Why do many societies moralize apparently harmless pleasures, such as lust, gluttony, alcohol, drugs, and even music and dance? Why do they erect temperance, asceticism, sobriety, modesty, and piety as cardinal moral virtues? According to existing theories, this puritanical morality cannot be reduced to concerns for harm and fairness: it must emerge from cognitive systems that did not evolve for cooperation (e.g., disgust-based "Purity" concerns). Here, we argue that, despite appearances, puritanical morality is no exception to the cooperative function of moral cognition. It emerges in response to a key feature of cooperation, namely that cooperation is (ultimately) a long-term strategy, requiring (proximately) the self-control of appetites for immediate gratification. Puritanical moralizations condemn behaviors which, although inherently harmless, are perceived as indirectly facilitating uncooperative behaviors, by impairing the self-control required to refrain from cheating. Drinking, drugs, immodest clothing, and unruly music and dance, are condemned as stimulating short-term impulses, thus facilitating uncooperative behaviors (e.g., violence, adultery, free-riding). Overindulgence in harmless bodily pleasures (e.g., masturbation, gluttony) is perceived as making people slave to their urges, thus altering abilities to resist future antisocial temptations. Daily self-discipline, ascetic temperance, and pious ritual observance are perceived as cultivating the self-control required to honor prosocial obligations. We review psychological, historical, and ethnographic evidence supporting this account. We use this theory to explain the fall of puritanism in WEIRD societies, and discuss the cultural evolution of puritanical norms. Explaining puritanical norms does not require adding mechanisms unrelated to cooperation in our models of the moral mind.
Wednesday, October 05, 2022
Monday, October 03, 2022
A fascinating open source article from Margaret Livingstone carrying forward the famous experiments by Harry Harlow:
Harry Harlow found that infant monkeys form strong and lasting attachments to inanimate surrogates, but only if the surrogate is soft; here I report that postpartum monkey mothers can also form strong and lasting attachments to soft inanimate objects. Thus, mother/infant and infant/mother bonds may both be triggered by soft touch.Abstract
Previous studies showed that baby monkeys separated from their mothers develop strong and lasting attachments to inanimate surrogate mothers, but only if the surrogate has a soft texture; soft texture is more important for the infant’s attachment than is the provision of milk. Here I report that postpartum female monkeys also form strong and persistent attachments to inanimate surrogate infants, that the template for triggering maternal attachment is also tactile, and that even a brief period of attachment formation can dominate visual and auditory cues indicating a more appropriate target.
Friday, September 30, 2022
Trigger warnings, content warnings, or content notes are alerts about upcoming content that may contain themes related to past negative experiences. Advocates claim that warnings help people to emotionally prepare for or completely avoid distressing material. Critics argue that warnings both contribute to a culture of avoidance at odds with evidence-based treatment practices and instill fear about upcoming content. Recently, a body of psychological research has begun to investigate these claims empirically. We present the results of a meta-analysis of all empirical studies on the effects of these warnings. Overall, we found that warnings have no effect on affective responses to negative material nor on educational outcomes (i.e., comprehension). However, warnings reliably increase anticipatory affect. Findings on avoidance were mixed, suggesting either that warnings have no effect on engagement with material, or that they increase engagement with negative material under specific circumstances. Limitations and implications for policy and therapeutic practice are discussed.Manson also discusses the dying fad of "safety-ism" noted by Jonathan Haidt and Greg Lukianoff in their book "The Coddling of the American Mind," and makes the point that...
The human mind is antifragile—that is, it gains from discomfort and strain. That means to grow stronger, the human mind needs to regularly be confronted with difficult and upsetting experiences to develop stability and serenity for itself.
Wednesday, September 28, 2022
From Li et al.:
Humans establish intimate social and personal relationships with their partners, which enable them to survive, successfully mate, and raise offspring. Here, we examine the neurobiological basis of marital satisfaction in humans using naturalistic, ecologically relevant, interpersonal communicative cues that capture shared neural representations between married couples. We show that in contrast to demographic and personality measures, which are unreliable predictors of marital satisfaction, neural synchronization of brain responses during viewing of naturalistic maritally relevant movies predicted higher levels of marital satisfaction in couples. Our findings demonstrate that brain similarities that reflect real-time mental responses to subjective perceptions, thoughts, and feelings about interpersonal and social interactions are strong predictors of marital satisfaction and advance our understanding of human marital bonding.Abstract
Marital attachment plays an important role in maintaining intimate personal relationships and sustaining psychological well-being. Mate-selection theories suggest that people are more likely to marry someone with a similar personality and social status, yet evidence for the association between personality-based couple similarity measures and marital satisfaction has been inconsistent. A more direct and useful approach for understanding fundamental processes underlying marital satisfaction is to probe similarity of dynamic brain responses to maritally and socially relevant communicative cues, which may better reflect how married couples process information in real time and make sense of their mates and themselves. Here, we investigate shared neural representations based on intersubject synchronization (ISS) of brain responses during free viewing of marital life-related, and nonmarital, object-related movies. Compared to randomly selected pairs of couples, married couples showed significantly higher levels of ISS during viewing of marital movies and ISS between married couples predicted higher levels of marital satisfaction. ISS in the default mode network emerged as a strong predictor of marital satisfaction and canonical correlation analysis revealed a specific relation between ISS in this network and shared communication and egalitarian components of martial satisfaction. Our findings demonstrate that brain similarities that reflect real-time mental responses to subjective perceptions, thoughts, and feelings about interpersonal and social interactions are strong predictors of marital satisfaction, reflecting shared values and beliefs. Our study advances foundational knowledge of the neurobiological basis of human pair bonding.
Monday, September 26, 2022
Since living in cities is associated with an increased risk for mental disorders such as anxiety disorders, depression, and schizophrenia, it is essential to understand how exposure to urban and natural environments affects mental health and the brain. It has been shown that the amygdala is more activated during a stress task in urban compared to rural dwellers. However, no study so far has examined the causal effects of natural and urban environments on stress-related brain mechanisms. To address this question, we conducted an intervention study to investigate changes in stress-related brain regions as an effect of a one-hour walk in an urban (busy street) vs. natural environment (forest). Brain activation was measured in 63 healthy participants, before and after the walk, using a fearful faces task and a social stress task. Our findings reveal that amygdala activation decreases after the walk in nature, whereas it remains stable after the walk in an urban environment. These results suggest that going for a walk in nature can have salutogenic effects on stress-related brain regions, and consequently, it may act as a preventive measure against mental strain and potentially disease. Given rapidly increasing urbanization, the present results may influence urban planning to create more accessible green areas and to adapt urban environments in a way that will be beneficial for citizens’ mental health.A few previous MindBlog posts on this topic:
Friday, September 23, 2022
Machine-learning systems, which use algorithms to detect patterns in large collections of data, have excelled at analyzing human language, giving rise to voice assistants that recognize speech, transcription software that converts speech to text and digital tools that translate between human languages.
...this technology can be deployed to decode animal communication, working towards finding a Google Translate for animals, using machine-learning algorithms to identify when squeaking mice are stressed or why fruit bats are shouting. Even more ambitious projects are underway — to create a comprehensive catalog of crow calls, map the syntax of sperm whales and even to build technologies that allow humans to talk back.
...machine-learning algorithms can spot subtle patterns that might elude human listeners...these programs can tell apart the voices of individual animals, distinguish between sounds that animals make in different circumstances and break their vocalizations down into smaller parts, a crucial step in deciphering meaning.
