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).

Volatile hexadecanal emitted by babies could make men more docile and women more aggressive

Interesting observations from Mishor et al.:

In terrestrial mammals, body volatiles can effectively trigger or block conspecific aggression. Here, we tested whether hexadecanal (HEX), a human body volatile implicated as a mammalian-wide social chemosignal, affects human aggression. 

Using validated behavioral paradigms, we observed a marked dissociation: Sniffing HEX blocked aggression in men but triggered aggression in women. Next, using functional brain imaging, we uncovered a pattern of brain activity mirroring behavior: In both men and women, HEX increased activity in the left angular gyrus, an area implicated in perception of social cues. HEX then modulated functional connectivity between the angular gyrus and a brain network implicated in social appraisal (temporal pole) and aggressive execution (amygdala and orbitofrontal cortex) in a sex-dependent manner consistent with behavior: increasing connectivity in men but decreasing connectivity in women. These findings implicate sex-specific social chemosignaling at the mechanistic heart of human aggressive behavior.

From the author's discussion:

....what behavioral setting could underlie selection for a body volatile that increases aggression in women but decreases it in men? Or in other words, what could be the ecological relevance of these results? In this respect, we call attention to the setting of infant rearing. Parents across cultures are encouraged to sniff their babies, an action that activates brain reward circuits in women. Our results imply that sniffing babies may increase aggression in mothers but decrease aggression in fathers. Whereas maternal aggression has a direct positive impact on offspring survival in the animal world, paternal aggression has a negative impact on offspring survival. This is because maternal aggression (also termed maternal defense behavior) is typically directed at intruders, yet paternal aggression, and more so nonpaternal male aggression, is often directed at the offspring themselves. If babies had a mechanism at their disposal that increased aggression in women but decreased it in men, this would likely increase their survival. With the hypothesis in mind that HEX provides babies with exactly such a mechanism, we first note that infant rearing is the one social setting where humans have extensive exposure to conspecific feces, a rich source of HEX. We also turned to a recently published analysis of baby-head volatiles, yet in contrast to our hypothesis, this report did not mention HEX. We turned to the authors of that report, who explained that the published analysis was not tuned to the near semivolatile range of HEX. With our question in mind, they (now coauthors T.U. and M.O.) sampled an additional 19 babies, using gas chromatography (GC) × GC–mass spectrometry, and observed that HEX is one of the most abundant baby-head volatiles...

Socrates, Diderot, and Wolpert on Writing and Printing

I have to pass on these quotes sent by one my Chaos and Complexity Seminar colleagues at the University of Wisconsin:

Socrates on writing, from Phaedrus, 275a-b

"For this invention will produce forgetfulness in the minds of those who learn to use it, because they will not practice their memory. Their trust in writing, produced by external characters which are no part of themselves, will discourage the use of their own memory within them. You have invented an elixir not of memory, but of reminding; and you offer your pupils the appearance of wisdom, not true wisdom, for they will read many things without instruction and will therefore seem to know many things, when they are for the most part ignorant and hard to get along with, since they are not wise, but only appear wise."

Denis Diderot, Encyclopédie, 1755

"As long as the centuries continue to unfold, the number of books will grow continually, and one can predict that a time will come when it will be almost as difficult to learn anything from books as from the direct study of the whole universe. It will be almost as convenient to search for some bit of truth concealed in nature as it will be to find it hidden away in an immense multitude of bound volumes."

Lewis Wolpert (1929--2021) Lewis Wolpert - Scientist - Web of Stories

"Reading rots the mind."

Fluid intelligence and the locus coeruleus-norepinephrine system

Tsukahara and Engle suggest that the cognitive mechanisms of fluid intelligence map onto the locus coeruleus–norepinephrine system. I pass on their introductory paragraph (the link takes you to their abstract, which I think is less informative):

In this article, we outline what we see as a potentially important relationship for understanding the biological basis of intelligence: that is, the relationship between fluid intelligence and the locus coeruleus–norepinephrine system. This is largely motivated by our findings that baseline pupil size is related to fluid intelligence; the larger the pupils, the higher the fluid intelligence. The connection to the locus coeruleus is based on research showing that the size of the pupil can be used as an indicator of locus coeruleus activity. A large body of research on the locus coeruleus–norepinephrine system in animal and human studies has shown how this system is critical for an impressively wide range of behaviors and cognitive processes, from regulating sleep/wake cycles, to sensation and perception, attention, learning and memory, decision making, and more. The locus coeruleus–norepinephrine system achieves this primarily through its widespread projection system throughout the cortex, strong connections with the prefrontal cortex, and the effect of norepinephrine at many levels of brain function. Given the broad role of this system in behavior, cognition, and brain function, we propose that the locus coeruleus–norepinephrine system is essential for understanding the biological basis of intelligence.

Drifting nerve assemblies can maintain persistent memories

A prevailing model has been that a memory in our brains is stored in a specific set of nerve connections, that, like a book in a library, stays where it belongs. Over the past few years, however, it has become more and more clear that 'representational plasticity' may be the norm. A recent article by Kossio et al. proposes a contrasting memory model (motivated readers can obtain the whole article from me):

Change is ubiquitous in living beings. In particular, the connectome and neural representations can change. Nevertheless, behaviors and memories often persist over long times. In a standard model, associative memories are represented by assemblies of strongly interconnected neurons. For faithful storage these assemblies are assumed to consist of the same neurons over time. Here we propose a contrasting memory model with complete temporal remodeling of assemblies, based on experimentally observed changes of synapses and neural representations. The assemblies drift freely as noisy autonomous network activity and spontaneous synaptic turnover induce neuron exchange. The gradual exchange allows activity-dependent and homeostatic plasticity to conserve the representational structure and keep inputs, outputs, and assemblies consistent. This leads to persistent memory. Our findings explain recent experimental results on temporal evolution of fear memory representations and suggest that memory systems need to be understood in their completeness as individual parts may constantly change.

