Higher performance and fronto-parietal brain activity following active versus passive learning

From a brief open source PNAS report by Stillesjö et al. that has a nice graphic of the fMRI data supporting their observations:

We here demonstrate common neurocognitive long-term memory effects of active learning that generalize over course subjects (mathematics and vocabulary) by the use of fMRI. One week after active learning, relative to more passive learning, performance and fronto-parietal brain activity was significantly higher during retesting, possibly related to the formation and reactivation of semantic representations. These observations indicate that active learning conditions stimulate common processes that become part of the representations and can be reactivated during retrieval to support performance. Our findings are of broad interest and educational significance related to the emerging consensus of active learning as critical in promoting good long-term retention.

The Power of Us

A recent New York Times essay by Jon Mooallem, "Is life better when we're together?" is worth a read, and references work of Packer and Van Bavel described in their new book "The Power of Us." Their experiments, a continuation of work started by psychologist Henri Tafjel in the 1970s, illustrate how our social brains are programmed to organize us into "us" and "them" groups on the basis of sometimes completely arbitrary and trivial criteria, as in assigning a study group of subjects into groups A and B on the basis of a coin toss.  Tafjel's work is also referenced in another excellent article by Elizabeth Kolbert in The New Yorker, "How Politics Got So Polarized."  She reviews a number of recent books in this area, and also notes the phenomenon of "false polarization" - views of the extremes predominate as the moderate majority of people withdraw from the fray of commentary.

Here are some clips from the Mooallem article, the first noting Tafjel's experiments on high school students in Bristol, England.

...biases locked in right away. Overwhelmingly, people in Dr. Tajfel’s experiment gave more of the money he put at their disposal to members of their own group than the other. Moreover, they were bent on creating as large a disparity as possible, even when offered the option of maximizing the amount of money for everyone, at no cost. Their behavior seemed vindictive, “a clear case of gratuitous discrimination,” Dr. Tajfel wrote.

Since then, other researchers have run their own minimal group experiments, pushing those findings further. Dr. Packer and Dr. Van Bavel have split people into leopards and tigers, for example. Others have gone maximally minimal and divided people into group A and group B. Still, the pride — the readiness to connect — is always there. When you tell people they’re in group A, Dr. Packer says, those people are reliably psyched to be in group A. Stick leopard people in a brain imaging machine and show them a picture of a stranger, and their brain activity changes if they know that the stranger is a leopard person, too. Their positivity toward other leopard people increases and even supersedes racial biases that cut the other way.

Dr. Packer and Dr. Van Bavel call the minimal group studies “among the most important studies in the history of psychology.” They demonstrate that “the human sense of self — your gravitational center — does not stay in the same place. With a flip of a coin, people constructed entirely new identities in a matter of minutes.”...The rewards of this kind of connectedness wind up driving all kinds of wonderful human behavior, sometimes less obviously than we’d assume.

But it also leads to the behaviors shown by the insurrections of the Jan. 6, 2021 attack on the U.S. Capitol.

It’s hard to imagine more antisocial behavior than attempting to undo a democratic election with mayhem and violence. But the insurrectionists were doing it together, and pretty joyously, it seemed — snapping selfies, posting them to Facebook with stupid jokes in real time. It was, within their community, a prosocial activity, too.

When a system appears to be malfunctioning, indifferent, reckless or corrupt, that’s a kind of disaster, and people are likely to come together and respond, for better or worse...Some will be volunteers, and some will be vigilantes. But both may be reacting to a similar feeling of free fall, of tumbling. This doesn’t make them morally equivalent; in the end, morality is what keeps them from being equivalent. I know it’s important to keep drawing that distinction, to keep calling it out. I also know it’s not enough.

The rise and fall of rationality in language

Fascinating language analysis from Scheffer et al. that illustrates over the past decades a marked shift in public interest from the collective to the individual, and from rationality toward emotion:  

Significance

The post-truth era has taken many by surprise. Here, we use massive language analysis to demonstrate that the rise of fact-free argumentation may perhaps be understood as part of a deeper change. After the year 1850, the use of sentiment-laden words in Google Books declined systematically, while the use of words associated with fact-based argumentation rose steadily. This pattern reversed in the 1980s, and this change accelerated around 2007, when across languages, the frequency of fact-related words dropped while emotion-laden language surged, a trend paralleled by a shift from collectivistic to individualistic language.