...the technology could also be deployed for the benefit of animals, helping experts monitor the welfare of both wild and domestic fauna. Scientists also said that they hoped that by providing new insight into animal lives, this research might prompt a broader societal shift. Many pointed to the galvanizing effect of the 1970 album “Songs of the Humpback Whale,” which featured recordings of otherworldly whale calls and has been widely credited with helping to spark the global Save the Whales movement...many scientists said they hoped these new, high-tech efforts to understand the vocalizations of whales — and crows and bats and even naked mole rats — will be similarly transformative, providing new ways to connect with and understand the creatures with whom we share the planet.
Wednesday, September 21, 2022
The development of technologies to protect or enhance memory in older people is an enduring goal of translational medicine. Here we describe repetitive (4-day) transcranial alternating current stimulation (tACS) protocols for the selective, sustainable enhancement of auditory–verbal working memory and long-term memory in 65–88-year-old people. Modulation of synchronous low-frequency, but not high-frequency, activity in parietal cortex preferentially improved working memory on day 3 and day 4 and 1 month after intervention, whereas modulation of synchronous high-frequency, but not low-frequency, activity in prefrontal cortex preferentially improved long-term memory on days 2–4 and 1 month after intervention. The rate of memory improvements over 4 days predicted the size of memory benefits 1 month later. Individuals with lower baseline cognitive function experienced larger, more enduring memory improvements. Our findings demonstrate that the plasticity of the aging brain can be selectively and sustainably exploited using repetitive and highly focalized neuromodulation grounded in spatiospectral parameters of memory-specific cortical circuitry.
Monday, September 19, 2022
We show that the sex of human experimenters affects mouse behaviors and responses following administration of the rapid-acting antidepressant ketamine and its bioactive metabolite (2R,6R)-hydroxynorketamine. Mice showed aversion to the scent of male experimenters, preference for the scent of female experimenters and increased stress susceptibility when handled by male experimenters. This human-male-scent-induced aversion and stress susceptibility was mediated by the activation of corticotropin-releasing factor (CRF) neurons in the entorhinal cortex that project to hippocampal area CA1. Exposure to the scent of male experimenters before ketamine administration activated CA1-projecting entorhinal cortex CRF neurons, and activation of this CRF pathway modulated in vivo and in vitro antidepressant-like effects of ketamine. A better understanding of the specific and quantitative contributions of the sex of human experimenters to study outcomes in rodents may improve replicability between studies and, as we have shown, reveal biological and pharmacological mechanisms.
Friday, September 16, 2022
I've done a bit more reading on alpha-ketoglutarate, a natural component of the Krebs biochemical cycle that generates body energy and whose levels normally decline with aging. It was the subject of a recent post pointing to studies indicating the positive effects of its supplementation on health and longevity in mice. So...I have started taking 300 mg capsules of the stuff with my other breakfast supplements. I decided to pass on the pricey 'Rejuvant Life Tabs', containing 1000 mg and offered by Ponce de Leon Health, a company set up by some of the researchers, and instead got the compound from Kirkman, one of the supplement providers. I'm inclined not to be too paranoid about their sending sawdust instead of the real product. I noted that I could buy the >98% pure dry powder from the Sigma-Aldrich company, the supplier my biochemisty lab used for over 30 years, but decided the hassle of dealing with bulk powder wasn't worth it. The compound is quite acidic, so best taken as the Calcium or Magnesium salt and with a meal. I had an unhappy tummy when I tried it without food.
I will continue taking the compound, will report imagined positive or negative effects as addenda to this post. Undesirable side effects will lead me to discontinue the supplement, as was the case with my 2010 (Acetyl L-carnitine, alpha-lipoic acid, and the B-vitamin biotin) and 2016 (pterostilbene and nicotinamide riboside) self experiments. The latter, like a 2008 experiment with resveratrol was terminated because of increasing arthritic symptoms. The 2008 post had 33 comments reporting negative effects resveratrol.
And, a necessary comment regarding Ponce de Leon Health and other purveyors of life extension elixirs:
You're gonna die..there is compelling evidence that none of us will make it past ~120 years of age.
Wednesday, September 14, 2022
Marx posits cultural evolution as a sort of perpetual motion machine driven by people’s desire to ascend the social hierarchy. Artists innovate to gain status, and people unconsciously adjust their tastes to either signal their status tier or move up to a new one. As he writes in the introduction, “Status struggles fuel cultural creativity in three important realms: competition between socioeconomic classes, the formation of subcultures and countercultures, and artists’ internecine battles.”Marx uses the rise of avant-garde compose John Cage after his first major orchestral piece premiered at Lincoln Center in 1964, as an example the introduction of a radical new perspective that would most likely be impossible today.
“There was a virtuous cycle for Cage: His originality, mystery and influence provided him artist status; this encouraged serious institutions to explore his work; the frequent engagement with his work imbued Cage with cachet among the public, who then received a status boost for taking his work seriously,” writes Marx. For Marx, this isn’t a matter of pretension. Cachet, he writes, “opens minds to radical propositions of what art can be and how we should perceive it.”
The internet, Marx writes in his book’s closing section, changes this dynamic. With so much content out there, the chance that others will recognize the meaning of any obscure cultural signal declines. Challenging art loses its prestige. Besides, in the age of the internet, taste tells you less about a person. You don’t need to make your way into any social world to develop a familiarity with Cage — or, for that matter, with underground hip-hop, weird performance art, or rare sneakers.
...people are, obviously, no less obsessed with their own status today than they were during times of fecund cultural production. It’s just that the markers of high social rank have become more philistine...When the value of cultural capital is debased, it makes “popularity and economic capital even more central in marking status...there’s “less incentive for individuals to both create and celebrate culture with high symbolic complexity.” ...We live in a time of rapid and disorienting shifts in gender, religion and technology. Aesthetically, thanks to the internet, it’s all quite dull.
Monday, September 12, 2022
There can be confusion over what is meant by no-self in various meditative traditions. It’s not the claim that people are illusions, or that you can’t say anything about the psychological or biological continuity of a person. It’s not mysterious that we wake up today as ourselves and not someone else. These are not the puzzles being addressed.
The core insight, the illusion that is cut through, conceptually and experientially, is our apparent normal default condition of feeling like there is a subject in the center of experience. Most people don’t merely feel identical to experience, they feel like they are having an experience, they feel like they are appropriating their experience from some point - very likely in their heads - the witness, the thinker of thoughts, the willer of will, the guy in the boat who has free will, who can decide what to think and do next. That’s the default state for almost everybody, and commonplace as it is, it is a peculiar point of view. It doesn’t make a lot of sense, particularly biological sense. It’s not the same thing as feeling identical to our bodies, because we usually don’t feel identical to our bodies, we feel like we are subjects who have bodies, there is a kind of Cartesian dualism that is intuitive. People are ‘common sense dualists.’ As a matter of experience there is this feeling that “I am a subject behind my face.” “I” have a body, am a subject who is thinking, internal to the body, has a body. It is the final representation of the subject that is the illusion.
To put this in neurological terms, let’s just say for the sake of argument at all of this is just neurophysiological events in the brain delivering these representations. It is plausible that any one of these processes can be interrupted, so that you can cease to faithfully or coherently represent a world. You can suddenly go blind, may not be able to name living things but still be able to name tools, suddenly not be able to perceive motion or location, those things can break apart. All kinds of things can be disrupted for the worse certainly. But what these contemplative traditions have recognized is that certain things can be disrupted or brought to a halt for the better. The thing that can interrupt the usual cascade of mediocrity and suffering psychologically speaking is this representation of self as subject in the middle of experience.
You can cease to construct a subject that is internal to the body. What remains in that case is a sense that mind is much vaster than it was a moment ago, because it is no longer confined to the sense that there is this central thinker of thoughts. There is a recognition that thoughts arise all by themselves, just as sounds do, no one is authoring your thoughts - you certainly aren’t. The sense that you are is what it feels like to be identified with this next spontaneously arising thought.
