The tabula sapiens consortium - mapping cell types in the human body

It is hard to keep up with the mind boggling advances that pop up in almost every issue of Science Magazine. In a perspective article Liu and Zhang describe the findings of the “Tabula Sapiens Consortium” that has now provided a molecular reference atlas for more than 400 cell types of the human body by measuring the messenger RNA molecules in each of nearly 500,000 cells from 24 tissues and organs. Multiple laboratories used single-cell transcriptomics to measure the messenger RNA molecules in each of nearly 500,000 cells from 24 tissues and organs Here is a single clip summary clip from Liu and Zhang:

...the Tabula Sapiens Consortium discovered that endothelial cells from lung, heart, uterus, liver, pancreas, fat, and muscle exhibit the most distinct transcriptional signatures, suggesting highly specialized functions, whereas endothelial cells from the thymus, vasculature, prostate, and eye resemble one another. The pan-tissue approach led to the discovery of SLC14A1 (solute carrier family 14 member 1) as a marker for heart endothelial cells, likely reflecting specialized metabolism in cardiac blood vessels. Eraslan et al. also found rare cell types, such as neuroendocrine cells in the prostate and enteric neurons in the esophagus. Additionally, the corroborative use of both high-throughput 10X and full-length SMART-seq2 single-cell transcriptome data allowed the quantification of splicing isoform usage at the single-cell level, thereby revealing differential exon usage patterns for genes, including MYL6 (myosin light chain 6) and CD47, in different cell-type compartments.

Increases and decreases in affective polarization over the past 40 years in advanced democracies

An interesting study from Boxell et al. shows that across 12 advanced democracies, affective polarization, the degree to which people feel more negatively toward other political parties than toward their own, has increased the most since the 1980s in the United States and to a lesser extent in Canada, Denmark, France, New Zealand, and Switzerland, and has decreased in Australia, Britain, (West) Germany, Japan, Norway, and Sweden. The authors derived theses conclusions from harmonizing results from 149 surveys and assembled data on economic, media, demographic, and political trends. Trends in the nonwhite share of the population and in the polarization of political elites were most strongly associated with trends in polarization of the general public.

Graziano's conceptual framework for consciousness

I would like to pass on this link to Graziano's latest (open source) explication of his theory of consciousness, continuing a MindBlog thread that started with a 2014 post on his 2013 book "Consciousness and the Social Brain." Here is his abstact:

This article argues that consciousness has a logically sound, explanatory framework, different from typical accounts that suffer from hidden mysticism. The article has three main parts. The first describes background principles concerning information processing in the brain, from which one can deduce a general, rational framework for explaining consciousness. The second part describes a specific theory that embodies those background principles, the Attention Schema Theory. In the past several years, a growing body of experimental evidence—behavioral evidence, brain imaging evidence, and computational modeling—has addressed aspects of the theory. The final part discusses the evolution of consciousness. By emphasizing the specific role of consciousness in cognition and behavior, the present approach leads to a proposed account of how consciousness may have evolved over millions of years, from fish to humans. The goal of this article is to present a comprehensive, overarching framework in which we can understand scientifically what consciousness is and what key adaptive roles it plays in brain function.

The article is worth a read, and here is Graziano's bottom line, from the last paragraph of his article:

If you start your search for consciousness by assuming the existence of a subjective feeling—a private component that cannot be measured and can only be felt and attested to, experienceness itself—then you are assuming the literal accuracy of an internal model. By principle 1, your conviction that you have consciousness depends on an information set in your brain. By principle 2, the brain’s models are never accurate. You have accepted the literal truth of a caricature, and you will never find the answer to your ill-posed question. When the police draw a sketch of a suspect, and you set yourself the task of finding a flat man made of graphite, you will fail. Yet at the same time, if you take the opposite approach and insist that the sketch is an empty illusion, you are missing the point. Instead, understand the sketch for what it is: a schematic representation of something real. We can explain physical processes in the brain; we can explain the models constructed by the brain to represent those physical processes; we can explain the way those models depict reality in a schematic, imperfect manner; we can explain the cognitive beliefs that stem from those imperfect models; and most importantly, we can explain the adaptive, cognitive benefits served by those models. AST is not just a theory of consciousness. It is a theory of adaptive mechanisms in the brain.

The prosocial effect of touching - the Midas touch effect.

Schaefer et al. (open source) examine the neural underpinnings of how light touching enhances prosocial behavior. Their abstract:

Giving and receiving touch are some of the most important social stimuli we exchange in daily life. By touching someone, we can communicate various types of information. Previous studies have also demonstrated that interpersonal touch may affect our altruistic behavior. A classic study showed that customers give bigger tips when they are lightly touched by a waitress, which has been called the Midas touch effect. Numerous studies reported similar effects of touch on different kinds of helping or prosocial behaviors. Here, we aim to examine the neural underpinnings of this effect by employing a functional magnetic resonance imaging approach. While lying in the scanner, participants played different rounds of the dictator game, a measure of prosocial behavior. Before each round, participants were touched (or not touched in the control condition) by an experimenter. We found that touching the hand increased the likeliness to behave prosocial (but not the general liking of control stimuli), thereby confirming the Midas touch effect. The effect was predicted by activity in the primary somatosensory cortex, indicating that the somatosensory cortex here plays a causal role in prosocial behavior. We conclude that the tactile modality in social life may be much more important than previously thought.

Questioning common claims about human brain evolution

From DeCasien et al.:

Highlights

New research has questioned or contradicted multiple long-standing claims about human brain evolution.

Contrary to the social brain hypothesis, new work suggests that ecological factors, rather than social complexity, best predict relative brain size across primate species.

Brain size does not have similar effects or cognitive implications in different phylogenetic lineages since it is associated with different mosaic structural changes.

Although the human prefrontal cortex is proportionally large, this may not represent an adaptive specialization and research emphasis on this region has distracted attention from the importance of wider neural networks.

Functional and anatomical integration, rather than developmental constraints, may primarily explain patterns of brain region size covariation across species.

Abstract

Human brains are exceptionally large, support distinctive cognitive processes, and evolved by natural selection to mediate adaptive behavior. Comparative biology situates the human brain within an evolutionary context to illuminate how it has been shaped by selection and how its structure relates to evolutionary function, while identifying the developmental and molecular changes that were involved. Recent applications of powerful phylogenetic methods have uncovered new findings, some of which overturn conventional wisdom about how and why brains evolve. Here, we focus on four long-standing claims about brain evolution and discuss how new work has either contradicted these claims or shown the relevant phenomena to be more complicated than previously appreciated. Throughout, we emphasize studies of non-human primates and hominins, our close relatives and recent ancestors.

The authors dispute the following common claims about human brain evolution: (Motivated readers can obtain the whole text with their detailed arguments from me.)

Claim 1. Social complexity is the primary driver of non-human primate and human brain evolution

Claim 2. Brain size has similar effects and cognitive implications across a wide range of species

Claim 3. The proportionally large human PFC reflects selection on PFC-specific functions

Claim 4. Developmental constraints play a major role in the evolution of brain structure

Older adults store too much information.

From Amer et al.:  

Highlights

Healthy aging is accompanied by declines in control of attention.

These reductions in the control of attention, result in older adults processing too much information, creating cluttered memory representations.

Cluttered representations can impair memory by interfering with the retrieval of target information, but can also provide an advantage on tasks that benefit from extensive knowledge.

Abstract

Declines in episodic memory in older adults are typically attributed to differences in encoding strategies and/or retrieval processes. These views omit a critical factor in age-related memory differences: the nature of the representations that are formed. Here, we review evidence that older adults create more cluttered (or richer) representations of events than do younger adults. These cluttered representations might include target information along with recently activated but no-longer-relevant information, prior knowledge cued by the ongoing situation, as well as irrelevant information in the current environment. Although these representations can interfere with the retrieval of target information, they can also support other memory-dependent cognitive functions.

The human fear paradox: Affective origins of cooperative care

On the same morning last week that I read a NYTimes essay by Thomas Edsall "The Politics of Fear Show No Sign of Abating" I received an email from the journal Behavioral and Brain Science soliciting reviews on an upcoming article by Tobias Grossmann with an interesting hypothesis on why we humans are so fearful: "The human fear paradox: Affective origins of cooperative care." His 'fearful ape hypothesis' proposes that, in the context of the strong interdependence reflected in cooperative caregiving and provisioning unique to human great ape group life, heightened fearfulness was adaptive. Here I pass on the abstract of Grossmann's piece, and motivated readers can obtain the whole text from me.

