country, with longer life expectancies than whites! We’d better make sure they know that their food ways are not approved of!

I have been saving this graph for just such an occasion.
Only now I feel bad because I forgot to write down who made this graph so I can properly credit them. If you know, please tell me!

(Just in case it is not clear already: different people are adapted to and will be healthy on different diets. There is no magical, one-size-fits-all diet.)

And finally, to bring this full circle, it’s hard to miss the folks claiming that Kids Who Eat Fast Food Have Lower IQs:

4,000 Scottish children aged 3-5 years old were examined to compare the intelligence dampening effects of fast food consumption versus  “from scratch”  fare prepared with only fresh ingredients.

Higher fast food consumption by the children was linked with lower intelligence and this was even after adjustments for wealth and social status were taken into account.

It’d be better if they controlled for parental IQ.

The conclusions of this study confirm previous research which shows long lasting effects on IQ from a child’s diet. An Australian study from the University of Adelaide published in August 2012 showed that toddlers who consume junk food grow less smart as they get older. In that study, 7000 children were examined at the age of 6 months, 15 months, 2 years to examine their diet.

When the children were examined again at age 8, children who were consuming the most unhealthy food had IQs up to 2 points lower than children eating a wholesome diet.

 

 

The Neurology of Cross-Cultural Authority? pt 2

As we were discussing yesterday, I theorize that people have neural feedback loops that reward them for conforming/imitating others/obeying authorities and punish them for disobeying/not conforming.

This leads people to obey authorities or go along with groups even when they know, logically, that they shouldn’t.

There are certainly many situations in which we want people to conform even though they don’t want to, like when my kids have to go to bed or buckle their seatbelts–as I said yesterday, the feedback loop exists because it is useful.

But there are plenty of situations where we don’t want people to conform, like when trying to brainstorm new ideas.

Under what conditions will people disobey authority?

As we previously discussed, using technology to create anonymous, a-reputational conversations may allow us to avoid some of the factors that lead to group think.

But in person, people may disobey authorities when they have some other social systtem to fall back on. If disobeying an authority in Society A means I lose social status in Society A, I will be more likely to disobey if I am a member in good standing in Society B.

If I can use my disobedience against Authority A as social leverage to increase my standing in Society B, then I am all the more likely to disobey. A person who can effectively stand up to an authority figure without getting punished must be, our brains reason, a powerful person, an authority in their own right.

Teenagers do this all the time, using their defiance against adults, school, teachers, and society in general to curry higher social status among other teenagers, the people they actually care about impressing.

SJWs do this, too:



I normally consider the president of Princeton an authority figure, and even though I probably disagree with him on far more political matters than these students do, I’d be highly unlikely to be rude to him in real life–especially if I were a student he could get expelled from college.

But if I had an outside audience–Society B–clapping and cheering for me behind the scenes, the urge to obey would be weaker. And if yelling at the President of Princeton could guarantee me high social status, approval, job offers, etc., then there’s a good chance I’d do it.

But then I got to thinking: Are there any circumstances under which these students would have accepted the president’s authority?

Obviously if the man had a proven track record of competently performing a particular skill the students wished to learn, they might follow hi example.

Or not.

If authority works via neural feedback loops, employing some form of “mirror neurons,” do these systems activate more strongly when the people we are perceiving look more like ourselves (or our internalized notion of people in our “tribe” look like, since mirrors are a recent invention)?

In other words, what would a cross-racial version of the Milgram experiment look like?

Unfortunately, it doesn’t look like anyone has tried it (and to do it properly, it’d need to be a big experiment, involving several “scientists” of different races [so that the study isn’t biased by one “scientist” just being bad at projecting authority] interacting with dozens of students of different races, which would be a rather large undertaking.) I’m also not finding any studies on cross-racial authority (I did find plenty of websites offering practical advice about different groups’ leadership styles,) though I’m sure someone has studied it.