So, you loose sense that you are on the edge of your life, looking over your own shoulder, appropriating experience and what you can feel very vividly here is a real unity. emptyness, non-duality of subjects and objects, such that there is really just experience. This is not a new way of thinking about yourself in the world, this is a ceasing to identify with thought. This is making no metaphysical claims about how this relates to matter or the universe.
As as matter of experience you can feel identical to experience itself. You are not standing on the river bank watching things go by, you are the river, and that solves a very wide class of problems, psychologically speaking, with respect to suffering. And, it does land one in a surprising kind of equanimity and even eudemonia (well being) that may seem counter intuitive in the midst of the cacophony of daily life. But again, it’s not about the negation of personhood, it is just a recognition that as a matter of experience there is just experience, and the feeling that there is an experiencer is yet more experience, so that if you just drop back… there is just everything in its own place.
Friday, September 09, 2022
Since the discovery of rapid eye movement (REM) sleep, the nature of the eye movements that characterize this sleep phase has remained elusive. Do they reveal gaze shifts in the virtual environment of dreams or simply reflect random brainstem activity? We harnessed the head direction (HD) system of the mouse thalamus, a neuronal population whose activity reports, in awake mice, their actual HD as they explore their environment and, in sleeping mice, their virtual HD. We discovered that the direction and amplitude of rapid eye movements during REM sleep reveal the direction and amplitude of the ongoing changes in virtual HD. Thus, rapid eye movements disclose gaze shifts in the virtual world of REM sleep, thereby providing a window into the cognitive processes of the sleeping brain.
Wednesday, September 07, 2022
The End of History was supposed to have happened back in 1989, the year the Berlin Wall fell and Francis Fukuyama announced the conclusive triumph of liberal democracy. We know how that thesis worked out. But what happens when the other kind of History — academic, not Hegelian — starts to collapse?...That’s a question that James H. Sweet, a professor of history at the University of Wisconsin, Madison, and the president of the American Historical Association, tried to raise earlier this month in a column titled “Is History History?” for the organization’s newsmagazine. It didn’t go well...Sweet’s core concern in the piece was the “trend toward presentism” — the habit of weighing the past against the social concerns and moral categories of the present.Sweet was immediately attacked by the cancel culture of left-wing academics and felt obliged to issue an apology. Stevens notes that
...the larger shame is that Sweet had important things to say in his thoughtful column — things that the reaction to the column (and the reaction to the reaction) now risk burying...Between 2003 and 2013, a dwindling number of history Ph.D.s, he noted, were going to students doing work on topics preceding 1800. At the same time, historians were producing works that “collapse into the familiar terms of contemporary debates,” particularly those connected to identity politics.....“This new history,” he wrote, “often ignores the values and mores of people in their own times, as well as change over time, neutralizing the expertise that separates historians from those in other disciplines.”
...Sweet was warning that historians risked doing an injustice both to their own profession as well as to the past itself by falling victim to “the allure of political relevance.” His main example came from a recent visit to the Elmina Castle in Ghana..which has become a kind of shrine for African Americans seeking a place to memorialize enslaved ancestors...Sweet says as a historian of Africa, “less than 1 percent of the Africans passing through Elmina arrived in North America” — most...ended up in Brazil or the Caribbean. And those who were enslaved were often first brought to Elmina by other African brokers who promoted the slave trade just as cruelly and greedily as the Europeans with whom they did business.
That does nothing to diminish the evil of the trade, much less its relevance to America’s past and present...But it helps put it into a global context in which the roles of victim and victimizer seldom fall neatly along a color line. If that challenges current orthodoxy, it’s only because that orthodoxy is based on a simplistic understanding of history. The proper role of the historian is to complexify, not simplify; to show us historical figures in the context of their time, not reduce them to figurines that can be weaponized in our contemporary debates.
Above all, historians should make us understand the ways in which the past was distinct. This shouldn’t prevent us from making moral judgments about it. But we can make better judgments, informed by the knowledge that our forebears rarely acted with the benefit (or burden) of our assumptions, expectations, experiences and values. There’s a lesson in humility in that, as well as a reminder that we are only actors in time whose most cherished ideas may eventually seem strange, and sometimes abhorrent, to our descendants.Sweet's column...
— which bent over backward to showcase his liberal bona fides — ignited the usual progressive furies. Anyone looking for further confirmation that modern academia has become a fundamentally ideological and coercive exercise masquerading as a scholarly and collegial one need have looked no further. It will be interesting to see if Sweet manages to hold on to his post as the American Historical Association’s president...If people are wondering how history ends, maybe this is how: when a scholarly discipline tries to turn itself into something it isn’t, making itself increasingly irrelevant in its desperate bid for relevancy.
Monday, September 05, 2022
Superstitious learning is usually thought to be accounted for by conditioned association, but Jin et al. now show that monkeys can develop more complex cognitive structures independent of reinforcement:
Past studies on learning and decision-making usually rely on the assumption that the task is learnable. However, humans and other animals often infer spurious relationships from coincidental associations, and it is unknown if this could be achieved without reward conditioning. Here, we exposed monkeys to sets of images that had a hidden hierarchical order and to unordered sets that lacked an underlying structure. Monkeys treated the unordered sets as if they had a hierarchical order even under reward schedules that incentivized random choices. The results cannot be explained by simple associative mechanisms that account for other types of spurious learning, suggesting that when presented with random events animals conjure elaborate model-based structures.Abstract
Humans and other animals often infer spurious associations among unrelated events. However, such superstitious learning is usually accounted for by conditioned associations, raising the question of whether an animal could develop more complex cognitive structures independent of reinforcement. Here, we tasked monkeys with discovering the serial order of two pictorial sets: a “learnable” set in which the stimuli were implicitly ordered and monkeys were rewarded for choosing the higher-rank stimulus and an “unlearnable” set in which stimuli were unordered and feedback was random regardless of the choice. We replicated prior results that monkeys reliably learned the implicit order of the learnable set. Surprisingly, the monkeys behaved as though some ordering also existed in the unlearnable set, showing consistent choice preference that transferred to novel untrained pairs in this set, even under a preference-discouraging reward schedule that gave rewards more frequently to the stimulus that was selected less often. In simulations, a model-free reinforcement learning algorithm (Q-learning) displayed a degree of consistent ordering among the unlearnable set but, unlike the monkeys, failed to do so under the preference-discouraging reward schedule. Our results suggest that monkeys infer abstract structures from objectively random events using heuristics that extend beyond stimulus–outcome conditional learning to more cognitive model-based learning mechanisms.
Friday, September 02, 2022
I want to pass on a few items from my list of putative MindBlog posts on A.I.
The first derives from an series of emails on A.I. sent to the listserve of the "Chaos and Complex Systems Discussion Group" at Univ. of Wisconsin, Madison, that I attended until my move to Austin Tx. They point to the kerfuffle started by suspended Google engineer Blake Lemoine over whether one of the company's experimental AIs called LaMDA had achieved sentience, and How belief in AI sentience is becoming a problem.
(By the way, If you want to set up your own chatbot for self therapy, that won't collect and sell personal info you may divulge to it, visit https://replika.com/.... I actually tried it out, was underwhelmed by its responses, so deleted my account.)
An article by Kevin Roose on the potentials and risks of A.I. is worth reading. One amazing feat of A.I. has been solving the "protein-folding problem," which I (as a trained biochemist) have been following for over 50 years.
This summer, DeepMind announced that AlphaFold (an A.I. system descended from the Go-playing one) had made predictions of the three-dimensional structures of proteins from their one-dimensional amino acid sequences for nearly all of the 200 million proteins known to exist — producing a treasure trove of data that will help medical researchers develop new drugs and vaccines for years to come. Last year, the journal Science recognized AlphaFold’s importance, naming it the biggest scientific breakthrough of the year.