Here is an explanatory graphic from the article:

Assembly drift and persistent memory. (A) At two nearby times a similar ensemble of neurons forms the neural representation of, for example, “apple” (compare the blue-colored assembly neurons at the first and the second time point). At distant times the representation consists of completely different ensembles (blue-colored assembly neurons at the first and the third time point). Due to their gradual change, temporally distant representations are indirectly related via ensembles in the time period between them. (B) Parts of a thread possess the same form of indirect relation: Nearby parts are composed of similar ensembles of fibers, while distant ones consist of different ensembles, which are connected by those in between. (C) The complete change of memory representations still allows for stable behavior. In the schematic, a tasty apple is perceived. At different times, this triggers different ensembles that presently form the representation of “apple”; see A. Assembly activation initiates a reaching movement toward the apple, despite the dissimilarity of the activated neuron ensembles. Memory and behavior are conserved because the gradual change of assembly neurons enables the inputs (green) and outputs (orange) to track the neural representation.

Our brainstems respond to fake therapies and fake side effects.

Here is the abstract from a Journal of Neuroscience paper by Crawford et al. titled "Brainstem mechanisms of pain modulation: a within-subjects 7T fMRI study of Placebo Analgesic and Nocebo Hyperalgesic Responses":

Pain perception can be powerfully influenced by an individual’s expectations and beliefs. Whilst the cortical circuitry responsible for pain modulation has been thoroughly investigated, the brainstem pathways involved in the modulatory phenomena of placebo analgesia and nocebo hyperalgesia remain to be directly addressed. This study employed ultra-high field 7 Tesla functional MRI (fMRI) to accurately resolve differences in brainstem circuitry present during the generation of placebo analgesia and nocebo hyperalgesia in healthy human participants (N = 25; 12 Male). Over two successive days, through blinded application of altered thermal stimuli, participants were deceptively conditioned to believe that two inert creams labelled ‘lidocaine’ (placebo) and ‘capsaicin’ (nocebo) were acting to modulate their pain relative to a third ‘Vaseline’ (control) cream. In a subsequent test phase, fMRI image sets were collected whilst participants were given identical noxious stimuli to all three cream sites. Pain intensity ratings were collected and placebo and nocebo responses determined. Brainstem-specific fMRI analysis revealed altered activity in key pain-modulatory nuclei, including a disparate recruitment of the periaqueductal gray (PAG) – rostral ventromedial medulla (RVM) pathway when both greater placebo and nocebo effects were observed. Additionally, we found that placebo and nocebo responses differentially activated the parabrachial nucleus but overlapped in their engagement of the substantia nigra and locus coeruleus. These data reveal that placebo and nocebo effects are generated through differential engagement of the PAG-RVM pathway, which in concert with other brainstem sites likely influence the experience of pain by modulating activity at the level of the dorsal horn.

Snippets of Bach

To give MindBlog readers a bit of a break from brain and mind posts, I want to point out that the New York Times has a great series of articles that present roughly five minutes of music chosen by artists and composers to make you fall in love with different genres of classical music: piano, opera, cello, Mozart, 21st-century composers, violin, Baroque music, sopranos, Beethoven, flute, string quartets, tenors, Brahms, choral music, percussion, symphonies, Stravinsky, trumpet and Maria Callas. 

 

The most recent installment presents the stirring, consoling music of Johann Sebastian Bach, the grand master of the Western classical tradition.

Coevolution of tool use and language - shared syntactic processes and basal ganglia substrates

Thibault et al. show that tool use and language share syntactic processes. Functional magnetic resonance imaging reveals that tool use and syntax in language elicit similar patterns of brain activation within the basal ganglia. This indicates common neural resources for the two abilities. Indeed, learning transfer occurs across the two domains: Tool-use motor training improves syntactic processing in language and, reciprocally, linguistic training with syntactic structures improves tool use. Here is their entire structured abstract:   

INTRODUCTION

Tool use is a hallmark of human evolution. Beyond its sensorimotor components, the complexity of which has been extensively investigated, tool use affects cognition from a different perspective. Indeed, tool use requires integrating an external object as a body part and embedding its functional structure in the motor program. This adds a hierarchical level into the motor plan of manual actions, subtly modifying the relationship between interdependent subcomponents. Embedded structures also exist in language, and syntax is the cognitive function handling these linguistic hierarchies. One example is center-embedded object-relative clauses: “The poet [that the scientist admires] reads the paper.” Accordingly, researchers have advanced a role for syntax in action and the existence of similarities between the processes underlying tool use and language, so that shared neural resources for a common cognitive function could be at stake.

RATIONALE

We first tested the existence of shared neural substrates for tool use and syntax in language. Second, we tested the prediction that training one ability should affect performance in the other. In a first experiment, we measured participants’ brain activity with functional magnetic resonance imaging during tool use or, as a control, manual actions. In separate runs, the same participants performed a linguistic task on complex syntactic structures. We looked for common activations between tool use and the linguistic task, predicting similar patterns of activity if they rely on common neural resources. In further behavioral experiments, we tested whether motor training with the tool selectively improves syntactic performance in language and if syntactic training in language, in turn, selectively improves motor performance with the tool.

RESULTS

Tool-use planning and complex syntax processing (i.e., object relatives) elicited neural activity anatomically colocalized within the basal ganglia. A control experiment ruled out verbal working memory and manual (i.e., without a tool) control processes as an underlying component of this overlap. Multivariate analyses revealed similar spatial distributions of neural patterns prompted by tool-use planning and object-relative processing. This agrees with the recruitment of the same neural resources by both abilities and with the existence of a supramodal syntactic function. The shared neurofunctional resources were moreover reflected behaviorally by cross-domain learning transfer. Indeed, tool-use training significantly improved linguistic performance with complex syntactic structures. No learning transfer was observed on language syntactic abilities if participants trained without the tool. The reverse was also true: Syntactic training with complex sentences improved motor performance with the tool more than motor performance in a task without the tool and matched for sensorimotor difficulty. No learning transfer was observed on tool use if participants trained with simpler syntactic structures in language.

CONCLUSION

These findings reveal the existence of a supramodal syntactic function that is shared between language and motor processes. As a consequence, training tool-use abilities improves linguistic syntax and, reciprocally, training linguistic syntax abilities improves tool use. The neural mechanisms allowing for boosting performance in one domain by training syntax in the other may involve priming processes through preactivation of common neural resources, as well as short-term plasticity within the shared network. Our findings point to the basal ganglia as the neural site of supramodal syntax that handles embedded structures in either domain and also support longstanding theories of the coevolution of tool use and language in humans.

