Despite our fluency in reading human faces, sometimes we mistakenly perceive illusory faces in objects, a phenomenon known as face pareidolia. Although illusory faces share some neural mechanisms with real faces, it is unknown to what degree pareidolia engages higher-level social perception beyond the detection of a face. In a series of large-scale behavioral experiments (ntotal = 3,815 adults), we found that illusory faces in inanimate objects are readily perceived to have a specific emotional expression, age, and gender. Most strikingly, we observed a strong bias to perceive illusory faces as male rather than female. This male bias could not be explained by preexisting semantic or visual gender associations with the objects, or by visual features in the images. Rather, this robust bias in the perception of gender for illusory faces reveals a cognitive bias arising from a broadly tuned face evaluation system in which minimally viable face percepts are more likely to be perceived as male.
This blog reports new ideas and work on mind, brain, behavior, psychology, and politics - as well as random curious stuff. (Try the Dynamic Views at top of right column.)
Friday, February 18, 2022
Illusory faces are more likely to be perceived as male than female
Wednesday, February 16, 2022
Our brains store concepts as sensory-motor and affective information
Fascinating work from Fernandino et al., who show that concept representations are not independent of sensory-motor experience:
Significance
The ability to identify individual objects or events as members of a kind (e.g., “knife,” “dog,” or “party”) is a fundamental aspect of human cognition. It allows us to quickly access a wealth of information pertaining to a newly encountered object or event and use it to guide our behavior. How is this information represented in the brain? We used functional MRI to analyze patterns of brain activity corresponding to hundreds of familiar concepts and quantitatively characterized the informational structure of these patterns. Our results indicate that conceptual knowledge is stored as patterns of neural activity that encode sensory-motor and affective information about each concept, contrary to the long-held idea that concept representations are independent of sensory-motor experience.Abstract
The nature of the representational code underlying conceptual knowledge remains a major unsolved problem in cognitive neuroscience. We assessed the extent to which different representational systems contribute to the instantiation of lexical concepts in high-level, heteromodal cortical areas previously associated with semantic cognition. We found that lexical semantic information can be reliably decoded from a wide range of heteromodal cortical areas in the frontal, parietal, and temporal cortex. In most of these areas, we found a striking advantage for experience-based representational structures (i.e., encoding information about sensory-motor, affective, and other features of phenomenal experience), with little evidence for independent taxonomic or distributional organization. These results were found independently for object and event concepts. Our findings indicate that concept representations in the heteromodal cortex are based, at least in part, on experiential information. They also reveal that, in most heteromodal areas, event concepts have more heterogeneous representations (i.e., they are more easily decodable) than object concepts and that other areas beyond the traditional “semantic hubs” contribute to semantic cognition, particularly the posterior cingulate gyrus and the precuneus.
Monday, February 14, 2022
How to want less
In fact, our natural state is dissatisfaction punctuated by brief moments of satisfaction. You might not like the hedonic treadmill, but Mother Nature thinks it’s pretty great. She likes watching you strive to achieve an elusive goal, because strivers get the goods—even if they don’t enjoy them for long. More mates, better mates, better chances of survival for our children—these ancient mandates are responsible for much of the code that runs incessantly in the deep recesses of our brains. It doesn’t matter whether you’ve found your soul mate and would never stray; the algorithms designed to get us more mates (or allow us to make an upgrade) continue whirring, which is why you still want to be attractive to strangers. Neurobiological instinct—which we experience as dissatisfaction—is what drives us forward....There are many other, related examples of evolved tendencies that militate against enduring happiness—for example, the tendency toward jealous misery in our romantic relationships.He notes the history of similar recurring solutions to these problems, for example in the sayings of the Buddha, St. Thomas Aquinas - and even Mick Jagger (in his classic "I can't get no satisfaction"). His self help suggestion is to:
...absorb the teachings of Thomas Aquinas and the Buddha—or for that matter, modern social science—and commit to stop trying to add more and more, but instead start taking things away.