Already as infants humans are more fearful than our closest living primate relatives, the chimpanzees. Yet heightened fearfulness is mostly considered maladaptive, as it is thought to increase the risk of developing anxiety and depression. How can this human fear paradox be explained? The fearful ape hypothesis presented herein stipulates that, in the context of cooperative caregiving and provisioning unique to human great ape group life, heightened fearfulness was adaptive. This is because from early in ontogeny fearfulness expressed and perceived enhanced care-based responding and provisioning from, while concurrently increasing cooperation with, mothers and others. This explanation is based on a synthesis of existing research with human infants and children, demonstrating a link between fearfulness, greater sensitivity to and accuracy in detecting fear in others, and enhanced levels of cooperative behaviors. These insights critically advance current evolutionary theories of human cooperation by adding an early-developing affective component to the human cooperative makeup. Moreover, the current proposal has important cultural, societal and health implications, as it challenges the predominant view in WEIRD societies that commonly construe fearfulness as a maladaptive trait, potentially ignoring its evolutionary adaptive functions.

The cultural evolution of love in literary history

An interesting article from Baumard et al. in Nature Human Behaviour:

Since the late nineteenth century, cultural historians have noted that the importance of love increased during the Medieval and Early Modern European period (a phenomenon that was once referred to as the emergence of ‘courtly love’). However, more recent works have shown a similar increase in Chinese, Arabic, Persian, Indian and Japanese cultures. Why such a convergent evolution in very different cultures? Using qualitative and quantitative approaches, we leverage literary history and build a database of ancient literary fiction for 19 geographical areas and 77 historical periods covering 3,800 years, from the Middle Bronze Age to the Early Modern period. We first confirm that romantic elements have increased in Eurasian literary fiction over the past millennium, and that similar increases also occurred earlier, in Ancient Greece, Rome and Classical India. We then explore the ecological determinants of this increase. Consistent with hypotheses from cultural history and behavioural ecology, we show that a higher level of economic development is strongly associated with a greater incidence of love in narrative fiction (our proxy for the importance of love in a culture). To further test the causal role of economic development, we used a difference-in-difference method that exploits exogenous regional variations in economic development resulting from the adoption of the heavy plough in medieval Europe. Finally, we used probabilistic generative models to reconstruct the latent evolution of love and to assess the respective role of cultural diffusion and economic development.

Are we seeing the beginning of World War III?

Below, I am passing on some links to background reading for this Sunday's Austin Rainbow Forum (email forumaustin@gmail.com for information), whose discussion topic is "The War in Ukraine: Start of World War III?." 

David Brooks - Globalization Is Over. The Global Culture Wars Have Begun

Thomas Friedman - Putin Had No Clue How Many of Us Would Be Watching 

Yuval Harari - What’s at stake in Ukraine is the direction of human history 

Fareed Zakaria - Russia is the last multinational empire, fighting to keep its colonies  

Ezra Klein - The Enemies of Liberalism Are Showing Us What It Really Means  

 

Insight from Jonathan Haidt - "After Babel"

This article by Jonathan Haidt in the May 2022 print edition of The Atlantic is a long, frightening, and rewarding read. It lays out the mechanisms by which social media have catalyzed civil society's world wide disintegration over the past 10 years. I will not presume to do my usual extracting of summary chunks apart from passing on the first few paragraphs to whet your appetite:

The story of Babel is the best metaphor I have found for what happened to America in the 2010s, and for the fractured country we now inhabit. Something went terribly wrong, very suddenly. We are disoriented, unable to speak the same language or recognize the same truth. We are cut off from one another and from the past.

It’s been clear for quite a while now that red America and blue America are becoming like two different countries claiming the same territory, with two different versions of the Constitution, economics, and American history. But Babel is not a story about tribalism; it’s a story about the fragmentation of everything. It’s about the shattering of all that had seemed solid, the scattering of people who had been a community. It’s a metaphor for what is happening not only between red and blue, but within the left and within the right, as well as within universities, companies, professional associations, museums, and even families.

Babel is a metaphor for what some forms of social media have done to nearly all of the groups and institutions most important to the country’s future—and to us as a people. How did this happen? And what does it portend for American life?

How the gut talks to the brain.

Gabanyi et al. show that bacterial cell wall molecules that travel to the brain could trigger a host of behaviors. Here is the abstract of a Perspectives essay on this work by Adamantidis:

The mammalian gastrointestinal tract hosts a community of diverse micro-organisms, including bacteria, archea, fungi, and viruses. Bacterial products, such as metabolites and cell wall fragments, are implicated in host metabolic functions. In addition, the gut microbiota influences the immune and central nervous systems, and it has emerged as a key regulator of brain development and the modulation of behaviors, including stress and anxiety, often in a sex-specific manner. Disruption of gut microbiota–brain interactions contribute to the pathogenesis of neurodevelopmental and psychiatric disorders in animal models. ...Gabanyi et al. show that bacterial peptidoglycans, a by-product of bacterial cell wall degradation during cell division and cell death, directly inhibit the activity of feeding-promoting neurons in the hypothalamus and ultimately decrease appetite and body temperature, mostly in female mice. This finding may open new approaches for the treatment of metabolic disorders, including obesity.

A magisterial summary of the new world disorder by David Brooks

A few clips that attempt to summarize a David Brooks essay that does a beautiful job of putting all the pieces together:

I can remember a time — about a quarter-century ago — when the world seemed to be coming together. The great Cold War contest between communism and capitalism appeared to be over. Democracy was still spreading. Nations were becoming more economically interdependent. The internet seemed ready to foster worldwide communications. It seemed as if there would be a global convergence around a set of universal values — freedom, equality, personal dignity, pluralism, human rights...it was sometimes assumed that nations all around the world would admire the success of the Western democracies and seek to imitate us...They’d be more driven by the desire to settle down into suburban homes than by the fanatical ideologies or the sort of hunger for prestige and conquest that had doomed humanity to centuries of war.

...this vision does not describe the world we live in today. The world is not converging anymore; it’s diverging...The 2008 financial crisis delegitimized global capitalism for many people...Global flows of long-term investment fell by half between 2016 and 2019...All manner of antiglobalization movements have arisen: those of the Brexiteers, xenophobic nationalists, Trumpian populists, the antiglobalist left...The world economy seems to be gradually decoupling into, for starters, a Western zone and a Chinese zone. Foreign direct investment flows between China and America were nearly $30 billion per year five years ago. Now they are down to $5 billion...Economic rivalries have now merged with political, moral and other rivalries into one global contest for dominance. Globalization has been replaced by something that looks a lot like global culture war.

The fact is that human behavior is often driven by forces much deeper than economic and political self-interest, at least as Western rationalists typically understand these things...First, human beings are powerfully driven by what are known as the thymotic desires. These are the needs to be seen, respected, appreciated. If you give people the impression that they are unseen, disrespected and unappreciated, they will become enraged, resentful and vengeful. They will perceive diminishment as injustice and respond with aggressive indignation...Global politics over the past few decades functioned as a massive social inequality machine. In country after country, groups of highly educated urban elites have arisen to dominate media, universities, culture and often political power. Great swaths of people feel looked down upon and ignored.

Second, most people have a strong loyalty to their place and to their nation. But over the past few decades many people have felt that their places have been left behind and that their national honor has been threatened. In the heyday of globalization, multilateral organizations and global corporations seemed to be eclipsing nation-states...In country after country, highly nationalistic movements have arisen to insist on national sovereignty and to restore national pride: Modi in India, Recep Tayyip Erdogan in Turkey, Trump in the United States, Boris Johnson in Britain.

Third, people are driven by moral longings — by their attachment to their own cultural values, by their desire to fiercely defend their values when they seem to be under assault. For the past few decades, globalization has seemed to many people to be exactly this kind of assault...The problem is that Western values are not the world’s values. In fact, we in the West are complete cultural outliers. In his book “The WEIRDest People in the World,” Joseph Henrich amasses hundreds of pages of data to show just how unusual Western, Educated, Industrialized, Rich and Democratic values are...Many people around the world look at our ideas about gender roles and find them foreign or repellent...The idea that it’s up to each person to choose one’s own identity and values — that seems ridiculous to many. The idea that the purpose of education is to inculcate critical thinking skills so students can liberate themselves from the ideas they received from their parents and communities — that seems foolish to many.

Finally, people are powerfully driven by a desire for order. Nothing is worse than chaos and anarchy...Today, many democracies appear less stable than they did and many authoritarian regimes appear more stable. American democracy, for example, has slid toward polarization and dysfunction. Meanwhile, China has shown that highly centralized nations can be just as technologically advanced as the West. Modern authoritarian nations now have technologies that allow them to exercise pervasive control of their citizens in ways that were unimaginable decades ago...Autocratic regimes are now serious economic rivals to the West. They account for 60 percent of patent applications. In 2020, the governments and businesses in these countries invested $9 trillion in things like machinery, equipment and infrastructure, while democratic nations invested $12 trillion. If things are going well, authoritarian governments can enjoy surprising popular support.

