The life prospects of female co-twins are diminished by prenatal testosterone from their male twins.

From Bütikofe et al.:

During sensitive periods in utero, gonadal steroids help organize biological sex differences in humans and other mammals. In litter-bearing species, chromosomal females passively exposed to prenatal testosterone from male littermates exhibit altered physical and behavioral traits as adults. The consequences of such effects are less well understood in humans, but recent near-doubling of twinning rates in many countries since 1980, secondary to advanced maternal age and increased reliance on in vitro fertilization, means that an increasing subset of females in many populations may be exposed to prenatal testosterone from their male co-twin. Here we use data on all births in Norway (n = 728,842, including 13,800 twins) between 1967 and 1978 to show that females exposed in utero to a male co-twin have a decreased probability of graduating from high school (15.2%), completing college (3.9%), and being married (11.7%), and have lower fertility (5.8%) and life-cycle earnings (8.6%). These relationships remain unchanged among the subsets of 583 and 239 females whose male co-twin died during the first postnatal year and first 28 days of life, respectively, supporting the interpretation that they are due primarily to prenatal exposure rather than to postnatal socialization effects of being raised with a male sibling. Our findings provide empirical evidence, using objectively measured nation-level data, that human females exposed prenatally to a male co-twin experience long-term changes in marriage, fertility, and human capital. These findings support the hypothesis of in utero testosterone transfer between twins, which is likely affecting a small but growing subset of females worldwide.

One mechanism of a basic life choice - to ‘go for it’ or to ‘scram’

Miller et al. use a variety of methods to find subpopulations of dopamine sensitive neurons in the amygdala of mice, projecting to different brain areas, that become active either either during explorative approach or threat-avoiding behaviors:

Avoidance of innate threats is often in conflict with motivations to engage in exploratory approach behavior. The neural pathways that mediate this approach–avoidance conflict are not well resolved. Here we isolated a population of dopamine D1 receptor (D1R)-expressing neurons within the posteroventral region of the medial amygdala (MeApv) in mice that are activated either during approach or during avoidance of an innate threat stimulus. Distinct subpopulations of MeApv-D1R neurons differentially innervate the ventromedial hypothalamus and bed nucleus of the stria terminalis, and these projections have opposing effects on investigation or avoidance of threatening stimuli. These projections are potently modulated through opposite actions of D1R signaling that bias approach behavior. These data demonstrate divergent pathways in the MeApv that can be differentially weighted toward exploration or evasion of threats.

Students of color are healthier in schools that emphasize the value of diversity

From Levine et al.:

Significance

The United States is increasingly diverse, especially among youth. At the same time, racial and ethnic gaps persist in many domains, including risk for cardiovascular disease. Here, we use a diverse sample of adolescents in a mostly urban setting to show that when schools emphasize the value of diversity, students of color are healthier. Thus, schools’ climates around diversity may have a role to play in reducing health disparities.

Abstract

As the United States becomes more diverse, the ways in which mainstream institutions recognize and address race and ethnicity will be increasingly important. Here, we show that one novel and salient characteristic of an institutional environment, that is, whether a school emphasizes the value of racial and ethnic diversity, predicts better cardiometabolic health among adolescents of color. Using a diverse sample of adolescents who attend more than 100 different schools in predominantly urban locations, we find that when schools emphasize the value of diversity (operationalized as mentioning diversity in their mission statements), students of color, but not white students, have lower values on a composite of five biomarkers of inflammation, have less insulin resistance and compensatory β-cell activity, and have fewer metabolic syndrome signs and score lower on a continuous metabolic syndrome composite. These results suggest that institutions that emphasize diversity may play an unacknowledged role in protecting the health of people of color and, thus, may be a site for future interventions to reduce health disparities.

American geography of opportunity reveals European origins

Interesting analysis from Berger and Engzell. They use microlevel Census data on self-reported ancestry to characterize the European origins of US places. They then examine whether variation in income inequality and intergenerational mobility across these places mirror differences between European countries. While parts of the Southeast contain places that are among the least mobile in the developed world, some areas in the Midwest show mobility rates similar to the Scandinavian countries. Evidence of stark regional divides that are seemingly stable over time suggests that some of this variation may be historical in origin. Their work confirms the inverse relationship between inequality and intergenerational mobility.