In truth, our formula, Satisfaction = getting what you want, leaves out one key component. To be more accurate, it should be:
Satisfaction = what you have ÷ what you want
All of our evolutionary and biological imperatives focus us on increasing the numerator—our haves. But the more significant action is in the denominator—our wants. The modern world is made up of clever ways to make our wants explode without us realizing it.
Brooks offers three habits he has found useful in beating the dissatisfaction curse:
I. Go from Prince to Sage (the models of Thomas Aquinas and the Buddha...repudiating the world's reward in favor of inner wisdom and helping others)
II Make a Reverse Bucket List (repudiate getting more 'stuff' and instead list intrinsic sources of happiness or satisfaction that come from with and revolve around love, relationships, and deep purpose...having little to do with the admiration of strangers.)
III. Get Smaller (live in the present, not the past or future.)
Friday, February 11, 2022
A special issue of Social Cognitive and Affective Neuroscience on tDCS
Wednesday, February 09, 2022
Expression unleashed: The evolutionary & cognitive foundations of human communication
Human expression is open-ended, versatile and diverse, ranging from ordinary language use to painting, from exaggerated displays of affection to micro-movements that aid coordination. Here we present and defend the claim that this expressive diversity is united by an interrelated suite of cognitive capacities, the evolved functions of which are the expression and recognition of informative intentions. We describe how evolutionary dynamics normally leash communication to narrow domains of statistical mutual benefit, and how they are unleashed in humans. The relevant cognitive capacities are cognitive adaptations to living in a partner choice social ecology; and they are, correspondingly, part of the ordinarily developing human cognitive phenotype, emerging early and reliably in ontogeny. In other words, we identify distinctive features of our species’ social ecology to explain how and why humans, and only humans, evolved the cognitive capacities that, in turn, lead to massive diversity and open-endedness in means and modes of expression. Language use is but one of these modes of expression, albeit one of manifestly high importance. We make cross-species comparisons, describe how the relevant cognitive capacities can evolve in a gradual manner, and survey how unleashed expression facilitates not only language use but novel behaviour in many other domains too, focusing on the examples of joint action, teaching, punishment and art, all of which are ubiquitous in human societies but relatively rare in other species. Much of this diversity derives from graded aspects of human expression, which can be used to satisfy informative intentions in creative and new ways. We aim to help reorient cognitive pragmatics, as a phenomenon that is not a supplement to linguistic communication and on the periphery of language science, but rather the foundation of the many of the most distinctive features of human behaviour, society and culture.
Monday, February 07, 2022
MindBlog is 16 years old... It's first post: "Dangerous Ideas"
I repeat MindBlog's first post... of ideas that are now considered more commonplace than dangerous. Edge.org soldiers on, but its 'annual question' addressed to prominent thinkers disappeared several years ago. Here is the post:
Edge.org is a website sponsored by the
"Reality Club" (i.e. John Brockman, literary
agent/impressario/socialite). Brockman has assembled a stable of
scientists and other thinkers that he defines as a "third culture" that
takes the place of traditional intellectuals in redefining who and what
we are.... Each year a question is formulated for all to write on...
In 2004 it was "What do you believe is true even though you cannot prove
it?" The question for 2005 was "What is your dangerous idea?"
The
responses organize themselves into several areas. Here are selected
thumbnail summaries most directly relevant to human minds. I've not
included cosmology and physics. Go to edge.org to read the essays
I. Nature of the human self or mind (by the way see my "I-Illusion" essay on my website):
Paulos - The self is a conceptual chimera
Shirky - Free will is going away
Nisbett - We are ignorant of our thinking processes
Horgan - We have no souls
Bloom - There are no souls, mind has a material basis.
Provine - This is all there is.
Anderson - Brains cannot become minds without bodies
Metzinger - Is being intellectually honest about the issue of free will compatible with preserving one's mental health?
Clark - Much of our behavior is determined by non-conscious, automatic uptake of cues and information
Turkle - Simulation will replace authenticity as computer simulation becomes fully naturalized.
Dawkins
- A faulty person is no different from a faulty car. There is a
mechanism determining behavior that needs to be fixed. The idea of
responsibility is nonsense.
