Tuesday, May 14, 2024

Brain Bias, Male and Female



Image by The Conversation

“On the basis of the information available it seems unrealistic to deny any longer the existence of male and female brain differences.”  

                                                --Richard Restak, The Brain: The Last Frontier (1979)


In the late 1970s, neuroscience investigator Richard Restak was excoriated as a sexist for suggesting—based on evidence, that is, expert opinion—that the brains of human males and females are different.  To hold this opinion is to risk accusations of neurosexism. However, for “gender justice” advocates, female (but not male) brain differences are now insisted on.  This advocacy is mobilized in order to distinguish uniquely women’s issues as the platform for rights and protections, including diversity, health, social, and psychological.

Ongoing studies show a mosaic of male and female features in virtually every brain; there is no pure male or female exhibit.  Yet certain structures and chemistry occur more commonly in each gender.  Male and female brains show bias in a continuum across a number of aspects, from drug processing to reasoning style, mental states to mental disorders. 

One of the reasons brain-sex dimorphism is controversial, Restak explains, is that sex identity and behavior in our species aren’t neatly compartmentalized as in other research subjects like mice and monkeys.  Many question whether animal studies are analogous to studies of brains in primates.  In humans, genotypic sex, phenotypic sex, sex attraction, and gender identity are not reliably aligned.  Sex organs and hormone effects are visible evidence markers between the sexes.   However, these are aligned by genes and their expression throughout the body, like testosterone (male) and estrogen (female) hormones, influencing thinking and behavior in the brain.  These include connections happening prenatally, before exposure to cultural or environmental experience.  The female brain is the default through the X chromosome, meaning that every brain begins as female but only half develop as male.

Stepping outside the research lab, what is the first thing you notice when meeting a new person?  The only biological difference between people isn’t race, class, or age.  It is gender.  We depend on gender knowledge to adjust our communication style to suit male or female.  Gender is embedded in our DNA as chromosomes XY or XX. No matter how gender is expressed or repressed within cultural norms (epigenetics), these genes wire our secondary physical expression as breast size, genitalia, height, weight, muscle size, hip width, sex drive, voice pitch, facial features, and pubic hair.  Unsurprisingly, gender also sets up the male and female brain in distinctive ways.  Whatever gender persona you might decide to exude, your DNA doesn’t migrate between the two gender codes, XX and XY. 

Sex hormones are important to the way people look, feel, and behave.   In men, the Y chromosome carries a protein promoting testes formation, testosterone production, and creation of the male brain.  While this protein makes males more prone to retardation and learning / speech disorders, dyslexia, and autism, males also make up the majority of geniuses at the opposite end of the intelligence scale.  Female fetuses are better able than male to recover from prebirth brain damage. 

Estrogen in women encodes language as spoken sounds (phonemes) as well as the visual coding of written language, and also plays a role in long-term memory (so women are slower to forgive and forget than men).  Testosterone predisposes males to risk danger and aggression, so that most murderers are male.  The male hormone sets desire in men, but testosterone also drives sexual desire in women, even with far less of it in the female brain mix.   

Whatever the differences, Restak concludes, “it helps to keep in mind that such differences do not imply that one sex is superior to the other” (Mysteries of the Mind, 2000, p. 64).   Only that each has a likely inbuilt bias to prefer one type of thinking or acting over others—and therefore, to practice and excel at that behavior.   An article on The Conversation site ventures that  On the other extreme, we are dismissed by women’s health advocates, who believe research has overlooked women’s brains – and that neuroscientists should intensify our search for sex differences to better treat female-dominant disorders, such as depression and Alzheimer’s disease” (April 22, 2021).

For example, women perform better than men on verbal tasks (estrogen-promoted), as well as intuitive reasoning, motor skills, and scanning environments for select features (finding all the green chairs in a mostly blue auditorium, or the best fruits on the tree, or a child on a bustling playground).  The hippocampus, the human memory center, is larger in females, with a higher density of neural connections.  It facilitates memory for people and reading their emotions.

Men excel at spatial tasks, including rotation of objects in mental space, and do better at math, logical reasoning, and motor skills directed at distant targets (aiming and tracking).  Men in mazes navigate by dead reckoning, while women rely on landmarks sequenced in memory. This is why men generally ask for directions much later than women. This is the root of the difference between hunters and gatherers, and why hunter-gatherer societies were based on gendered division of labor.