Abstract

The surge of post-truth political argumentation suggests that we are living in a special historical period when it comes to the balance between emotion and reasoning. To explore if this is indeed the case, we analyze language in millions of books covering the period from 1850 to 2019 represented in Google nGram data. We show that the use of words associated with rationality, such as “determine” and “conclusion,” rose systematically after 1850, while words related to human experience such as “feel” and “believe” declined. This pattern reversed over the past decades, paralleled by a shift from a collectivistic to an individualistic focus as reflected, among other things, by the ratio of singular to plural pronouns such as “I”/”we” and “he”/”they.” Interpreting this synchronous sea change in book language remains challenging. However, as we show, the nature of this reversal occurs in fiction as well as nonfiction. Moreover, the pattern of change in the ratio between sentiment and rationality flag words since 1850 also occurs in New York Times articles, suggesting that it is not an artifact of the book corpora we analyzed. Finally, we show that word trends in books parallel trends in corresponding Google search terms, supporting the idea that changes in book language do in part reflect changes in interest. All in all, our results suggest that over the past decades, there has been a marked shift in public interest from the collective to the individual, and from rationality toward emotion.

Senolytic therapies for healthy longevity

An article on increasing longevity by getting rid of senescent cells (cells that have stopped dividing and generate products that accelerate aging) has been languishing in my queue of potential posts for over a year, and I want to finally give it a mention. (This continues the thread of MindBlog posts over the years that have dealt with anti-aging supplements. You can enter 'resveratrol' in the search box in the right column of this blog to get a sample. I've reported on several self experiments, none of which ended all that well. A 2008 post on my experimenting with a resveratrol supplement generated a comment thread that has continued for many years.)

Here is the abstract of the review article by Jan M. van Deursen in Science Magazine:

The estimated “natural” life span of humans is ∼30 years, but improvements in working conditions, housing, sanitation, and medicine have extended this to ∼80 years in most developed countries. However, much of the population now experiences aging-associated tissue deterioration. Healthy aging is limited by a lack of natural selection, which favors genetic programs that confer fitness early in life to maximize reproductive output. There is no selection for whether these alterations have detrimental effects later in life. One such program is cellular senescence, whereby cells become unable to divide. Cellular senescence enhances reproductive success by blocking cancer cell proliferation, but it decreases the health of the old by littering tissues with dysfunctional senescent cells (SNCs). In mice, the selective elimination of SNCs (senolysis) extends median life span and prevents or attenuates age-associated diseases (1, 2). This has inspired the development of targeted senolytic drugs to eliminate the SNCs that drive age-associated disease in humans.

A few clips from the article:

Much of our current knowledge about the properties of SNCs is based on experiments in cultured cells, largely because SNCs in tissues and organs are difficult to identify and collect. One key characteristic of SNCs is that they are in a state of permanent cell-cycle arrest....SNCs produce a bioactive “secretome,” referred to as the senescence-associated secretory phenotype (SASP). This can disrupt normal tissue architecture and function through diverse mechanisms, including recruitment of inflammatory immune cells, remodeling of the extracellular matrix, induction of fibrosis, and inhibition of stem cell function . Paradoxically, although cellular senescence has evolved as a tumor protective program, the SASP can include factors that stimulate neoplastic cell growth, tumor angiogenesis, and metastasis, thereby promoting the development of late-life cancers. Indeed, elimination of SNCs with aging attenuates tumor formation in mice, raising the possibility that senolysis might be an effective strategy to treat cancer.

The article proceeds to outline several different efforts to identify senolytic drug targets. It notes that:

...natural products with anticancer properties, such as quercetin and fisetin, and quercetin in combination with the pan-tyrosine kinase inhibitor dasatinib, have been reported to eliminate SNCs in vitro and in mice [M. Xu et al., Nat. Med. 24, 1246 (2018); M. J. Yousefzadeh et al., EBioMedicine 36, 18 (2018)]. Although quercetin, fisetin, and dasatinib are often referred to as senolytics, it should be noted that they each act on a myriad of pathways and mechanisms implicated in diverse biological processes. This makes it difficult to decipher how these drugs eliminate or otherwise impact SNCs and to attribute any therapeutic or detrimental effects they may have in clinical trials to senolysis.

A brief google search on these flavinoid antioxidant compounds (found in fruits and vegetables...strawberries, watercress, cilantro, etc.) finds a large number of "Life Extension" dietary supplements featuring them. There is no data on their effects on senolysis or life span in humans.