Significance

The United States is an immigrant nation and consists of places that differ widely in social, cultural, and economic makeup. Recent research finds striking regional variation in economic opportunity—the prospects of poor children to escape poverty as adults. Here, we show that the dominant European ancestry of a place does much to explain such differences: Levels of income equality and mobility across US communities with different European heritage mirror those across corresponding European countries. This finding sheds light on the historical roots of the American geography of opportunity.

Abstract

A large literature documents how intergenerational mobility—the degree to which (dis)advantage is passed on from parents to children—varies across and within countries. Less is known about the origin or persistence of such differences. We show that US areas populated by descendants to European immigrants have similar levels of income equality and mobility as the countries their forebears came from: highest in areas dominated by descendants to Scandinavian and German immigrants, lower in places with French or Italian heritage, and lower still in areas with British roots. Similar variation in mobility is found for the black population and when analyzing causal place effects, suggesting that mobility differences arise at the community level and extend beyond descendants of European immigrant groups. Our findings indicate that the geography of US opportunity may have deeper historical roots than previously recognized.

Infants and toddlers expect different third party punishment behaviors from ingroup and outgroup members.

Yet another example of how our brains are wired to distinguish ingroup and outgroup at a very early age...Ting et al. find sophisticated social analysis performed by 1- and 2.5-year-olds, who show different expectations of the behavior of a third party who has viewed an ingroup-outgroup versus an ingroup-ingroup transgression:

Significance

Adults are more likely to punish transgressions that do not affect them when these transgressions victimize ingroup members. Such third-party punishment (TPP) often takes an indirect form, such as the withholding of help. Building on these results, we showed 2.5- and 1-year-olds scenarios involving a wrongdoer, a victim, and a bystander, and we manipulated the minimal-group memberships of the wrongdoer and the victim relative to that of the bystander. When the victim belonged to the bystander’s group, children expected TPP: They detected a violation when the bystander chose to help the wrongdoer. When the victim did not belong to the bystander’s group, however, children no longer expected TPP. Young children thus selectively expect indirect TPP for harm to ingroup members.

Abstract

Adults and older children are more likely to punish a wrongdoer for a moral transgression when the victim belongs to their group. Building on these results, in violation-of-expectation experiments (n = 198), we examined whether 2.5-year-old toddlers (Exps. 1 and 2) and 1-year-old infants (Exps. 3 and 4) would selectively expect an individual in a minimal group to engage in third-party punishment (TPP) for harm to an ingroup victim. We focused on an indirect form of TPP, the withholding of help. To start, children saw a wrongdoer steal a toy from a victim while a bystander watched. Next, the wrongdoer needed assistance with a task, and the bystander either helped or hindered her. The group memberships of the wrongdoer and the victim were varied relative to that of the bystander and were marked with either novel labels (Exps. 1 and 2) or novel outfits (Exps. 3 and 4). When the victim belonged to the same group as the bystander, children expected TPP: At both ages, they detected a violation when the bystander chose to help the wrongdoer. Across experiments, this effect held whether the wrongdoer belonged to the same group as the bystander and the victim or to a different group; it was eliminated when the victim belonged to a different group than the bystander, when groups were not marked, and when either no theft occurred or the wrongdoer was unaware of the theft. Toddlers and infants thus expect individuals to refrain from helping an ingroup victim’s aggressor, providing further evidence for an early-emerging expectation of ingroup support.

Yet another longevity predictor?

The NYTimes and WaPo must have a substantial number of readers in my 75-80 year old demographic, an age interval during which physical capabilities are rapidly diminishing. Strout offers yet another article pointing to research on physical tests that measure life expectancy:

The test requires you to lower yourself to the floor, crisscross style, without bracing yourself with your hands, knees, arms, or sides of your legs. If you can stand back up, again without the aid of those body parts, you’ve scored a perfect 10 (five points for sitting, five points for standing). You lose a point every time you support yourself with a forbidden joint or appendage...The researchers tested 2,002 adults 51 to 80 years old, and then followed them until a participant died or until the study concluded, which was a median of 6.3 years. In that time, 159 people died — only two of whom had scored a perfect 10. Those who had the lowest score of zero to three points had a risk of death that was five to six times higher than those who scored eight to 10 points.