Another sex-brain disposition is in the anatomical balance of gray and white matter—women have more grey (the core of nerve cell bodies) while men have more white matter (nerve fibers for signaling around the nervous system) involved in connecting brain and body.  Female brains show increased coordination between regions, whereas males have a more separated left-right structure and connect back to front versus women’s hemispheric coordination left to right.  Men and women process neurochemicals differently using different receptors, as for example serotonin synthesis, seen in dominant primates, is over 50% higher in males.

Experience and attitude influence brain dynamics and the development of structure and function.  Lived experience, for example, education, can establish new circuits and outputs, facilitating the hardwiring of the brain. Upbringing and culture can activate or repress brain functions and their genetics, creating new nerve cells and connections, the essence of neuroplasticity.  Adaptability through specific action and memory is our species’ main strength: the ability to connect our biology to our cultural learning by brain growth. The human ability is to adapt to new circumstances over generations, as well as from moment to moment to meet needs and build opportunities. 

The question now arises: How do we know these abilities and their sex DNA are not simply cultural rather than hormonal, as in biodeterminism? For example, Jews make up 2.4% of the US population, but 35% of US Nobel prize winners. Is this nature, or nurture?  The simple response is that culture tends to follow rather than determine biology, reinforcing rather than forcing brain bias. In the Jewish case, this bias is an environment of reward for literacy, encouraging questioning to find answers.  Culture is built on the existing body and brain, but then determines how they work within the process of cultural values and conditioning—for instance, in the way we think about and recognize gender.  This bio-cultural feedback loop is our uniquely human heritage.


Thanks to Dr. Herb Adler for consulting on this topic.

Wednesday, April 24, 2024

Phoenicians – Early Trade in Ideas


“Trade and travel bring people into relationships with each other with resulting disruption of the local religious and ethical life, and then some political invention—foreign rule, or an imperial system, perhaps—is developed.”

--Robert Redfield, The Primitive World and Its Transformations (1953)

Model of a Phoenician bireme ship, c. 700 BC.  Science Museum Group collection


The original merchant seamen used the north star to navigate under sails red and blue.  The Phoenicians deployed the power of sea travel in the Mediterranean to become a connecting force between cultures.  Their navigation skills, legendary in the ancient world, allowed them to travel farther than other traders while keeping on course.  Coming from Tyre in Lebanon between the mountains and the seacoast, they left land hard to farm, sailing as far west as Spain, south to Egypt, east to Asia Minor, and even (reportedly, by Herodotus) around the African cape: a voyage of three years. 

For these voyages they developed seagoing ships with cedar planks, as well as multi-story concrete homes to save space on the coasts where trading centers were established.  This was their legacy to the Persians and Greeks who followed them, building on sea-going networks by assimilating seagoing knowledge.  Besides the keel and the bow battering ram, the Phoenicians have been credited with inventing caulking between planks as well as concrete construction.  

Their territory was the city ports of Tyre, Sidon, and Byblos, profiting from the breakdown of empires at the close of the Bronze Age until the Iron Age boom (around 1200 – 330 BC, predating and following classical antiquity).  The costs were developed into multicultural exchange posts for ideas as well as goods, and a new worldview orientation, based on what writer Adam Nicolson terms “harbor minds” (How to Be: Life Lessons from the Early Greeks, 2023).  “The whole of the Mediterranean was beginning to become a single maritime space…. that liberation from the overwhelming fixity of fate is an aspect of what we should think of as the dolphin mind, the mindset of entrepreneurial, adventuring people.  It is a form of mercantile courage, of reliance on fluidity” (pp.12, 289). As the first to chart the Mediterranean in total, Phoenicians set the model for the study of geography.

The pre-Socratic Greek philosopher Thales would conclude that the foundational principle of reality was in fact water, as in fluidity, transience, and motion, based in part on the role of sea power.   He proposed an earth floating in space like a ship on the water.