Freedom From Illusion

A friend who attended the lecture I gave last Sunday (A New Vision of how our Minds Work), and mentioned in a Monday post, sent me an article from The Buddhist Review "TRICYCLE" by Pema Düddul titled "Freedom From Illusion". If you scan both texts, I suspect you will find, as I do, a striking consonance between the neuroscientific and Buddhist perspectives on "Illusion." 

From the beginning of the Düddul article:

A shooting star, a clouding of the sight, 

a lamp, an illusion, a drop of dew, a bubble, 

a dream, a lightning’s flash, a thunder cloud: 

this is the way one should see the conditioned.

This revered verse from the Diamond Sutra points to one of Buddhism’s most profound yet confounding truths—the illusory nature of all things. The verse is designed to awaken us to ultimate reality, specifically to the fact that all things, especially thoughts and feelings, are the rainbow-like display of the mind. One of the Tibetan words for the dualistic mind means something like “a magician creating illusions.” As my teacher Ngakpa Karma Lhundup Rinpoche explained: “All of our thoughts are magical illusions created by our mind. We get trapped, carried away by our own illusions. We forget that we are the magician in the first place!”

Compare this with my talk's description of predictive processing, and how what we see, hear, touch, taste, and smell are largely simulations or illusions about the world. Here is a summary sentence in one of my slides, taken from a lecture by Ruben Laukkonen, in which I replace his last word, 'fantasies,' with the word 'illusions.'

Everything we do and experience is in service of reducing surprises by fulfilling illusions.

Computational evidence that predictive processing shapes language comprehension mechanisms in the brain.

Having just posted a lecture on predictive processing that I gave two days ago, I come across this fascinating work from Schrimpf et al.:  

Significance

Language is a quintessentially human ability. Research has long probed the functional architecture of language in the mind and brain using diverse neuroimaging, behavioral, and computational modeling approaches. However, adequate neurally-mechanistic accounts of how meaning might be extracted from language are sorely lacking. Here, we report a first step toward addressing this gap by connecting recent artificial neural networks from machine learning to human recordings during language processing. We find that the most powerful models predict neural and behavioral responses across different datasets up to noise levels. Models that perform better at predicting the next word in a sequence also better predict brain measurements—providing computationally explicit evidence that predictive processing fundamentally shapes the language comprehension mechanisms in the brain.

Abstract

The neuroscience of perception has recently been revolutionized with an integrative modeling approach in which computation, brain function, and behavior are linked across many datasets and many computational models. By revealing trends across models, this approach yields novel insights into cognitive and neural mechanisms in the target domain. We here present a systematic study taking this approach to higher-level cognition: human language processing, our species’ signature cognitive skill. We find that the most powerful “transformer” models predict nearly 100% of explainable variance in neural responses to sentences and generalize across different datasets and imaging modalities (functional MRI and electrocorticography). Models’ neural fits (“brain score”) and fits to behavioral responses are both strongly correlated with model accuracy on the next-word prediction task (but not other language tasks). Model architecture appears to substantially contribute to neural fit. These results provide computationally explicit evidence that predictive processing fundamentally shapes the language comprehension mechanisms in the human brain.

A MindBlog lecture - A New Vision of how our Minds Work

Yesterday I gave a short talk to the Austin Rainbow Forum discussion group that I started up with several other members of the Austin Prime Timers in January 2018. As I promised at the outset of the talk, which was fairly intense, I am now putting a PDF of the lecture text and slides on my website, and here am passing it on to MindBlog readers who might be interested in having a look. Here is the second slide of the talk, listing its topics:

 

It’s Quitting Season

I want to pass on two articles with the similar themes of people taking stock of their lives and deciding to stop making themselves unhappy. The piece by Crouse and Ferguson is a video, by and directed towards, Millenials, with the following introductory text:

It’s been a brutal few years. But we’ve gritted through. We’ve spent time languishing. We’ve had one giant national burnout. And now, finally, we’re quitting...We are quitting our jobs. Our cities. Our marriages. Even our Twitter feeds...And as we argue in the video, we’re not quitting because we’re weak. We’re quitting because we’re smart...younger Americans like 18-year-old singer Olivia Rodrigo and the extraordinary Simone Biles are barely old enough to rent a car but they are already teaching us about boundaries. They’ve seen enough hollowed-out millennials to know what the rest of us are learning: Don’t be a martyr to grit.

I feel some personal resonance with points made about a whole career path in the piece by Arthur Brooks, To Be Happy, Hide From the Spotlight, because this clip nails a part of the reason I keep driving myself to performances (writing, lecturing, music) by rote habit:

Assuming that you aren’t a pop star or the president, fame might seem like an abstract problem. The thing is, fame is relative, and its cousin, prestige — fame among a particular group of people — is just as fervently chased in smaller communities and fields of expertise. In my own community of academia, honors and prestige can be highly esoteric but deeply desired.

I suggest you read the whole article, but here are a few further clips:

Even if a person’s motive for fame is to set a positive example, it mirrors the other, less flattering motives insofar as it depends on other people’s opinions. And therein lies the happiness problem. Thomas Aquinas wrote in the 13th century, “Happiness is in the happy. But honor is not in the honored.” ...research shows that fame ...based on what scholars call extrinsic rewards... brings less happiness than intrinsic rewards...fame has become a form of addiction. This is especially true in the era of social media, which allows almost anyone with enough motivation to achieve recognition by some number of strangers...this is not a new phenomenon. The 19th-century philosopher Arthur Schopenhauer said fame is like seawater: “The more we have, the thirstier we become.”

No social scientists I am aware of have created a quantitative misery index of fame. But the weight of the indirect evidence above, along with the testimonies of those who have tasted true fame in their time, should be enough to show us that it is poisonous. It is “like a river, that beareth up things light and swollen,” said Francis Bacon, “and drowns things weighty and solid.” Or take it from Lady Gaga: “Fame is prison.”

...Pay attention to when you are seeking fame, prestige, envy, or admiration—especially from strangers. Before you post on social media, for example, ask yourself what you hope to achieve with it...Say you want to share a bit of professional puffery or photos of your excellent beach body. The benefit you experience is probably the little hit of dopamine you will get as you fire it off while imagining the admiration or envy others experience as they see it. The cost is in the reality of how people will actually see your post (and you): Research shows that people will largely find your boasting to be annoying—even if you disguise it with a humblebrag—and thus admire you less, not more. As Shakespeare helpfully put it, “Who knows himself a braggart, / Let him fear this, for it will come to pass / that every braggart shall be found an ass.”