MindBlog gets an extreme comment on Covid

I've debated on whether it would be better to ignore (and not amplify by passing on) an extreme comment of a sort MindBlog almost never receives. It is sent as a response to, but does not actually comment on, last Wednesday's post on the David Brooks article "What Happened to American Conservatism."  Although I am in complete disagreement with the comment's content, I've decided to pass it on because  it is an instructive example of the quality, style, stance and arguments of a fraction of America's population large enough to guarantee the continued generation of Covid variants that will maintain Covid as a chronic disease for the foreseeable future.  Here's the comment:

Re the "the human condition"... The TRUE human condition or world we live in is about 2 pink elephants in the room and has never been on clearer display than with the deliberate global Covid Scam atrocity — check out “The 2 Married Pink Elephants In The Historical Room –The Holocaustal Covid-19 Coronavirus Madness: A Sociological Perspective & Historical Assessment Of The Covid “Phenomenon”” at w w w d o t CovidTruthBeKnown d o t c o m 

“[…] when you do things to people against their will and force them it destroys their spirit, it destroys the integrity of their body. […]. Being an adult is meaningless if you cannot even protect the integrity of your own body.” -- Jennifer Daniels, MD, MBA, Holistic Doctor 

If your employer (even educational or federal employers) wants you to take a Covid vaccine give him/her one of these form letters of exemption found at w w w d o t lc d o t o r g/exempt 

By the way, with the letters of "omicron" an alleged Covid variant you can spell "moronic"...

And further speaking of stupid herd people not getting the glaringly obvious truth/ie not getting the constant onslaught of BIG lies of the official authorities, the world we live in and what the human condition is really is encapsulated in the following reality... 

"2 weeks to flatten the curve has turned into...3 shots to feed your family!" --- Unknown

A musical offering.

For this day that was central in my Protestant Christian Texas childhood: a performance by the Netherlands Bach Society of the Gloria in Excelsis Deo from Bach's  Christmas Cantata BVW 191 first performed in Leipzig ~1742. There is joy in this music that transcends it’s religious origins. 

What Happened to American Conservatism?

I want to strongly recommed that you read David Brooks' article on conservatism in the January/February 2022 issue of The Atlantic. I read slowly though it three times, think it makes a compelling summary of our current political quandry, and wish that it offered more insight into possible ways out of our current predicament as we watch what seems to be an unstopable slippage back to pre-Enlightenment mentalities. Just a few clips of text towards the end of the piece:

...perhaps the biggest reason for conservatism’s decay into Trumpism was spiritual. The British and American strains of conservatism were built on a foundation of national confidence...By 2016, that confidence was in tatters. Communities were falling apart, families were breaking up, America was fragmenting. Whole regions had been left behind, and many elite institutions had shifted sharply left and driven conservatives from their ranks. Social media had instigated a brutal war of all against all, social trust was cratering, and the leadership class was growing more isolated, imperious, and condescending. “Morning in America” had given way to “American carnage” and a sense of perpetual threat.

...a pessimistic shadow conservatism has always lurked in the darkness, haunting the more optimistic, confident one. The message this shadow conservatism conveys is the one that Trump successfully embraced in 2016: Evil outsiders are coming to get us. But in at least one way, Trumpism is truly anti-conservative. Both Burkean conservatism and Lockean liberalism were trying to find ways to gentle the human condition, to help society settle differences without resort to authoritarianism and violence. Trumpism is pre-Enlightenment. Trumpian authoritarianism doesn’t renounce holy war; it embraces holy war, assumes it is permanent, in fact seeks to make it so. In the Trumpian world, disputes are settled by raw power and intimidation. The Trumpian epistemology is to be anti-epistemology, to call into question the whole idea of truth, to utter whatever lie will help you get attention and power. Trumpism looks at the tender sentiments of sympathy as weakness. Might makes right.

...the populist and nationalist forces are rising. All of life is seen as an incessant class struggle between oligarchic elites and the common volk. History is a culture-war death match. Today’s mass-market, pre-Enlightenment authoritarianism is not grateful for the inherited order but sees menace pervading it: You’ve been cheated. The system is rigged against you. Good people are dupes. Conspiracists are trying to screw you. Expertise is bogus. Doom is just around the corner. I alone can save us.

Trumpian Republicanism plunders, degrades, and erodes institutions for the sake of personal aggrandizement. The Trumpian cause is held together by hatred of the Other. Because Trumpians live in a state of perpetual war, they need to continually invent existential foes—critical race theory, nongendered bathrooms, out-of-control immigration. They need to treat half the country, metropolitan America, as a moral cancer, and view the cultural and demographic changes of the past 50 years as an alien invasion. Yet pluralism is one of America’s oldest traditions; to conserve America, you have to love pluralism. As long as the warrior ethos dominates the GOP, brutality will be admired over benevolence, propaganda over discourse, confrontation over conservatism, dehumanization over dignity. A movement that has more affection for Viktor Orbán’s Hungary than for New York’s Central Park is neither conservative nor American. This is barren ground for anyone trying to plant Burkean seedlings.