However, I did find cross-racial experiments on empathy, which may involve the same brain systems, and so are suggestive:

From Racial Bias Reduces Empathic Sensorimotor Resonance with Other-Race Pain, by Avenanti et al:

Using transcranial magnetic stimulation, we explored sensorimotor empathic brain responses in black and white individuals who exhibited implicit but not explicit ingroup preference and race-specific autonomic reactivity. We found that observing the pain of ingroup models inhibited the onlookers’ corticospinal system as if they were feeling the pain. Both black and white individuals exhibited empathic reactivity also when viewing the pain of stranger, very unfamiliar, violet-hand models. By contrast, no vicarious mapping of the pain of individuals culturally marked as outgroup members on the basis of their skin color was found. Importantly, group-specific lack of empathic reactivity was higher in the onlookers who exhibited stronger implicit racial bias.

From Taking one’s time in feeling other-race pain: an event-related potential investigation on the time-course of cross-racial empathy, by Sessa et al.:

Using the event-related potential (ERP) approach, we tracked the time-course of white participants’ empathic reactions to white (own-race) and black (other-race) faces displayed in a painful condition (i.e. with a needle penetrating the skin) and in a nonpainful condition (i.e. with Q-tip touching the skin). In a 280–340 ms time-window, neural responses to the pain of own-race individuals under needle penetration conditions were amplified relative to neural responses to the pain of other-race individuals displayed under analogous conditions.

In Seeing is believing: neural mechanisms of action-perception are biased by team membership, Molenberghs et al. write:

In this study, we used functional magnetic resonance imaging (fMRI) to investigate how people perceive the actions of in-group and out-group members, and how their biased view in favor of own team members manifests itself in the brain. We divided participants into two teams and had them judge the relative speeds of hand actions performed by an in-group and an out-group member in a competitive situation. Participants judged hand actions performed by in-group members as being faster than those of out-group members, even when the two actions were performed at physically identical speeds. In an additional fMRI experiment, we showed that, contrary to common belief, such skewed impressions arise from a subtle bias in perception and associated brain activity rather than decision-making processes, and that this bias develops rapidly and involuntarily as a consequence of group affiliation. Our findings suggest that the neural mechanisms that underlie human perception are shaped by social context.

None of these studies shows definitevely whether or not in-group vs. out-group biases are an inherent feature of neurological systems, or Avenanti’s finding that people were more empathetic toward a purple-skinned person than to a member of a racial out-group suggests that some amount of learning is involved in the process–and that rather than comparing people against one’s in-group, we may be comparing them against our out-group.

At any rate, you may get similar outcomes either way.

In cases where you want to promote group cohesion and obedience, it may be beneficial to sort people by self-identity.

In cases where you want to guard against groupthink, obedience, or conformity, it may be beneficial to mix up the groups. Intellectual diversity is great, but even ethnic diversity may help people resist defaulting to obedience, especially when they know they shouldn’t.

A study by McKinsey and Company suggests that mixed-race companies outperform more homogenous companies:

web_diversity_matters_ex_mk_v2

but I can find other studies that suggest the opposite, eg, Women Don’t Mean Business? Gender Penalty in Board Appointments, by Isabelle Solal:

Using data from two panel studies on U.S. firms and an online experiment, we examine investor reactions to increases in board diversity. Contrary to conventional wisdom, we find that appointing female directors has no impact on objective measures of performance, such as ROA, but does result in a systematic decrease in market value.

(Solal argues that investors may perceive the hiring of women–even competent ones–as a sign that the company is pursuing social justice goals instead of money-making goals and dump the stock.)

Additionally, diverse companies may find it difficult to work together toward a common goal–there is a good quantity of evidence that increasing diversity decreases trust and inhibits group cohesion. EG, from The downside of diversity:

IT HAS BECOME increasingly popular to speak of racial and ethnic diversity as a civic strength. From multicultural festivals to pronouncements from political leaders, the message is the same: our differences make us stronger.