...more variables apply to our health (and our longevity) than those this particular test focuses on. It’s important to remember that the study results are most relevant to those the same age as the subjects in the testing group, who were ages 51 and up — a point often lost in discussion. Most of the people who scored the lowest on the test were in the 76-to-80 age range, a group that generally experiences decreased mobility and coordination. The research also didn’t reveal the causes of the 159 deaths during the follow-up period. Should we assume they all died of complications from falling, instead of cardiovascular disease or cancer? We don’t know.

The article points to other work showing correlations between physical performance and health. Men who can complete 40 push-ups over a ten year period have a 96% lower risk of cardiovascular disease. People over 65 who walk one meter per second or faster live longer than those who can't.

Using artificial intelligence for medical billing scams.

As a 76 year old Medicare beneficiary, I am frequently annoyed by the blatant ploys that medical care providers use to game the 'fee for services' system: notably scheduling unnecessary appointments and procedures. Metz and Smith describe how this behavior could be enhanced by a dark side of the use of A.I. in health care, as A.I. image analysis technology spreads across medicine, and systems are developed that can detect diabetic retinopathy, as well as lung and brain diseases.

Similar forms of artificial intelligence are likely to move beyond hospitals into the computer systems used by health care regulators, billing companies and insurance providers. Just as A.I. will help doctors check your eyes, lungs and other organs, it will help insurance providers determine reimbursement payments and policy fees.

Ideally, such systems would improve the efficiency of the health care system. But they may carry unintended consequences, a group of researchers at Harvard and M.I.T. warns. In a paper published on Thursday in the journal Science, the researchers raise the prospect of “adversarial attacks” — manipulations that can change the behavior of A.I. systems using tiny pieces of digital data. By changing a few pixels on a lung scan, for instance, someone could fool an A.I. system into seeing an illness that is not really there, or not seeing one that is.

...doctors, hospitals and other organizations could manipulate the A.I. in billing or insurance software in an effort to maximize the money coming their way...If an insurance company uses A.I. to evaluate medical scans, for instance, a hospital could manipulate scans in an effort to boost payouts. If regulators build A.I. systems to evaluate new technology, device makers could alter images and other data in an effort to trick the system into granting regulatory approval.

In their paper, the researchers demonstrated that, by changing a small number of pixels in an image of a benign skin lesion, a diagnostic A.I system could be tricked into identifying the lesion as malignant. Simply rotating the image could also have the same effect, they found.

Small changes to written descriptions of a patient’s condition also could alter an A.I. diagnosis: “Alcohol abuse” could produce a different diagnosis than “alcohol dependence,” and “lumbago” could produce a different diagnosis than “back pain."

In turn, changing such diagnoses one way or another could readily benefit the insurers and health care agencies that ultimately profit from them. Once A.I. is deeply rooted in the health care system, the researchers argue, business will gradually adopt behavior that brings in the most money.

Inflam-aging

Leucht and collaborators show that injured bones do not heal as well with age because of the increases in chronic inflammation that occur with aging.

Significance

As we age, our capacity for tissue repair and regeneration in response to injury declines. Accordingly, bone repair is delayed and impaired in older patients. At the cornerstone of bone healing is the skeletal stem/progenitor cell (SSPC), whose function and number diminishes with age. However, the mechanisms driving this decline remain unclear. Here, we identify age-associated inflammation (“inflamm-aging”) as the main culprit of SSPC dysfunction and provide support for a central role of NF-κB as a mediator of inflamm-aging. Our results show that modification of the inflammatory environment may be a translational approach to functionally rejuvenate the aged SSPC, thereby improving the regenerative capacity of the aged skeleton.