Smith - What we know may not change us.
We will continue to conceive ourselves as centres of experience,
self-knowing and free willing agents.
II. Natural explanations of culture
Sperber - Culture is natural.
Taylor - The human brain is a cultural artifact.
Hauser- There is a universal grammar of mental life.
Pinker - People differ genetically in their average talents and temperaments.
Goodwin - Similar coordinating patterns underlie biological and cultural evolution.
Venter - Revealing the genetic basis of personality and behavior will create societal conflicts.
III. Fundamental changes in political, economic, social order
O'donnell - The state will disappear.
Ridley - Government is the problem not the solution.
Shermer - Where goods cross frontiers armies won't.
Harari -Democracy is on its way out.
Csikszentmihalyi- The free market myth is destroying culture.
Goleman - The internet undermines the quality of human interaction.
Harris - Science must destroy religion.
Porco
- Confrontation between science and religion might end when role played
by science in lives of people is the same played by religion
today.
Bering - Science will never silence God
Fisher - Drugs such as antidepressants jeopardize feelings of attachment and love
Iacoboni - Media Violence Induces Imitative Violence - the Problem with Mirrors
Morton - Our planet is not in peril, just humans are.
Friday, February 04, 2022
Attention and executive functions - improvements and declines with ageing.
Many but not all cognitive abilities decline during ageing. Some even improve due to lifelong experience. The critical capacities of attention and executive functions have been widely posited to decline. However, these capacities are composed of multiple components, so multifaceted ageing outcomes might be expected. Indeed, prior findings suggest that whereas certain attention/executive functions clearly decline, others do not, with hints that some might even improve. We tested ageing effects on the alerting, orienting and executive (inhibitory) networks posited by Posner and Petersen’s influential theory of attention, in a cross-sectional study of a large sample (N = 702) of participants aged 58–98. Linear and nonlinear analyses revealed that whereas the efficiency of the alerting network decreased with age, orienting and executive inhibitory efficiency increased, at least until the mid-to-late 70s. Sensitivity analyses indicated that the patterns were robust. The results suggest variability in age-related changes across attention/executive functions, with some declining while others improve.
Wednesday, February 02, 2022
How fast people respond to each other is a metric of social connection.
From Templeton et al.:
Significance
Social connection is critical for our mental and physical health yet assessing and measuring connection has been challenging. Here, we demonstrate that a feature intrinsic to conversation itself—the speed with which people respond to each other—is a simple, robust, and sufficient metric of social connection. Strangers and friends feel more connected when their conversation partners respond quickly. Because extremely short response times (less than 250 ms) preclude conscious control, they provide an honest signal that even eavesdroppers use to judge how well two people “click.”Abstract
Clicking is one of the most robust metaphors for social connection. But how do we know when two people "click"? We asked pairs of friends and strangers to talk with each other and rate their felt connection. For both friends and strangers, speed in response was a robust predictor of feeling connected. Conversations with faster response times felt more connected than conversations with slower response times, and within conversations, connected moments had faster response times than less-connected moments. This effect was determined primarily by partner responsivity: People felt more connected to the degree that their partner responded quickly to them rather than by how quickly they responded to their partner. The temporal scale of these effects (less than 250 ms) precludes conscious control, thus providing an honest signal of connection. Using a round-robin design in each of six closed networks, we show that faster responders evoked greater feelings of connection across partners. Finally, we demonstrate that this signal is used by third-party listeners as a heuristic of how well people are connected: Conversations with faster response times were perceived as more connected than the same conversations with slower response times. Together, these findings suggest that response times comprise a robust and sufficient signal of whether two minds “click.”