But a massive new study, based on detailed interviews of nearly 30,000 people across America, has concluded just the opposite. Harvard political scientist Robert Putnam — famous for “Bowling Alone,” his 2000 book on declining civic engagement — has found that the greater the diversity in a community, the fewer people vote and the less they volunteer, the less they give to charity and work on community projects. In the most diverse communities, neighbors trust one another about half as much as they do in the most homogenous settings. The study, the largest ever on civic engagement in America, found that virtually all measures of civic health are lower in more diverse settings.

As usual, I suspect there is an optimum level of diversity–depending on a group’s purpose and its members’ preferences–that helps minimize groupthink while still preserving most of the benefits of cohesion.

The neurology of cross-cultural authority?

So I was thinking the other day about the question of why do people go along with others and do things even when they know they believe (or know) they shouldn’t. As Tolstoy asks, why did the French army go along with this mad idea to invade Russia in 1812? Why did Milgram’s subjects obey his orders to “electrocute” people? Why do I feel emotionally distressed when refusing to do something, even when I have very good reasons to refuse?

As I mentioned ages ago, I suspect that normal people have neural circuits that reward them for imitating others and punish them for failing to imitate. Mirror neurons probably play a critical role in this process, but probably aren’t the complete story.

A mirror neuron is a neuron that fires both when an animal acts and when the animal observes the same action performed by another.[1][2][3] Thus, the neuron “mirrors” the behavior of the other, as though the observer were itself acting. …  In humans, brain activity consistent with that of mirror neurons has been found in the premotor cortex, the supplementary motor area, the primary somatosensory cortex and the inferior parietal cortex.[6] (Wikipedia)

These feedback loops are critical for learning–infants only a few months old begin the process of learning to talk by moving their mouths and making “ba ba” noises in imitation of their parents. (Hence why it is called “babbling.”) They do not consciously say to themselves, “let me try to communicate with the big people by making their noises;” they just automatically move their faces to match the faces you make at them. It’s an instinct.

You probably do this, too. Just watch what happens when one person in a room yawns and then everyone else feels compelled to do it, too. Or if you suddenly turn and look at something behind the group of people you’re with–others will likely turn and look, too.

Autistic infants have trouble with imitation, (and according to Wikipedia, several studies have found abnormalities in their mirror neuron systems, though I suspect the matter is far from settled–among other things, I am not convinced that everyone with an ASD diagnosis actually has the same thing going on.) Nevertheless, there is probably a direct link between autistic infants’ difficulties with imitation and their difficulties learning to talk.

For adults, imitation is less critical (you can, after all, consciously decide to learn a new language,) but still important for survival. If everyone in your village drinks out of one well and avoids the other well, even if no one can explain why, it’s probably a good idea to go along and only drink out of the “good” well. Something pretty bad probably happened to the last guy who drank out of the “bad” well, otherwise the entire village wouldn’t have stopped drinking out of it. If you’re out picking berries with your friends when suddenly one of them runs by yelling “Tiger!” you don’t want to stand there and yell, “Are you sure?” You want to imitate them, and fast.

Highly non-conformist people probably have “defective” or low-functioning feedback loops. They simply feel less compulsion to imitate others–it doesn’t even occur to them to imitate others! These folks might die in interesting ways, but in the meanwhile, they’re good sources for ideas other people just wouldn’t have thought of. I suspect they are concentrated in the arts, though clearly some of them are in programming.

Normal people’s feedback loops kick in when they are not imitating others around them, making them feel embarrassed, awkward, or guilty. When they imitate others, their brains reward them, making them feel happy. This leads people to enjoy a variety of group-based activities, from football games to prayer circles to line dancing to political rallies.

Normal people having fun by synchronizing their bodily movements.
Normal people having fun by synchronizing their bodily movements.

At its extreme, these groups become “mobs,” committing violent acts that many of the folks involved wouldn’t under normal circumstances.

Highly conformist people’s feedback loops are probably over-active, making them feel awkward or uncomfortable while simply observing other people not imitating the group. This discomfort can only be relieved by getting those other people to conform. These folks tend to favor more restrictive social policies and can’t understand why other people would possibly want to do those horrible, non-conforming things.

