Can You Have More Than 150 Friends?

MindBlog has done more than 9 posts over the past 15 years (enter Dunbar in the search box in the left column of this web page) pointing to Robin Dunbar's work showing that for a large number of animal species brain size and social group size get larger together, with his curve predicting that the optimal group size for humans is about 150. The staus of this widely accepted number has been challenged by Lind and collaborators, whose article suggests that the number could be much higher. Here is their abstract and a few clips from their discussion:

A widespread and popular belief posits that humans possess a cognitive capacity that is limited to keeping track of and maintaining stable relationships with approximately 150 people. This influential number, ‘Dunbar's number’, originates from an extrapolation of a regression line describing the relationship between relative neocortex size and group size in primates. Here, we test if there is statistical support for this idea. Our analyses on complementary datasets using different methods yield wildly different numbers. Bayesian and generalized least-squares phylogenetic methods generate approximations of average group sizes between 69–109 and 16–42, respectively. However, enormous 95% confidence intervals (4–520 and 2–336, respectively) imply that specifying any one number is futile. A cognitive limit on human group size cannot be derived in this manner.

Ruiter et al. make the point that

Dunbar's assumption that the evolution of human brain physiology corresponds with a limit in our capacity to maintain relationships ignores the cultural mechanisms, practices, and social structures that humans develop to counter potential deficiencies...Human information process management, we argue, cannot be understood as a simple product of brain physiology. Cross-cultural comparison of not only group size but also relationship-reckoning systems like kinship terminologies suggests that although neocortices are undoubtedly crucial to human behavior, they cannot be given such primacy in explaining complex group composition, formation, or management.

An article by Jenny Gross quotes Dunbar's responses to the above.

The new analysis, he said, “is bonkers, absolutely bonkers,” adding that the Stockholm University researchers conducted a flawed statistical analysis and misunderstood both the nuances of his analyses and of human connections. “I marvel at their apparent failure to understand relationships.”

Dr. Dunbar defines meaningful relationships as those people you know well enough to greet without feeling awkward if you ran into them in an airport lounge. That number typically ranges from 100 to 250, with the average around 150...Around 6000 B.C., the size of Neolithic villages from the Middle East was 120 to 150 people, judging by the number of dwellings. In 1086, the average size of most English villages recorded in the Domesday Book was 160 people. In modern armies, fighting units contain an average of 130 to 150 people, he said...Dr. Dunbar contended that his theory is still viable, even in today’s hyper-connected world, since the quality of connections on social networks is often low. “These are not personalized relationships,” he said...“It’s fairly blatantly obvious to most people when they sit down and think about it that that’s how their social network is organized,” he said. Dunbar’s number, he said, is not going anywhere.

For consciousness theory mavens: an argument against Tononi’s Integrated Information Theory.

Behavioral and Brain Science invites commentary on a forthcoming article by Merker et al. Here is the abstract:

Giulio Tononi's Integrated Information Theory (IIT) proposes explaining consciousness by directly identifying it with integrated information. We examine the construct validity of IIT's measure of consciousness, phi (Φ), by analyzing its formal properties, its relation to key aspects of consciousness, and its co-variation with relevant empirical circumstances. Our analysis shows that IIT's identification of consciousness with the causal efficacy with which differentiated networks accomplish global information transfer (which is what Φ in fact measures) is mistaken. This misidentification has the consequence of requiring the attribution of consciousness to a range of natural systems and artifacts that include, but are not limited to, large-scale electrical power grids, gene-regulation networks, some electronic circuit boards, and social networks. Instead of treating this consequence of the theory as a disconfirmation, IIT embraces it. By regarding these systems as bearers of consciousness ex hypothesi, IIT is led towards the orbit of panpsychist ideation. This departure from science as we know it can be avoided by recognizing the functional misattribution at the heart of IIT's identity claim. We show, for example, what function is actually performed, at least in the human case, by the cortical combination of differentiation with integration that IIT identifies with consciousness. Finally, we examine what lessons may be drawn from IIT's failure to provide a credible account of consciousness for progress in the very active field of research concerned with exploring the phenomenon from formal and neural points of view.

I owe my soul to the company store (Google).

As I pass through my 79th birthday I offer a cathartic rant - without worrying about whether its parts cohere:

I am the white collar equivalent of the coal miner in Tennessee Ernie Fords classic “16 Tons” lyric line that provides the title of this post.... except that I am shoveling information in bytes rather than shoveling coal. The tendrils of google extend into all my internet activities, it is a virtual prosthesis. I am symbiotic with the cloud, losing access to it is like losing the use of my limbs. Yuval Harari has it exactly right - Google’s A.I. knows more about me than I know about myself... what YouTube movies, programs, and classical piano performances with scrolling scores I want to watch, where I go (my google maps) and what I do (my google calendar). 