The poet Emily Dickinson called fame a “fickle food / Upon a shifting plate.” But far from a harmless meal, “Men eat of it and die.” It’s a good metaphor, because we have the urge to consume all kinds of things that appeal to some anachronistic neurochemical impulse but that nevertheless will harm us. In many cases—tobacco, drugs of abuse, and, to some extent, unhealthy foods—we as a society have recognized these tendencies and taken steps to combat them by educating others about their ill effects.

Why have we failed to do so with fame? None of us, nor our children, will ever find fulfillment through the judgment of strangers. The right rule of thumb is to treat fame like a dangerous drug: Never seek it for its own sake, teach your kids to avoid it, and shun those who offer it.

Variability, not stereotypical expressions, in facial portraying of emotional states.

Barrett and collaborators use a novel method to offer more evidence against reliable mapping between certain emotional states and facial muscle movements:

It is long hypothesized that there is a reliable, specific mapping between certain emotional states and the facial movements that express those states. This hypothesis is often tested by asking untrained participants to pose the facial movements they believe they use to express emotions during generic scenarios. Here, we test this hypothesis using, as stimuli, photographs of facial configurations posed by professional actors in response to contextually-rich scenarios. The scenarios portrayed in the photographs were rated by a convenience sample of participants for the extent to which they evoked an instance of 13 emotion categories, and actors’ facial poses were coded for their specific movements. Both unsupervised and supervised machine learning find that in these photographs, the actors portrayed emotional states with variable facial configurations; instances of only three emotion categories (fear, happiness, and surprise) were portrayed with moderate reliability and specificity. The photographs were separately rated by another sample of participants for the extent to which they portrayed an instance of the 13 emotion categories; they were rated when presented alone and when presented with their associated scenarios, revealing that emotion inferences by participants also vary in a context-sensitive manner. Together, these findings suggest that facial movements and perceptions of emotion vary by situation and transcend stereotypes of emotional expressions. Future research may build on these findings by incorporating dynamic stimuli rather than photographs and studying a broader range of cultural contexts.

This perspective is opposite to that expressed by Cowen, Keltner et al. who use another novel method to reach opposite conclusions, in work that was noted in MindBlog's 12/29/20 post, along with some reservations about their conclusions.

People mistake the internet’s knowledge for their own

Fascinating experiments from Adrian Ward:   

Significance

In the current digital age, people are constantly connected to online information. The present research provides evidence that on-demand access to external information, enabled by the internet and search engines like Google, blurs the boundaries between internal and external knowledge, causing people to believe they could—or did—remember what they actually just found. Using Google to answer general knowledge questions artificially inflates peoples’ confidence in their own ability to remember and process information and leads to erroneously optimistic predictions regarding how much they will know without the internet. When information is at our fingertips, we may mistakenly believe that it originated from inside our heads.

Abstract

People frequently search the internet for information. Eight experiments (n = 1,917) provide evidence that when people “Google” for online information, they fail to accurately distinguish between knowledge stored internally—in their own memories—and knowledge stored externally—on the internet. Relative to those using only their own knowledge, people who use Google to answer general knowledge questions are not only more confident in their ability to access external information; they are also more confident in their own ability to think and remember. Moreover, those who use Google predict that they will know more in the future without the help of the internet, an erroneous belief that both indicates misattribution of prior knowledge and highlights a practically important consequence of this misattribution: overconfidence when the internet is no longer available. Although humans have long relied on external knowledge, the misattribution of online knowledge to the self may be facilitated by the swift and seamless interface between internal thought and external information that characterizes online search. Online search is often faster than internal memory search, preventing people from fully recognizing the limitations of their own knowledge. The internet delivers information seamlessly, dovetailing with internal cognitive processes and offering minimal physical cues that might draw attention to its contributions. As a result, people may lose sight of where their own knowledge ends and where the internet’s knowledge begins. Thinking with Google may cause people to mistake the internet’s knowledge for their own.

What the mind is - similarities and differences in concepts of mental life in five cultures

From Weisman et al., who do a fascinating study of cognitive structures 'from the bottom up', allowing data to give rise to ontological structures, rather than working 'from the top down' by using a theory to guide hypothesis-driven data collection. :

How do concepts of mental life vary across cultures? By asking simple questions about humans, animals and other entities – for example, ‘Do beetles get hungry? Remember things? Feel love?’ – we reconstructed concepts of mental life from the bottom up among adults (N = 711) and children (ages 6–12 years, N = 693) in the USA, Ghana, Thailand, China and Vanuatu. This revealed a cross-cultural and developmental continuity: in all sites, among both adults and children, cognitive abilities travelled separately from bodily sensations, suggesting that a mind–body distinction is common across diverse cultures and present by middle childhood. Yet there were substantial cultural and developmental differences in the status of social–emotional abilities – as part of the body, part of the mind or a third category unto themselves. Such differences may have far-reaching social consequences, whereas the similarities identify aspects of human understanding that may be universal.

People listening to the same story synchronize their heart rates.

Several studies have shown that people paying attention to the same videos or listening to the same stories show similar brain activity, as measured by electroencephalogram (EEG). Electrocardiogram (EKG) measurements are experimentally much easier to perform. Pérez et al. now show that heart rates of participants of their study measured by EKG tended to speed up or slow down at the same points in the story, demonstrating that conscious processing of narrative stimuli synchronizes heart rate between individuals. Here is their abstract:  

Highlights

• Narrative stimuli can synchronize fluctuations of heart rate between individuals 

• This interpersonal synchronization is modulated by attention and predicts memory 

• These effects on heart rate cannot be explained by modulation of respiratory patterns 

• Synchrony is lower in patients with disorders of consciousness

Summary

Heart rate has natural fluctuations that are typically ascribed to autonomic function. Recent evidence suggests that conscious processing can affect the timing of the heartbeat. We hypothesized that heart rate is modulated by conscious processing and therefore dependent on attentional focus. To test this, we leverage the observation that neural processes synchronize between subjects by presenting an identical narrative stimulus. As predicted, we find significant inter-subject correlation of heart rate (ISC-HR) when subjects are presented with an auditory or audiovisual narrative. Consistent with our hypothesis, we find that ISC-HR is reduced when subjects are distracted from the narrative, and higher ISC-HR predicts better recall of the narrative. Finally, patients with disorders of consciousness have lower ISC-HR, as compared to healthy individuals. We conclude that heart rate fluctuations are partially driven by conscious processing, depend on attentional state, and may represent a simple metric to assess conscious state in unresponsive patients.