To reiterate: this feedback system exists because helped your ancestors survive. It is not people being “sheep;” it is a perfectly sensible approach to learning about the world and avoiding dangers. And different people have stronger or weaker feedback loops, resulting in more or less instinctual desire to go along with and imitate others.

However, there are times when you shouldn’t imitate others. Times when, in fact, everyone else is wrong.

The Milgram Experiment places the subject in a situation where their instinct to obey the experimenter (an “authority figure”) is in conflict with their rational desire not to harm others (and their instinctual empathizing with the person being “electrocuted.”)

In case you have forgotten the Milgram Experiment, it went like this: an unaware subject is brought into the lab, where he meets the “scientist” and a “student,” who are really in cahoots. The subject is told that he is going to assist with an experiment to see whether administering electric shocks to the “student” will make him learn faster. The “student” also tells the student, in confidence, that he has a heart condition.

The real experiment is to see if the subject will shock the “student” to death at the “scientist’s” urging.

No actual shocks are administered, but the “student” is a good actor, making out that he is in terrible pain and then suddenly going silent, etc.

Before the experiment, Milgram polled various people, both students and “experts” in psychology, and pretty much everyone agreed that virtually no one would administer all of the shocks, even when pressured by the “scientist.”

In Milgram’s first set of experiments, 65 percent (26 of 40) of experiment participants administered the experiment’s final massive 450-volt shock,[1] though many were very uncomfortable doing so; at some point, every participant paused and questioned the experiment; some said they would refund the money they were paid for participating in the experiment. Throughout the experiment, subjects displayed varying degrees of tension and stress. Subjects were sweating, trembling, stuttering, biting their lips, groaning, digging their fingernails into their skin, and some were even having nervous laughing fits or seizures. (bold mine)

I’m skeptical about the seizures, but the rest sounds about right. Resisting one’s own instinctual desire to obey–or putting the desire to obey in conflict with one’s other desires–creates great emotional discomfort.

To Be Continued.

Further implications of hippocampal theory

So while on my walk today, I got to thinking about various potential implications of the hippocampal theory of time preference.

The short version if you don’t want to read yesterday’s post is that one’s degree of impulsivity/ability to plan / high or low time preference seems to be mediated by an interaction between the nucleus accumbens, which seems to a desire center, and the hippocampus, which does a lot of IQ-related tasks like learn new things and track objects through space. Humans with hippocampal damage become amnesiacs; rats with the connection between their nucleus accumbens and hipocampus severed lose their ability to delay gratification even for superior rewards, becoming slaves to instant gratification.

So, my suspicion:

Relatively strong hippocampus => inhibition of the nucleus accumbens => low time preference.

Relatively weak hippocamus => uninhibited nucleus accumbens => high time preference (aka impulsivity.)

Also, Strong hippocampus = skill at high IQ tasks.

Incentivise traits accordingly.

Anyway, so I was thinking about this, and it occurred to me that it could explain a number of phenomena, like the negative correlation between weight and IQ, eg:

Shamelessly stolen from Jayman's post.
Shamelessly stolen from Jayman’s post. As usual, I recommend it.

(Other theories on the subject: Intelligent people make lots of money and so marry attractive people, resulting in a general correlation between IQ and attractiveness; there is something about eating too much or the particular foods being eaten that causes brain degeneration.)

People generally claim that overweight people lack “willpower.” Note that I am not arguing about willpower; willpower is only a tiny part of the equation.

The skinny people I know do not have willpower. They just do not have big appetites. They are not sitting there saying, “OMG, I am so hungry, but I am going to force myself not to eat right now;” they just don’t actually feel that much hunger.

The fat people I know have big appetites. They’ve always had big appetites. Some of them have documented large appetites going back to infancy. Sure, their ability to stay on a diet may be directly affected by willpower, but they’re starting from a fundamentally different hunger setpoint.