Here are a few further clips:
Even if the skeptics are right, and A.I. doesn’t achieve human-level sentience for many years, it’s easy to see how systems like GPT-3, LaMDA (language models) and DALL-E 2 (generating images from language descriptions) could become a powerful force in society. In a few years, the vast majority of the photos, videos and text we encounter on the internet could be A.I.-generated. Our online interactions could become stranger and more fraught, as we struggle to figure out which of our conversational partners are human and which are convincing bots. And tech-savvy propagandists could use the technology to churn out targeted misinformation on a vast scale, distorting the political process in ways we won’t see coming.
Ajeya Cotra, a senior analyst with Open Philanthropy who studies A.I. risk, estimated two years ago that there was a 15 percent chance of “transformational A.I.” — which she and others have defined as A.I. that is good enough to usher in large-scale economic and societal changes, such as eliminating most white-collar knowledge jobs — emerging by 2036...But in a recent post, Ms. Cotra raised that to a 35 percent chance, citing the rapid improvement of systems like GPT-3.
Because of how new many of these A.I. systems are, few public officials have any firsthand experience with tools like GPT-3 or DALL-E 2, nor do they grasp how quickly progress is happening at the A.I. frontier...we could end up with a repeat of what happened with social media companies after the 2016 election — a collision of Silicon Valley power and Washington ignorance, which resulted in nothing but gridlock and testy hearings...big tech companies investing billions in A.I. development — the Googles, Metas and OpenAIs of the world — need to do a better job of explaining what they’re working on, without sugarcoating or soft-pedaling the risks.
Wednesday, August 31, 2022
Does crypto-world really give us trustworthyness without gate keepers...? The answer is NO - It hides a new elite.
“...Blackburn developed hacks for the period of time that was of particular interest: from the cryptocurrency’s start to when Bitcoin achieved parity with the U.S. dollar in February 2011, which coincided with the establishment of the Silk Road, a Bitcoin-based black market...Drip-by-drip, information leakage erodes the once-impenetrable blocks, carving out a new landscape of socioeconomic data,” Ms. Blackburn and her collaborators report in their new paper...Aggregating multiple leakages, Ms. Blackburn consolidated many Bitcoin addresses, which might have seemed to represent many miners, into few. She pieced together a catalog of agents and concluded that, in those first two years, 64 key players — some of whom were the community’s “founders,” as the researchers called them — mined most of the Bitcoin that existed at the time.
Although the analysis showed that the big players numbered 64 over two years, at any given moment, according to the researchers’ modeling, the effective size of that population was only five or six. And on many occasions, just one or two people held most of the mining power...As Ms. Blackburn described it, there were very few people “wearing the crown,” functioning as arbiters of the network — “which is not the ethos of decentralized trustless crypto,”...
Once Ms. Blackburn had assembled the catalog of agents, she analyzed the income they had reaped from mining. She found that within a few months of the cryptocurrency’s introduction — and contrary to Bitcoin’s egalitarian promise — a classic distribution of income inequality emerged: A small fraction of the miners held most of the wealth and power. (Mining income demonstrated what is called a Pareto distribution, after Vilfredo Pareto, a 19th-century economist.)
On several occasions, individual miners wielded more than 50 percent of the computational power and, as a result, could have taken over like a tyrant using what’s called a “51 percent attack.” For instance, they could have cheated the system and repeatedly spent the same Bitcoins on different transactions...to add a twist, Ms. Blackburn found that while some miners had the power to execute 51 percent attacks, they repeatedly chose not to. Rather, they acted altruistically — preserving the cryptocurrency’s integrity, even though the decentralization-based fraud-prevention mechanism had been compromised...Although Bitcoin was designed to rely on a decentralized, trustless network of anonymous agents, its early success rested instead on cooperation among a small group of altruistic founders.
For Glen Weyl, an economist at Microsoft Research who was consulted on the research, this finding demonstrates how decentralization played a rhetorical rather than substantive role. “And that rhetorical role was very powerful — it bound together this community, much as other myths have bound together other communities, like nations,” Dr. Weyl said; he and Mr. Lanier wrote about this research for CoinDesk. But the myth and the promise, he said, were in tension with the reality that emerged. “It’s just fascinatingly ironic, and also predictable, repeating the historical patterns it aspires to erase.”
Mr. Lanier called it “decentralization theater.” Cryptocurrencies create an illusion: “‘Now we’re in utopia. Everything’s decentralized. Everybody’s equal.’ There’s this notion of democracy without annoyance.”...But, he said, these systems end up hiding a new elite, which is probably just an old elite in a new arena. And the technology cuts both ways. “Whatever you think you can achieve using new algorithms, or big data, or whatever, can also be used against you,” Mr. Lanier said. “The same algorithms can be used by scientists to interrogate and investigate these castles that are put up by the new elite.”
One moral of the story, Ms. Blackburn said, is simply: “You have to be careful.” There is a limited timeline for encryption, “a horizon beyond which it will no longer be useful. When you are encrypting private data and making it public, you cannot assume that it’ll be private forever.”
Monday, August 29, 2022
Carr’s argument began with an observation, one that felt familiar:
The very way my brain worked seemed to be changing. It was then that I began worrying about my inability to pay attention to one thing for more than a couple of minutes. At first I’d figured that the problem was a symptom of middle-age mind rot. But my brain, I realized, wasn’t just drifting. It was hungry. It was demanding to be fed the way the Net fed it — and the more it was fed, the hungrier it became. Even when I was away from my computer, I yearned to check email, click links, do some Googling. I wanted to be connected.
McLuhan’s view is that mediums matter more than content; it’s the common rules that govern all creation and consumption across a medium that change people and society. Oral culture teaches us to think one way, written culture another. Television turned everything into entertainment, and social media taught us to think with the crowd...All this happens beneath the level of content. CNN and Fox News and MSNBC are ideologically different. But cable news in all its forms carries a sameness: the look of the anchors, the gloss of the graphics, the aesthetics of urgency and threat, the speed, the immediacy, the conflict, the conflict, the conflict.Klein's (edited) comments on Postman's prophetic 1985 book "Amusing Ourselves to Death":
...the dystopia we must fear is not the totalitarianism of George Orwell’s “1984” but the narcotized somnolence of Aldous Huxley’s “Brave New World.” Television teaches us to expect that anything and everything should be entertaining. But not everything should be entertainment, and the expectation that it will be is a vast social and even ideological change...The border between entertainment and everything else has, and entertainers become the only ones able to fulfill our expectations for politicians....People who were viable politicians in a textual era are locked out of politics because they can not command the screen...Television, he writes, “serves us most ill when it co-opts serious modes of discourse — news, politics, science, education, commerce, religion — and turns them into entertainment packages...the line of Postman’s that holds me is his challenge to the critics who spend their time urging television to be better rather than asking what television is: “The trouble with such people is that they do not take television seriously enough.”Klein continues:
I have come to think the same of today’s technologists: Their problem is that they do not take technology seriously enough. They refuse to see how it is changing us or even how it is changing them...Over the past decade, the narrative has turned against Silicon Valley. Puff pieces have become hit jobs, and the visionaries inventing our future have been recast as the Machiavellians undermining our present. My frustration with these narratives, both then and now, is that they focus on people and companies, not technologies. I suspect that is because American culture remains deeply uncomfortable with technological critique.
Americans are capitalists, and we believe nothing if not that if a choice is freely made, that grants it a presumption against critique. That is one reason it’s so hard to talk about how we are changed by the mediums we use. That conversation, on some level, demands value judgments. This was on my mind recently, when I heard Jonathan Haidt, a social psychologist who’s been collecting data on how social media harms teenagers, say, bluntly, “People talk about how to tweak it — oh, let’s hide the like counters. Well, Instagram tried — but let me say this very clearly: There is no way, no tweak, no architectural change that will make it OK for teenage girls to post photos of themselves, while they’re going through puberty, for strangers or others to rate publicly.”