What are our brains doing when they are (supposedly) doing nothing?

Pezullo et al. address the question of this post's title in an article in Trends in Cognitive Sciences: "The secret life of predictive brains: what's spontaneous activity for?" (motivated readers can obtain a PDF of the article by emailing me). They suggest an explanation for why brains are constantly active, displaying sophisticated dynamical patterns of spontaneous activity, even when not engaging in tasks or receiving external sensory stimuli. I pass on the article highlights and summary: 

Spontaneous brain dynamics are manifestations of top-down dynamics of generative models detached from action–perception cycles. 

Generative models constantly produce top-down dynamics, but we call them expectations and attention during task engagement and spontaneous activity at rest. 

Spontaneous brain dynamics during resting periods optimize generative models for future interactions by maximizing the entropy of explanations in the absence of specific data and reducing model complexity. 

Low-frequency brain fluctuations during spontaneous activity reflect transitions between generic priors consisting of low-dimensional representations and connectivity patterns of the most frequent behavioral states. 

High-frequency fluctuations during spontaneous activity in the hippocampus and other regions may support generative replay and model learning.

Brains at rest generate dynamical activity that is highly structured in space and time. We suggest that spontaneous activity, as in rest or dreaming, underlies top-down dynamics of generative models. During active tasks, generative models provide top-down predictive signals for perception, cognition, and action. When the brain is at rest and stimuli are weak or absent, top-down dynamics optimize the generative models for future interactions by maximizing the entropy of explanations and minimizing model complexity. Spontaneous fluctuations of correlated activity within and across brain regions may reflect transitions between ‘generic priors’ of the generative model: low dimensional latent variables and connectivity patterns of the most common perceptual, motor, cognitive, and interoceptive states. Even at rest, brains are proactive and predictive.

Scientific fields don't advance if too many papers are published.

Fascinating work from Chu and Evans: 

Significance

The size of scientific fields may impede the rise of new ideas. Examining 1.8 billion citations among 90 million papers across 241 subjects, we find a deluge of papers does not lead to turnover of central ideas in a field, but rather to ossification of canon. Scholars in fields where many papers are published annually face difficulty getting published, read, and cited unless their work references already widely cited articles. New papers containing potentially important contributions cannot garner field-wide attention through gradual processes of diffusion. These findings suggest fundamental progress may be stymied if quantitative growth of scientific endeavors—in number of scientists, institutes, and papers—is not balanced by structures fostering disruptive scholarship and focusing attention on novel ideas.

Abstract

In many academic fields, the number of papers published each year has increased significantly over time. Policy measures aim to increase the quantity of scientists, research funding, and scientific output, which is measured by the number of papers produced. These quantitative metrics determine the career trajectories of scholars and evaluations of academic departments, institutions, and nations. Whether and how these increases in the numbers of scientists and papers translate into advances in knowledge is unclear, however. Here, we first lay out a theoretical argument for why too many papers published each year in a field can lead to stagnation rather than advance. The deluge of new papers may deprive reviewers and readers the cognitive slack required to fully recognize and understand novel ideas. Competition among many new ideas may prevent the gradual accumulation of focused attention on a promising new idea. Then, we show data supporting the predictions of this theory. When the number of papers published per year in a scientific field grows large, citations flow disproportionately to already well-cited papers; the list of most-cited papers ossifies; new papers are unlikely to ever become highly cited, and when they do, it is not through a gradual, cumulative process of attention gathering; and newly published papers become unlikely to disrupt existing work. These findings suggest that the progress of large scientific fields may be slowed, trapped in existing canon. Policy measures shifting how scientific work is produced, disseminated, consumed, and rewarded may be called for to push fields into new, more fertile areas of study.

Metabolism modulates network synchrony in the aging brain

Wow, this work from Weistuch et al. temps me to reconsider my decision to stay away from the various mitochondrial metabolism stimulating supplements I have experimented with over the past 10-15 years (they made me a bit hyper). It has been hypothesized that declining glucose metabolism in older brains drives the loss of high-cost (integrated) functional activities (activities of the sort I'm trying to carry out at the moment in cobbling together a coherent lecture from diverse sources). From the paper's introduction:

We draw on two types of experimental evidence. First, as established using positron emission tomography, older brains show reduced glucose metabolism. Second, as established by functional MRI (fMRI), aging is associated with weakened functional connectivity (FC; i.e., reduced communication [on average] between brain regions). Combining both observations suggests that impaired glucose metabolism may underlie changes in FC. Supporting this link are studies showing disruptions similar to those seen with aging in type 2 diabetic subjects.

The Significance Statement and Abstract:  

Significance

How do brains adapt to changing resource constraints? This is particularly relevant in the aging brain, for which the ability of neurons to utilize their primary energy source, glucose, is diminished. Through experiments and modeling, we find that changes to brain activity patterns with age can be understood in terms of decreasing metabolic activity. Specifically, we find that older brains approach a critical point in our model, enabling small changes in metabolic activity to give rise to an abrupt reconfiguration of functional brain networks.

Abstract

Brain aging is associated with hypometabolism and global changes in functional connectivity. Using functional MRI (fMRI), we show that network synchrony, a collective property of brain activity, decreases with age. Applying quantitative methods from statistical physics, we provide a generative (Ising) model for these changes as a function of the average communication strength between brain regions. We find that older brains are closer to a critical point of this communication strength, in which even small changes in metabolism lead to abrupt changes in network synchrony. Finally, by experimentally modulating metabolic activity in younger adults, we show how metabolism alone—independent of other changes associated with aging—can provide a plausible candidate mechanism for marked reorganization of brain network topology.

A debate over stewardship of global collective behavior

In this post I'm going to pass on the abstract of a PNAS perspective piece by Bak-Coleman et al., a critique by Cheong and Jones and a reply to the critique by Bak-Coleman and Bergstrom. First the Bak-Coleman et al. abstract:

Collective behavior provides a framework for understanding how the actions and properties of groups emerge from the way individuals generate and share information. In humans, information flows were initially shaped by natural selection yet are increasingly structured by emerging communication technologies. Our larger, more complex social networks now transfer high-fidelity information over vast distances at low cost. The digital age and the rise of social media have accelerated changes to our social systems, with poorly understood functional consequences. This gap in our knowledge represents a principal challenge to scientific progress, democracy, and actions to address global crises. We argue that the study of collective behavior must rise to a “crisis discipline” just as medicine, conservation, and climate science have, with a focus on providing actionable insight to policymakers and regulators for the stewardship of social systems.