...something bigger is happening today that is different from the great power struggles of the past, that is different from the Cold War. This is not just a political or an economic conflict. It’s a conflict about politics, economics, culture, status, psychology, morality and religion all at once. More specifically, it’s a rejection of Western ways of doing things by hundreds of millions of people along a wide array of fronts...To define this conflict most generously, I’d say it’s the difference between the West’s emphasis on personal dignity and much of the rest of the world’s emphasis on communal cohesion. But that’s not all that’s going on here. What’s important is the way these longstanding and normal cultural differences are being whipped up by autocrats who want to expand their power and sow chaos in the democratic world. Authoritarian rulers now routinely weaponize cultural differences, religious tensions and status resentments to mobilize supporters, attract allies and expand their own power. This is cultural difference transmogrified by status resentment into culture war.

...rejection of Western liberalism, individualism, pluralism, gender equality and all the rest is not only happening between nations but also within nations. The status resentment against Western cultural, economic and political elites that flows from the mouths of illiberal leaders like Putin and Modi and Jair Bolsonaro of Brazil sounds quite a lot like the status resentment that flows from the mouths of the Trumpian right, from the French right, from the Italian and Hungarian right...How do you win a global culture war in which differing views on secularism and gay rights parades are intertwined with nuclear weapons, global trade flows, status resentments, toxic masculinity and authoritarian power grabs?

The critiques that so many people are making about the West, and about American culture — for being too individualistic, too materialistic, too condescending — these critiques are not wrong. We have a lot of work to do if we are going to be socially strong enough to stand up to the challenges that are coming over the next several years, if we are going to persuade people in all those swing countries across Africa, Latin America and the rest of the world that they should throw their lot in with the democracies and not with the authoritarians — that our way of life is the better way of life.

At the end of the day, only democracy and liberalism are based on respect for the dignity of each person. At the end of the day, only these systems and our worldviews offer the highest fulfillment for the drives and desires I’ve tried to describe here...I have faith in the ideas and the moral systems that we have inherited. What we call “the West” is not an ethnic designation or an elitist country club. The heroes of Ukraine are showing that at its best, it is a moral accomplishment, and unlike its rivals, it aspires to extend dignity, human rights and self-determination to all. That’s worth reforming and working on and defending and sharing in the decades ahead.

The Dance of Sleep

Sleep and wakefulness are characterized by unique intrinsic activity patterns and are usually thought to be two distinct global states, with the preoptic area of the hypothalamus being the regulator of brain state changes. Yamagata et al. find that this area also affects within-state changes of sleep and wake intensity.  

Significance

Our current understanding of how sleep is regulated is based upon the model of sleep homeostasis, which defines a variable called Process S as a measure of sleep need, and a so-called “flip-flop” model of state switching, which builds on a notion of a mutually antagonistic relationship between subcortical sleep-promoting and wake-promoting circuits. The neurobiological substrates of the interaction between the sleep switch and Process S are unknown. Our study identifies a previously unrecognized role of hypothalamic circuitry in tuning within-state brain activity or levels of arousal, which in turn determine the homeostatic drive for sleep.

Abstract

Sleep and wakefulness are not simple, homogenous all-or-none states but represent a spectrum of substates, distinguished by behavior, levels of arousal, and brain activity at the local and global levels. Until now, the role of the hypothalamic circuitry in sleep–wake control was studied primarily with respect to its contribution to rapid state transitions. In contrast, whether the hypothalamus modulates within-state dynamics (state “quality”) and the functional significance thereof remains unexplored. Here, we show that photoactivation of inhibitory neurons in the lateral preoptic area (LPO) of the hypothalamus of adult male and female laboratory mice does not merely trigger awakening from sleep, but the resulting awake state is also characterized by an activated electroencephalogram (EEG) pattern, suggesting increased levels of arousal. This was associated with a faster build-up of sleep pressure, as reflected in higher EEG slow-wave activity (SWA) during subsequent sleep. In contrast, photoinhibition of inhibitory LPO neurons did not result in changes in vigilance states but was associated with persistently increased EEG SWA during spontaneous sleep. These findings suggest a role of the LPO in regulating arousal levels, which we propose as a key variable shaping the daily architecture of sleep–wake states.

The road to our larger brains

Bertrand et al. address the question of how and why mammals evolved large brain sizes relative to their body mass by characterizing the timing and pattern of mammal brain development across the Early Jurassic to the middle Cenozoic (∼200 million to 30 million years ago) when the ecological niches vacated by the extinction of large reptiles were being filled by large mammals. Here is their abstract:

Mammals are the most encephalized vertebrates, with the largest brains relative to body size. Placental mammals have particularly enlarged brains, with expanded neocortices for sensory integration, the origins of which are unclear. We used computed tomography scans of newly discovered Paleocene fossils to show that contrary to the convention that mammal brains have steadily enlarged over time, early placentals initially decreased their relative brain sizes because body mass increased at a faster rate. Later in the Eocene, multiple crown lineages independently acquired highly encephalized brains through marked growth in sensory regions. We argue that the placental radiation initially emphasized increases in body size as extinction survivors filled vacant niches. Brains eventually became larger as ecosystems saturated and competition intensified.

Humans don’t have culture because we’re smart, we’re smart because we have culture.

The title of this post is a sentence taken from the final paragraph of Henrich's Perspective article in Science on the work of Thompson et al. which notes that Thompson et al.'s results

...highlight a deeper point: Humans don’t have culture because we’re smart, we’re smart because we have culture. The selective processes of cultural evolution not only generate more sophisticated practices and technologies but also produce new cognitive tools—algorithms—that make humans better adapted to the ecological and institutional challenges that we confront. Thompson et al.’s results underline the need for the psychological sciences to abandon their implicit reliance on a digital computer metaphor of the mind (hardware versus software) and transform into a historical science that considers not just how cultural evolution shapes what we think (our mental contents) but also how we think [our cognitive processes].

Here I pass on the introductory paragraphs and then the abstract of the Thompson et al. article. Motivated readers can obtain the full text by emailing me.

Reading, counting, cooking, and sailing are just some of the human abilities passed from generation to generation through social learning... Complex abilities like these often depend on learned cognitive algorithms: procedural representations of a problem that coordinate memory, attention, and perception into sequences of useful computations and actions. Accumulation of complex algorithms—from ancient tool-making techniques to bread making, boat building, or horticulture—is central to human adaptation yet challenging to explain because algorithmic concepts can be difficult to discover, communicate, and learn from observation, making them vulnerable to loss. Theories of cultural evolution suggest that human social learning may help overcome this fragility. For example, mathematical models predict that choosing to learn from successful or prestigious individuals can prevent the loss of rare innovations. However, this potential link between sociality and complex abilities is challenging to establish.

We conducted large-scale simulations of cultural evolution with human participants to assess how selective social learning influenced the evolution of cognitive algorithms. Prior research shows that social learning can improve decisions in multiple-choice tasks, perceptual judgments, and search problems and can improve artifacts such as physical structures or computer programs. However, the evolution of cognitive algorithms at the population level has been difficult to study. We developed custom software to recruit large numbers of participants online and organize them into evolving societies facing a common problem. Twenty populations tackled a sequential decision problem... Presented with six images, participants attempted to establish hidden arbitrary orderings using pairwise comparisons. Out-of-order pairs swapped positions when compared. Participants were rewarded for establishing the ordering using fewer comparisons. This task poses a sorting problem, requiring a strategy for executing appropriate sequences of actions, analogous to culturally evolved strategies for making tools or food.

Abstract:

Many human abilities rely on cognitive algorithms discovered by previous generations. Cultural accumulation of innovative algorithms is hard to explain because complex concepts are difficult to pass on. We found that selective social learning preserved rare discoveries of exceptional algorithms in a large experimental simulation of cultural evolution. Participants (N = 3450) faced a difficult sequential decision problem (sorting an unknown sequence of numbers) and transmitted solutions across 12 generations in 20 populations. Several known sorting algorithms were discovered. Complex algorithms persisted when participants could choose who to learn from but frequently became extinct in populations lacking this selection process, converging on highly transmissible lower-performance algorithms. These results provide experimental evidence for hypothesized links between sociality and cognitive function in humans.

The Science of Consciousness - Tucson 2022

For junkies of consciousness and altered states thereof, as in anesthesia or psychedelic-induced states, a browsing of the abstracts submitted for The Science of Consciousness 2022 in Tucson April 18-22 makes for stimulating reading (though I found pauses to recover from input overload to be necessary.) I attended the first “Towards a Science of Consciousness” - now known as TSC “The Science of Consciousness” - in 1994, as well as a number of subsequent meetings, and it was encouragement from several then luminaries in the field that emboldened me to turn the lecture notes from my “Biology of Mind” course at the University of Wisconsin into a book of that title which was published in 1999. There are numerous bon-bons to be found in this year's set of abstracts, one example from many being Huang’s noting of his work on how the anterior insula, situated between unimodal and transmodal cortical areas along the brain’s primary functional gradient, regulates the default mode – dorsal attention network transitions, and gates conscious access of sensory information.

Magic mind therapy….. Moving your body.