Abstract

Aging is associated with impaired tissue regeneration. Stem cell number and function have been identified as potential culprits. We first demonstrate a direct correlation between stem cell number and time to bone fracture union in a human patient cohort. We then devised an animal model recapitulating this age-associated decline in bone healing and identified increased cellular senescence caused by a systemic and local proinflammatory environment as the major contributor to the decline in skeletal stem/progenitor cell (SSPC) number and function. Decoupling age-associated systemic inflammation from chronological aging by using transgenic Nfkb1KO mice, we determined that the elevated inflammatory environment, and not chronological age, was responsible for the decrease in SSPC number and function. By using a pharmacological approach inhibiting NF-κB activation, we demonstrate a functional rejuvenation of aged SSPCs with decreased senescence, increased SSPC number, and increased osteogenic function. Unbiased, whole-genome RNA sequencing confirmed the reversal of the aging phenotype. Finally, in an ectopic model of bone healing, we demonstrate a functional restoration of regenerative potential in aged SSPCs. These data identify aging-associated inflammation as the cause of SSPC dysfunction and provide mechanistic insights into its reversal.

Affect theory and the new age of anxiety.

Hua Hsu, in the March 25, 2019, issue of The New Yorker, does a fascinating presentation of the work and ideas of Lauren Berlant, whose writing is an example of new field of literary criticism, termed "affect theory", that focuses on nonlinguistic feelings and emotions. Here are a few clips from the article:

In October, 2011, the literary scholar and cultural theorist Lauren Berlant published “Cruel Optimism,” a meditation on our attachment to dreams that we know are destined to be dashed...We like to imagine that our life follows some kind of trajectory, like the plot of a novel, and that by recognizing its arc we might, in turn, become its author. But often what we feel instead is a sense of precariousness—a gut-level suspicion that hard work, thrift, and following the rules won’t give us control over the story, much less guarantee a happy ending. For all that, we keep on hoping, and that persuades us to keep on living...The persistence of the American Dream, Berlant suggests, amounts to a cruel optimism, a condition “when something you desire is actually an obstacle to your own flourishing.”

...our Sisyphean pursuit of the good life has high stakes, and its amalgam of fantasy and futility is something that we process as experience before we rationalize it in thought. These feelings, Berlant says, are the “body’s response to the world, something you’re always catching up to.”...We dream of swimming toward a beautiful horizon, but in truth, Berlant evocatively observed, we are constantly “dogpaddling around a space whose contours remain obscure.” What stories do we tell ourselves in order to stay afloat?

“The Hundreds” (Duke), Berlant’s latest book, co-written with Kathleen Stewart, an anthropologist at the University of Texas at Austin, grows out of ... short writing exercises. Each entry is an experiment in “following out the impact of things” in a hundred words, or a multiple of a hundred words...The result is a strange and captivating book.

In Berlant and Stewart’s hands, affect theory provides a way of understanding the sensations and resignations of the present, the normalized exhaustion that comes with life in the new economy. It is a way of framing uniquely modern questions: Where did the seeming surplus of emotionality that we see on the Internet come from, and what might it become? What new political feelings were being produced by the rudderless drift of life in the gig economy? What if millennials were unintelligible to their parents simply because they have resigned themselves to precariousness as life’s defining feature?

Berlant’s work can feel strangely and kindly optimistic...Maybe relinquishing or recalibrating our fantasies of the good life doesn’t lead to absolute darkness. It can simply be a matter of coming to grips with different possibilities of communion, figuring out who benefits from our collective weariness...But attentiveness to affect encourages us to imagine ourselves beyond the present: even if feelings of exhaustion, indifference, or disillusionment may have been naturalized, that doesn’t mean they’re natural...

“No one wants to be a bad or compromised kind of force in the world, but the latter is just inevitable,” Berlant once wrote in a short essay on her personal credos. “The question is how to develop ways to accentuate those contradictions, to interrupt their banality and to move them somewhere.” We can build worlds out of these small ambitions. We continue to write, even if it occasionally feels as though we were spinning our wheels, and we continue to live, even if it means giving up the certainty that our story is going to end the way we want it to. Writing on her blog a few years ago, Berlant issued what she described as her collective’s secret motto: “We refuse to be worn out.”

More green space in childhood, fewer psychiatric disorders in adulthood.