So what might be going on is just a matter of whether the hippocampus or nucleus accumbens happens to be dominant. Where the NE is dominant, the person feels hunger (and all desires) quite strongly. Where the hippocampus is dominant, the person simply doesn’t feel as much hunger (or other desires.)

That a strong hippocampus also leads to high IQ may just be, essentially, a side effect of this trade-off between the two regions.

We might expect, therefore, to see higher inhibition in smart people across a range of behaviors–take socializing, sex, and drug use. *Wanders off to Google*

So, first of all, it looks like there’s a study that claims that higher IQ people do more drugs than lower IQ people. Since the study only looks at self-reported drug use, and most people lie about their illegal drug use, I consider this study probably not very useful; also, drug use is not the same as drug addiction, and there’s a big difference between trying something once and doing it compulsively.

Heroin and cocaine abusers have higher discount rates for delayed rewards than alcoholics or non-drug-using controls

IQ and personality traits assessed in childhood as predictors of drinking and smoking behaviour in middle-aged adults: a 24-year follow-up study (they found that lower IQ people smoke more)

Severity of neuropsychological impairment in cocaine and alcohol addiction: association with metabolism in the prefrontal cortex (Cocaine users are dumb)

HighAbility: The Gifted Introvert claims that 75% of people over 160 IQ are introverts.

Research Links High Sex Drive To High IQ, But Brainiacs Still Have Less Sex Than Everyone Else (Spoiler alert: research does not link high sex drive to IQ. Also, NSFW picture alert.)

I am reminded here of a story about P. A. M. Dirac, one of my favorite scientists:

“An anecdote recounted in a review of the 2009 biography tells of Werner Heisenberg and Dirac sailing on an ocean liner to a conference in Japan in August 1929. “Both still in their twenties, and unmarried, they made an odd couple. Heisenberg was a ladies’ man who constantly flirted and danced, while Dirac—’an Edwardian geek’, as biographer Graham Farmelo puts it—suffered agonies if forced into any kind of socialising or small talk. ‘Why do you dance?’ Dirac asked his companion. ‘When there are nice girls, it is a pleasure,’ Heisenberg replied. Dirac pondered this notion, then blurted out: ‘But, Heisenberg, how do you know beforehand that the girls are nice?'”[30]” (from the Wikipedia.)

Folks speculate that Dirac was autistic; obviously folks don’t speculate such things about Heisenberg.

Autism I have previously speculated may be a side effect of the recent evolution of high math IQ, and the current theory implies a potential correlation between various ASDs and inhibition.

Looks like I’m not the first person to think of that: Atypical excitation–inhibition balance in autism captured by the gamma response to contextual modulation:

The atypical gamma response to contextual modulation that we identified can be seen as the link between the behavioral output (atypical visual perception) and the underlying brain mechanism (an imbalance in excitatory and inhibitory neuronal processing). The impaired inhibition–excitation balance is suggested to be part of the core etiological pathway of ASD (Ecker et al., 2013). Gamma oscillations emerge from interactions between neuronal excitation and inhibition (Buzsaki and Wang, 2012), are important for neuronal communication (Fries, 2009), and have been associated with e.g., perceptual grouping mechanisms (Singer, 1999).

Also, Response inhibition and serotonin in autism: a functional MRI study using acute tryptophan depletion:

“It has been suggested that the restricted, stereotyped and repetitive behaviours typically found in autism are underpinned by deficits of inhibitory control. … Following sham, adults with autism relative to controls had reduced activation in key inhibitory regions of inferior frontal cortex and thalamus, but increased activation of caudate and cerebellum. However, brain activation was modulated in opposite ways by depletion in each group. Within autistic individuals depletion upregulated fronto-thalamic activations and downregulated striato-cerebellar activations toward control sham levels, completely ‘normalizing’ the fronto-cerebellar dysfunctions. The opposite pattern occurred in controls. Moreover, the severity of autism was related to the degree of differential modulation by depletion within frontal, striatal and thalamic regions. Our findings demonstrate that individuals with autism have abnormal inhibitory networks, and that serotonin has a differential, opposite, effect on them in adults with and without autism. Together these factors may partially explain the severity of autistic behaviours and/or provide a novel (tractable) treatment target.”