Gretchen Reynolds interviews Jennifer Heisz about the contents of her new book "Move the Body, Heal the Mind," which details the latest science about exercise and mental health, especially its potential to reduce anxiety and stress. The brief reprieve from anxiety than can sometimes be experienced after a workout is due to the release of neuropeptide Y, known to dampen hyperactivity of the anxious amygdala. Exercise also can reduce stress-induced body inflammation that damages cells and affects mood. These effects require only about a quarter of the normally recommended 150 minutes of moderate to vigorous exercise a week, so the exercise prescription for mental health seems to be less than that for physical health.

Losing sleep with age.

Jacobson and Hoyer summarize experiments of Li et al.:

Humans spend approximately one-third of their lives asleep, but this is not distributed equally across their life span. Sleep quantity and quality decline as age advances, and insomnia and sleep fractionation are common in older people. Sleep is essential for vitality and health. At any age, chronic sleep deprivation causes a range of issues, including disrupted cognition and memory. Correspondingly, sleep complaints in older people are associated with increased risks of impaired physical and mental health and with mortality. Beyond evidence of degenerating subcortical nuclei in age-associated sleep disturbances, the underlying mechanisms remain unclear despite decades of awareness of the problem and its consequences...Li et al.report the hyperexcitability of hypocretin neurons as a core mechanism underlying sleep disruption in aged mice, explaining why sleep is punctuated by intruding wakefulness despite the loss of wake-promoting neurons.

A few clips from the Li et al. article: 

RATIONALE

We hypothesized that the decline in sleep quality could be due to malfunction of the neural circuits associated with sleep/wake control. It has been established that hypocretin/orexin (Hcrt/OX) neuronal activity is tightly associated with wakefulness and initiates and maintains the wake state. In this study, we investigated whether the intrinsic excitability of Hcrt neurons is altered, leading to a destabilized control of sleep/wake states during aging.

RESULTS

Aged mice exhibited sleep fragmentation and a significant loss of Hcrt neurons. Hcrt neurons manifested a more frequent firing pattern, driving wake bouts and disrupting sleep continuity in aged mice. Aged Hcrt neurons were capable of eliciting more prolonged wake bouts upon optogenetic stimulations. These results suggested that hyperexcitability of Hcrt neurons emerges with age. Patch clamp recording in genetically identified Hcrt neurons revealed distinct intrinsic properties between the young and aged groups. Aged Hcrt neurons were hyperexcitable with depolarized membrane potentials (RMPs) and a smaller difference between RMP and the firing threshold.

CONCLUSION

Aged mice exhibited sleep fragmentation and a significant loss of Hcrt neurons. Hcrt neurons manifested a more frequent firing pattern, driving wake bouts and disrupting sleep continuity in aged mice. Aged Hcrt neurons were capable of eliciting more prolonged wake bouts upon optogenetic stimulations. These results suggested that hyperexcitability of Hcrt neurons emerges with age. Patch clamp recording in genetically identified Hcrt neurons revealed distinct intrinsic properties between the young and aged groups. Aged Hcrt neurons were hyperexcitable with depolarized membrane potentials (RMPs) and a smaller difference between RMP and the firing threshold.

Re-energizing the aged brain

Alderton does a brief summary of work by Brakedal et al.:

Nicotinamide adenine dinucleotide (NAD) is an important cofactor in numerous metabolic reactions. NAD concentrations decline with age, which may contribute to age-associated conditions such as Parkinson’s disease. Preclinical studies show that replenishing NAD by supplementation with nicotinamide riboside (NR), a biosynthetic precursor to NAD, can promote health span and neuroprotection. Brakedal et al. performed a randomized, double-blind phase 1 clinical trial of NR supplementation in 30 patients newly diagnosed with Parkinson’s disease. They found that NR supplementation was safe and that concentrations of NAD in the brain increased in most patients receiving NR. These patients had signs of altered cerebral metabolism and mild clinical improvement, although further testing is needed with a larger cohort to confirm any clinical benefit.

Added note: I realized I had bought a jar of nicotinamide riboside some time ago ("TRU - Niagen" at an outrageious price), decided not to take it after reading about possible side effects, but relented after reading the Brakedal et al. article. I've been taking a 150 mg capsule daily for the past 10 days, half the recommended dosage. I haven't detected any noticable effects on my general energy levels.

Abnormal hemispheric interactions of Autism Spectrum Disorder present in 1st year of life.

From Rolison et al.:

Autism spectrum disorder (ASD) is characterized by atypical connectivity lateralization of functional networks. However, previous studies have not directly investigated if differences in specialization between ASD and typically developing (TD) peers are present in infancy, leaving the timing of onset of these differences relatively unknown. We studied the hemispheric asymmetries of connectivity in children with ASD and infants later meeting the diagnostic criteria for ASD. Analyses were performed in 733 children with ASD and TD peers and in 71 infants at high risk (HR) or normal risk (NR) for ASD, with data collected at 1 month and 9 months of age. Comparing children with ASD (n = 301) to TDs (n = 432), four regions demonstrated group differences in connectivity: posterior cingulate cortex (PCC), posterior superior temporal gyrus, extrastriate cortex, and anterior prefrontal cortex. At 1 month, none of these regions exhibited group differences between ASD (n = 10), HR-nonASD (n = 15), or NR (n = 18) infants. However, by 9 months, the PCC and extrastriate exhibited atypical connectivity in ASD (n = 11) and HR-nonASD infants (n = 24) compared to NR infants (n = 22). Connectivity did not correlate with symptoms in either sample. Our results demonstrate that differences in network asymmetries associated with ASD risk are observable prior to the age of a reliable clinical diagnosis.

Trust is needed to run the world, and crypto can make trusting easier

I want to pass on a few clips from a recent screed by Mark Manson in his usual explitive-rich style. I regret that he doesn't make clear the central point that it is the blockchain concept underlying various cryptocurrencies that is responsible for generating trustworthy transactions, without requiring the intervention of third parties like banks, inspectors, and regulators to certify trustworthiness. Here are my clips and pastings:

The problem is that trust-building institutions are human. And humans are, uh, not really trustworthy....there are millions of people in the world whose entire jobs are to verify trustworthiness. Insurance companies, banks, legal firms, universities, regulatory agencies, and government programs have massive office buildings full of nothing but people doing this trustworthy verification thing, all day every day... because we have not other better way to do it...and the process is corruptible because it is human.

The way Uber automated away taxi drivers, crypto will automate away millions of these trust verifiers...you can shake your fist and make please about job security and income inequality or whatever, but at the end of the day...we will all love it and use it for the same reason we love and use Uber...because it makes our lives a hundred times easier...dealing with human-led institution to constantly verify trust is a never-ending nightmare...submissionsw of hundreds of pages of paperwork...All it takes is one pissed off guy at the DMV to literally prevent you from being able to legally drive. All it takes is one asshoel banker on a power trip to fuck up your ability to buy a home.

That is why I believe crypto is inevitable...but messy...crypto is market-testing hundreds of different types of governance models, security protocols, capitalization allocations, wealth redistribution, brand-building. What happend in 100 years in the real world happens in a couple months in the crypto world...eventually, it will catch up. The governance systems will be better, faster, more reliable, more secure, and censorship-proof. But part of that market-testing is subjecting itself to hundreds of hacks, ponzis, rug pulls, saboteurs, scam artists, rip-offs, and dum dog coins. ...in order to automate and upgrade trust-verifying institutions, you must rebuild and/or replace those institutions. And those institutions are unlikely to go quietly.

Neurons in the brain that respond mainly to singing

New work from Norman-Haignere et al. describes a population of cells in our auditory cortex, located between the music and speech-selective areas, that is responsive to singing, but not to instrumental music or speech. (Their experiments were done on patients who were in hospital with electrodes implanted into their heads for epilepsy treatment, allowing more precise location data than can be obtained from fMRI scans.) Their result is consonant with a popular theory that singing has an important role in the evolution of music and language. Their abstract:  

Highlights

• Neural population responsive to singing, but not instrumental music or speech 

• New statistical method infers neural populations from human intracranial responses 

• fMRI used to map the spatial distribution of intracranial responses 

• Intracranial responses replicate distinct music- and speech-selective populations

Summary

How is music represented in the brain? While neuroimaging has revealed some spatial segregation between responses to music versus other sounds, little is known about the neural code for music itself. To address this question, we developed a method to infer canonical response components of human auditory cortex using intracranial responses to natural sounds, and further used the superior coverage of fMRI to map their spatial distribution. The inferred components replicated many prior findings, including distinct neural selectivity for speech and music, but also revealed a novel component that responded nearly exclusively to music with singing. Song selectivity was not explainable by standard acoustic features, was located near speech- and music-selective responses, and was also evident in individual electrodes. These results suggest that representations of music are fractionated into subpopulations selective for different types of music, one of which is specialized for the analysis of song.