From Engemann et al.:

Urban residence is associated with a higher risk of some psychiatric disorders, but the underlying drivers remain unknown. There is increasing evidence that the level of exposure to natural environments impacts mental health, but few large-scale epidemiological studies have assessed the general existence and importance of such associations. Here, we investigate the prospective association between green space and mental health in the Danish population. Green space presence was assessed at the individual level using high-resolution satellite data to calculate the normalized difference vegetation index within a 210 × 210 m square around each person’s place of residence (∼1 million people) from birth to the age of 10. We show that high levels of green space presence during childhood are associated with lower risk of a wide spectrum of psychiatric disorders later in life. Risk for subsequent mental illness for those who lived with the lowest level of green space during childhood was up to 55% higher across various disorders compared with those who lived with the highest level of green space. The association remained even after adjusting for urbanization, socioeconomic factors, parental history of mental illness, and parental age. Stronger association of cumulative green space presence during childhood compared with single-year green space presence suggests that presence throughout childhood is important. Our results show that green space during childhood is associated with better mental health, supporting efforts to better integrate natural environments into urban planning and childhood life.

Neural signal diversity is increased by psychedelics

From Carhart-Harris and collaborators:

What is the level of consciousness of the psychedelic state? Empirically, measures of neural signal diversity such as entropy and Lempel-Ziv (LZ) complexity score higher for wakeful rest than for states with lower conscious level like propofol-induced anesthesia. Here we compute these measures for spontaneous magnetoencephalographic (MEG) signals from humans during altered states of consciousness induced by three psychedelic substances: psilocybin, ketamine and LSD. For all three, we find reliably higher spontaneous signal diversity, even when controlling for spectral changes. This increase is most pronounced for the single-channel LZ complexity measure, and hence for temporal, as opposed to spatial, signal diversity. We also uncover selective correlations between changes in signal diversity and phenomenological reports of the intensity of psychedelic experience. This is the first time that these measures have been applied to the psychedelic state and, crucially, that they have yielded values exceeding those of normal waking consciousness. These findings suggest that the sustained occurrence of psychedelic phenomenology constitutes an elevated level of consciousness - as measured by neural signal diversity.

Knowing your own heart - distinguishing interoceptive accuracy and awareness

Garfinkel et al. categorize three different aspects of the internal bodily sensing (interoception) that informs our interactions with the external world, focusing on heartbeats - whose frequency and intensity vary with the degree of our emotional arousal (calm, anticipating, fearful, excited, etc.).

Highlights

• Interoception refers to the signalling and perception of internal bodily sensations.

• We validate a three dimensional construct of interoception.

• This comprises: interoceptive accuracy, sensibility and awareness (metacognition).

• These interoceptive dimensions represent dissociable interoceptive processes.

• Interoceptive accuracy serves as the core (central) construct.

Abstract

Interoception refers to the sensing of internal bodily changes. Interoception interacts with cognition and emotion, making measurement of individual differences in interoceptive ability broadly relevant to neuropsychology. However, inconsistency in how interoception is defined and quantified led to a three-dimensional model. Here, we provide empirical support for dissociation between dimensions of: (1) interoceptive accuracy (performance on objective behavioural tests of heartbeat detection), (2) interoceptive sensibility (self-evaluated assessment of subjective interoception, gauged using interviews/questionnaires) and (3) interoceptive awareness (metacognitive awareness of interoceptive accuracy, e.g. confidence-accuracy correspondence). In a normative sample (N = 80), all three dimensions were distinct and dissociable. Interoceptive accuracy was only partly predicted by interoceptive awareness and interoceptive sensibility. Significant correspondence between dimensions emerged only within the sub-group of individuals with greatest interoceptive accuracy. These findings set the context for defining how the relative balance of accuracy, sensibility and awareness dimensions explain cognitive, emotional and clinical associations of interoceptive ability.

Lethal mass partisanship

I think everyone should read this lucid piece by Thomas Edsall, which describes the emerging consensus on the stark biological and evolved psychological roots of the contempt. moral disgust, and aggression that individual members of right and left wing political groups are now directing toward members of the opposing camp, playing out a primitive tribal in-group/out-group dynamic that has ancient evolutionary roots in primate and other social animal behaviors. We seem to be tearing down the fragile political and legal structures, erected by framers of the US constitution, that allowed this country to at least briefly transcend the warring tribes scenario that has prevailed through most of human history.