I’m content, as my hero Isaiah Berlin put it, to plant myself instead on the rightward edge of the leftward tendency—in the more promising soil of the moderate wing of the Democratic Party. If its progressive wing sometimes seems to have learned nothing from the failures of government and to promote cultural stances that divide Americans, at least the party as a whole knows what year it is. In 1980, the core problem of the age was statism, in the form of communism abroad and sclerotic, dynamism-sapping bureaucracies at home. In 2021, the core threat is social decay. The danger we should be most concerned with lies in family and community breakdown, which leaves teenagers adrift and depressed, adults addicted and isolated. It lies in poisonous levels of social distrust, in deepening economic and persisting racial disparities that undermine the very goodness of America—in political tribalism that makes government impossible.

To reduce the economic chasm that separates class from class, to ease the financial anxiety that renders life unstable for many people, to support parenting so that children can grow up with more stability—these are the goals of a party committed to ameliorating, not exploiting, a growing sense of hopelessness and alienation, of vanishing opportunity. Daniel Patrick Moynihan’s brilliant dictum—which builds on a Burkean wisdom forged in a world of animosity and corrosive flux—has never been more worth heeding than it is now: The central conservative truth is that culture matters most; the central liberal truth is that politics can change culture.

The Point is to Stop - a farewell to self help coaching

I want to pass on some points, paraphrase, and central clips from what is essentially a swan song offered by Mark Manson in his latest newsletter - a newsletter whose contents I have mentioned in a number of previous MindBlog posts. This Manson essay hits me between the eyes, because I'm very aware that one of my main motivations for doing this MindBlog since Feb. 2006, with it's 5,220 posts (and counting) is that it has turned out to be valuable self therapy for Deric (with this abstracting of Manson's current article being one example). 

He begins by referencing an older article noting that 

...the best way to judge the usefulness of self-help advice is by now many people eventually leave it behind.

He notes that people who seek out self help..

...do so with two different mindsets... the "Doctor People" ...look to a book, website or seminar to cure their emotional ails... the "Coach People"...want a mentor or coach..They want strategies, roadmaps, to know the right moves...the problem is that Doctor People see personal growth as information that is to be learned rather than a skill that must be practiced...Self-awareness, managing emotions, empathy, vulnerability are skills ..it can take years to become somewhat good at them... Coach People are in it for the long haul.

But what the Coach People don't get is that the whole point is to eventually stop. It's to leave. Because unlike chess or basketball, there's no world championship for anger management. Nobody is going to give you a trophy for mindfulness...the skill curves are different...In basketball or chess, the better you get, the more effort is required to further improve...in personal growth, the better you get, the less effort is required to further improve...personal growth skills have positive feedback loops bakes into them.. like skiing downhill..it takes a lot of effort to get some speed going, but once you're on your way, the most effective thing you can do to gain speed is nothing.

...what the Coach People miss is that the whole point of this stuff, the way to 'win,' is to one day be free of consciously having to think about it...At some point, you just have to live your damn life...Coach People who identify as the "personal growth" not only get trapped by it, but are likely to bore you at dinner parties with their stories about their ayahuasca retreats.

And, at this point in the article, Mason declares that he is going to leave behind his career as a Coach Person, move on from the self help world he started writing a blog about in 2008, the blog being his own therapy as "I tried to sort through my own shit." 

And now,

I'm no longer the guy at the top of the ski hill struggling to get going. I feel like the guy flying down, full speed ahead..to continue writing about these topics feels like unnecessarily planting my poles into the snow...the standard roadmap for self-help authors when they produce a hit book is to spend the next 20-30 years regurgitating the same ideas over and over again in various formats, on various stages, cashing the checks as they go. To me that sounds about as interesting as sticking my dick in a light socket...I've spent a lot of the past few years anxious and insecure that I would "lose my audience," by stepping away from self-help content. It's taken me way too long to listen to my own advice and just not give a fuck.

Manson then describes how he plans to leave behind a repository (The Subtle Art School) of what he has worked so hard to learn the past ten years, and leave his blog as an archive for posterity. 

The active grandparent hypothesis

Lieberman et al. suggest that selection in humans for lifelong physical activity, including during postreproductive years to provision offspring, promoted selection for energy allocation pathways which synergistically slow senescence and reduce vulnerability to many forms of chronic diseases. Here is their abstract (motivated readers can obtain a copy of the article from me):

The proximate mechanisms by which physical activity (PA) slows senescence and decreases morbidity and mortality have been extensively documented. However, we lack an ultimate, evolutionary explanation for why lifelong PA, particularly during middle and older age, promotes health. As the growing worldwide epidemic of physical inactivity accelerates the prevalence of noncommunicable diseases among aging populations, integrating evolutionary and biomedical perspectives can foster new insights into how and why lifelong PA helps preserve health and extend lifespans. Building on previous life-history research, we assess the evidence that humans were selected not just to live several decades after they cease reproducing but also to be moderately physically active during those postreproductive years. We next review the longstanding hypothesis that PA promotes health by allocating energy away from potentially harmful overinvestments in fat storage and reproductive tissues and propose the novel hypothesis that PA also stimulates energy allocation toward repair and maintenance processes. We hypothesize that selection in humans for lifelong PA, including during postreproductive years to provision offspring, promoted selection for both energy allocation pathways which synergistically slow senescence and reduce vulnerability to many forms of chronic diseases. As a result, extended human healthspans and lifespans are both a cause and an effect of habitual PA, helping explain why lack of lifelong PA in humans can increase disease risk and reduce longevity.