These seafaring people also provided a central communication device to the Western world. The written alphabet they carried was a sound-based language adaptable to all cultures as the prototype of all phonetic tongues.  This was as important between cultures as to the international polyglot populations of melting-pot trading ports. By 730 BC Greece had adopted the alphabet as the foundation for widespread literacy that anchored the rise of an astonishing creativity—starting with the justice system based on the written law of statutes.  Latin further evolved this writing into the letters we know today. It is where we get the word alphabet, from the first two letters of ancient Greek – Alpha and Beta.  

Founding Carthage as a major colony, ruling by merchant oligarchies, the Phoenicians had devised a regional order, an integrated culture based around the central sea.  “By around 800 BC, the Mediterranean was in touch with itself, a spinning, fractalizing, and hybridizing whirlpool of expanding and interacting cultures….in which the seed of early philosophy began to grow. (pp. 12-13).  This seed was nurtured by an alphabet mutually shared between city states, from Italy to the Black Sea by the time of the Odyssey, to include the artists’ signatures on the artifacts they were creating: statues, pottery, glass, jewelry; these items are among the rare archaeological evidence left behind.  Surprisingly, such evidence does not include written records of poetry, song, or narrative. 

The color purple made from tens of thousands of snails was the signature of Phoenicia off the Atlantic coast of Morocco. The famous purple dye, drawn from murex, was named after Tyre as Tyrian purple. This red-purple became the standard hue of power and prestige for the imperial rank in ancient Rome. 

However, as traders, they facilitated the large-scale sharing of cultural resources, the core of a cosmopolitan world.  Nicolson cites Ezekiel’s imagining the city of Tyre as a ship assembled from across the Mediterranean market: “her planks were of pine from what is now southern Turkey, her mast a cedar of Lebanon, her oars of oak from the woods above the Sea of Galilee.  Her bulwarks were inlaid with ivory carved in Cyprus, her sails and pennants of Egyptian linen” (p. 81). 

These ancient emporia gave rise to a world culture of trade, in ideas as well as goods, that began a reorientation to a wider world and the cities that anchored that world of exchanges. Such a realignment yielded innovations of every kind to build a world civilization.  We can look at the earliest organized traders as the entrepreneurs of poly-cultural skill, an interchange basic to a global civilization and its bias for a global emporium of creative power. 

Thursday, March 14, 2024

In and Out: Group Bias


“A prejudice, unlike a simple misconception, is actively resistant to all evidence that would unseat it." -- Gordon W. Allport, Psychologist

 Us v. Them

In a social psychology experiment, subjects formed two groups.  Not based on gender, politics, age, race, education, wealth, or anything so salient to identity.  The two groups were divided solely on one criterion: whether their birthdays fell on even or odd days of the calendar.  Not even on astrological sign, or year, or season--just either/or numbers, 1 through 31.

Laboratory experiments have shown how easy it can be to create group identity as well as group divisions that line up loyalties to one group and hostility toward another.  This identification reinforces the differences between us and them.  Favoritism for our group, bias against theirs.  Neuroeconomists George A. Akerlof and Robert J. Shiller, in their review of such experiments, said:   

Even in this division, where the groups are totally pallid and meaningless, subjects who were born on the even days of the month showed a preference toward fellow evens and bias against odds, and odd subjects showed preference toward fellow odds and bias against their rival evens.  Even Dr. Seuss has also gotten into the act.  His Butter Battle Book depicts the Great War that ensues between those who prefer their bread butter side up and those who prefer it butter side down (pp. 158-59, Animal Spirits, 2009).

Blue v. Brown

A well-publicized example of in- and out-group bias is Jane Elliott’s “Blue Eyes/Brown Eyes 1968 exercise in an Iowa public school, following the assassination of Martin Luther King, Jr.   This activist wanted her class to understand what discrimination really feels like--at first hand.  Accordingly, Elliott divided her all-white third-grade classroom into blue-eyed versus brown-eyed students, rotating favored status between them.  On the first day, the blue eyes were told they were smarter, nicer, and better than brown eyes. They were given special privileges.  Results were instant:  the stigmatized group was marginalized by the favored group, shunned, talked about prejudicially, shamed, and otherwise humiliated—while their tormentors’ own grades improved. 