Some clips of points that I found fascinating:

As partisan hostility deepens, there is one group that might ordinarily be expected to help pull the electorate out of this morass — the most knowledgeable and sophisticated voters... In “Understanding Partisan Cue Receptivity,” Bert N. Bakker and Yphtach Lelkes...find...the most active voters — those notably “high in cognitive resources” — are the most willing to accept policy positions endorsed by their party, and they are doing so not out of principle, but to affirm their identity as a Democrat or Republican. They are expressing “the desire to reach conclusions that are consistent with a valued identity.”

Ironically, reflective citizens, who are sometimes seen as ideal citizens, might be the subset of strong partisan identifiers most likely to fall in line with the party. Since higher levels of cognitive resources and partisan social identity are associated with higher levels of political activism, the effect may be self-reinforcing, wherein political elites polarize the strongly identified and cognitively reflective, who then elect more polarized elites. The democratic dilemma may not be whether low information citizens can learn what they need to know, but whether high information citizens can set aside their partisan predispositions.

And, some quotes from Steven Pinker:

Certainly there is a tribal flavor to political polarization. Men’s testosterone rises or falls on election night, depending on whether their side wins, just as it does on Super Bowl Sunday...the coalitions clustering at the poles are not tribes in the classical anthropological sense. Today’s left- and right-wingers for the most part aren’t inventing myths of shared blood and common ancestry, or binding together in ritual ordeals, or blending in appearance with a common uniform...I think we’re seeing a somewhat different psychological phenomenon: dynamically sorting ourselves into coalitions defined by moralistic condemnation of designated enemies.

From John Hibbing, a political scientist at the University of Nebraska,

...the central political issues of the day revolve around in-group versus out-group, the definition of the in-group, and the unity and security of the in-group...the problem today is that there are so few cross-cutting cleavages. There is only one cleavage and it is the most evolutionarily primal cleavage of them all...people became tribal because the fundamental substantive issues today are about tribe. We are a group-based species.

From Cosmides and Tooby at UC Santa Barbara,

The set of evolved programs that enable and drive warfare and politics strongly overlap with the set of evolved programs that drive human morality. The mapping of these evolved programs and their embedded circuit logic is only in its infancy, and we have only sketched out some of the known or predicted features of our coalitional and moral psychologies. However, progress in this enterprise holds out the possibility of gradually throwing light on some of the darkest areas of human life...everybody benefits from participating in groups of alliances and factions on different scales, and people also benefit by fractionating solidarity in such a way that those on the far side of the boundary seem undesirable, worth spurning, contemptible, deplorable.

And, the most sobering note from NYU psychologist Jonathan Haidt:

I am expecting that America’s political dysfunction and anger will worsen, and will continue to worsen even after Donald Trump leaves the White House....The reasons for my pessimism are that 1) social media gets ever more effective at drowning us in outrage; 2) overall trust in institutions continues to decline, which makes it seem ever more urgent that “our” side take total control; 3) the younger generations have not seen effective political institutions or norms during their lives, and also seem less adept at handling political disagreements; and 4) the norms of campus regarding call-out culture seem to be spreading quickly into business and many other institutions.

MRI can detect the content of decisions 11 seconds before they are made.

Goldhill points to and summarizes work of Koening-Rober and Pearson. Their abstract:

Is it possible to predict the freely chosen content of voluntary imagery from prior neural signals? Here we show that the content and strength of future voluntary imagery can be decoded from activity patterns in visual and frontal areas well before participants engage in voluntary imagery. Participants freely chose which of two images to imagine. Using functional magnetic resonance (fMRI) and multi-voxel pattern analysis, we decoded imagery content as far as 11 seconds before the voluntary decision, in visual, frontal and subcortical areas. Decoding in visual areas in addition to perception-imagery generalization suggested that predictive patterns correspond to visual representations. Importantly, activity patterns in the primary visual cortex (V1) from before the decision, predicted future imagery vividness. Our results suggest that the contents and strength of mental imagery are influenced by sensory-like neural representations that emerge spontaneously before volition.

Why science needs philosophy

I have always been in awe of the clarity and precision of the thinking of one of my Univ. of Wisconsin colleagues, philosopher Elliott Sober. He is one of the coauthors of a fascinating article on the uses science has for the tools of philosophers (for example, to clean up their fuzzy thinking.) The article might be a bit intense for many readers, but I recommend reading through it. Just a few clips:

...philosophy’s contribution can take at least four forms: the clarification of scientific concepts, the critical assessment of scientific assumptions or methods, the formulation of new concepts and theories, and the fostering of dialogue between different sciences, as well as between science and society.