What struck me about Haidt’s comment is how rarely I hear anything structured that way. He’s arguing three things. First, that the way Instagram works is changing how teenagers think. It is supercharging their need for approval of how they look and what they say and what they’re doing, making it both always available and never enough. Second, that it is the fault of the platform — that it is intrinsic to how Instagram is designed, not just to how it is used. And third, that it’s bad. That even if many people use it and enjoy it and make it through the gantlet just fine, it’s still bad. It is a mold we should not want our children to pass through.
Or take Twitter. As a medium, Twitter nudges its users toward ideas that can survive without context, that can travel legibly in under 280 characters. It encourages a constant awareness of what everyone else is discussing. It makes the measure of conversational success not just how others react and respond but how much response there is. It, too, is a mold, and it has acted with particular force on some of our most powerful industries — media and politics and technology. These are industries I know well, and I do not think it has changed them or the people in them (including me) for the better.
But what would? I’ve found myself going back to a wise, indescribable book that Jenny Odell, a visual artist, published in 2019, “How to Do Nothing: Resisting the Attention Economy.” In it she suggests that any theory of media must start with a theory of attention. “One thing I have learned about attention is that certain forms of it are contagious,” she writes. She continues:
When you spend enough time with someone who pays close attention to something (if you were hanging out with me, it would be birds), you inevitably start to pay attention to some of the same things. I’ve also learned that patterns of attention — what we choose to notice and what we do not — are how we render reality for ourselves, and thus have a direct bearing on what we feel is possible at any given time. These aspects, taken together, suggest to me the revolutionary potential of taking back our attention.
I think Odell frames both the question and the stakes correctly. Attention is contagious. What forms of it, as individuals and as a society, do we want to cultivate? What kinds of mediums would that cultivation require?
This is anything but an argument against technology, were such a thing even coherent. It’s an argument for taking technology as seriously as it deserves to be taken, for recognizing, as McLuhan’s friend and colleague John M. Culkin put it, “we shape our tools, and thereafter, they shape us.”
There is an optimism in that, a reminder of our own agency. And there are questions posed, ones we should spend much more time and energy trying to answer: How do we want to be shaped? Who do we want to become?
Friday, August 26, 2022
Our anterior insula signals salience and deviations from expectations via bursts of beta oscillations
Haufler et al. show that the insula signals salience and prediction errors via amplitude modulations of beta bursts (~15-40 Hertz, or cycles per second), which coincide with the near simultaneous recruitment of vast cortical territories.
NEW & NOTEWORTHY
Functional imaging studies indicate that the anterior insula encodes salience and deviations from expectations. Beyond changing BOLD signals, however, the physiological underpinnings of these signals are unknown. By recording local field potentials in patients with epilepsy, we found that the anterior insula generates large bursts of beta oscillations whose amplitude is modulated by the salience of outcomes and deviations from expectations. Moreover, insular beta bursts coincide with the activation of many high-order cortical areas.ABSTRACT:
Functional imaging studies indicate that the insula encodes the salience of stimuli and deviations from expectations, signals that can mobilize cognitive resources and facilitate learning. However, there is no information about the physiological underpinnings of these phenomena beyond changing BOLD signals. To shed light on this question, we analyzed intracerebral local field potentials (LFPs) in five patients with epilepsy of both genders performing a virtual reality task that featured varying odds of monetary rewards and losses. Upon outcome disclosure, the anterior (but not the posterior) insula generated bursts of beta oscillations whose amplitudes were lower for neutral than positive and negative outcomes, consistent with a salience signal. Moreover, beta burst power was higher when outcomes deviated from expectations, whether the outcome was better or worse than expected, indicating that the insula provides an unsigned prediction error signal. Last, in relation to insular beta bursts, many higher-order cortical areas exhibited robust changes in LFP activity that ranged from spectrally nonspecific or differentiated increases in gamma power to bursts of beta activity that closely resembled the insular beta bursts themselves. Critically, the activity of these other cortical regions was more closely tied in time to insular bursts than task events, suggesting that they are associated with particularly significant cognitive phenomena. Overall, our findings suggest that the insula signals salience and prediction errors via amplitude modulations of beta bursts, which coincide with the near simultaneous recruitment of vast cortical territories.
Wednesday, August 24, 2022
The researchers divided 39 paid study participants into two groups, assigning one to a series of difficult cognitive tasks that were designed to induce mental exhaustion. In one, participants had to decide whether letters and numbers flashing on a computer screen in quick succession were green or red, uppercase or lowercase, and other variations. In another, volunteers had to remember whether a number matched one they’d seen three characters earlier...As the day dragged on, the researchers repeatedly measured cognitive fatigue by asking participants to make choices that required self-control—deciding to forgo cash that was immediately available so they could earn a larger amount later, for example. The group that had been assigned to more difficult tasks made about 10% more impulsive choices than the group with easier tasks, the researchers observed. At the same time, their glutamate levels rose by about 8% in the lateral prefrontal cortex—a pattern that did not show up in the other group...
Here is the Wiehler et al. abstract:
• Cognitive fatigue is explored with magnetic resonance spectroscopy during a workday
• Hard cognitive work leads to glutamate accumulation in the lateral prefrontal cortex
• The need for glutamate regulation reduces the control exerted over decision-making
• Reduced control favors the choice of low-effort actions with short-term rewardsSummary
Behavioral activities that require control over automatic routines typically feel effortful and result in cognitive fatigue. Beyond subjective report, cognitive fatigue has been conceived as an inflated cost of cognitive control, objectified by more impulsive decisions. However, the origins of such control cost inflation with cognitive work are heavily debated. Here, we suggest a neuro-metabolic account: the cost would relate to the necessity of recycling potentially toxic substances accumulated during cognitive control exertion. We validated this account using magnetic resonance spectroscopy (MRS) to monitor brain metabolites throughout an approximate workday, during which two groups of participants performed either high-demand or low-demand cognitive control tasks, interleaved with economic decisions. Choice-related fatigue markers were only present in the high-demand group, with a reduction of pupil dilation during decision-making and a preference shift toward short-delay and little-effort options (a low-cost bias captured using computational modeling). At the end of the day, high-demand cognitive work resulted in higher glutamate concentration and glutamate/glutamine diffusion in a cognitive control brain region (lateral prefrontal cortex [lPFC]), relative to low-demand cognitive work and to a reference brain region (primary visual cortex [V1]). Taken together with previous fMRI data, these results support a neuro-metabolic model in which glutamate accumulation triggers a regulation mechanism that makes lPFC activation more costly, explaining why cognitive control is harder to mobilize after a strenuous workday.
Monday, August 22, 2022
Humans spontaneously invent songs from an early age. Here, we exploit this natural inclination to probe implicit musical knowledge in 33 untrained and poor singers (amusia). Each sang 28 long improvisations as a response to a verbal prompt or a continuation of a melodic stem. To assess the extent to which each improvisation reflects tonality, which has been proposed to be a core organizational principle of musicality and which is present within most music traditions, we developed a new algorithm that compares a sung excerpt to a probability density function representing the tonal hierarchy of Western music. The results show signatures of tonality in both nonmusicians and individuals with congenital amusia, who have notorious difficulty performing musical tasks that require explicit responses and memory. The findings are a proof of concept that improvisation can serve as a novel, even enjoyable method for systematically measuring hidden aspects of musicality across the spectrum of musical ability.