The two groups stopped playing together.  For their part, brown-eyed kids isolated themselves during recess to avoid the blue-eyed scourge, acting intimidated and despondent, while their grades suffered.  The following day, the brown eyes were favored in the same way, with like results, just reversed.  As the odd / even birthdates experiment showed, any trait, including eye color, birthdates, and bread-buttering, can be employed to direct bad behavior towards others. 

However, as a critique, Elliott’s use of eye color has a strong correlation with ethnicity (not exclusively, just correlated).  The choice of eye color is not a neutral factor.  This choice of difference linked her classroom groups to in- and out-groups outside, as they operated in the wider sphere of race stigma--except when the brown eyes were shifted to the top rank over blue.  Said Elliott about her experiment, “You are not born racist. You are born into a racist society. And like anything else, if you can learn it, you can unlearn it. But some people choose not to unlearn it, because they're afraid they'll lose power if they share with other people. We are afraid of sharing power. That's what it's all about.

Language and species

Related to the classroom treatment are studies that show female teachers favor girls over boys, to the detriment of boys’ academic achievement.  Language mastery—a strong pro-bias for teachers in general—comes earlier to girls than to boys.  Dyslexic students are especially disfavored.  Middle-class students, already more successful than lower- or lower-middle, are also favored, as language is correlated positively with class.  Thus a cultural advantage, that of speech, is routinely enhanced through nurturing by teachers—favoring those already versed and skilled as speakers, listeners, readers, and writers by their home environments.  Efforts to transmit this class-based literacy face an uphill struggle.

The story is told in Hollywood about the bias of the Planet of the Apes (“a planet where apes evolved from men”) cast members for their own kind, as the denizens of the post-apocalyptic ape planet in costume gravitated on their own preference to sit down to lunch.  Each type sought out the bench seated with their own ape species – chimps, bonobos, gorillas, orangutans, or humans.

Anti-stigma traits are favored as a sign of ultimate fitness—for example, marriageability. Traits valued are especially:  beauty, fitness and health, vitality (at any age), bilateral symmetry, social graces, competence (a good earner, organized thinker), caring behavior, non-criminal, and lack of negative mental states (neurodiversity). (Plato declared “Beauty is a natural superiority.”)

Salient features of human divisions are age, gender, and race – but primarily age and gender, since definitions of race shift within and between cultures (German and Italian, for example, were considered races within earlier American culture).  The winners and losers effect reflects the ongoing outcomes of class divisions.  Even the evolutionary hierarchies in wild baboons are perpetuated across generations of winners, who most often dominate, and losers, who are most often dominated.   Height estimation goes with dominance and prestige, with observers in the lab estimating higher status for taller men.  More muscular men are seen as more dominant as well, whatever their actual social status (Mark van Vagt, Dutch evolutionary psychologist).

Cultural fitness

The aspirational drive to attain a higher social status—an expression of fitness-- appears to be universal across all human populations and cultures (Peter Erdi, Ranking, 2020).  This is, naturally, an impulse consistently shifted by competition between individuals and their groups, especially when stigma is agreed and applied by the mainstream in which they must operate.   

Psychologist Philip Zimbardo’s infamous Stanford Prison Experiment of 1971 studied the effects of power and powerlessness in a simulated prison cellblock set to run over two weeks.  Twenty-four Stanford students were randomly assigned roles either as wardens and guards or as prisoners.  However, the extent of the abuse meted out by the “guards” on the “inmates” called for the experiment to be terminated early, after only six days.  The prisoners began to show extreme signs of stress and de-individualization.  A humanitarian graduate student pointed out to Zimbardo (who was playing a warden himself) the actual psychic damage being done to real human beings.  The Stanford study remains a landmark example of abuse based on a role-playing exercise.  The parallels to Elliott’s exercise with eye color are all too apparent.

Friday, February 2, 2024

Division of Labor: Excelling v. Extinction

    “When the whole man is involved there is no work.  Work begins with the division of labor.”

                                                                                                --Marshall McLuhan


                                                                     White House kitchen staff division of labor

Economist Michael Kremer posed a cultural equation in which shared ideas, free as a public good, begin to be exchanged and grown across space and time.  As populations expanded, “more people, more ideas,” the higher concentrations gave rise to culture.