Google knows what I think and write from https://mindblog.dericbownds.net/ (powered by Google’s Blogger platform), as well from my google cloud drive that holds my important legal and financial documents.  I put my piano performances on my YouTube channel at https://www.youtube.com/DericPiano. My techie son’s Google workspace account supporting the bownds.com domain provides me with a deric@bownds.com email address and youtube without advertisements. Underground Google fiber was recently installed on my street and suddenly this week I have 1 GB down internet and google drive cloud storage of 1 terabyte for the same amount that I had been paying another fiber optic provider for 300 MB down with no extras.

My only non-Google platform, http://www.dericbownds.net/  (the archive of my lectures, writing, personal and laboratory history), is a historical relic dating back to geocities.com and now called  'Yahoo Small Business." I tried switching mainly to Apple’s iCloud in early 2020, because it is more protective of privacy, but after a year of trying I have given up and returned to the evil empire. Apple’s web interface for word processing is slow and klutzy, has unnecessary prompts, is crash prone, and too frequently requires relogging into iCloud. 

Governance of me, along with the rest of the human herd, is quietly being transferred from nation states - whose internal conflicts render them ineffective - to an oligarchy of IT companies like Google, Apple, Microsoft, Facebook, and Amazon, along with their European and Asian counterparts. Tech companies are pretending to be governments, as in the quasi-governmental posturing of Amazon and Facebook . Their cloud based artificial intelligence analyzes and manipulates what we want and sells it to us.

After doing numerous posts on the sociopathy of social media, you might think I would practice what I preach and abstain from having a facebook and twitter account. But no, I maintain both accounts (Deric Bownds and @DericBownds)  to re-broadcast the posts I compose on the Blogger platform that masquerades as coming from mindblog.dericbownds.net. I don’t look at tweets or re-tweets on my twitter account, but I do check facebook for news of my family and two facebook social groups. 

I am continually amazed by my occasional looks down the rabbit hole of social media (See How Roblox Sparked a Chaotic Music Scene)  Realizing that this is the generation that contains our future leaders reminds me of Willian Butler Yeats' poem “The Second Coming” in which he seems to have seen it long ago:

Things fall apart; the centre cannot hold; 

Mere anarchy is loosed upon the world, The blood-dimmed tide is loosed, and everywhere

The ceremony of innocence is drowned;

The best lack all conviction, while the worst

Are full of passionate intensity.

Surely some revelation is at hand; 

Surely the Second Coming is at hand.

What's not to enjoy?  Sit back and read Niall Ferguson on "The Politics of Catastrophe" as our humanity slowly and surely chaotically merges with the great A.I. in the cloud!

Educational attainment does not influence brain aging

Well...so much for my smugness over knowing that educational attainment slows brain aging. Nyberg et al. (open souce) show that it ain't so. Check out the link for some nice graphic of their data:

Education has been related to various advantageous lifetime outcomes. Here, using longitudinal structural MRI data (4,422 observations), we tested the influential hypothesis that higher education translates into slower rates of brain aging. Cross-sectionally, education was modestly associated with regional cortical volume. However, despite marked mean atrophy in the cortex and hippocampus, education did not influence rates of change. The results were replicated across two independent samples. Our findings challenge the view that higher education slows brain aging.

The curiosity circuits of our brains.

Every morning, as I am passing through the waking, exercise, and breakfast rituals that finally deliver me to my 'professor is in' office - a converted front bedroom of our house - I marvel at parallel ritualistic behaviors in my two abyssinian 1 year old cats, driven by an almost manic curiosity that impells them to seek new objects, crannies and nooks that hey can explore, occasionally hitting the jackpot of finding a cockroach, or a new object that they can break or brush onto the floor. Curiosity is one of the most important innate drives that they or I posses, and many think it should elevated to join the list of the four F's we teach first year Medical Students (fighting, feeding, fleeing, and fornicating). As Farahbakhsh and Siciliano note in their perspectives article on the work of Ahmadlout et al., "Attraction to the unknown, or curiosity, is a prerequisite for higher-order knowledge. Innate attraction to novelty is thought to be an evolutionary prerequisite for complex learning and guides organisms toward acquisition of adaptive behavioral repertoires."

Ahmadlou et al. have found circuitry in the mouse brain that is necessary for the exploration of new objects and conspecifics. A specific population of genetically identified γ-aminobutyric acid (GABA)—ergic neurons in a brain region called the zona incerta receive excitatory input in the form of novelty and/or arousal information from the prelimbic cortex, and these neurons send inhibitory projections to the periaqueductal gray region. Here is a summary graphic from the perspectives article (click to enlarge):

 

Liberal fact-master nerds go down the rabbit hole of a social media conspiracy.

I pass on this clip from the Morning Dispatch sent by a friend. Check out the link to the NYTimes article it refers to. Ben Smith describes how hundreds of “Jeopardy!” contestants talked themselves into a baseless conspiracy theory — and won’t be talked out of it.