New articles on exercise and the brain

Gretchen Reynolds has done two recent brief reviews:

 The Quiet Brain of the Athlete describes work showing that the brains of fit, young athletes dial down extraneous noise and attend to important sounds better than those of other young people. 

And, 

 Staying physically active may protect the aging brain. Simple activities like walking boost immune cells in the brain that may help to keep memory sharp and even ward off Alzheimer’s disease.

Temporal Self-Compression

Brietzke and Meyer (open source) provide behavioral and neural evidence that our past and future selves are compressed as they move away from the present:  

Significance

For centuries, great thinkers have struggled to understand how people represent a personal identity that changes over time. Insight may come from a basic principle of perception: as objects become distant, they also become less discriminable or “compressed.” In Studies 1–3, we demonstrate that people’s ratings of their own personality become increasingly less differentiated as they consider more distant past and future selves. In Study 4, we found neural evidence that the brain compresses self-representations with time as well. When we peer out a window, objects close to us are in clear view, whereas distant objects are hard to tell apart. We provide evidence that self-perception may operate similarly, with the nuance of distant selves increasingly harder to perceive.

Abstract

A basic principle of perception is that as objects increase in distance from an observer, they also become logarithmically compressed in perception (i.e., not differentiated from one another), making them hard to distinguish. Could this basic principle apply to perhaps our most meaningful mental representation: our own sense of self? Here, we report four studies that suggest selves are increasingly non-discriminable with temporal distance from the present as well. In Studies 1 through 3, participants made trait ratings across various time points in the past and future. We found that participants compressed their past and future selves, relative to their present self. This effect was preferential to the self and could not be explained by the alternative possibility that individuals simply perceive arbitrary self-change with time irrespective of temporal distance. In Study 4, we tested for neural evidence of temporal self-compression by having participants complete trait ratings across time points while undergoing functional MRI. Representational similarity analysis was used to determine whether neural self-representations are compressed with temporal distance as well. We found evidence of temporal self-compression in areas of the default network, including medial prefrontal cortex and posterior cingulate cortex. Specifically, neural pattern similarity between self-representations was logarithmically compressed with temporal distance. Taken together, these findings reveal a “temporal self-compression” effect, with temporal selves becoming increasingly non-discriminable with distance from the present.

Severity and clinical course of depression correlates with altered connectivity in sensorimotor cortices.

Interesting work from Ray et al.,  

Significance

Research into neurobiology of depression primarily focuses on its complex psychological aspects. Here we propose an alternative approach and target sensorimotor alterations—a prominent but often neglected feature of depression. We demonstrated using resting-state functional MRI data and computational modeling that top-down and bottom-up information flow in sensory and motor cortices is altered with increasing depression severity in a way that is consistent with depression symptoms. Depression-associated changes were found to be consistent across sessions, amenable to treatment and of effect size sufficiently large to predict whether somebody has mild or severe depression. These results pave the way for an avenue of research into the neural underpinnings of mental health conditions.

Abstract

Functional neuroimaging research on depression has traditionally targeted neural networks associated with the psychological aspects of depression. In this study, instead, we focus on alterations of sensorimotor function in depression. We used resting-state functional MRI data and dynamic causal modeling (DCM) to assess the hypothesis that depression is associated with aberrant effective connectivity within and between key regions in the sensorimotor hierarchy. Using hierarchical modeling of between-subject effects in DCM with parametric empirical Bayes we first established the architecture of effective connectivity in sensorimotor cortices. We found that in (interoceptive and exteroceptive) sensory cortices across participants, the backward connections are predominantly inhibitory, whereas the forward connections are mainly excitatory in nature. In motor cortices these parities were reversed. With increasing depression severity, these patterns are depreciated in exteroceptive and motor cortices and augmented in the interoceptive cortex, an observation that speaks to depressive symptomatology. We established the robustness of these results in a leave-one-out cross-validation analysis and by reproducing the main results in a follow-up dataset. Interestingly, with (nonpharmacological) treatment, depression-associated changes in backward and forward effective connectivity partially reverted to group mean levels. Overall, altered effective connectivity in sensorimotor cortices emerges as a promising and quantifiable candidate marker of depression severity and treatment response.