Friday, August 19, 2022
Wednesday, August 17, 2022
Consumption of alcohol creates a sense of euphoria, reduces inhibition, and increases sociability and impulsivity. The age at which alcohol is first experienced is a key factor contributing to the likelihood to misuse alcohol. However, the impacts of the first experience of alcohol on the molecules in the brain at these key developmental stages are not well understood. Knabbe et al. endeavored to address the neuromolecular alterations resulting from acute alcohol by combining hippocampal proteomics with somatosensory and motor cortex protein, dendrite, axon, and mitochondrial analysis in adolescent mice. Evidence from this array of preparations led to the hypothesis that alcohol disrupted mitochondrial trafficking, and using Drosophila they demonstrated a functional role for mitochondrial trafficking in cue-induced alcohol preference.
The cross-assay and cross-species approach outlined in Knabbe et al. proved to be an effective way of discovering how alcohol hijacks brain mechanisms. Animals from flies to humans maintain functionally consistent neurotransmitter systems, neural circuit mechanisms, and molecular pathways underlying reward.And here is the abstract from Knabbe et al.:
Alcohol intoxication at early ages is a risk factor for the development of addictive behavior. To uncover neuronal molecular correlates of acute ethanol intoxication, we used stable-isotope-labeled mice combined with quantitative mass spectrometry to screen more than 2,000 hippocampal proteins, of which 72 changed synaptic abundance up to twofold after ethanol exposure. Among those were mitochondrial proteins and proteins important for neuronal morphology, including MAP6 and ankyrin-G. Based on these candidate proteins, we found acute and lasting molecular, cellular, and behavioral changes following a single intoxication in alcohol-naïve mice. Immunofluorescence analysis revealed a shortening of axon initial segments. Longitudinal two-photon in vivo imaging showed increased synaptic dynamics and mitochondrial trafficking in axons. Knockdown of mitochondrial trafficking in dopaminergic neurons abolished conditioned alcohol preference in Drosophila flies. This study introduces mitochondrial trafficking as a process implicated in reward learning and highlights the potential of high-resolution proteomics to identify cellular mechanisms relevant for addictive behavior.
Monday, August 15, 2022
The use of low doses of psychedelic substances (microdosing) is attracting increasing interest. This systematic review summarises all empirical microdosing research to date, including a set of infrequently cited studies that took place prior to prohibition. Specifically, we reviewed 44 studies published between 1955 and 2021, and summarised reported effects across six categories: mood and mental health; wellbeing and attitude; cognition and creativity; personality; changes in conscious state; and neurobiology and physiology. Studies showed a wide range in risk of bias, depending on design, age, and other study characteristics. Laboratory studies found changes in pain perception, time perception, conscious state, and neurophysiology. Self-report studies found changes in cognitive processing and mental health. We review data related to expectation and placebo effects, but argue that claims that microdosing effects are largely due to expectancy are premature and possibly wrong. In addition, we attempt to clarify definitional inconsistencies in the microdosing literature by providing suggested dose ranges across different substances. Finally, we provide specific design suggestions to facilitate more rigorous future research.
Wednesday, August 10, 2022
From Neves et al.:
• Systematic review and meta-analysis of neurobehavioral effects of music training.
• We ask whether music training shapes auditory-perceptual and linguistic skills.
• Multivariate meta-analytic models are combined with narrative synthesis.
• Music training has a positive effect on auditory and linguistic processing.
• Our work informs research on plasticity, transfer, and music-based interventions.Abstract
It is often claimed that music training improves auditory and linguistic skills. Results of individual studies are mixed, however, and most evidence is correlational, precluding inferences of causation. Here, we evaluated data from 62 longitudinal studies that examined whether music training programs affect behavioral and brain measures of auditory and linguistic processing (N = 3928). For the behavioral data, a multivariate meta-analysis revealed a small positive effect of music training on both auditory and linguistic measures, regardless of the type of assignment (random vs. non-random), training (instrumental vs. non-instrumental), and control group (active vs. passive). The trim-and-fill method provided suggestive evidence of publication bias, but meta-regression methods (PET-PEESE) did not. For the brain data, a narrative synthesis also documented benefits of music training, namely for measures of auditory processing and for measures of speech and prosody processing. Thus, the available literature provides evidence that music training produces small neurobehavioral enhancements in auditory and linguistic processing, although future studies are needed to confirm that such enhancements are not due to publication bias.
Monday, August 08, 2022
Aging-related diseases such as heart failure and other cardiovascular disorders are the leading causes of death in many countries, and they are becoming increasingly common worldwide as the number of older people increases. The ability of the heart to produce new cardiomyocytes decreases with age, which makes it more difficult to repair damage and increases the risk of heart failure. However, a study by Lerchenmüller et al. suggests that exercise may offer some help in this regard even if started late in life. The authors had previously reported that voluntary exercise can stimulate the generation of cardiomyocytes in young adult mouse hearts, and now they have also observed this phenomenon in aged animals.Here is the results statement of the article:
Cardiomyogenesis was observed at a significantly higher frequency in exercised compared with sedentary aged hearts on the basis of the detection of mononucleated/diploid 15N-thymidine–labeled cardiomyocytes. No mononucleated/diploid 15N-thymidine–labeled cardiomyocyte was detected in sedentary aged mice. The annual rate of mononucleated/diploid 15N-thymidine–labeled cardiomyocytes in aged exercised mice was 2.3% per year. This compares with our previously reported annual rate of 7.5% in young exercised mice and 1.63% in young sedentary mice. Transcriptional profiling of young and aged exercised murine hearts and their sedentary controls revealed that exercise induces pathways related to circadian rhythm, irrespective of age. One known oscillating transcript, however, that was exclusively upregulated in aged exercised hearts, was isoform 1.4 of regulator of calcineurin, whose regulation and functional role were explored further.
Friday, August 05, 2022
From the introduction of Elvira et al. (open source):
We designed a study intended to identify (i) the main factors leading to differences in motor skill acquisition with aging and (ii) the effect of applying noninvasive brain stimulation during motor training. Comparing different components of motor skill acquisition in young and older adults, constituting the extremes of performance in this study, we found that the improvement of the sequence-tapping task is maximized by the early consolidation of the spatial properties of the sequence in memory (i.e., sequence order), leading to a reduced error of execution, and by the optimization of its temporal features (i.e., chunking). We found the consolidation of spatiotemporal features to occur early in training in young adults, suggesting the emergence of motor chunks to be a direct consequence of committing the sequence elements to memory. This process, seemingly less efficient in older adults, could be partially restored using atDCS by enabling the early consolidation of spatial features, allowing them to prioritize the increase of their speed of execution, ultimately leading to an earlier consolidation of motor chunks. This separate consolidation of spatial and temporal features seen in older adults suggests that the emergence of temporal patterns, commonly identified as motor chunks at a behavioral level, stem from the optimization of the execution of the motor sequence resulting from practice, which can occur only after the sequence order has been stored in memory.Here is their abstract:
Practicing a previously unknown motor sequence often leads to the consolidation of motor chunks, which enable its accurate execution at increasing speeds. Recent imaging studies suggest the function of these structures to be more related to the encoding, storage, and retrieval of sequences rather than their sole execution. We found that optimal motor skill acquisition prioritizes the storage of the spatial features of the sequence in memory over its rapid execution early in training, as proposed by Hikosaka in 1999. This process, seemingly diminished in older adults, was partially restored by anodal transcranial direct current stimulation over the motor cortex, as shown by a sharp improvement in accuracy and an earlier yet gradual emergence of motor chunks. These results suggest that the emergence of motor chunks is preceded by the storage of the sequence in memory but is not its direct consequence; rather, these structures depend on, and result from, motor practice.