This may not have anything at all to do with the hippocampus-NA system, of course.

Schizophrenic patients, on the other hand, appear to have the opposite problem: Hyper Hippocampus Fuels Schizophrenia?:

““What we found in animal models and others have found postmortem in schizophrenic patients is that the hippocampus is lacking a certain type of GABA-ergic [GABA-producing] neuron that puts the brakes on the system,” says Grace. “What we’re trying to do is fix the GABA system that’s broken and, by doing that, stabilize the system so the dopamine system responses are back to normal, so that we can actually fix what’s wrong rather than trying to patch it several steps downstream.””

Wow, I made it through two whole posts on the brain without mentioning the amygdala even once.

Time Preference: the most under-appreciated mental trait

Time Preference isn’t sexy and exciting, like anything related to, well, sex. It isn’t controversial like IQ and gender. In fact, most of the ink spilled on the subject isn’t even found in evolutionary or evolutionary psychology texts, but over in economics papers about things like interest rates that no one but economists would want to read.

So why do I think Time Preference is so important?

Because I think Low Time Preference is the true root of high intelligence.

First, what is Time Preference?

Time Preference (aka future time orientation, time discounting, delay discounting, temporal discounting,) is the degree to which you value having a particular item today versus having it tomorrow. “High time preference” means you want things right now, whereas “low time preference” means you’re willing to wait.

A relatively famous test of Time Preference is to offer a child a cookie right now, but tell them they can have two cookies if they wait 10 minutes. Some children take the cookie right now, some wait ten minutes, and some try to wait ten minutes but succumb to the cookie right now about halfway through.

Obviously, many factors can influence your Time Preference–if you haven’t eaten in several days, for example, you’ll probably not only eat the cookie right away, but also start punching me until I give you the second cookie. If you don’t like cookies, you won’t have any trouble waiting for another, but you won’t have much to do with it. Etc. But all these things held equal, your basic inclination toward high or low time preference is probably biological–and by “biological,” I mean, “mostly genetic.”

Luckily for us, scientists have actually discovered where to break your brain to destroy your Time Preference, which means we can figure out how it works.

The scientists train rats to touch pictures with their noses in return for sugar cubes. Picture A gives them one cube right away, while picture B gives them more cubes after a delay. If the delay is too long or the reward too small, the rats just take the one cube right away. But there’s a sweet spot–apparently 4 cubes after a short wait—where the rats will figure it’s worth their while to tap picture B instead of picture A.

But if you snip the connection between the rats’ hippocampi and nucleus accumbenses, suddenly they lose all ability to wait for sugar cubes and just eat their sugar cubes right now, like a pack of golden retrievers in a room full of squeaky toys. They become completely unable to wait for the better payout of four sugar cubes, no matter how much they might want to.

So we know that this connection between the hippocampus and the nucleus accumbens is vitally important to your Time Orientation, though I don’t know what other modifications, such as low hippocampal volume or low nucleus accumbens would do.

So what do the hippocampus and nucleus accumbens do?

According to the Wikipedia, the hippocampus plays an important part in inhibition, memory, and spatial orientation. People with damaged hippocampi become amnesiacs, unable to form new memories.There is a pretty direct relationship between hippocampus size and memory, as documented primarily in old people:

“There is, however, a reliable relationship between the size of the hippocampus and memory performance — meaning that not all elderly people show hippocampal shrinkage, but those who do tend to perform less well on some memory tasks.[71] There are also reports that memory tasks tend to produce less hippocampal activation in elderly than in young subjects.[71] Furthermore, a randomized-control study published in 2011 found that aerobic exercise could increase the size of the hippocampus in adults aged 55 to 80 and also improve spatial memory.” (wikipedia)

Amnesiacs (and Alzheimer’s patients) also get lost a lot, which seems like a perfectly natural side effect of not being able to remember where you are, except that rat experiments show something even more interesting: specific cells that light up as the rats move around, encoding data about where they are.