Mellow Mice - Why deep breathing can keep us calm

How we are breathing is usally a good indicator of whether we are calm or aroused. When we become anxious or aroused, usually the best thing we can do is stop and take a deep breath. Gretchen Reynolds points to interesting work in mice that suggests that taking deep breaths is calming because it does not activate neurons in the brain's breathing center that communicate with the brain's arousal center (breathing pacemakers in humans closely resemble those in mice). Here is the abstract from Yackle et al.:

Slow, controlled breathing has been used for centuries to promote mental calming, and it is used clinically to suppress excessive arousal such as panic attacks. However, the physiological and neural basis of the relationship between breathing and higher-order brain activity is unknown. We found a neuronal subpopulation of about 350 neurons in the mouse preBötzinger complex (preBötC), the primary breathing rhythm generator, which regulates the balance between calm and arousal behaviors. Conditional, bilateral genetic ablation of the ~175 Cdh9/Dbx1 double-positive preBötC neurons in adult mice left breathing intact but increased calm behaviors and decreased time in aroused states. These neurons project to, synapse on, and positively regulate noradrenergic neurons in the locus coeruleus, a brain center implicated in attention, arousal, and panic that projects throughout the brain.

Difference in knowledge production by global north and south

Torres et al. do an interesting analysis:

Significance

Contemporary social sciences aim to be diverse and inclusive, but traces of the historical dominance of Western European and North American academic institutions persist in scientific practices. One such practice is the phrasing of article titles. Our analysis shows that articles studying the global North are systematically less likely to mention the name of the country they study in their title compared to articles on the global South. This constitutes, potentially, an unwarranted claim on universality and may lead to lesser recognition of global South studies. Social and behavioral scientists must reflect on the phrasing of their article titles to avoid reproducing harmful relations of intellectual domination which limit inclusivity and constitute a barrier to the generalizability of scientific knowledge.

Abstract

The legacy of Eurocentrism continues to affect knowledge production in the social sciences. Evidence produced in and about the global North is assumed to be more “universal,” whereas evidence from or produced in the global South is considered valid only for specific contexts (i.e., “localized”). We argue that these dynamics are evident in the phrasing of articles’ titles based on the examination of more than half a million social science research articles indexed by Scopus (1996 to 2020). We find that empirical articles written by authors affiliated to institutions of the global North, using data from these countries, are less likely to include a concrete geographical reference in their titles. When authors are affiliated to global South institutions, and use evidence from global South countries, the names of these countries are more likely to be part of the article’s title. We confirm this overarching pattern by looking at 1) differences between world regions, 2) differences within world regions, and 3) patterns in 23 social science subfields. These gaps are large and consistent, yet article naming conventions are merely the “tip of the iceberg” of the imbalances in knowledge production between the global North and South.

How exercise supports the brain

From Leiter et al. "Selenium mediates exercise-induced adult neurogenesis and reverses learning deficits induced by hippocampal injury and aging":

Highlights 

• Selenium mediates the exercise-induced increase in adult hippocampal neurogenesis 

• Selenium increases hippocampal precursor proliferation and adult neurogenesis 

• Selenium reverses cognitive decline in aging and in hippocampal injury 

Summary 

Although the neurogenesis-enhancing effects of exercise have been extensively studied, the molecular mechanisms underlying this response remain unclear. Here, we propose that this is mediated by the exercise-induced systemic release of the antioxidant selenium transport protein, selenoprotein P (SEPP1). Using knockout mouse models, we confirmed that SEPP1 and its receptor low-density lipoprotein receptor-related protein 8 (LRP8) are required for the exercise-induced increase in adult hippocampal neurogenesis. In vivo selenium infusion increased hippocampal neural precursor cell (NPC) proliferation and adult neurogenesis. Mimicking the effect of exercise through dietary selenium supplementation restored neurogenesis and reversed the cognitive decline associated with aging and hippocampal injury, suggesting potential therapeutic relevance. These results provide a molecular mechanism linking exercise-induced changes in the systemic environment to the activation of quiescent hippocampal NPCs and their subsequent recruitment into the neurogenic trajectory.

Addicted to dreaming.

Dopamine (DA) is usually associated with pleasure and addiction. Now Hasegawa et al. show that release of DA in the basolateral amygdala (BLA), a brain structure associated with emotional processing, can trigger rapid eye movement (REM) dreaming sleep in mice.

The sleep cycle is characterized by alternating non–rapid eye movement (NREM) and rapid eye movement (REM) sleeps. The mechanisms by which this cycle is generated are incompletely understood. We found that a transient increase of dopamine (DA) in the basolateral amygdala (BLA) during NREM sleep terminates NREM sleep and initiates REM sleep. DA acts on dopamine receptor D2 (Drd2)–expressing neurons in the BLA to induce the NREM-to-REM transition. This mechanism also plays a role in cataplectic attacks—a pathological intrusion of REM sleep into wakefulness—in narcoleptics. These results show a critical role of DA signaling in the BLA in initiating REM sleep and provide a neuronal basis for sleep cycle generation.

The manly art of self-promotion

Exley and Kessler suggest that gender wage gaps may have roots in men being more self-promoting than women:

We run a series of experiments involving over 4,000 online participants and over 10,000 school-aged youth. When individuals are asked to subjectively describe their performance on a male-typed task relating to math and science, we find a large gender gap in self-evaluations. This gap arises when self-evaluations are provided to potential employers, and thus measure self-promotion, and when self-evaluations are not driven by incentives to promote. The gender gap in self-evaluations proves to be persistent and arises as early as the sixth grade. No gender gap arises if individuals are asked about their performance on a more female-typed task.

Genes for loving nature.

From Chang et al.:

Nature experiences have been linked to mental and physical health. Despite the importance of understanding what determines individual variation in nature experience, the role of genes has been overlooked. Here, using a twin design (TwinsUK, number of individuals = 2,306), we investigate the genetic and environmental contributions to a person’s nature orientation, opportunity (living in less urbanized areas), and different dimensions of nature experience (frequency and duration of public nature space visits and frequency and duration of garden visits). We estimate moderate heritability of nature orientation (46%) and nature experiences (48% for frequency of public nature space visits, 34% for frequency of garden visits, and 38% for duration of garden visits) and show their genetic components partially overlap. We also find that the environmental influences on nature experiences are moderated by the level of urbanization of the home district. Our study demonstrates genetic contributions to individuals’ nature experiences, opening a new dimension for the study of human–nature interactions.

The Life Cycle of Outrage

 I have to pass on this great piece by Mark Manson on the life cycle of a 'significant event'.  

A feeling of loss in the abstraction of all those beautiful things into streams and algorithms...

I pass on a single paragraph from A.O.Scott's recent essay "Shelf Life: Our Collections and the Passage of Time" and suggest you read the whole piece, an engaging illustrated commentary on generational and cultural change:

And that is the substance, so to speak, of Klosterman’s (author of "The Nineties") relentless cataloging and Aksel’s (a character in "The Worst Person in the World" comedy series) lamentation for lost record stores. The digitization of culture — the abstraction of all those beautiful things into streams and algorithms — feels to many of us like a permanent loss. What kind of a loss can be hard to specify, since there is also clearly a benefit. In the old days, Aksel might not have been able to watch “Dog Day Afternoon” over and over again. He might have had to wait until it showed up at a revival house, or until the previous customer returned the only VHS copy to the video store. Now he can stream “Back to Dungaree High” on a playlist with his other favorites. Klosterman can watch any episode of “Seinfeld” or “The Simpsons” any time he wants.

Listening to our bodies can make us more resilient to stress

Jane Brody points to work from Haas et al. suggesting that resilience is more about body awareness than rational thinking. In their experiments subjects who had more subjective awareness of their internal feelings were less emotionally reactive to stress (showing less heart rate increase, shallow breathing, blood adrenaline increase), and recovered more quickly from it. Increased awareness of interoceptive stress signals from the body appears to enable stronger top-down suppression of the stress response. Here is the abstract from the Haas et al. article:

This study examined neural processes of resilience during aversive interoceptive processing. Forty-six individuals were divided into three groups of resilience Low (LowRes), high (HighRes), and normal (NormRes), based on the Connor-Davidson Resilience Scale (2003). Participants then completed a task involving anticipation and experience of loaded breathing during functional magnetic resonance imaging (fMRI) recording. Compared to HighRes and NormRes groups, LowRes self-reported lower levels of interoceptive awareness and demonstrated higher insular and thalamic activation across anticipation and breathing load conditions. Thus, individuals with lower resilience show reduced attention to bodily signals but greater neural processing to aversive bodily perturbations. In low resilient individuals, this mismatch between attention to and processing of interoceptive afferents may result in poor adaptation in stressful situations.

AI-synthesized faces are indistinguishable from real faces and more trustworthy

A sobering open source aricle from Nightingale and Farid than suggests the impossibility of sorting our the real from the fake. Synthesized faces tend to look more like average faces which themselves are deemed more trustworthy.