It’s tempting to believe that conspiratorial, tin-hat thinking is something only other people are susceptible to—especially people less educated and more credulous than we imagine ourselves to be. Which is why this piece from the New York Times’s Ben Smith is so fascinating in its depiction of a moral panic that descended on a small online community of former winners of the quiz show Jeopardy! after a contestant who had just won his third game held up three fingers on his right hand—a gesture which, the contestants quickly decided, was likely some sort of white power symbol. “The element of this story that interests me most is how the beating heart of nerdy, liberal fact-mastery can pump blood into wild social media conspiracy, and send all these smart people down the sort of rabbit hole that leads other groups of Americans to believe that children are being transported inside refrigerators,” Smith wrote. “It reflects a depth of alienation among Americans, in which our warring tribes squint through the fog at one another for mysterious and abstruse signs of malice.”

How both tribes are missing the mark

Continuing in the thread of last Monday's post, I can't resist passing on three articles that absolutely nail the current dilemma in the U.S. and Western Europe over finding a middle way between the extremes of reactionary progressivism and conservatism. Here is a clip from Andrew Sullivan, that includes reference to a must read article by Tony Blair. His point is that the current GOP is missing an opportunity to capitalize on the following opportunity:

Everywhere in the West, this is now the winning electoral formula: left on economics, right on culture. By “left on economics”, I mean a recognition that market capitalism has been too successful for its and our own good, and that spreading the wealth to more people is needed both for social stability and to rescue capitalism from itself. And by “right on culture”, I do not mean some kind of revived Christianism. I mean affirming a critical but undeniable love of country and its flawed but inspiring history, reforming rather than defunding the police, enforcing the nation’s borders with firmness and compassion, embracing color-blind policies on race, and viewing our common humanity and citizenship as deeper principles than the modern left’s and radical right’s obsession with group identity.

Get that balance right, and the future is yours. In a must-read essay in Britain’s New Statesman, Tony Blair spells out how the progressive left is still misreading the public mood, allowing a cannier, less rigid right to entrench power. Money quote: “‘Defund the police’ may be the left’s most damaging political slogan since ‘the dictatorship of the proletariat’ … It leaves the right with an economic message which seems more practical, and a powerful cultural message around defending flag, family and fireside traditional values.” Some key principles Blair lays out:

People do not like their country, their flag or their history being disrespected. The left always gets confused by this sentiment and assume this means people support everything their country has done or think all their history is sacrosanct. They don’t. But they query imposing the thinking of today on the practices of yesterday … People like common sense, proportion and reason. They dislike prejudice; but they dislike extremism in combating prejudice.

The third article I point to is an add-on to the above. Brooks' piece suggests that the wokeness, social justice, or critical race theory of the left is likely to be co-opted by the meritocratic elite of corporations and other establishment organizations. "In the 1960s, left-wing radicals wanted to overthrow capitalism. We ended up with Whole Foods. The co-optation of wokeness seems to be happening right now."

Two promising post-traumatic stress disorder treatments

I want to pass on references to two new approaches to relieving the symptoms of post-traumatic stress disorder (PTSD). Nuwer describes a new study showing that MDMA (known as the party drug Ecstasy, or Molly) can bring relief to PTSD when used in conjunction with talk therapy. Ressler et al. address the problem that human patients cannot be directly re-exposed to trauma-cues of the sort that have been used in animal studies to induce and then disrupt reconsolidation of traumatic memories. They devise a procedure for covertly capturing and attenuating a hippocampu-dependent fear memory in male rats, a procedure that might prove to be useful in human therapy. Here is their abstract:

Reconsolidation may be a viable therapeutic target to inhibit pathological fear memories. In the clinic, incidental or imaginal reminders are used for safe retrieval of traumatic memories of experiences that occurred elsewhere. However, it is unknown whether indirectly retrieved traumatic memories are sensitive to disruption. Here we used a backward (BW) conditioning procedure to indirectly retrieve and manipulate a hippocampus (HPC)-dependent contextual fear engram in male rats. We show that conditioned freezing to a BW conditioned stimulus (CS) is mediated by fear to the conditioning context, activates HPC ensembles that can be covertly captured and chemogenetically activated to drive fear, and is impaired by post-retrieval protein synthesis inhibition. These results reveal that indirectly retrieved contextual fear memories reactivate HPC ensembles and undergo protein synthesis-dependent reconsolidation. Clinical interventions that rely on indirect retrieval of traumatic memories, such as imaginal exposure, may open a window for editing or erasure of neural representations that drive pathological fear.

Social isolation makes us stupid.