The critique by Cheong and Jones:

In vivid detail, Bak-Coleman et al. describe explosively multiplicative global pathologies of scale posing existential risk to humanity. They argue that the study of collective behavior in the age of digital social media must rise to a “crisis discipline” dedicated to averting global ruin through the adaptive manipulation of social dynamics and the emergent phenomenon of collective behavior. Their proposed remedy is a massive global, multidisciplinary coalition of scientific experts to discover how the “dispersed networks” of digital media can be expertly manipulated through “urgent, evidence-based research” to “steward” social dynamics into “rapid and effective collective behavioral responses,” analogous to “providing regulators with information” to guide the stewardship of ecosystems. They picture the enlightened harnessing of yet-to-be-discovered scale-dependent rules of internet-age social dynamics as a route to fostering the emergent phenomenon of adaptive swarm intelligence.

We wish to issue an urgent warning of our own: Responding to the self-evident fulminant, rampaging pathologies of scale ravaging the planet with yet another pathology of scale will, at best, be ineffective and, at worst, counterproductive. It is the same thing that got us here. The complex international coalition they propose would be like forming a new, ultramodern weather bureau to furnish consensus recommendations to policy makers while a megahurricane is already making landfall. This conjures images of foot dragging, floor fights, and consensus building while looking for actionable “mechanistic insight” into social dynamics on the deck of the Titanic. After lucidly spotlighting the urgent scale-dependent mechanistic nature of the crisis, Bak-Coleman et al. do not propose any immediate measures to reduce scale, but rather offer that there “is reason to be hopeful that well-designed systems can promote healthy collective action at scale...” Hope is neither a strategy nor an action.

Despite lofty goals, the coalition they propose does not match the urgency or promise a rapid and collective behavioral response to the existential threats they identify. Scale reduction may be “collective,” but achieving it will have to be local, authentic, and without delay—that is, a response conforming to the “all hands on deck” swarm intelligence phenomena that are well described in eusocial species already. When faced with the potential for imminent global ruin lurking ominously in the fat tail (5) of the future distribution, the precautionary principle dictates that we should respond with now-or-never urgency. This is a simple fact. A “weather bureau” for social dynamics would certainly be a valuable, if not indispensable, institution for future generations. But there is no reason that scientists around the world, acting as individuals within their own existing social networks and spheres of influence, observing what is already obvious with their own eyes, cannot immediately create a collective chorus to send this message through every digital channel instead of waiting for a green light from above. “Urgency” is euphemistic. It is now or never.

The Bak-Coleman and Bergstrom reply to the critique:

In our PNAS article “Stewardship of global collective behavior”, we describe the breakneck pace of recent innovations in information technology. This radical transformation has transpired not through a stewarded effort to improve information quality or to further human well-being. Rather, current technologies have been developed and deployed largely for the orthogonal purpose of keeping people engaged online. We cannot expect that an information ecology organized around ad sales will promote sustainability, equity, or global health. In the face of such impediments to rational democratic action, how can we hope to overcome threats such as global warming, habitat destruction, mass extinction, war, food security, and pandemic disease? We call for a concerted transdisciplinary response, analogous to other crisis disciplines such as conservation ecology and climate science.

In their letter, Cheong and Jones share our vision of the problem—but they express frustration at the absence of an immediately actionable solution to the enormity of challenges that we describe. They assert “swarm intelligence begins now or never” and advocate local, authentic, and immediate “scale reduction.” It’s an appealing thought: Let us counter pathologies of scale by somehow reversing course.

But it’s not clear what this would entail by way of practical, safe, ethical, and effective intervention. Have there ever been successful, voluntary, large-scale reductions in the scale of any aspect of human social life?

Nor is there reason to believe that an arbitrary, hasty, and heuristically decided large-scale restructuring of our social networks would reduce the long tail of existential risk. Rather, rapid shocks to complex systems are a canonical source of cascading failure. Moving fast and breaking things got us here. We can’t expect it to get us out.

Nor do we share the authors’ optimism about what scientists can accomplish with “a collective chorus … through every digital channel”. It is difficult to envision a louder, more vehement, and more cohesive scientific response than that to the COVID-19 pandemic. Yet this unified call for basic public health measures—grounded in centuries of scientific knowledge—nonetheless failed to mobilize political leadership and popular opinion.

Our views do align when it comes to the “now-or-never urgency” that Cheong and Jones highlight. Indeed, this is a key feature of a crisis discipline: We must act without delay to steer a complex system—while still lacking a complete understanding of how that system operates.

As scholars, our job is to call attention to underappreciated threats and to provide the knowledge base for informed decision-making. Academics do not—and should not—engage in large-scale social engineering. Our grounded view of what science can and should do in a crisis must not be mistaken for lassitude or unconcern. Worldwide, the unprecedented restructuring of human communication is having an enormous impact on issues of social choice, often to our detriment. Our paper is intended to raise the alarm. Providing the definitive solution will be a task for a much broader community of scientists, policy makers, technologists, ethicists, and other voices from around the globe.

Paws for thought: Dogs have a theory of mind?

In a very simple experiment, Schünemann et al. appear to demonstrate that dogs can attribute thoughts and motivations to humans, distinguishing intentional from unintentional actions. From The Guardian summary of the work:

...A researcher was asked...to pass treats to a dog through a gap in a screen. During the process the researcher tested the dog on three conditions: in one they attempted to offer a treat but “accidentally” dropped it on their side of the screen and said “oops!”, in another, they tried to offer a treat but the gap was blocked. In a third, the researcher offered the treat, but then suddenly withdrew it and said: “Ha ha!”...in all three situations they don’t get the food for some reason...The results, based on analysis of video recordings of 51 dogs, reveal that the dogs waited longer before walking around the screen to get the treat directly in the case of the sudden withdrawal of the morsel than for the other two situations. They were also more likely stop wagging their tail and sit or lie down...the dogs clearly show different behaviour between the different conditions, suggesting that they distinguish intentional actions from unintentional behavior.