Over the centuries, population growth and technological change have expanded, including the division of labor (time and talent) that is the hallmark of the world’s great civilizations, marked by the growth of cities as wealth centers.

In fact, one of the great contrasts between the now-extinct Neanderthals and our species--homo sapiens--is this very ability.  Labor division allocates resources between those with differing skillsets and the time to learn and perfect them.  It is also what distinguishes talent in many arenas from those less talented, leading to status and class divisions. But the Neanderthal home showed no dedicated spaces there, nor any evidence of trading goods and behavior. 

Even their hunter-gatherer behavior seemed to be evenly distributed between men and women (Tim Harford, The Logic of Life, (2008) p. 208-09):  This original division of labor, between male and female, is quite ancient as a shared tradition.  “Today’s simple hunter-gatherer societies divide tasks between the sexes.  Men hunt big game and not much else; women hunt small animals, gather berries and nuts, make clothes, and look after the kids.  Early humans, too, seem to have divided jobs between hunters and gatherers, presumably along the same lines.  Neanderthals, apparently, did not.”

Nor do we know if they had language, indispensable to trading information between or within groups, and record-keeping of assignments.  Language and its concepts are essential to cooperation and role designation as well as task assignment.  The difference may be genetic. Reported in Science in 2022 (Sept. 9) is the discovery of a gene mutation in our species.  This mutation signals the development of extra neurons in the frontal neocortex that greatly enhance connectivity. This TKTL1 gene is lacking in all previous hominids.  Homo sapiens’ birth might come down to this single unique trait.

Division of labor is not as simple as dealing out work to be done equally by effort and hours, but applying the principle of diversity to project and process, both simple and complex—from building huts to bridges to cities.  Using the idea of comparative advantage, any group effort leverages the various capabilities within the group (the job of management expertise), including skills, age, gender, ability, experience, strengths, aptitudes, and weaknesses.  The project is taken apart with a view to splitting subtasks so that they can be assigned by talent as well as time. 

Expertise is developed as a cultural tradition: craft, battle, agriculture, hunting, exploration, planning, engineering, building, language, the arts.  Childcare and foraging were classical women’s work, whereas menfolk specialized in hunting, defense, exploration, and leadership.  Human resources is ideally the science of understanding human capabilities and allocating them in the most productive way (beyond just signing up insurance plans). 

The wealth of cities consists in their ability to instantly draw upon large arrays of these specialized traditions, putting these to work in organized group form.  Organizing human talent and skill, beyond just tool-making or invention, is the basis of any civilized order.  Even the division of domestic spaces designated for separate activities is evidence of thinking in terms of labor division and the special needs of any specific job.  From Egypt onward, homes showed the first-discovered spaces dedicated to leisure pursuits alone, diffusing throughout the human indoor landscape.  In the Neanderthal case, low populations, besides keeping cities in the future, also stymied the technological innovations that generate the cross-fertilized energy and growth of cities. 

Failure to think in this way might be the reason behind the fading of Neanderthals, our close cousins, as they become superseded by homo sapiens 40,000 years ago.  Harford speculates that this approach to working was not evident from the Neanderthal record. 

Division of labor was theorized by French social philosopher Emile Durkheim (1893) to correlate to the moral and communal power of groups to be productive and influential.  This mentality was the way humans were not only able to survive but to thrive as well as prevail.  Another expression of labor division is trade, sharing resources by relocation and speculation by importing novelty and specialization (a kind of cultural arbitrage)—evidence also absent from the Neanderthal record. 

Trade also underlies our social nature as a formalized endeavor between unrelated groups—a necessary parallel to the exogamy of marriage and mating between unlike genetic pools. “Computer simulations show that the propensity to track, barter, and exchange could easily have allowed humans to wipe out Neanderthals in a few thousand years, even if the typical Neanderthal was faster and stronger and perhaps smarter, too" (Hartford p. 208). While 99.7% of genetic material is shared by modern humans and Neanderthals—more closely related than chimpanzees—we diverged over half a million years ago from the last common ancestor.  The DNA record also shows evidence of incestuous mating in these late relatives.