The summary of an open source article from Ingram et al. in the Journal of Applied Cognitive Psychology:

Studies examining the effect of social isolation on cognitive function typically involve older adults and/or specialist groups (e.g., expeditions). We considered the effects of COVID‐19‐induced social isolation on cognitive function within a representative sample of the general population. We additionally considered how participants ‘shielding’ due to underlying health complications, or living alone, performed. We predicted that performance would be poorest under strictest, most‐isolating conditions. At five timepoints over 13 weeks, participants (N = 342; aged 18–72 years) completed online tasks measuring attention, memory, decision‐making, time‐estimation, and learning. Participants indicated their mood as ‘lockdown’ was eased. Performance typically improved as opportunities for social contact increased. Interactions between participant sub‐groups and timepoint demonstrated that performance was shaped by individuals' social isolation levels. Social isolation is linked to cognitive decline in the absence of ageing covariates. The impact of social isolation on cognitive function should be considered when implementing prolonged pandemic‐related restrictive conditions.

Tribe trumps truth.

I've been trying to cut down on the number of posts on politics, but with the republican party now requiring a loyalty test that is the modern equivalent the firewalking rituals of Polynesia, Spain, and Greece I want to pass on a few articles relevant to their transition into a white anglo-saxon tribe that seeks to establish an autocratic regime that will preserve their minority ruling status. First, Brooks notes that

...Since the election, large swaths of the Trumpian right have decided America is facing a crisis like never before and they are the small army of warriors fighting with Alamo-level desperation to ensure the survival of the country as they conceive it...When asked in late January if politics is more about “enacting good public policy” or “ensuring the survival of the country as we know it,” 51 percent of Trump Republicans said survival; only 19 percent said policy...The level of Republican pessimism is off the charts. A February Economist-YouGov poll asked Americans which statement is closest to their view: “It’s a big, beautiful world, mostly full of good people, and we must find a way to embrace each other and not allow ourselves to become isolated” or “Our lives are threatened by terrorists, criminals and illegal immigrants, and our priority should be to protect ourselves.”...Over 75 percent of Biden voters chose “a big, beautiful world.” Two-thirds of Trump voters chose “our lives are threatened.”

Douthat describes the two crises of conservatism:

The normal crisis is a party crisis, the sort that afflicts all political coalitions. The Republican Party 40 years ago coalesced around a set of appeals that enabled its leaders to win large presidential majorities and set the national agenda. At a certain point the issue landscape changed, so did the country’s demographics, and the G.O.P. has struggled to adapt — cycling through compassionate conservatism, Tea Party conservatism and Trumpist populism without reproducing Ronald Reagan’s success.

But beneath this party crisis there is the deeper one, having to do with what conservatism under a liberal order exists to actually conserve...One powerful answer is that conservatism-under-liberalism should defend human goods that are threatened by liberal ideas taken to extremes. The family, when liberal freedom becomes a corrosive hyper-individualism. Traditional religion, when liberal toleration becomes a militant and superstitious secularism. Local community and local knowledge, against expert certainty and bureaucratic centralization. Artistic and intellectual greatness, when democratic taste turns philistine or liberal intellectuals become apparatchiks. The individual talent of the entrepreneur or businessman, against the leveling impulses of egalitarianism and the stultifying power of monopoly...

but,

What does it mean to conserve the family in an era when not just the two-parent household but childbearing and sex itself are in eclipse? What does it mean to defend traditional religion in a country where institutional faith is either bunkered or rapidly declining? How do you defend localism when the internet seems to nationalize every political and cultural debate? What does the conservation of the West’s humanistic traditions mean when pop repetition rules the culture, and the great universities are increasingly hostile to even the Democratic-voting sort of cultural conservative?

A further Douthat piece suggests that it is capitalism itself that is killing conservatism:

...the social trends American conservatives most dislike, the rise of expressive individualism and the decline of religion, marriage and the family, are driven by socioeconomic forces the right’s free-market doctrines actively encourage. “America’s moral traditionalists are wedded to an economic system that is radically anti-traditional,” he writes, and “Republicans can neither wage war on capitalism nor make peace with its social implications.”

...it’s not that capitalist dynamism inevitably dissolves conservative habits. It’s more that the wealth this dynamism piles up, the liberty it enables and the technological distractions it invents, let people live more individualistically — at first happily, with time perhaps less so — in ways that eventually undermine conservatism and dynamism together. At which point the peril isn’t markets red in tooth and claw, but a capitalist endgame that resembles Aldous Huxley’s “Brave New World,” with a rich and technologically proficient world turning sterile and dystopian.

...let’s not let liberals off the hook. If capitalist churn isn’t what it used to be, if taming its excesses in the style of France or Sweden isn’t enough to restore family and community, if the combination of welfare-state liberalism and personal emancipation trends toward a Huxleyan dystopia, do liberals have any resources besides complaints about capitalism that might help pull us off that course?...Because if conservatism’s responses are incoherent and insufficient, I fear that liberalism has no response at all.