“Neural activity sampled from 30 to 40 randomly chosen place cells carries enough information to allow a rat’s location to be reconstructed with high confidence.” (wikipedia)

"Spatial firing patterns of 8 place cells recorded from the CA1 layer of a rat. The rat ran back and forth along an elevated track, stopping at each end to eat a small food reward. Dots indicate positions where action potentials were recorded, with color indicating which neuron emitted that action potential." (from Wikipedia)
“Spatial firing patterns of 8 place cells recorded from the CA1 layer of a rat. The rat ran back and forth along an elevated track, stopping at each end to eat a small food reward. Dots indicate positions where action potentials were recorded, with color indicating which neuron emitted that action potential.” (from Wikipedia)

According to Wikipedia, the Inhibition function theory is a little older, but seems like a perfectly reasonable theory to me.

“[Inhibition function theory] derived much of its justification from two observations: first, that animals with hippocampal damage tend to be hyperactive; second, that animals with hippocampal damage often have difficulty learning to inhibit responses that they have previously been taught, especially if the response requires remaining quiet as in a passive avoidance test.”

This is, of course, exactly what the scientists found when they separated the rats’ hippocampi from their nucleus accumbenses–they lost all ability to inhibit their impulses in order to delay gratification, even for a better payout.

In other word, the hippocampus lets you learn, process the moment of objects through space (spatial reasoning) and helps you suppress your inhibitions–that is, it is directly involved in IQ and Time Preference.

 

So what is the Nucleus Accumbens?

According to Wikipedia:

“As a whole, the nucleus accumbens has a significant role in the cognitive processing of aversion, motivation, pleasure, reward and reinforcement learning;[5][6][7] hence, it has a significant role in addiction.[6][7] It plays a lesser role in processing fear (a form of aversion), impulsivity, and the placebo effect.[8][9][10] It is involved in the encoding of new motor programs as well.[6]

Dopaminergic input from the VTA modulate the activity of neurons within the nucleus accumbens. These neurons are activated directly or indirectly by euphoriant drugs (e.g., amphetamine, opiates, etc.) and by participating in rewarding experiences (e.g., sex, music, exercise, etc.).[11][12] …

The shell of the nucleus accumbens is involved in the cognitive processing of motivational salience (wanting) as well as reward perception and positive reinforcement effects.[6] Particularly important are the effects of drug and naturally rewarding stimuli on the NAc shell because these effects are related to addiction.[6] Addictive drugs have a larger effect on dopamine release in the shell than in the core.[6] The specific subset of ventral tegmental area projection neurons that synapse onto the D1-type medium spiny neurons in the shell are responsible for the immediate perception of the rewarding property of a stimulus (e.g., drug reward).[3][4] …

The nucleus accumbens core is involved in the cognitive processing of motor function related to reward and reinforcement.[6] Specifically, the core encodes new motor programs which facilitate the acquisition of a given reward in the future.[6]

So it sounds to me like the point of the nucleus accumbens is to learn “That was awesome! Let’s do it again!” or “That was bad! Let’s not do it again!”

Together, the nucleus accumbens + hippocampus can learn “4 sugar cubes in a few seconds is way better than 1 sugar cube right now.” Apart, the nucleus accumbens just says, “Sugar cubes! Sugar cubes! Sugar cubes!” and jams the lever that says “Sugar cube right now!” and there is nothing the hippocampus can do about it.

 

What distinguishes humans from all other animals? Our big brains, intellects, or impressive vocabularies?

It is our ability to acquire new knowledge and use it to plan and build complex, multi-generational societies.

Ants and bees live in complex societies, but they do not plan them. Monkeys, dolphins, squirrels, and even rats can plan for the future, but only humans plan and build cities.