An example of conceptual clarification:

The definition of stem cells is a prime example. Philosophy has a long tradition of investigating properties, and the tools in use in this tradition have recently been applied to describe “stemness,” the property that defines stem cells. One of us has shown that four different kinds of properties exist under the guise of stemness in current scientific knowledge (1). Depending on the type of tissue, stemness can be a categorical property (an intrinsic property of the stem cell, independent of its environment), a dispositional property (an intrinsic property of the stem cell that is controlled by the microenvironment), a relational property (an extrinsic property that can be conferred to non–stem cells by the microenvironment), or a systemic property (a property that is maintained and controlled at the level of the entire cell population).

Spinning drops!

Here is a really neat, gee whiz kind of study:

To make the water droplets spin, researchers first had to make sure they didn’t wet the surface they fell on—otherwise, they’d just splash. The researchers did this by coating alumina plates with a fluorinated nonstick coating, similar to those found in nonstick cooking pans. Next, they masked some regions of the surface and shone ultraviolet (UV) light on the entire plate. The regions exposed to the UV became highly “wettable,” meaning water touching those regions spread out immediately rather than bouncing back up. The team created several designs of the wettable regions, including one with spiral arms radiating out from a center, much like a pinwheel.

As the droplet bounds up from the patterned surface, the portions encountering the wettable spirals stick to the surface, whereas the parts of the droplet in contact with the water-repelling surface rebound immediately. This creates a set of unbalanced forces, pulling on the droplet more in some parts than in others, twisting it.

Psychological underpinnings of politics

I want to point to a number of commentaries on psychological determinants of political behavior that have been languishing in my queue of potential posts...

How brain science could determine the election. A review of differences between liberals and conservatives in brain processes - with a strong genetic component - that regulate risk tolerance, openness to novelty, fearfulness, etc.

Why Trump will win a second term. Amy Chozick discusses Trump's uncanny grasp, deriving from his experience as a reality show host, of how to keep people's attention by creating an unscripted drama that fills living rooms everywhere, providing entertainment value in the chaos.

The end of the two-party system. David Brooks describes the dissolution of political parties into warring clans competing for declining resources.

Our Culture of Contempt.  Arthur Brooks notes that the problem in America today is not incivility or intolerance, it is contempt for those with opposing views. This is based on motive attribution asymmetry, which leads one side to consider itself driven by benevolence while thinking the other side is motivated by evil and hatred.

Is there such a thing as an authoritarian voter?  Molly Worthen review work studying the psychological traits of voters who are attracted to authoritarian personalities. 

Why is it so hard for democracy to deal with inequality? The Brahmins vs the Merchants

I want to pass on an article that I wish I had made the subject of a longer post when it first appeared.

Thomas Edsall, in "Why is it so hard for democracy to deal with inequality" points to a Power Point presentation by Thomas Piketty, "Brahmin Left vs Merchant Right," that notes a straightforward answer:

Traditional parties of the left no longer represent the working and lower middle classes...the domination of the Democratic Party here (and of socialist parties in France) by voters without college or university degrees came to an end over the period from 1948 to 2017. Both parties are now led by highly educated voters whose interests are markedly different from those in the working class...The result, Piketty argues, is a political system that pits two top-down coalitions against each other...high-education elites vote for the left, while high-income/high-wealth elites for the right, i.e., intellectual elite (Brahmin Left) vs business elite (Merchant Right).

Social threat learning transfers to our decision making.

Lindström et al. (open source) demonstrate that threat associations acquired both by social observation (e.g., through video) and by instruction (e.g., through spoken language) strongly transfer to decision making. This transfer leads to maladaptive decisions when socially acquired associations are outdated rather than valid. The full text describes the three different experimental paradigms noted in the abstract below:

Significance

In today’s world, indirect exposure to threatening situations is more common than ever, as illustrated by footage of terror and disaster in social media. How do such social threat learning experiences shape our decisions? We found that learning about threats from both observation and verbal information strongly influenced decision making. As with learning from our own experience, this influence could be either adaptive or maladaptive depending on whether the social information provided accurate expectations about the environment. Our findings can help explain both adaptive and pathological behaviors resulting from the indirect exposure to threatening events.