Structural Whitening

I pass on this summary by Rai of a study by Anicich et al. in J. Exp. Soc. Psychol:

As the US population becomes more racially diverse, it is unclear how ethnic white populations will respond to these demographic changes. Anicich et al. found experimentally that when white Americans were given the opportunity to populate fictional cities, they imposed greater racial segregation in areas that they frequented more often, such as work or school, because they feel greater anxiety around non-whites. In a follow-up study, the authors examined policies at tennis and golf clubs across the United States, and found that in areas with higher racial diversity, clubs engaged in more exclusionary behavior, such as enacting strict dress codes. These findings suggest that as racial diversity increases, white Americans may respond by trying to structure their environment in more segregated ways.

And here is the abstract of the article:

The current research explores how local racial diversity affects Whites' efforts to structure their local communities to avoid incidental intergroup contact. In two experimental studies (N = 509; Studies 1a-b), we consider Whites' choices to structure a fictional, diverse city and find that Whites choose greater racial segregation around more (vs. less) self-relevant landmarks (e.g., their workplace and children's school). Specifically, the more time they expect to spend at a landmark, the more they concentrate other Whites around that landmark, thereby reducing opportunities for incidental intergroup contact. Whites also structure environments to reduce incidental intergroup contact by instituting organizational policies that disproportionately exclude non-Whites: Two large-scale archival studies (Studies 2a-b) using data from every U.S. tennis (N = 15,023) and golf (N = 10,949) facility revealed that facilities in more racially diverse communities maintain more exclusionary barriers (e.g., guest policies, monetary fees, dress codes) that shield the patrons of these historically White institutions from incidental intergroup contact. In a final experiment (N = 307; Study 3), we find that Whites' anticipated intergroup anxiety is one driver of their choices to structure environments to reduce incidental intergroup contact in more (vs. less) racially diverse communities. Our results suggest that despite increasing racial diversity, White Americans structure local environments to fuel a self-perpetuating cycle of segregation.

Evidence that monkeys have conscious awareness of self - they know what they saw.

Ben-Haim et al. Disentangle perceptual awareness from nonconscious processing in rhesus monkeys  

Significance

Many animals perform complex intelligent behaviors, but the question of whether animals are aware while doing so remains a long debated but unanswered question. Here, we develop a new approach to assess whether nonhuman animals have awareness by utilizing a well-known double dissociation of visual awareness—cases in which people behave in completely opposite ways when stimuli are processed consciously versus nonconsciously. Using this method, we found that a nonhuman species—the rhesus monkey—exhibits the very same behavioral signature of both nonconscious and conscious processing. This opposite double dissociation of awareness firstly allows stripping away the long inherent ambiguity when interpreting the processes governing animal behavior. Collectively, it provides robust support for two distinct awareness modes in nonhuman animals.

Abstract

Scholars have long debated whether animals, which display impressive intelligent behaviors, are consciously aware or not. Yet, because many complex human behaviors and high-level functions can be performed without conscious awareness, it was long considered impossible to untangle whether animals are aware or just conditionally or nonconsciously behaving. Here, we developed an empirical approach to address this question. We harnessed a well-established cross-over double dissociation between nonconscious and conscious processing, in which people perform in completely opposite ways when they are aware of stimuli versus when they are not. To date, no one has explored if similar performance dissociations exist in a nonhuman species. In a series of seven experiments, we first established these signatures in humans using both known and newly developed nonverbal double-dissociation tasks and then identified similar signatures in rhesus monkeys (Macaca mulatta). These results provide robust evidence for two distinct modes of processing in nonhuman primates. This empirical approach makes it feasible to disentangle conscious visual awareness from nonconscious processing in nonhuman species; hence, it can be used to strip away ambiguity when exploring the processes governing intelligent behavior across the animal kingdom. Taken together, these results strongly support the existence of both nonconscious processing as well as functional human-like visual awareness in nonhuman animals.

(Note: Establishing double dissociation of awareness used a nonverbal spatial-cueing paradigm. Motivated readers can email me to obtain a PDF of the article which describes this paradigm.)

People have shaped most of terrestrial nature for at least 12,000 years

From Ellis et al.L 

Significance

The current biodiversity crisis is often depicted as a struggle to preserve untouched habitats. Here, we combine global maps of human populations and land use over the past 12,000 y with current biodiversity data to show that nearly three quarters of terrestrial nature has long been shaped by diverse histories of human habitation and use by Indigenous and traditional peoples. With rare exceptions, current biodiversity losses are caused not by human conversion or degradation of untouched ecosystems, but rather by the appropriation, colonization, and intensification of use in lands inhabited and used by prior societies. Global land use history confirms that empowering the environmental stewardship of Indigenous peoples and local communities will be critical to conserving biodiversity across the planet.