There is debate over whether this behavior - distinguishing human behaviors based on their intentions rather than some other cue - meets the level of understanding that qualifies as having a 'theory of Mind.'

The dark side of Eureka: Artificially induced Aha moments make facts feel true

Fascinating observations from Laukkonen et al:

Some ideas that we have feel mundane, but others are imbued with a sense of profundity. We propose that Aha! moments make an idea feel more true or valuable in order to aid quick and efficient decision-making, akin to a heuristic. To demonstrate where the heuristic may incur errors, we hypothesized that facts would appear more true if they were artificially accompanied by an Aha! moment elicited using an anagram task. In a preregistered experiment, we found that participants (n = 300) provided higher truth ratings for statements accompanied by solved anagrams even if the facts were false, and the effect was particularly pronounced when participants reported an Aha! experience (d = .629). Recent work suggests that feelings of insight usually accompany correct ideas. However, here we show that feelings of insight can be overgeneralized and bias how true an idea or fact appears, simply if it occurs in the temporal ‘neighbourhood’ of an Aha! moment. We raise the possibility that feelings of insight, epiphanies, and Aha! moments have a dark side, and discuss some circumstances where they may even inspire false beliefs and delusions, with potential clinical importance.

National religiosity eases the psychological burden of poverty

From Berkessel et al.:  

Significance

According to a fundamental assumption in the social sciences, the burden of lower socioeconomic status (SES) is more severe in developing nations. In contrast to this assumption, recent research has shown that the burden of lower SES is less—not more—severe in developing nations. In three large-scale global data sets, we show that national religiosity can explain this puzzling finding. Developing nations are more religious, and most world religions uphold norms that, in part, function to ease the burden of lower SES and to cast a bad light on higher SES. In times of declining religiosity, this finding is a call to scientists and policymakers to monitor the increasingly harmful effects of lower SES and its far-reaching social consequences.

Abstract

Lower socioeconomic status (SES) harms psychological well-being, an effect responsible for widespread human suffering. This effect has long been assumed to weaken as nations develop economically. Recent evidence, however, has contradicted this fundamental assumption, finding instead that the psychological burden of lower SES is even greater in developed nations than in developing ones. That evidence has elicited consternation because it suggests that economic development is no cure for the psychological burden of lower SES. So, why is that burden greatest in developed nations? Here, we test whether national religiosity can explain this puzzle. National religiosity is particularly low in developed nations. Consequently, developed nations lack religious norms that may ease the burden of lower SES. Drawing on three different data sets of 1,567,204, 1,493,207, and 274,393 people across 156, 85, and 92 nations, we show that low levels of national religiosity can account for the greater burden of lower SES in developed nations. This finding suggests that, as national religiosity continues to decline, lower SES will become increasingly harmful for well-being—a societal change that is socially consequential and demands political attention.

Precision and the Bayesian brain

I've been studying and trying to understand the new prevailing model of how our brains work that is emerging - the brain as a Baysean predictive processing machine that compares its prior knowledge with incoming evidence of its correctness. If a mis-match occurs that might suggest alterning a prior expectation, the precision of the incoming evidence is very important. In a recent issue of Current Biology Yon and Frith offer a very simple and lucid primer (open source) on what precision is how it influences adrenergic and dopaminergic neuromodulatory systems to alter the synaptic gain afforded to top-down predictions and bottom-up evidence.:

Scientific thinking about the minds of humans and other animals has been transformed by the idea that the brain is Bayesian. A cornerstone of this idea is that agents set the balance between prior knowledge and incoming evidence based on how reliable or ‘precise’ these different sources of information are — lending the most weight to that which is most reliable. This concept of precision has crept into several branches of cognitive science and is a lynchpin of emerging ideas in computational psychiatry — where unusual beliefs or experiences are explained as abnormalities in how the brain estimates precision. But what precisely is precision? In this Primer we explain how precision has found its way into classic and contemporary models of perception, learning, self-awareness, and social interaction. We also chart how ideas around precision are beginning to change in radical ways, meaning we must get more precise about how precision works.

Reconsolidation of a reactivated memory can be altered by stress hormone levels.

Stern's summary in Science Magazine of work by Antypa et al.:

Reactivation of a memory can make it malleable to subsequent change during reconsolidation. Targeted pharmacological and behavioral manipulations after memory reactivation can modulate reconsolidation and modify the memory. Antypa et al. investigated whether changes in stress hormone levels during sleep affected later memory of a reactivated episode. The authors recited a story accompanied by a slide show to a group of male and female subjects. If subjects were given treatment to block cortisol synthesis during early morning sleep, then their 3-day-old memory of the story was more precisely recalled than if the early morning cortisol spike was uncontrolled. However, this improvement only occurred if the subjects had been given a visual cue for the story just before anti-cortisol treatment.

Perceived voice emotions evolve from categories to dimensions

Whether emotions are best characterized as discrete catagories (anger, fear, joy, etc.) or as points on continuums of valence (positive/negative) and arousal (calm/agitated) has been debated by emotion researchers for many years. Work from Giordano et al. suggests that both descriptions may be appropriate. They find that categories prevail in perceptual and early (less than 200 ms) frontotemporal cerebral representational geometries and that dimensions impinge predominantly on a later limbic–temporal network (at 240 ms and after 500 ms).

Long-standing affective science theories conceive the perception of emotional stimuli either as discrete categories (for example, an angry voice) or continuous dimensional attributes (for example, an intense and negative vocal emotion). Which position provides a better account is still widely debated. Here we contrast the positions to account for acoustics-independent perceptual and cerebral representational geometry of perceived voice emotions. We combined multimodal imaging of the cerebral response to heard vocal stimuli (using functional magnetic resonance imaging and magneto-encephalography) with post-scanning behavioural assessment of voice emotion perception. By using representational similarity analysis, we find that categories prevail in perceptual and early (less than 200 ms) frontotemporal cerebral representational geometries and that dimensions impinge predominantly on a later limbic–temporal network (at 240 ms and after 500 ms). These results reconcile the two opposing views by reframing the perception of emotions as the interplay of cerebral networks with different representational dynamics that emphasize either categories or dimensions.