Artificial intelligence (AI)–synthesized text, audio, image, and video are being weaponized for the purposes of nonconsensual intimate imagery, financial fraud, and disinformation campaigns. Our evaluation of the photorealism of AI-synthesized faces indicates that synthesis engines have passed through the uncanny valley and are capable of creating faces that are indistinguishable—and more trustworthy—than real faces.

Seven Habits That Lead to Happiness in Old Age

I want to point to this self-help article by Arthur Brooks in The Atlantic, part of his 'How to Build a Life' series. It's bottom line, derived from data in the famous Harvard Study of Adult Development begun in 1938, is that Happy-well seniors accumulate resources and habits in their Happiness 401(k)s during their younger lives by practicing the following injunctions. 

1. Don't smoke 

2. Watch your drinking 

3. Maintain a healthy body weight 

4. Prioritize physical movement in your life 

5. Practice coping mechanisms 

6 Keep learning 

 7 Cultivate stable long term relationships.

Reconsidering evidence of moral contagion in online social networks

Burton et al. raise some cautions about recent studies seeming to show that inclusion of emotional terms in social media text messages increases message diffusion. Here is a clip from their text, followed by the article abstract:

...we created an absurd factor for illustrative purposes, what we call XYZ contagion, and tested whether the number of X’s, Y’s and Z’s included in messages’ text predicted diffusion...Our analysis found XYZ contagion to be present in four of our six corpora such that the presence of the letters X, Y and Z predicted an increase in message diffusion: COVID-19 tweets...#MeToo tweets...#MuellerReport tweets...2016 US Election tweets...While there was no positive relationship between the presence of X, Y and Z and message diffusion in the #WomensMarch and Post-Brexit tweets, the finding that XYZ contagion passes a key test of robustness, viz. out-of-sample prediction, demonstrates the potential of large-scale social media datasets to contain spurious correlations

Abstract

The ubiquity of social media use and the digital data traces it produces has triggered a potential methodological shift in the psychological sciences away from traditional, laboratory-based experimentation. The hope is that, by using computational social science methods to analyse large-scale observational data from social media, human behaviour can be studied with greater statistical power and ecological validity. However, current standards of null hypothesis significance testing and correlational statistics seem ill-suited to markedly noisy, high-dimensional social media datasets. We explore this point by probing the moral contagion phenomenon, whereby the use of moral-emotional language increases the probability of message spread. Through out-of-sample prediction, model comparisons and specification curve analyses, we find that the moral contagion model performs no better than an implausible XYZ contagion model. This highlights the risks of using purely correlational evidence from large observational datasets and sounds a cautionary note for psychology’s merge with big data.

Predictions help neurons, and the brain, learn

From the PNAS Journal Club, a review of a publication by Luczak et. al. that suggest that neurons might be able to predict their own future activity, and learn to improve the accuracy of those predictions. The review expands on the Luczak et al abstract, which I pass on here:

Understanding how the brain learns may lead to machines with human-like intellectual capacities. It was previously proposed that the brain may operate on the principle of predictive coding. However, it is still not well understood how a predictive system could be implemented in the brain. Here we demonstrate that the ability of a single neuron to predict its future activity may provide an effective learning mechanism. Interestingly, this predictive learning rule can be derived from a metabolic principle, whereby neurons need to minimize their own synaptic activity (cost) while maximizing their impact on local blood supply by recruiting other neurons. We show how this mathematically derived learning rule can provide a theoretical connection between diverse types of brain-inspired algorithm, thus offering a step towards the development of a general theory of neuronal learning. We tested this predictive learning rule in neural network simulations and in data recorded from awake animals. Our results also suggest that spontaneous brain activity provides ‘training data’ for neurons to learn to predict cortical dynamics. Thus, the ability of a single neuron to minimize surprise—that is, the difference between actual and expected activity—could be an important missing element to understand computation in the brain.

Consciousness is supported by near-critical slow cortical electrodynamics

An open source offering from Toker et al. that has a nice summary graphic.:  

Significance

What changes in the brain when we lose consciousness? One possibility is that the loss of consciousness corresponds to a transition of the brain’s electric activity away from edge-of-chaos criticality, or the knife’s edge in between stability and chaos. Recent mathematical developments have produced tools for testing this hypothesis, which we apply to cortical recordings from diverse brain states. We show that the electric activity of the cortex is indeed poised near the boundary between stability and chaos during conscious states and transitions away from this boundary during unconsciousness and that this transition disrupts cortical information processing.

Abstract

Mounting evidence suggests that during conscious states, the electrodynamics of the cortex are poised near a critical point or phase transition and that this near-critical behavior supports the vast flow of information through cortical networks during conscious states. Here, we empirically identify a mathematically specific critical point near which waking cortical oscillatory dynamics operate, which is known as the edge-of-chaos critical point, or the boundary between stability and chaos. We do so by applying the recently developed modified 0-1 chaos test to electrocorticography (ECoG) and magnetoencephalography (MEG) recordings from the cortices of humans and macaques across normal waking, generalized seizure, anesthesia, and psychedelic states. Our evidence suggests that cortical information processing is disrupted during unconscious states because of a transition of low-frequency cortical electric oscillations away from this critical point; conversely, we show that psychedelics may increase the information richness of cortical activity by tuning low-frequency cortical oscillations closer to this critical point. Finally, we analyze clinical electroencephalography (EEG) recordings from patients with disorders of consciousness (DOC) and show that assessing the proximity of slow cortical oscillatory electrodynamics to the edge-of-chaos critical point may be useful as an index of consciousness in the clinical setting.

Illusory faces are more likely to be perceived as male than female

Interesting observations from Wardle et al.:

Despite our fluency in reading human faces, sometimes we mistakenly perceive illusory faces in objects, a phenomenon known as face pareidolia. Although illusory faces share some neural mechanisms with real faces, it is unknown to what degree pareidolia engages higher-level social perception beyond the detection of a face. In a series of large-scale behavioral experiments (ntotal = 3,815 adults), we found that illusory faces in inanimate objects are readily perceived to have a specific emotional expression, age, and gender. Most strikingly, we observed a strong bias to perceive illusory faces as male rather than female. This male bias could not be explained by preexisting semantic or visual gender associations with the objects, or by visual features in the images. Rather, this robust bias in the perception of gender for illusory faces reveals a cognitive bias arising from a broadly tuned face evaluation system in which minimally viable face percepts are more likely to be perceived as male.

Our brains store concepts as sensory-motor and affective information

Fascinating work from Fernandino et al., who show that concept representations are not independent of sensory-motor experience: 

Significance

The ability to identify individual objects or events as members of a kind (e.g., “knife,” “dog,” or “party”) is a fundamental aspect of human cognition. It allows us to quickly access a wealth of information pertaining to a newly encountered object or event and use it to guide our behavior. How is this information represented in the brain? We used functional MRI to analyze patterns of brain activity corresponding to hundreds of familiar concepts and quantitatively characterized the informational structure of these patterns. Our results indicate that conceptual knowledge is stored as patterns of neural activity that encode sensory-motor and affective information about each concept, contrary to the long-held idea that concept representations are independent of sensory-motor experience.

Abstract

The nature of the representational code underlying conceptual knowledge remains a major unsolved problem in cognitive neuroscience. We assessed the extent to which different representational systems contribute to the instantiation of lexical concepts in high-level, heteromodal cortical areas previously associated with semantic cognition. We found that lexical semantic information can be reliably decoded from a wide range of heteromodal cortical areas in the frontal, parietal, and temporal cortex. In most of these areas, we found a striking advantage for experience-based representational structures (i.e., encoding information about sensory-motor, affective, and other features of phenomenal experience), with little evidence for independent taxonomic or distributional organization. These results were found independently for object and event concepts. Our findings indicate that concept representations in the heteromodal cortex are based, at least in part, on experiential information. They also reveal that, in most heteromodal areas, event concepts have more heterogeneous representations (i.e., they are more easily decodable) than object concepts and that other areas beyond the traditional “semantic hubs” contribute to semantic cognition, particularly the posterior cingulate gyrus and the precuneus.

How to want less

I've just enjoyed reading through an article by Arthur Brooks, "How to want less" in The Atlantic, which is adapted from his new book "From Strength to Strength: Finding Success, Happiness, and Deep Purpose in the Second Half of Life." I recommend that you read through it. After repeating the point that evolution didn't design us to be happy, but rather to pass on our genes, he notes:

In fact, our natural state is dissatisfaction punctuated by brief moments of satisfaction. You might not like the hedonic treadmill, but Mother Nature thinks it’s pretty great. She likes watching you strive to achieve an elusive goal, because strivers get the goods—even if they don’t enjoy them for long. More mates, better mates, better chances of survival for our children—these ancient mandates are responsible for much of the code that runs incessantly in the deep recesses of our brains. It doesn’t matter whether you’ve found your soul mate and would never stray; the algorithms designed to get us more mates (or allow us to make an upgrade) continue whirring, which is why you still want to be attractive to strangers. Neurobiological instinct—which we experience as dissatisfaction—is what drives us forward....There are many other, related examples of evolved tendencies that militate against enduring happiness—for example, the tendency toward jealous misery in our romantic relationships.