And of course, these labor divisions are far from equal in either their demands or rewards, further dividing the merit landscape that says which groups can aspire to and occupy roles in the professions, politics, celebrity, athletics and in the arts, crafts, and letters.   When Americans meet for the first time, our first question is “What do you do?”  We are looking for clues to background, merit, aspiration, and status. We are, on the scale of world cultures, closely identified with our careers as an index to our background, class, and potential.  Our places in work role diversity are equally important a social index as ethnicity, education, and earnings. 

Thursday, January 18, 2024

Small Bias – Big Effects


We associate the term bias with “bias against,” but not so often “bias towards,” or pro bias.  But in a famous simulation by economist Thomas Schelling, it is the pro bias, or general preference, that can finally create an outcome of de facto segregation of housing. People feel more comfortable in the company of people like themselves.  It is not so much a matter of what they look like as how they think. Shared values, which in this case means a mindset of assumptions - values collectively accepted as true - trumps everything else, regardless of other differences.   

Here is the way this pro bias operates to create housing choice—where people choose to live based on what group the neighbors belong to, as described by economist Tim Harford in The Logic of Life (2008). 

People are happy to live in mixed neighborhoods until they are outnumbered 2 to 1, or one-third of the area population, using a chessboard as a model of an integrated society of households. As white pieces get too many black neighbors (and vice-versa), a wave of segregation washes over the board.  Chess pieces surrounded by too many of the opposition move away, and doing so consolidates a picture of black homogeneity and white homogeneity (p.111). 

This process of a simple rule about preference for living in a place not too dominated by the “other side” was first modelled by Schelling, a game theorist who wondered what kind of social behavior could be explained by game theory: what happened when a single person moved to avoid being socially isolated (Schelling won the Noble Prize in 2005 by pursuing this question). 

“Schelling’s chessboard models showed that all it takes is a mild preference against being too heavily outnumbered…. Pessimists would point out that his model suggests that extreme segregation is almost inevitable” (Harford, p. 115).  Some claim that as little as a 10% incursion by a different group is enough to launch an avalanche of movers away (“white flight”) and thereby toward a more homogeneous settlement.  By following the outcome of game theory simulations, we can see that final outcomes can be unexpected, unintended, and perhaps even less than desired by any and all players. 

Stanford Encyclopedia of Philosophy opens its definition of Game Theory with this statement:

Game theory is the study of the ways in which interacting choices of economic agents produce outcomes with respect to the preferences (or utilities) of those agents, where the outcomes in question might have been intended by none of the agents (Sept. 3, 2023 ed.).

What appears to be an anti-bias against those different from ourselves can be seen, at the same time, not as an inbred prejudice against those unlike us but as a pro-bias preference for living among those whom we better relate to.  Flexing the reward system for “otherness” into some sort of affinity for those unlike ourselves can dull or nullify the expected social effects of housing location, if these rewards operate within the value bias of the group.  Class can overcome race, for example.

College towns and tourist destinations display a greater mix of ethnic types based on a common bond as middle-class.  And at the Disney parks, an enclave of highly mixed types and origins, race is rarely an issue because the park is recognized as a safe space.  Gay enclaves are known for both mixing and stabilizing what were once lower-end city districts, because gays generally do not need to prioritize good school districts in their housing agenda. Their social lives also generate more public safety by keeping streets and bistros busy well into the evening. 

Harford’s book offers several related examples of large effects from small biases.  Some depend on time of day and weather. For example, public playgrounds such as Hackney Downs in London experience social swings from moms and their children during the day to the young male teens who move in to dominate after twilight. This incursion switches the family-friendly sunlit atmosphere to edgy and unwelcoming.  The social theme instantly transforms from warm to cold with the teen “negative externality” transfer.  The openness of public space means that more negative behavior drives out the genteel and middle-class ethic--the ongoing problem with "public" parks.

In the same way, a city’s preference for tall building blocks exerts a bias toward street crime.  How?  By limiting the effect of “eyes on the street” that keeps crime rates down by citizen surveillance and intervention.  In areas with eyes at street level, safety increases as more pedestrians are attracted in.  The safety bias is self-sustaining and positively reinforcing.  Gay gentrification promotes such busy, safe, and engaging street dynamics in a “positive externality.”  This is one reason the middle class, whatever its politics, does not mind gay neighbors--especially homeowners