Music can be infectious like a virus - the same mathematical model works for both

Rosati et al. find that a standard model of epidemic disease, called the SIR model, fitts trends in song downloads over time:

Popular songs are often said to be ‘contagious’, ‘infectious’ or ‘viral’. We find that download count time series for many popular songs resemble infectious disease epidemic curves. This paper suggests infectious disease transmission models could help clarify mechanisms that contribute to the ‘spread’ of song preferences and how these mechanisms underlie song popularity. We analysed data from MixRadio, comprising song downloads through Nokia cell phones in Great Britain from 2007 to 2014. We compared the ability of the standard susceptible–infectious–recovered (SIR) epidemic model and a phenomenological (spline) model to fit download time series of popular songs. We fitted these same models to simulated epidemic time series generated by the SIR model. Song downloads are captured better by the SIR model, to the same extent that actual SIR simulations are fitted better by the SIR model than by splines. This suggests that the social processes underlying song popularity are similar to those that drive infectious disease transmission. We draw conclusions about song popularity within specific genres based on estimated SIR parameters. In particular, we argue that faster spread of preferences for Electronica songs may reflect stronger connectivity of the ‘susceptible community’, compared with the larger and broader community that listens to more common genres.

Can we get human nature right?

Iris Berent does an interesting Perspective artice in PNAS that considers the strong intuitions that laypeople hold about human nature. People's attitudes bifurcate for "hot emotions" and "cold ideas." Emotions, people believe, are innate, whereas ideas must be learned. She suggests that the dissonance between intuitive dualism and essentialism explains why emotions and ideas elicit such conflicting reactions. Here is her summary graphic, followed by the article's abstract: 

Few questions in science are as controversial as human nature. At stake is whether our basic concepts and emotions are all learned from experience, or whether some are innate. Here, I demonstrate that reasoning about innateness is biased by the basic workings of the human mind. Psychological science suggests that newborns possess core concepts of “object” and “number.” Laypeople, however, believe that newborns are devoid of such notions but that they can recognize emotions. Moreover, people presume that concepts are learned, whereas emotions (along with sensations and actions) are innate. I trace these beliefs to two tacit psychological principles: intuitive dualism and essentialism. Essentialism guides tacit reasoning about biological inheritance and suggests that innate traits reside in the body; per intuitive dualism, however, the mind seems ethereal, distinct from the body. It thus follows that, in our intuitive psychology, concepts (which people falsely consider as disembodied) must be learned, whereas emotions, sensations, and emotions (which are considered embodied) are likely innate; these predictions are in line with the experimental results. These conclusions do not speak to the question of whether concepts and emotions are innate, but they suggest caution in its scientific evaluation.

How the unvaccinated threaten the vaccinated for COVID-19: A Darwinian perspective

From the current issue of PNAS that just appeared I want to immediately pass on the entire text of the  open source piece by Emanuel Goldman. Its points crystallize my anger at those across the globe whose resistance to vaccination for COVID-19 puts us all at risk by making more likely the emergence of a new variant against which our existing vaccinations are ineffective. The text:

Imai et al. (1) have characterized yet another variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for COVID-19, this one originating in Brazil. The good news is that it appears that vaccines currently available are still expected to provide protection against this variant. However, what about the next variant, one we have not seen yet? Will we still be protected?

In 1859, Charles Darwin published On the Origin of Species (2), in which he outlined the principles of natural selection and survival of the fittest. The world presently has the unwelcome opportunity to see the principles of evolution as enumerated by Darwin play out in real time, in the interactions of the human population with SARS-CoV-2. The world could have easily skipped this unpleasant lesson, had there not been such large numbers of the human population unwilling to be vaccinated against this disease.

SARS-CoV-2 has shown that it can mutate into many variants of the original agent (3). An unvaccinated pool of individuals provides a reservoir for the virus to continue to grow and multiply, and therefore more opportunities for such variants to emerge. When this occurs within a background of a largely vaccinated population, natural selection will favor a variant that is resistant to the vaccine.

So far, we have been lucky that the variants that have emerged can still be somewhat controlled by current vaccines, probably because these variants evolved in mostly unvaccinated populations and were not subject to selective pressure of having to grow in vaccinated hosts. Nevertheless, the Delta variant is exhibiting increased frequency of breakthrough infections among the vaccinated (4).

The real danger is a future variant, which will be the legacy of those people who are not getting vaccinated providing a breeding ground for the virus to continue to generate variants. A variant could arise that is resistant to current vaccines, rendering those already vaccinated susceptible again.

Progress we have made in overcoming the pandemic will be lost. New vaccines will have to be developed. Lockdowns and masks will once again be required. Many more who are currently protected, especially among the vulnerable, will die.

This dire prediction need not occur if universal vaccination is adopted, or mandated, to protect everyone, including those who are already vaccinated.

Darwinian selection may also yet solve the problem with a much crueler calculus. The unvaccinated will either get sick and survive, and therefore be the equivalent of vaccinated, or they will die and therefore be removed as breeding grounds for the virus.

The National Archives in the United Kingdom note that, in 1665, during the Black Death plague, “to prevent the disease spreading, a victim was locked in their house with their entire family, condemning them all to death” (5). Vaccinations offer a much more humane response to prevent spread of this disease. The path forward is in the hands of the unvaccinated, and in the political will of the authorities.

References

1. ↵
   1. M. Imai et al

   ., Characterization of a new SARS-CoV-2 variant that emerged in Brazil. Proc. Natl. Acad. Sci. U.S.A. 118, e2106535118 (2021).

   Abstract/FREE Full TextGoogle Scholar
2. ↵
   1. C. Darwin

   , On the Origin of Species by Means of Natural Selection, or Preservation of Favoured Races in the Struggle for Life (John Murray, London, 1859), pp. 1809–1882.

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3. ↵
   1. Centers for Disease Control and Prevention

   , SARS-CoV-2 variant classifications and definitions. https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-info.html. Accessed 31 August 2021.

   Google Scholar
4. ↵
   1. T. Farinholt et al

   ., Transmission event of SARS-CoV-2 Delta variant reveals multiple vaccine breakthrough infections medRxiv [Preprint] (2021). https://www.medrxiv.org/content/10.1101/2021.06.28.21258780v1 (Accessed 31 August 2021).

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5. ↵
   1. The National Archives

   , The Black Death https://www.nationalarchives.gov.uk/museum/item.asp?item_id=23. Accessed 31 August 2021.

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