He notes the history of similar recurring solutions to these problems, for example in the sayings of the Buddha, St. Thomas Aquinas - and even Mick Jagger (in his classic "I can't get no satisfaction"). His self help suggestion is to:

...absorb the teachings of Thomas Aquinas and the Buddha—or for that matter, modern social science—and commit to stop trying to add more and more, but instead start taking things away.

In truth, our formula, Satisfaction = getting what you want, leaves out one key component. To be more accurate, it should be:

Satisfaction = what you have ÷ what you want

All of our evolutionary and biological imperatives focus us on increasing the numerator—our haves. But the more significant action is in the denominator—our wants. The modern world is made up of clever ways to make our wants explode without us realizing it.

Brooks offers three habits he has found useful in beating the dissatisfaction curse: 

I. Go from Prince to Sage (the models of Thomas Aquinas and the Buddha...repudiating the world's reward in favor of inner wisdom and helping others) 

II Make a Reverse Bucket List (repudiate getting more 'stuff' and instead list intrinsic sources of happiness or satisfaction that come from with and revolve around love, relationships, and deep purpose...having little to do with the admiration of strangers.) 

III. Get Smaller (live in the present, not the past or future.)

A special issue of Social Cognitive and Affective Neuroscience on tDCS

I want to point to this special open source issue of Social Cognitive and Affective Neuroscience. Paulo Boggio provides an interesting historical introduction, staring in Roman times with the use of the electrical discharge of the torpedo fish to treat headaches (imagine being treated with fish applications over your head!). The articles in the issue consider the effects of low-intensity direct current stimulation of the surface of the scalp on prosocial behavior, aggression, impulsivity, etc. A review article by Galli et al. considers the use of tDCS to relieve the symptomatology of individuals with affective or social cognition disorders. (DIY kits for home experimentrs - which I would not recommend - abound on the internet, regular flashlight batteries being a sufficient source of the low currents used.)

Expression unleashed: The evolutionary & cognitive foundations of human communication

I'm passing on the abstract of a dense but interesting article by Christophe Heintz and Thom Scott-Phillips that will be published in Behavioral and Brain Science and is now being circulated for comment by reviewers. Motivated readers can request a PDF of the article from me.

Human expression is open-ended, versatile and diverse, ranging from ordinary language use to painting, from exaggerated displays of affection to micro-movements that aid coordination. Here we present and defend the claim that this expressive diversity is united by an interrelated suite of cognitive capacities, the evolved functions of which are the expression and recognition of informative intentions. We describe how evolutionary dynamics normally leash communication to narrow domains of statistical mutual benefit, and how they are unleashed in humans. The relevant cognitive capacities are cognitive adaptations to living in a partner choice social ecology; and they are, correspondingly, part of the ordinarily developing human cognitive phenotype, emerging early and reliably in ontogeny. In other words, we identify distinctive features of our species’ social ecology to explain how and why humans, and only humans, evolved the cognitive capacities that, in turn, lead to massive diversity and open-endedness in means and modes of expression. Language use is but one of these modes of expression, albeit one of manifestly high importance. We make cross-species comparisons, describe how the relevant cognitive capacities can evolve in a gradual manner, and survey how unleashed expression facilitates not only language use but novel behaviour in many other domains too, focusing on the examples of joint action, teaching, punishment and art, all of which are ubiquitous in human societies but relatively rare in other species. Much of this diversity derives from graded aspects of human expression, which can be used to satisfy informative intentions in creative and new ways. We aim to help reorient cognitive pragmatics, as a phenomenon that is not a supplement to linguistic communication and on the periphery of language science, but rather the foundation of the many of the most distinctive features of human behaviour, society and culture.

MindBlog is 16 years old... It's first post: "Dangerous Ideas"

I repeat MindBlog's first post... of ideas that are now considered more commonplace than dangerous. Edge.org soldiers on, but its 'annual question' addressed to prominent thinkers disappeared several years ago. Here is the post: 

Edge.org is a website sponsored by the "Reality Club" (i.e. John Brockman, literary agent/impressario/socialite). Brockman has assembled a stable of scientists and other thinkers that he defines as a "third culture" that takes the place of traditional intellectuals in redefining who and what we are.... Each year a question is formulated for all to write on... In 2004 it was "What do you believe is true even though you cannot prove it?" The question for 2005 was "What is your dangerous idea?"

The responses organize themselves into several areas. Here are selected thumbnail summaries most directly relevant to human minds. I've not included cosmology and physics. Go to edge.org to read the essays

I. Nature of the human self or mind (by the way see my "I-Illusion" essay on my website):

Paulos - The self is a conceptual chimera
Shirky - Free will is going away
Nisbett - We are ignorant of our thinking processes
Horgan - We have no souls
Bloom - There are no souls, mind has a material basis.
Provine - This is all there is.
Anderson - Brains cannot become minds without bodies
Metzinger - Is being intellectually honest about the issue of free will compatible with preserving one's mental health?
Clark - Much of our behavior is determined by non-conscious, automatic uptake of cues and information
Turkle - Simulation will replace authenticity as computer simulation becomes fully naturalized.
Dawkins - A faulty person is no different from a faulty car. There is a mechanism determining behavior that needs to be fixed. The idea of responsibility is nonsense.
Smith - What we know may not change us. We will continue to conceive ourselves as centres of experience, self-knowing and free willing agents.

II. Natural explanations of culture

Sperber - Culture is natural.
Taylor - The human brain is a cultural artifact.
Hauser- There is a universal grammar of mental life.
Pinker - People differ genetically in their average talents and temperaments.
Goodwin - Similar coordinating patterns underlie biological and cultural evolution.
Venter - Revealing the genetic basis of personality and behavior will create societal conflicts.


III. Fundamental changes in political, economic, social order

O'donnell - The state will disappear.
Ridley - Government is the problem not the solution.
Shermer - Where goods cross frontiers armies won't.
Harari -Democracy is on its way out.
Csikszentmihalyi- The free market myth is destroying culture.
Goleman - The internet undermines the quality of human interaction.
Harris - Science must destroy religion.
Porco - Confrontation between science and religion might end when role played by science in lives of people is the same played by religion today.
Bering - Science will never silence God
Fisher - Drugs such as antidepressants jeopardize feelings of attachment and love
Iacoboni - Media Violence Induces Imitative Violence - the Problem with Mirrors
Morton - Our planet is not in peril, just humans are. 

Attention and executive functions - improvements and declines with ageing.

From Verissimo et al.:

Many but not all cognitive abilities decline during ageing. Some even improve due to lifelong experience. The critical capacities of attention and executive functions have been widely posited to decline. However, these capacities are composed of multiple components, so multifaceted ageing outcomes might be expected. Indeed, prior findings suggest that whereas certain attention/executive functions clearly decline, others do not, with hints that some might even improve. We tested ageing effects on the alerting, orienting and executive (inhibitory) networks posited by Posner and Petersen’s influential theory of attention, in a cross-sectional study of a large sample (N = 702) of participants aged 58–98. Linear and nonlinear analyses revealed that whereas the efficiency of the alerting network decreased with age, orienting and executive inhibitory efficiency increased, at least until the mid-to-late 70s. Sensitivity analyses indicated that the patterns were robust. The results suggest variability in age-related changes across attention/executive functions, with some declining while others improve.

How fast people respond to each other is a metric of social connection.

From Templeton et al.:  

Significance

Social connection is critical for our mental and physical health yet assessing and measuring connection has been challenging. Here, we demonstrate that a feature intrinsic to conversation itself—the speed with which people respond to each other—is a simple, robust, and sufficient metric of social connection. Strangers and friends feel more connected when their conversation partners respond quickly. Because extremely short response times (less than 250 ms) preclude conscious control, they provide an honest signal that even eavesdroppers use to judge how well two people “click.”

Abstract

Clicking is one of the most robust metaphors for social connection. But how do we know when two people "click"? We asked pairs of friends and strangers to talk with each other and rate their felt connection. For both friends and strangers, speed in response was a robust predictor of feeling connected. Conversations with faster response times felt more connected than conversations with slower response times, and within conversations, connected moments had faster response times than less-connected moments. This effect was determined primarily by partner responsivity: People felt more connected to the degree that their partner responded quickly to them rather than by how quickly they responded to their partner. The temporal scale of these effects (less than 250 ms) precludes conscious control, thus providing an honest signal of connection. Using a round-robin design in each of six closed networks, we show that faster responders evoked greater feelings of connection across partners. Finally, we demonstrate that this signal is used by third-party listeners as a heuristic of how well people are connected: Conversations with faster response times were perceived as more connected than the same conversations with slower response times. Together, these findings suggest that response times comprise a robust and sufficient signal of whether two minds “click.”