Abstract

Archaeological and paleoecological evidence shows that by 10,000 BCE, all human societies employed varying degrees of ecologically transformative land use practices, including burning, hunting, species propagation, domestication, cultivation, and others that have left long-term legacies across the terrestrial biosphere. Yet, a lingering paradigm among natural scientists, conservationists, and policymakers is that human transformation of terrestrial nature is mostly recent and inherently destructive. Here, we use the most up-to-date, spatially explicit global reconstruction of historical human populations and land use to show that this paradigm is likely wrong. Even 12,000 y ago, nearly three quarters of Earth’s land was inhabited and therefore shaped by human societies, including more than 95% of temperate and 90% of tropical woodlands. Lands now characterized as “natural,” “intact,” and “wild” generally exhibit long histories of use, as do protected areas and Indigenous lands, and current global patterns of vertebrate species richness and key biodiversity areas are more strongly associated with past patterns of land use than with present ones in regional landscapes now characterized as natural. The current biodiversity crisis can seldom be explained by the loss of uninhabited wildlands, resulting instead from the appropriation, colonization, and intensifying use of the biodiverse cultural landscapes long shaped and sustained by prior societies. Recognizing this deep cultural connection with biodiversity will therefore be essential to resolve the crisis.

Motivated readers can obtain a PDF of the article by emailing me.

Excess mortality rates since 2000 in the US compared with Europe.

Interesting, from Preston and Vierboom. Just the numbers, no commentary on the causes (mainly opioid crisis?).

We use three indexes to identify how age-specific mortality rates in the United States compare to those in a composite of five large European countries since 2000. First, we examine the ratio of age-specific death rates in the United States to those in Europe. These show a sharp deterioration in the US position since 2000. Applying European age-specific death rates in 2017 to the US population, we then show that adverse mortality conditions in the United States resulted in 400,700 excess deaths that year. Finally, we show that these excess deaths entailed a loss of 13.0 My of life. In 2017, excess deaths and years of life lost in the United States represent a larger annual loss of life than that associated with the COVID-19 epidemic in 2020.

Age-specific comparisons of US and European mortality: 2000, 2010,2017. Source: HMD (12). (A) Ratio of US age-specific death rate to Europeanstandard. (B) Change in US death count if US had European age-specificdeath rates. (C) Years of life lost based on US life expectancies and US/European comparisons of age-specific death rates

Embracing diversity can disadvantage minorities

From Starck et al.:  

Significance

There are numerous reasons why institutions of higher education may choose to embrace diversity. A common rationale sanctioned by the US Supreme Court is that diversity provides compelling educational benefits and is thus instrumentally useful. We show that such instrumental rationales are the predominant rationale for diversity efforts in American higher education, are preferred by White Americans and not by Black Americans, that they are expected to advantage White Americans, and that they correspond to greater racial disparities in academic achievement. Overall, these findings suggest that the rationales behind universities’ embrace of diversity have nonlegal consequences that should be considered in institutional decision making.

Abstract

It is currently commonplace for institutions of higher education to proclaim to embrace diversity and inclusion. Though there are numerous rationales available for doing so, US Supreme Court decisions have consistently favored rationales which assert that diversity provides compelling educational benefits and is thus instrumentally useful. Our research is a quantitative/experimental effort to examine how such instrumental rationales comport with the preferences of White and Black Americans, specifically contrasting them with previously dominant moral rationales that embrace diversity as a matter of intrinsic values (e.g., justice). Furthermore, we investigate the prevalence of instrumental diversity rationales in the American higher education landscape and the degree to which they correspond with educational outcomes. Across six experiments, we showed that instrumental rationales correspond to the preferences of White (but not Black) Americans, and both parents and admissions staff expect Black students to fare worse at universities that endorse them. We coded university websites and surveyed admissions staff to determine that, nevertheless, instrumental diversity rationales are more prevalent than moral ones are and that they are indeed associated with increasing White–Black graduation disparities, particularly among universities with low levels of moral rationale use. These findings indicate that the most common rationale for supporting diversity in American higher education accords with the preferences of, and better relative outcomes for, White Americans over low-status racial minorities. The rationales behind universities’ embrace of diversity have nonlegal consequences that should be considered in institutional decision making.

Sensitivity to geometric shape: A putative signature of human singularity

From Sablé-Meyer et al.:

Among primates, humans are special in their ability to create and manipulate highly elaborate structures of language, mathematics, and music. Here we show that this sensitivity to abstract structure is already present in a much simpler domain: the visual perception of regular geometric shapes such as squares, rectangles, and parallelograms. We asked human subjects to detect an intruder shape among six quadrilaterals. Although the intruder was always defined by an identical amount of displacement of a single vertex, the results revealed a geometric regularity effect: detection was considerably easier when either the base shape or the intruder was a regular figure comprising right angles, parallelism, or symmetry rather than a more irregular shape. This effect was replicated in several tasks and in all human populations tested, including uneducated Himba adults and French kindergartners. Baboons, however, showed no such geometric regularity effect, even after extensive training. Baboon behavior was captured by convolutional neural networks (CNNs), but neither CNNs nor a variational autoencoder captured the human geometric regularity effect. However, a symbolic model, based on exact properties of Euclidean geometry, closely fitted human behavior. Our results indicate that the human propensity for symbolic abstraction permeates even elementary shape perception. They suggest a putative signature of human singularity and provide a challenge for nonsymbolic models of human shape perception.