Wednesday, August 03, 2022
Fascinating work from Kim et al. on the influence of the prediction errors that are essential in calibrating actions of our predictive minds:
Our brains control aspects of our movements without conscious awareness, allowing many of us to effortlessly pick up a glass of water or wave hello. Here, we demonstrate that this implicit motor system can learn to refine movements that we plan but ultimately decide not to perform. Participants planned to reach to a target but sometimes withheld these reaches while an animation simulated missing the target. Afterward, participants unknowingly reached opposite the direction of the apparent mistake, indicating that the implicit motor system had learned from the animated error. These findings indicate that movement is not strictly necessary for motor adaptation, and we can learn to update our actions without physically performing them.Abstract
Prediction errors guide many forms of learning, providing teaching signals that help us improve our performance. Implicit motor adaptation, for instance, is thought to be driven by sensory prediction errors (SPEs), which occur when the expected and observed consequences of a movement differ. Traditionally, SPE computation is thought to require movement execution. However, recent work suggesting that the brain can generate sensory predictions based on motor imagery or planning alone calls this assumption into question. Here, by measuring implicit motor adaptation during a visuomotor task, we tested whether motor planning and well-timed sensory feedback are sufficient for adaptation. Human participants were cued to reach to a target and were, on a subset of trials, rapidly cued to withhold these movements. Errors displayed both on trials with and without movements induced single-trial adaptation. Learning following trials without movements persisted even when movement trials had never been paired with errors and when the direction of movement and sensory feedback trajectories were decoupled. These observations indicate that the brain can compute errors that drive implicit adaptation without generating overt movements, leading to the adaptation of motor commands that are not overtly produced.
Monday, August 01, 2022
Findings from a few small studies have permeated popular media with the notion that a few weeks of training in mindfulness-based stress reduction (MBSR) can lead to measurable changes in brain structure and have been cited over 3200 times, combined. However, there is a lack of replication (conceptual or direct) or confirmatory analysis of these findings in a fully randomized trial. Moreover, a recent meta-analysis found that the proportion of high-quality publications in this domain have not improved over time, although there are a growing number of high-quality studies being conducted.Their abstract:
Studies purporting to show changes in brain structure following the popular, 8-week mindfulness-based stress reduction (MBSR) course are widely referenced despite major methodological limitations. Here, we present findings from a large, combined dataset of two, three-arm randomized controlled trials with active and waitlist (WL) control groups. Meditation-naïve participants (n = 218) completed structural magnetic resonance imaging scans during two visits: baseline and postintervention period. After baseline, participants were randomly assigned to WL (n = 70), an 8-week MBSR program (n = 75), or a validated, matched active control (n = 73). We assessed changes in gray matter volume, gray matter density, and cortical thickness. In the largest and most rigorously controlled study to date, we failed to replicate prior findings and found no evidence that MBSR produced neuroplastic changes compared to either control group, either at the whole-brain level or in regions of interest drawn from prior MBSR studies.
Friday, July 29, 2022
Does the return of large carnivores affect voting behavior? We study this question through the lens of wolf attacks on livestock. Sustained environmental conservation has allowed the wolf (Canis lupus) to make an impressive and unforeseen comeback across Central Europe in recent years. While lauded by conservationists, local residents often see the wolf as a threat to economic livelihoods, particularly those of farmers. As populists appear to exploit such sentiments, the wolf’s reemergence is a plausible source for far-right voting behavior. To test this hypothesis, we collect fine-grained spatial data on wolf attacks and construct a municipality-level panel in Germany. Using difference-in-differences models, we find that wolf attacks are accompanied by a significant rise in far-right voting behavior, while the Green party, if anything, suffers electoral losses. We buttress this finding using local-level survey data, which confirms a link between wolf attacks and negative sentiment toward environmental protection. To explore potential mechanisms, we analyze Twitter posts, election manifestos, and Facebook ads to show that far-right politicians frame the wolf as a threat to economic livelihoods.
Wednesday, July 27, 2022
Rats and mice show robust emotional contagion by aligning their fear and pain to that of others.
Brain regions necessary for emotional contagion in rodents closely resemble those associated with human empathy; understanding the biology of emotional contagion in rodents can thus shed light on the evolutionary origin and mechanisms of human empathy.
Cingulate area 24 in rats and mice contains emotional mirror neurons that map the emotions of others onto the witnesses’ own emotions.
Emotional contagion prepares animals to deal with threats by using others as sentinels; the fact that rodents approach individuals in distress facilitates such contagion.
In some conditions, rats and mice learn to prefer actions that benefit others, with notable individual differences. This effect depends on structures that overlap with those of emotional contagion.
Monday, July 25, 2022
A central question for decision-making scholars is: why are humans and animals so predictably inconsistent in their choices? In the language of economics, why are they irrational?
Data suggest that this reflects an optimal trade-off between the precision with which the brain represents the values of choices and the biological costs of that precision. Increasing representational precision may improve choice consistency, but the metabolic cost of increased precision is significant.
Given the cost of precision, the brain might use efficient value-encoding mechanisms that maximize informational content. Mathematical analyses suggest that a mechanism called divisive normalization approximates maximal efficiency per action potential in decision systems.
Behavioral studies appear to validate this claim. Inconsistencies produced by decision-makers can be well modeled as the byproduct of efficient divisive normalization mechanisms that maximize information while minimizing metabolic costs.
Friday, July 22, 2022
In the new world that we are now entering America is one of the few countries that can both feed itself and make all the widgets that it needs. Together with its partners in the NAFTA alliance it is geographically and demographically secure, able to turn inwards and still maintain much of its population and lifestyle. Almost all other countries must either export or import energy, food, materials, or manufactured products. Free trade transport routes that have permitted this are crumbling as America continues its withdrawal from guaranteeing a world order formed to oppose a former Soviet Union that fell in 1990. As the level of global trade diminishes, most countries outside the North American group must reduce their population levels and living standards.I was pointed to this book by listening to a Sam Harris "Makeing Sense" podcast titled titled "The End of Global Order," an interview with Peter Zeihand and Ian Bremmer. Zeihan integrates geopolitical and demographic perspectives to make a compelling case that that past few decades have been the best it will ever be in our lifetime, because our world is breaking apart. For the past seventy-five years we have been living a a perfect moment made possible by post World War II American fostering:
“an environment of global security so that any partner could go anywhere, anytime, interface with anyone, in any economic manner, participate in any supply chain and access any material input—all without needing a military escort. This butter side of the Americans’ guns-and-butter deal created what we today recognize as free trade. Globalization.”But,
“Thirty years on from the Cold War’s end, the Americans have gone home. No one else has the military capacity to support global security, and from that, global trade. The American-led Order is giving way to Disorder. Global aging didn’t stop once we reached that perfect moment of growth...The global worker and consumer base is aging into mass retirement. In our rush to urbanize, no replacement generation was ever born...“The 2020s will see a collapse of consumption and production and investment and trade almost everywhere. Globalization will shatter into pieces. Some regional. Some national. Some smaller. It will be costly. It will make life slower. And above all, worse.”Zeihan shows that the America and its partners in the NAFTA accord, Canada and Mexico, enjoy a "Geography of Success" and demographics that will render it vastly better off than the rest of the world.
Perhaps the oddest thing of our soon-to-be present is that while the Americans revel in their petty, internal squabbles, they will barely notice that elsewhere the world is ending!!! Lights will flicker and go dark. Famine’s leathery claws will dig deep and hold tight. Access to the inputs—financial and material and labor—that define the modern world will cease existing in sufficient quantity to make modernity possible. The story will be different everywhere, but the overarching theme will be unmistakable: the last seventy-five years long will be remembered as a golden age, and one that didn’t last nearly long enough at that.In the introduction of his book, from which the above quotes are taken, Zeihan states that the book's real focus..
...is to map out what everything looks like on the other side of this change in condition. What are the new parameters of the possible? In a world deglobalized, what are the new Geographies of Success?The book's introduction and epilogue are useful summaries, and you should check out the very instructive graphics provided on Zeihan's website.