Threatening language is contagious - Tracking America’s collective response to threats with a linguistic tool

From Choi et al.:  

Significance

People are constantly exposed to threatening language in mass communication channels, yet we lack tools to identify language about threats and track its impact on human groups. We developed a threat dictionary, a computationally derived linguistic tool that indexes threat levels from texts with high temporal resolution, across media platforms, and for different levels of analysis. The dictionary shows convergent validity with objective threats in American history, including violent conflicts, natural disasters, and pathogen outbreaks. Moreover, fluctuations in threat levels from the past 100 years coincide with America’s shifting cultural norms, political attitudes, and macroeconomic activity, demonstrating how this linguistic tool can be applied to understand the collective shifts associated with mass communicated threats.

Abstract

In today’s vast digital landscape, people are constantly exposed to threatening language, which attracts attention and activates the human brain’s fear circuitry. However, to date, we have lacked the tools needed to identify threatening language and track its impact on human groups. To fill this gap, we developed a threat dictionary, a computationally derived linguistic tool that indexes threat levels from mass communication channels. We demonstrate this measure’s convergent validity with objective threats in American history, including violent conflicts, natural disasters, and pathogen outbreaks such as the COVID-19 pandemic. Moreover, the dictionary offers predictive insights on US society’s shifting cultural norms, political attitudes, and macroeconomic activities. Using data from newspapers that span over 100 years, we found change in threats to be associated with tighter social norms and collectivistic values, stronger approval of sitting US presidents, greater ethnocentrism and conservatism, lower stock prices, and less innovation. The data also showed that threatening language is contagious. In all, the language of threats is a powerful tool that can inform researchers and policy makers on the public’s daily exposure to threatening language and make visible interesting societal patterns across American history.

The stories we imagine while listening to music depends on our culture.

Margulis et al. (text from their introduction)

....compared quantitative measures of narrativity (the likelihood that an excerpt of music triggers a story in listeners minds) and narrative engagement (how vivid and clear the events of the story are in listeners minds) for a large set of musical excerpts from Western and Chinese musical traditions for listeners in the same three distinct geographical locations as the present investigation—two suburban college towns in the US Midwest and one rural village in the Chinese province of Guizhou. Results showed that people in all three locations readily narrativize to excerpts (i.e., narrativity scores were quite high) with varying levels of narrative engagement for both Western and Chinese instrumental music; moreover, people do so with about the same degree regardless of location. Notably, however, although both excerpt narrativity and narrative engagement scores were highly correlated across the two US locations, they were not correlated (not predictive) for cross-cultural comparisons between listeners in both of the US locations and the remote rural village in Guizhou.

Here is the article's abstsract:

The scientific literature sometimes considers music an abstract stimulus, devoid of explicit meaning, and at other times considers it a universal language. Here, individuals in three geographically distinct locations spanning two cultures performed a highly unconstrained task: they provided free-response descriptions of stories they imagined while listening to instrumental music. Tools from natural language processing revealed that listeners provide highly similar stories to the same musical excerpts when they share an underlying culture, but when they do not, the generated stories show limited overlap. These results paint a more complex picture of music’s power: music can generate remarkably similar stories in listeners’ minds, but the degree to which these imagined narratives are shared depends on the degree to which culture is shared across listeners. Thus, music is neither an abstract stimulus nor a universal language but has semantic affordances shaped by culture, requiring more sustained attention from psychology.

Our brains have multiple representations of the same body part.

Here is a neat finding. Remember your elementary biology textbook picture of the homunculi in our somatosensory and motor cortices? The small human figure spread across the surface of the brain, with a cortical location for each part of the hand or other body part? Matsumiya shows that when we direct our eye and hand movements to the same body part these two movements are found to be guided by different body maps! Here is his abstract:  

Significance

Accurate motor control depends on maps of the body in the brain, called the body schema. Disorders of the body schema cause motor deficits. Although we often execute actions with different motor systems such as the eye and hand, how the body schema operates during such actions is unknown. In this study, participants simultaneously directed eye and hand movements to the same body part. These two movements were found to be guided by different body maps. This finding demonstrates multiple motor system–specific representations of the body schema, suggesting that the choice of motor system toward one’s body can determine which of the brain’s body maps is observed. This may offer a new way to visualize patients’ body schema.

Abstract

Purposeful motor actions depend on the brain’s representation of the body, called the body schema, and disorders of the body schema have been reported to show motor deficits. The body schema has been assumed for almost a century to be a common body representation supporting all types of motor actions, and previous studies have considered only a single motor action. Although we often execute multiple motor actions, how the body schema operates during such actions is unknown. To address this issue, I developed a technique to measure the body schema during multiple motor actions. Participants made simultaneous eye and reach movements to the same location of 10 landmarks on their hand. By analyzing the internal configuration of the locations of these points for each of the eye and reach movements, I produced maps of the mental representation of hand shape. Despite these two movements being simultaneously directed to the same bodily location, the resulting hand map (i.e., a part of the body schema) was much more distorted for reach movements than for eye movements. Furthermore, the weighting of visual and proprioceptive bodily cues to build up this part of the body schema differed for each effector. These results demonstrate that the body schema is organized as multiple effector-specific body representations. I propose that the choice of effector toward one’s body can determine which body representation in the brain is observed and that this visualization approach may offer a new way to understand patients’ body schema.

Using big data to track major shifts in human cognition

I want to pass on the first few paragraphs of a fascinating commentary by Simon DeDao on an article by Scheffer et al. that was the subject of MindBlog's 12/31/21 post. Motivated readers can obtain a copy of the whole article by emailing me.:

Scheffer et al.’s (1) exciting new work reports an historic rearrangement, occurring in the late 20th century, of the balance between reason and emotion. Its approach is part of a new trend in the psychological sciences that uses extremely large volumes of text to study basic patterns of human cognition. Recent work in this vein has included studies of the universal properties of gender representations (2), the rise of causal thinking (3), and a cognitive bias towards positivity in language itself (4). The goal of going “from text to thought” (5) is an attractive one, and the promise of the machine learning era is that we will only get better at extracting the imprints left, in text, by the mechanisms of the mind.

To establish their claims, Scheffer et al. (1) use principal component analysis to identify two major polarities of correlated vocabulary words in the Google Books corpus (6). The first polarity (PC1) tracks a shift from archaic to modern, in both material life (“iron” is archaic, “computer” is modern) and culture (“liberty” is archaic, “privacy” is modern). The second polarity (PC2) that emerges is the intriguing one, and forms the basis of their paper: Its two poles, the authors argue, correspond to the distinction between “rational” and “intuitive” language.

Their main finding then has two pieces: a shift from the intuitive pole to the rational pole (the “rise” of rationality) and then back (the “fall”) (1). The rise has begun by the start of their data in 1850, and unfolds over the course of a century or more. They attribute it to a society increasingly concerned with quantifying, and justifying, the world through scientific and impersonal language—a gradual tightening of Max Weber’s famous “iron cage” of collectivized, rationalized bureaucracy in service of the capitalist profit motive (7). The fall, meaning a shift from the rational back to the intuitive, begins in 1980, and is more rapid than the rise: By 2020, the balance is similar to that seen in the early 1900s. The fall appears to accelerate in the early 2000s, which leads the authors to associate it with social media use and a “post-truth era” where “feelings trump facts.” Both these interpretations are supported by accompanying shifts toward “collective” pronouns (we, our, and they) in the Weberian period, and then toward the “individualistic” ones (I, my, he, and she) after.

The raw effect sizes the authors report are extraordinarily large (1). At the peak in 1980, rationality words outnumbered intuition words, on average, three to one. Forty years later (and 100 y earlier), however, the balance was roughly one to one. If these represent changes in actual language use, let alone the time devoted to the underlying cognitive processes, they are enormous shifts in the nature of human experience.

1. M. Scheffer, I. van de Leemput, E. Weinans, J. Bollen, The rise and fall of rationality in language. Proc. Natl. Acad. Sci. U.S.A. 118, e2107848118 (2021).

2. T. E. S. Charlesworth, V. Yang, T. C. Mann, B. Kurdi, M. R. Banaji, Gender stereotypes in natural language: Word embeddings show robust consistency across child and adult language corpora of more than 65 million words. Psychol. Sci. 32, 218–240 (2021).

3. R. Iliev, R. Axelrod, Does causality matter more now? Increase in the proportion of causal language in English texts. Psychol. Sci. 27, 635–643 (2016).

4. P. S. Dodds et al, Human language reveals a universal positivity bias. Proc. Natl. Acad. Sci. U.S.A. 112, 2389–2394 (2015).

5. J. C. Jackson et al, From text to thought: How analyzing language can advance psychological science. Perspect. Psychol. Sci., 10.117/17456916211004899 (2021).

6. J. B. Michel et al.; Google Books Team, Quantitative analysis of culture using millions of digitized books. Science 331, 176–182 (2011).