The Science of Mind Reading

James Somers offers a fascinating article in the Nov. 29 issue of The New Yorker, which I recommend that you read. It describes the development of the technique of Latent Semantic Analysis (L.S.A) originating in the work of a psychologist named Charles Osgood nearly 70 years ago and now being applied to the analysis of fMRI recordings from people to infer what they are internally thinking or seeing.

In 2013, researchers at Google unleashed a descendant of it onto the text of the whole World Wide Web. Google’s algorithm turned each word into a “vector,” or point, in high-dimensional space. The vectors generated by the researchers’ program, word2vec, are eerily accurate: if you take the vector for “king” and subtract the vector for “man,” then add the vector for “woman,” the closest nearby vector is “queen.” Word vectors became the basis of a much improved Google Translate, and enabled the auto-completion of sentences in Gmail. Other companies, including Apple and Amazon, built similar systems. Eventually, researchers realized that the “vectorization” made popular by L.S.A. and word2vec could be used to map all sorts of things. Today’s facial-recognition systems have dimensions that represent the length of the nose and the curl of the lips, and faces are described using a string of coördinates in “face space.” Chess A.I.s use a similar trick to “vectorize” positions on the board. The technique has become so central to the field of artificial intelligence that, in 2017, a new, hundred-and-thirty-five-million-dollar A.I. research center in Toronto was named the Vector Institute. Matthew Botvinick, a professor at Princeton whose lab was across the hall from Norman’s, and who is now the head of neuroscience at DeepMind, Alphabet’s A.I. subsidiary, told me that distilling relevant similarities and differences into vectors was “the secret sauce underlying all of these A.I. advances.”

 

Subsequent sections of the article describe how machine learning has been brought to brain imaging with voxels of neural activity serving as dimensions in a kind of thought space.

...today’s thought-decoding researchers mostly look for specific thoughts that have been defined in advance. But a “general-purpose thought decoder,” Norman told me, is the next logical step for the research. Such a device could speak aloud a person’s thoughts, even if those thoughts have never been observed in an fMRI machine. In 2018, Botvinick, Norman’s hall mate, co-wrote a paper in the journal Nature Communications titled “Toward a Universal Decoder of Linguistic Meaning from Brain Activation.” Botvinick’s team had built a primitive form of what Norman described: a system that could decode novel sentences that subjects read silently to themselves. The system learned which brain patterns were evoked by certain words, and used that knowledge to guess which words were implied by the new patterns it encountered.

In praise of Sheeple - why we shouldn't always think for ourselves

A friend pointed out this interesting article by Ian Leslie, which I recommend that you read. I pass on a few clips at the end of his exposition:

...the human instinct to copy rather than think for ourselves is good for us, up to a point. Cultural anthropologists have done the most to establish that our instinct to copy parents and peers helps us to learn, to get along, to organise, to bond, and ultimately to build the shared behaviours that enable us to survive and progress. They’ve discovered that compared to other primates humans “over-imitate”: we copy even when there’s no reason to.

In a much-replicated experiment, a complicated-looking box is presented to chimps and the researchers demonstrate how to access a bit of food inside. They include some unnecessary steps: tapping the box three times, fiddling with a bolt, whatever. The chimps quickly work out all they need to do is pull a door and grab the food, and ignore the superfluous actions. Do this experiment with very small humans, however, and the kids copy all the actions. The chimps are more efficient and in a way more ‘rational’ but it’s the other primate which has built cities, ships and cathedrals.

Traditions we don’t understand ought not to be dismissed too quickly, since the collective intelligence of the past dwarves our own. In The Secret of Our Success, the anthropologist Joseph Henrich argues that individual humans are not nearly as smart as we think and that it is culture that makes us a successful species. The Naskapi, a foraging tribe from north-eastern Canada, hunt caribou. They have to decide where to hunt, which isn’t straightforward because if they visit one location too often the caribou know to stay away. The best hunting strategy therefore requires randomisation.

But individuals like to think they’re smart and left to their own devices, Naskapi hunters probably wouldn’t be satisfied with setting out in a random direction every day; they’d come up with brilliant plans which proved to be disastrous. Tradition saves them. To decide where to go, the hunters use a divination ritual which involves heating a caribou shoulder blade over hot coals until cracks and spots start to appear on it; the resulting pattern is then used as a map. In a sense it’s a mindless ritual, but it’s also a randomising device which helps the hunters overcome their decision-making biases.

Here’s what I like about the dupes. When everyone around them behaved in a certain way, their first thought wasn’t “I must be smarter than them”. It was, “They must know something I don’t”. There is an admirable humility to that, even if, in this case, it led them to say or do something absurd. The ability of individual humans to think for ourselves is crucial to progress; equally crucial is that we trust, sometimes unthinkingly, in judgements made by others, alive or dead. Societies where too few people are willing to question norms and traditions tend to stagnate and to perpetuate injustices. But there is a positive side to conformism, too. Just as in an imaginary nightclub on fire there’s a good chance that a passing group will lead you to an exit, there’s a good chance that whatever the people around you say is right, is right, even if you don’t fully understand why yet. Society functions best when we’re sheepish.