Abstract

In today’s world, mass-media and online social networks present us with unprecedented exposure to second-hand, vicarious experiences and thereby the chance of forming associations between previously innocuous events (e.g., being in a subway station) and aversive outcomes (e.g., footage or verbal reports from a violent terrorist attack) without direct experience. Such social threat, or fear, learning can have dramatic consequences, as manifested in acute stress symptoms and maladaptive fears. However, most research has so far focused on socially acquired threat responses that are expressed as increased arousal rather than active behavior. In three experiments (n = 120), we examined the effect of indirect experiences on behaviors by establishing a link between social threat learning and instrumental decision making. We contrasted learning from direct experience (i.e., Pavlovian conditioning) (experiment 1) against two common forms of social threat learning—social observation (experiment 2) and verbal instruction (experiment 3)—and how this learning transferred to subsequent instrumental decision making using behavioral experiments and computational modeling. We found that both types of social threat learning transfer to decision making in a strong and surprisingly inflexible manner. Notably, computational modeling indicated that the transfer of observational and instructed threat learning involved different computational mechanisms. Our results demonstrate the strong influence of others’ expressions of fear on one’s own decisions and have important implications for understanding both healthy and pathological human behaviors resulting from the indirect exposure to threatening events.

How sleep aids recovery from infection, may protect brain from Alzheimer's disease

Dimitrov et al. show how a good night's sleep accelerates recovering from an infection. Glue like proteins (integrins) used by immune system T cells to attach to virus particles and mark them for destruction are produced at greater levels during sleep. In the awake state, signaling molecules like adrenaline are produced at greater levels and inhibit integrin production, reducing the ability of T cells to attach to invading microbes. Here is their technical abstract:

Efficient T cell responses require the firm adhesion of T cells to their targets, e.g., virus-infected cells, which depends on T cell receptor (TCR)–mediated activation of β2-integrins. Gαs-coupled receptor agonists are known to have immunosuppressive effects, but their impact on TCR-mediated integrin activation is unknown. Using multimers of peptide major histocompatibility complex molecules (pMHC) and of ICAM-1—the ligand of β2-integrins—we show that the Gαs-coupled receptor agonists isoproterenol, epinephrine, norepinephrine, prostaglandin (PG) E2, PGD2, and adenosine strongly inhibit integrin activation on human CMV- and EBV-specific CD8+ T cells in a dose-dependent manner. In contrast, sleep, a natural condition of low levels of Gαs-coupled receptor agonists, up-regulates integrin activation compared with nocturnal wakefulness, a mechanism possibly underlying some of the immune-supportive effects of sleep. The findings are also relevant for several pathologies associated with increased levels of Gαs-coupled receptor agonists (e.g., tumor growth, malaria, hypoxia, stress, and sleep disturbances).

Also, Holth et al. show that sleep appears to have a direct protective effect on a key protein that drives AD pathology. They provide direct evidence that disrupting sleep, or stimulating excitatory neurons in brain nuclei that control wakefulness and arousal, promotes the release and spread of damaging tau aggregates across the brains of mice, and that sleep deprivation leads to increased extracellular Aβ and tau in people.

The sleep-wake cycle regulates interstitial fluid (ISF) and cerebrospinal fluid (CSF) levels of β-amyloid (Aβ) that accumulates in Alzheimer’s disease (AD). Furthermore, chronic sleep deprivation (SD) increases Aβ plaques. However, tau, not Aβ, accumulation appears to drive AD neurodegeneration. We tested whether ISF/CSF tau and tau seeding and spreading were influenced by the sleep-wake cycle and SD. Mouse ISF tau was increased ~90% during normal wakefulness versus sleep and ~100% during SD. Human CSF tau also increased more than 50% during SD. In a tau seeding-and-spreading model, chronic SD increased tau pathology spreading. Chemogenetically driven wakefulness in mice also significantly increased both ISF Aβ and tau. Thus, the sleep-wake cycle regulates ISF tau, and SD increases ISF and CSF tau as well as tau pathology spreading.