What coffee does to body and mind

I am completely dependent on coffee, starting every morning with this stimulant and continuing small sips until a lunchtime cappuccino terminates my consumption for the day. Thus I found this article by Michael Gross on the history of caffeine consumption by humans and animals completely fascinating. I'll pass on just the first few paragraphs to whet your appetite, and let you download the complete article if you would like to continue reading on to Gross's discussion of coffee's effects on brain and mind. 

 

Johann Sebastian Bach never wrote an opera, simply because his employers had no use for one and kept him busy with other things. An intriguing glimpse at what the world missed is afforded by the secular cantata Schweigt stille, plaudert nicht (BWV 211), a half-hour mini-opera about a young woman addicted to coffee and her father trying to persuade her to quit. Bach is thought to have composed the work known as the ‘coffee cantata’ on the words of Picander in the 1730s, when he was the St Thomas Cantor at Leipzig and conducted an orchestra at the Café Zimmermann as a sideline.

It dates from a time when coffee was a new-fangled fashion craze gradually spreading across Europe. From myth-shrouded origins in the kingdom of Sheba, today’s Yemen or Ethiopia, the culture of making and drinking coffee expanded across the Arabian Peninsula and into the Ottoman Empire, reaching its capital, Istanbul, in 1554. After the Ottoman advance into Europe was stopped just outside Vienna in 1683, the victorious Austrians confiscated the coffee supplies of the fleeing Turks and used them to launch their legendary coffee-house culture, which spread across Europe. An independent early entry route was provided by Venetian traders.

From the beginnings of this spread there had been attempts by religious leaders, in both Islamic and Christian societies, to ban coffee, as they found its powerful stimulating effect suspicious. Thus, the lively conflict in Bach’s coffee cantata reflected a very real debate that must have taken place many times between lovers of the dark brew and authorities suspicious of its effects.

Ancient Greece's Army of Lovers

This post is under MindBlog's "random and curious stuff" category. A piece by Daniel Mendelsohn in The New Yorker:

Comprising a hundred and fifty male couples, Thebes’s Sacred Band was undefeated until it was wiped out in 338 B.C. In the nineteenth century, the mass grave of the men was found.

Image courtesy Hellenic Ministry of Culture and Sports, Directorate of the Management of the National Archive of Monuments, Department of the Historical Archive of Antiquities and Restorations

In June, 1818, during a visit to central Greece, a young English architect named George Ledwell Taylor went out riding with some friends in order to explore the ruins of an ancient town called Chaeronea. As Taylor’s party neared its destination, his horse took a “fearful stumble,” as he later recalled, on a stone in the roadway; on further inspection, he saw that the stone was, in fact, part of a sculpture. Energetic digging eventually revealed an animal head nearly six feet high—or, as Taylor put it, a “colossal head of the Lion.”

That definite article and the capital “L” are crucial. Taylor realized that he had uncovered a famous monument, mentioned in some historical sources but since lost, known as the Lion of Chaeronea. The Englishman had been studying a work called “The Description of Greece,” by Pausanias, a geographer of the second century A.D., which states that the gigantic figure of the sitting animal had been erected to commemorate a remarkable military unit that had perished there. The lion, Pausa­nias surmised, represented “the spirit of the men.”

The unit to which those men belonged was known as the Sacred Band. Comprising three hundred warriors from the city of Thebes, it was among the most fearsome fighting forces in Greece, undefeated until it was wiped out at the Battle of Chaeronea, in 338 B.C.—an engagement during which Philip of Macedon and his son, the ­future Alexander the Great, crushed a coalition of Greek city-states led by Athens and Thebes. Scholars see Chaeronea as the death knell of the Classi­cal Era of Greek history.

Others might find the story interesting for different reasons. Not the least of these is that the Band was composed entirely of lovers: precisely a hundred and fifty couples, whose valor, so the Greeks thought, was due to the fact that no man would ever exhibit cowardice or act dishonorably in front of his beloved. In Plato’s Symposium, a dialogue about love, a character remarks that an army made up of such lovers would “conquer all mankind.”

Sixty years after George Taylor’s horse stumbled, further excavations revealed a large rectangular burial site near the Lion. Drawings that were made at the site show seven rows of skeletons, two hundred and fifty-four in all. For “The Sacred Band” (Scribner), a forthcoming book by the classicist James Romm, the illustrator Markley Boyer collated those nineteenth-century drawings to produce a reconstruction of the entire mass grave. Black marks indicate wounds. A number of warriors were buried with arms linked; if you look closely, you can see that some were holding hands. ♦

Gamma-frequency oscillations link different brain regions during learning.