What is a DAO? Who needs humans?

A DAO is a Decentralised Autonomous Organisation. My son pointed out this intriguing and also somewhat terrifying video to me. Like Mark Zuckerberg's corporate "Meta" fantasies another step towards tearing our evolved biolgical bodies and social brains away from the organic tactile contacts with each other for which they were designed.

 

The Science of Hugs?

Schultz describes an entertaining bit of work pursuing the obvious done by Düren et.al. Guys hugging each other use their arms differently than women do, more frequently doing a crisscross hug (on the left) than a neck-waist hug (on the right), most likely because the neck-waist hug feels a bit more intimate.

Without prompting the students on how to hug, the researchers found the crisscross style was more common, accounting for 66 out of 100 hugs. The preference for crisscross was especially prevalent in pairs of men, with 82% of 28 observed pairs opting for the style. Neither emotional closeness nor height had significant effects on the style of hugging; however, the researchers note that most participants were relatively close in height, and they guess that neck-waist might be more common when heights differ more drastically.

Cannabis use during pregnancy correlates with cortisol, anxiety, aggression, and hyperactivity in young children.

Sobering results from Rompala et al.: 

Significance

Cannabis use is becoming more prevalent, including during developmentally sensitive periods such as pregnancy. Here we find that maternal cannabis use is associated with increased cortisol, anxiety, aggression, and hyperactivity in young children. This corresponded with widespread reductions in immune-related gene expression in the placenta which correlated with anxiety and hyperactivity. Future studies are needed to examine the effects of cannabis on immune function during pregnancy as a potential regulatory mechanism shaping neurobehavioral development.

Abstract

While cannabis is among the most used recreational drugs during pregnancy, the impact of maternal cannabis use (mCB) on fetal and child development remains unclear. Here, we assessed the effects of mCB on psychosocial and physiological measures in young children along with the potential relevance of the in utero environment reflected in the placental transcriptome. Children (∼3 to 6 y) were assessed for hair hormone levels, neurobehavioral traits on the Behavioral Assessment System for Children (BASC-2) survey, and heart rate variability (HRV) at rest and during auditory startle. For a subset of children with behavioral assessments, placental specimens collected at birth were processed for RNA sequencing. Hair hormone analysis revealed increased cortisol levels in mCB children. In addition, mCB was associated with greater anxiety, aggression, and hyperactivity. Children with mCB also showed a reduction in the high-frequency component of HRV at baseline, reflecting reduced vagal tone. In the placenta, there was reduced expression of many genes involved in immune system function including type I interferon, neutrophil, and cytokine-signaling pathways. Finally, several of these mCB-linked immune genes organized into coexpression networks that correlated with child anxiety and hyperactivity. Overall, our findings reveal a relationship between mCB and immune response gene networks in the placenta as a potential mediator of risk for anxiety-related problems in early childhood.

An artificial neural network that responds to written words like our brain's word form area

Interesting work from Dehaene and collaborators:  

Significance

Learning to read results in the formation of a specialized region in the human ventral visual cortex. This region, the visual word form area (VWFA), responds selectively to written words more than to other visual stimuli. However, how neural circuits at this site implement an invariant recognition of written words remains unknown. Here, we show how an artificial neural network initially designed for object recognition can be retrained to recognize words. Once literate, the network develops a sparse neuronal representation of words that replicates several known aspects of the cognitive neuroscience of reading and leads to precise predictions concerning how a small set of neurons implement the orthographic stage of reading acquisition using a compositional neural code.

Abstract

The visual word form area (VWFA) is a region of human inferotemporal cortex that emerges at a fixed location in the occipitotemporal cortex during reading acquisition and systematically responds to written words in literate individuals. According to the neuronal recycling hypothesis, this region arises through the repurposing, for letter recognition, of a subpart of the ventral visual pathway initially involved in face and object recognition. Furthermore, according to the biased connectivity hypothesis, its reproducible localization is due to preexisting connections from this subregion to areas involved in spoken-language processing. Here, we evaluate those hypotheses in an explicit computational model. We trained a deep convolutional neural network of the ventral visual pathway, first to categorize pictures and then to recognize written words invariantly for case, font, and size. We show that the model can account for many properties of the VWFA, particularly when a subset of units possesses a biased connectivity to word output units. The network develops a sparse, invariant representation of written words, based on a restricted set of reading-selective units. Their activation mimics several properties of the VWFA, and their lesioning causes a reading-specific deficit. The model predicts that, in literate brains, written words are encoded by a compositional neural code with neurons tuned either to individual letters and their ordinal position relative to word start or word ending or to pairs of letters (bigrams).