Even the hunter-gatherer must plan for the future; a small tendril only a few inches high is noted during the wet season, then returned to in the dry, when it is little more than a withered stem, and the water-storing root beneath it harvested. The farmer facing winter stores up grain and wood; the city engineer plans a water and sewer system large enough to handle the next hundred years’ projected growth.

All of these activities require the interaction between the hippocampus and nucleus accumbens. The nucleus accumbens tells us that water is good, grain is tasty, fire is warm, and that clean drinking water and flushable toilets are awesome. The hippocampus reminds us that the dry season is coming, and so we should save–and remember–that root until we need it. It reminds us that we will be cold and hungry in winter if we don’t save our grain and spend a hours and hours chopping wood right now. It reminds us that not only is it good to organize the city so that everyone can have clean drinking water and flushable toilets right now, but that we should also make sure the system will keep working even as new people enter the city over time.

Disconnect these two, and your ability to plan goes down the drain. You eat all of your roots now, devour your seed corn, refuse to chop wood, and say, well, yes, running water would be nice, but that would require so much planning.

 

As I have mentioned before, I think Europeans (and probably a few other groups whose history I’m just not as familiar with and so I cannot comment on) IQ increased quite a bit in the past thousand years or so, and not just because the Catholic Church banned cousin marriage. During this time, manorialism became a big deal throughout Western Europe, and the people who exhibited good impulse control, worked hard, delayed gratification, and were able to accurately calculate the long-term effects of their actions tended to succeed (that is, have lots of children) and pass on their clever traits to their children. I suspect that selective pressure for “be a good manorial employee” was particularly strong in German, (and possibly Japan, now that I think about it,) resulting in the Germanic rigidity that makes them such good engineers.

Nothing in the manorial environment directly selected for engineering ability, higher math, large vocabularies, or really anything that we mean when we normally talk about IQ. But I do expect manorial life to select for those who could control their impulses and plan for the future, resulting in a run-away effect of increasingly clever people constructing increasingly complex societies in which people had to be increasingly good at dealing with complexity and planning to survive.

Ultimately, I see pure mathematical ability as a side effect of being able to accurately predict the effects of one’s actions and plan for the future (eg, “It will be an extra long winter, so I will need extra bushels of corn,”) and the ability to plan for the future as a side effect of being able to accurately represent the path of objects through space and remember lessons one has learned. All of these things, ultimately, are the same operations, just oriented differently through the space-time continuum.

Since your brain is, of course, built from the same DNA code as the rest of you, we would expect brain functions to have some amount of genetic heritablity, which is exactly what we find:

Source: The Heritability of Impulse Control
Source: The Heritability of Impulse Control, Genetic and environmental influences on impulsivity: a meta-analysis of twin, family and adoption studies

“A meta-analysis of twin, family and adoption studies was conducted to estimate the magnitude of genetic and environmental influences on impulsivity. The best fitting model for 41 key studies (58 independent samples from 14 month old infants to adults; N=27,147) included equal proportions of variance due to genetic (0.50) and non-shared environmental (0.50) influences, with genetic effects being both additive (0.38) and non-additive (0.12). Shared environmental effects were unimportant in explaining individual differences in impulsivity. Age, sex, and study design (twin vs. adoption) were all significant moderators of the magnitude of genetic and environmental influences on impulsivity. The relative contribution of genetic effects (broad sense heritability) and unique environmental effects were also found to be important throughout development from childhood to adulthood. Total genetic effects were found to be important for all ages, but appeared to be strongest in children. Analyses also demonstrated that genetic effects appeared to be stronger in males than in females.”

 

“Shared environmental effects” in a study like this means “the environment you and your siblings grew up in, like your household and school.” In this case, shared effects were unimportant–that means that parenting had no effect on the impulsivity of adopted children raised together in the same household. Non-shared environmental influences are basically random–you bumped your head as a kid, your mom drank during pregnancy, you were really hungry or pissed off during the test, etc., and maybe even cultural norms.

So your ability to plan for the future appears to be part genetic, and part random luck.