Fernández-Ruiz et al. demonstrate that specific, projected gamma-frequency oscillation patterns dynamically engage functionally related cell assemblies across brain regions in a task-specific manner. I pass along their entire structured abstract:  

INTRODUCTION

Learning induces a dynamic reorganization of brain circuits but the neuronal mechanisms underlying this process are not well understood. Interregional gamma-frequency oscillations (~30 to 150 Hz) have been postulated as a mechanism to precisely coordinate upstream and downstream neuronal ensembles, for example, in the hippocampal system. The lateral (LEC) and medial (MEC) entorhinal cortex receive inputs from two distinct streams of cortical hierarchy (the “what” and the “where” pathways) and convey these neuronal messages to the hippocampus. However, the mechanisms by which such messages are packaged and integrated or segregated by hippocampal circuits had yet to be explored.

RATIONALE

Neuronal assemblies firing within gamma time frames in an upstream region can most effectively discharge their downstream partners. This gamma-time-scale organization appears essential for physiological functions because manipulations that impair precision timing of spikes in the hippocampus often affect behavior. However, direct support for distinct gamma-frequency communication in appropriate behavioral situations is missing. To bring physiological operations closer to behavior, we designed “spatial” and “object” learning tasks and examined the selective engagement of gamma-frequency communication between the MEC and LEC inputs and their target neuronal assemblies in the hippocampal dentate gyrus. We combined these correlational observations with optogenetic perturbation of gamma oscillations in LEC and MEC, respectively, to test their roles in pathway-specific neuronal communication and learning.

RESULTS

During spatial learning, fast gamma (100 to 150 Hz) oscillations synchronized MEC and dentate gyrus and entrained predominantly granule cells. During object learning, slow gamma (30 to 50 Hz) oscillations synchronized LEC and dentate gyrus and preferentially recruited mossy cells and CA3 pyramidal neurons, suggesting task-specific routing of MEC and LEC messages in the form of gamma-cycle-spike packets of selected cell types. The low- and high-frequency gamma sub-bands were dominant in the outer and middle third of the dentate molecular layer, respectively, and their amplitude maxima were locked to different phases of theta oscillations.

Gamma frequency optogenenetic perturbation of MEC and LEC led to learning impairments in a spatial and object learning task, respectively. In the same animals, the dentate layer–specific low- and high-frequency gamma sub-bands and spike-gamma LFP coupling were selectively reduced, coupled with deterioration of spatial and object-related firing of dentate neurons.

CONCLUSION

These findings demonstrate that distinct gamma-frequency-specific communication between MEC and LEC and hippocampal cell assemblies are critical for routing task-relevant information, and our selective gamma-band perturbation experiments suggest that they support specific aspects of learning. We hypothesize that sending neuronal messages by segregated gamma-frequency carriers allows a target “reader” area to disambiguate convergent inputs. In general, these results demonstrate that specific projected gamma patterns dynamically engage functionally related cell assemblies across brain regions in a task-specific manner.

Vision: What’s so special about words?

Readers are sensitive to the statistics of written language. New work by Vidal et al. suggests that this sensitivity may be driven by the same domain-general mechanisms that enable the visual system to detect statistical regularities in the visual environment. 

Highlights

• Readers presented with orthographic-like stimuli are sensitive to bigram frequencies 

• An analogous effect emerges with images of made-up objects and visual gratings 

• These data suggest that the reading system might rely on general-purpose mechanisms 

• This calls for considering reading in the broader context of visual neuroscience

Summary

As writing systems are a relatively novel invention (slightly over 5 kya), they could not have influenced the evolution of our species. Instead, reading might recycle evolutionary older mechanisms that originally supported other tasks and preceded the emergence of written language. Accordingly, it has been shown that baboons and pigeons can be trained to distinguish words from nonwords based on orthographic regularities in letter co-occurrence. This suggests that part of what is usually considered reading-specific processing could be performed by domain-general visual mechanisms. Here, we tested this hypothesis in humans: if the reading system relies on domain-general visual mechanisms, some of the effects that are often found with orthographic material should also be observable with non-orthographic visual stimuli. We performed three experiments using the same exact design but with visual stimuli that progressively departed from orthographic material. Subjects were passively familiarized with a set of composite visual items and tested in an oddball paradigm for their ability to detect novel stimuli. Participants showed robust sensitivity to the co-occurrence of features (“bigram” coding) with strings of letter-like symbols but also with made-up 3D objects and sinusoidal gratings. This suggests that the processing mechanisms involved in the visual recognition of novel words also support the recognition of other novel visual objects. These mechanisms would allow the visual system to capture statistical regularities in the visual environment. We hope that this work will inspire models of reading that, although addressing its unique aspects, place it within the broader context of vision.