Online spread of false information depends on cascade size

Juul and Ugander do an analysis of factors that influence the spread of false news, finding a central role for cascade size and suggesting that to limit the spread of false news, it may be enough to focus on reducing the mean “infectiousness” of the information.  

Significance

Do different types of information spread differently online? In recent years, studies have sought answers to such questions by comparing statistical properties of network paths taken by different kinds of content diffusing online. Here, we demonstrate the importance of controlling for correlations between properties being compared. In particular, we show that previously reported structural differences between diffusion paths of false and true news on Twitter disappear when comparing only cascades of the same size; differences between diffusion paths of images, videos, news, and petitions persist. Paired with a theoretical analysis of diffusion processes, our results suggest that, in order to limit the spread of false news, it may be enough to focus on reducing the mean “infectiousness” of the information.

Abstract

Do some types of information spread faster, broader, or further than others? To understand how information diffusions differ, scholars compare structural properties of the paths taken by content as it spreads through a network, studying so-called cascades. Commonly studied cascade properties include the reach, depth, breadth, and speed of propagation. Drawing conclusions from statistical differences in these properties can be challenging, as many properties are dependent. In this work, we demonstrate the essentiality of controlling for cascade sizes when studying structural differences between collections of cascades. We first revisit two datasets from notable recent studies of online diffusion that reported content-specific differences in cascade topology: an exhaustive corpus of Twitter cascades for verified true- or false-news content by Vosoughi et al. [S. Vosoughi, D. Roy, S. Aral. Science 359, 1146–1151 (2018)] and a comparison of Twitter cascades of videos, pictures, news, and petitions by Goel et al. [S. Goel, A. Anderson, J. Hofman, D. J. Watts. Manage. Sci. 62, 180–196 (2016)]. Using methods that control for joint cascade statistics, we find that for false- and true-news cascades, the reported structural differences can almost entirely be explained by false-news cascades being larger. For videos, images, news, and petitions, structural differences persist when controlling for size. Studying classical models of diffusion, we then give conditions under which differences in structural properties under different models do or do not reduce to differences in size. Our findings are consistent with the mechanisms underlying true- and false-news diffusion being quite similar, differing primarily in the basic infectiousness of their spreading process.

Caution around the fountain of youth.

Lee et al. do a review "Antiaging diets: Separating fact from fiction" in Science Magazine. The link takes you to their summary, abstract, and a nice graphic. I pass on a Box 1 from the body of the article titled "reclaiming the term 'anti-aging'":

The phrase “antiaging” is greatly abused in popular culture, often for the purpose of marketing cosmetic procedures or unproven nutritional supplements purported to slow or reverse aging. This has the unfortunate consequence of creating confusion among the general public and diminishing the impact of legitimate scientific discovery. Here, we define “antiaging” as delaying or reversing biological aging by targeting the established molecular mechanisms of aging, which have been formalized as “hallmarks” or “pillars” of aging (93, 94). Effective antiaging interventions in laboratory animals increase both median and maximum population life span and broadly delay the onset and progression of many age-related functional declines and diseases. The latter effect is often referred to as “extending health span,” which is a qualitative term referring to the period of life free from chronic disease and disability (95). Recent studies show that at least some antiaging interventions, such as the drug rapamycin, can reverse functional declines across multiple tissues in aged animals (96). On the basis of this definition, there are as yet no clinically validated antiaging interventions in humans. However, there is some evidence consistent with antiaging effects for CR and related diets in humans as well as a small number of putative geroprotective compounds, including metformin and rapamycin (97).

93. C. López-Otín, M. A. Blasco, L. Partridge, M. Serrano, G. Kroemer, The hallmarks of aging. Cell 153, 1194–1217 (2013).

94. B. K. Kennedy, S. L. Berger, A. Brunet, J. Campisi, A. M. Cuervo, E. S. Epel, C. Franceschi, G. J. Lithgow, R. I. Morimoto, J. E. Pessin, T. A. Rando, A. Richardson, E. E. Schadt, T. Wyss-Coray, F. Sierra, Geroscience: Linking aging to chronic disease. Cell 159, 709–713 (2014).

95 M. Kaeberlein, How healthy is the healthspan concept? Geroscience 40, 361–364 (2018).

96 R. Selvarani, S. Mohammed, A. Richardson, Effect of rapamycin on aging and age-related diseases-past and future. Geroscience 43, 1135–1158 (2021).

97 M. B. Lee, M. Kaeberlein, Translational Geroscience: From invertebrate models to companion animal and human interventions. Transl. Med. Aging 2, 15–29 (2018).