Wednesday, July 20, 2022
I pass on the summaries of work by Dickey et al.:
Different elements of a memory, or any mental event, are encoded in locations distributed across the cortex. A prominent hypothesis proposes that widespread networks are integrated with bursts of synchronized high-frequency oscillations called “ripples,” but evidence is limited. Here, using recordings inside the human brain, we show that ripples occur simultaneously in multiple lobes in both cortical hemispheres and the hippocampus, generally during sleep and waking, and especially during memory recall. Ripples phase-lock local cell firing and phase-synchronize with little decay between locations separated by up to 25 cm, enabling long-distance integration. Indeed, corippling sites have increased correlation of very-high-frequency activity which reflects cell firing. Thus, ripples may help bind information across the cortex in memory and other mental events.Abstract
Declarative memory encoding, consolidation, and retrieval require the integration of elements encoded in widespread cortical locations. The mechanism whereby such “binding” of different components of mental events into unified representations occurs is unknown. The “binding-by-synchrony” theory proposes that distributed encoding areas are bound by synchronous oscillations enabling enhanced communication. However, evidence for such oscillations is sparse. Brief high-frequency oscillations (“ripples”) occur in the hippocampus and cortex and help organize memory recall and consolidation. Here, using intracranial recordings in humans, we report that these ∼70-ms-duration, 90-Hz ripples often couple (within ±500 ms), co-occur (≥ 25-ms overlap), and, crucially, phase-lock (have consistent phase lags) between widely distributed focal cortical locations during both sleep and waking, even between hemispheres. Cortical ripple co-occurrence is facilitated through activation across multiple sites, and phase locking increases with more cortical sites corippling. Ripples in all cortical areas co-occur with hippocampal ripples but do not phase-lock with them, further suggesting that cortico-cortical synchrony is mediated by cortico-cortical connections. Ripple phase lags vary across sleep nights, consistent with participation in different networks. During waking, we show that hippocampo-cortical and cortico-cortical coripples increase preceding successful delayed memory recall, when binding between the cue and response is essential. Ripples increase and phase-modulate unit firing, and coripples increase high-frequency correlations between areas, suggesting synchronized unit spiking facilitating information exchange. co-occurrence, phase synchrony, and high-frequency correlation are maintained with little decrement over very long distances (25 cm). Hippocampo-cortico-cortical coripples appear to possess the essential properties necessary to support binding by synchrony during memory retrieval and perhaps generally in cognition.
Monday, July 18, 2022
Recent understanding of how the systemic environment shapes the brain throughout life has led to numerous intervention strategies to slow brain ageing. Cerebrospinal fluid (CSF) makes up the immediate environment of brain cells, providing them with nourishing compounds. We discovered that infusing young CSF directly into aged brains improves memory function. Unbiased transcriptome analysis of the hippocampus identified oligodendrocytes to be most responsive to this rejuvenated CSF environment. We further showed that young CSF boosts oligodendrocyte progenitor cell (OPC) proliferation and differentiation in the aged hippocampus and in primary OPC cultures. Using SLAMseq to metabolically label nascent mRNA, we identified serum response factor (SRF), a transcription factor that drives actin cytoskeleton rearrangement, as a mediator of OPC proliferation following exposure to young CSF. With age, SRF expression decreases in hippocampal OPCs, and the pathway is induced by acute injection with young CSF. We screened for potential SRF activators in CSF and found that fibroblast growth factor 17 (Fgf17) infusion is sufficient to induce OPC proliferation and long-term memory consolidation in aged mice while Fgf17 blockade impairs cognition in young mice. These findings demonstrate the rejuvenating power of young CSF and identify Fgf17 as a key target to restore oligodendrocyte function in the ageing brain.
Friday, July 15, 2022
What we remember is shaped by what we already know. For example, remembering the angelfish from a recent aquarium visit is easier for those who already know what angelfish are and know things about them. In addition to facilitating memory retrieval of specific items, prior knowledge also supports memory by providing an overarching organizational structure for new information. Here, we show how expert knowledge leads birdwatchers to organize birds based on conceptual features, in contrast to novices who organize birds based on perceptual features. In turn, experts’ organizational structure supports memory by reducing interference typically caused by high overlap among items, even when to-be-remembered birds were unfamiliar species. These findings demonstrate how the organization of generalized knowledge promotes memory.Abstract
The influence of prior knowledge on memory is ubiquitous, making the specific mechanisms of this relationship difficult to disentangle. Here, we show that expert knowledge produces a fundamental shift in the way that interitem similarity (i.e., the perceived resemblance between items in a set) biases episodic recognition. Within a group of expert birdwatchers and matched controls, we characterized the psychological similarity space for a set of well-known local species and a set of less familiar, nonlocal species. In experts, interitem similarity was influenced most strongly by taxonomic features, whereas in controls, similarity judgments reflected bird color. In controls, perceived episodic oldness during a recognition memory task increased along with measures of global similarity between items, consistent with classic models of episodic recognition. Surprisingly, for experts, high global similarity did not drive oldness signals. Instead, for local birds memory tracked the availability of species-level name knowledge, whereas for nonlocal birds, it was mediated by the organization of generalized conceptual space. These findings demonstrate that episodic memory in experts can benefit from detailed subcategory knowledge, or, lacking that, from the overall relational structure of concepts. Expertise reshapes psychological similarity space, helping to resolve mnemonic separation challenges arising from high interitem overlap. Thus, even in the absence of knowledge about item-specific details or labels, the presence of generalized knowledge appears to support episodic recognition in domains of expertise by altering the typical relationship between psychological similarity and memory.
Wednesday, July 13, 2022
Monday, July 11, 2022
Increased amygdala and decreased frontolimbic resting-state functional connectivity in children with aggressive behavior
Maladaptive self-focused attention and default mode network connectivity: a transdiagnostic investigation across social anxiety and body dysmorphic disorders
Friday, July 08, 2022
As the world’s population of older adults increases, understanding disparities in age-related health is essential. Age-related changes in the immune system play a critical role in age-related morbidity and mortality. This study assesses associations between social stress and immunophenotypes as immune age phenotype markers for the first time in a national sample of older US adults. This study helps clarify mechanisms involved in accelerated development of the immune age phenotype, including socioeconomic and lifestyle factors and cytomegalovirus infection and reactivation. This study also identifies important points of intervention that may be useful in addressing inequalities in aging.Abstract
Exposure to stress is a risk factor for poor health and accelerated aging. Immune aging, including declines in naïve and increases in terminally differentiated T cells, plays a role in immune health and tissue specific aging, and may contribute to elevated risk for poor health among those who experience high psychosocial stress. Past data have been limited in estimating the contribution of life stress to the development of accelerated immune aging and investigating mediators such as lifestyle and cytomegalovirus (CMV) infection. This study utilizes a national sample of 5,744 US adults over age 50 to assess the relationship of social stress (viz., everyday discrimination, stressful life events, lifetime discrimination, life trauma, and chronic stress) with flow cytometric estimates of immune aging, including naïve and terminally differentiated T cell percentages and the ratio of CD4+ to CD8+ cells. Experiencing life trauma and chronic stress was related to a lower percentage of CD4+ naïve cells. Discrimination and chronic stress were each associated with a greater percentage of terminally differentiated CD4+ cells. Stressful life events, high lifetime discrimination, and life trauma were related to a lower percentage of CD8+ naïve cells. Stressful life events, high lifetime discrimination, and chronic stress were associated with a higher percentage of terminally differentiated CD8+ cells. High lifetime discrimination and chronic stress were related to a lower CD4+:CD8+ ratio. Lifestyle factors and CMV seropositivity partially reduced these effects. Results identify psychosocial stress as a contributor to accelerating immune aging by decreasing naïve and increasing terminally differentiated T cells.