Monday, January 31, 2022
Threatening language is contagious - Tracking America’s collective response to threats with a linguistic tool
From Choi et al.:
Significance
People are constantly exposed to threatening language in mass communication channels, yet we lack tools to identify language about threats and track its impact on human groups. We developed a threat dictionary, a computationally derived linguistic tool that indexes threat levels from texts with high temporal resolution, across media platforms, and for different levels of analysis. The dictionary shows convergent validity with objective threats in American history, including violent conflicts, natural disasters, and pathogen outbreaks. Moreover, fluctuations in threat levels from the past 100 years coincide with America’s shifting cultural norms, political attitudes, and macroeconomic activity, demonstrating how this linguistic tool can be applied to understand the collective shifts associated with mass communicated threats.Abstract
In today’s vast digital landscape, people are constantly exposed to threatening language, which attracts attention and activates the human brain’s fear circuitry. However, to date, we have lacked the tools needed to identify threatening language and track its impact on human groups. To fill this gap, we developed a threat dictionary, a computationally derived linguistic tool that indexes threat levels from mass communication channels. We demonstrate this measure’s convergent validity with objective threats in American history, including violent conflicts, natural disasters, and pathogen outbreaks such as the COVID-19 pandemic. Moreover, the dictionary offers predictive insights on US society’s shifting cultural norms, political attitudes, and macroeconomic activities. Using data from newspapers that span over 100 years, we found change in threats to be associated with tighter social norms and collectivistic values, stronger approval of sitting US presidents, greater ethnocentrism and conservatism, lower stock prices, and less innovation. The data also showed that threatening language is contagious. In all, the language of threats is a powerful tool that can inform researchers and policy makers on the public’s daily exposure to threatening language and make visible interesting societal patterns across American history.
Friday, January 28, 2022
The stories we imagine while listening to music depends on our culture.
....compared quantitative measures of narrativity (the likelihood that an excerpt of music triggers a story in listeners minds) and narrative engagement (how vivid and clear the events of the story are in listeners minds) for a large set of musical excerpts from Western and Chinese musical traditions for listeners in the same three distinct geographical locations as the present investigation—two suburban college towns in the US Midwest and one rural village in the Chinese province of Guizhou. Results showed that people in all three locations readily narrativize to excerpts (i.e., narrativity scores were quite high) with varying levels of narrative engagement for both Western and Chinese instrumental music; moreover, people do so with about the same degree regardless of location. Notably, however, although both excerpt narrativity and narrative engagement scores were highly correlated across the two US locations, they were not correlated (not predictive) for cross-cultural comparisons between listeners in both of the US locations and the remote rural village in Guizhou.Here is the article's abstsract:
The scientific literature sometimes considers music an abstract stimulus, devoid of explicit meaning, and at other times considers it a universal language. Here, individuals in three geographically distinct locations spanning two cultures performed a highly unconstrained task: they provided free-response descriptions of stories they imagined while listening to instrumental music. Tools from natural language processing revealed that listeners provide highly similar stories to the same musical excerpts when they share an underlying culture, but when they do not, the generated stories show limited overlap. These results paint a more complex picture of music’s power: music can generate remarkably similar stories in listeners’ minds, but the degree to which these imagined narratives are shared depends on the degree to which culture is shared across listeners. Thus, music is neither an abstract stimulus nor a universal language but has semantic affordances shaped by culture, requiring more sustained attention from psychology.
Wednesday, January 26, 2022
Our brains have multiple representations of the same body part.
Here is a neat finding. Remember your elementary biology textbook picture of the homunculi in our somatosensory and motor cortices? The small human figure spread across the surface of the brain, with a cortical location for each part of the hand or other body part? Matsumiya shows that when we direct our eye and hand movements to the same body part these two movements are found to be guided by different body maps! Here is his abstract:
Significance
Accurate motor control depends on maps of the body in the brain, called the body schema. Disorders of the body schema cause motor deficits. Although we often execute actions with different motor systems such as the eye and hand, how the body schema operates during such actions is unknown. In this study, participants simultaneously directed eye and hand movements to the same body part. These two movements were found to be guided by different body maps. This finding demonstrates multiple motor system–specific representations of the body schema, suggesting that the choice of motor system toward one’s body can determine which of the brain’s body maps is observed. This may offer a new way to visualize patients’ body schema.Abstract
Purposeful motor actions depend on the brain’s representation of the body, called the body schema, and disorders of the body schema have been reported to show motor deficits. The body schema has been assumed for almost a century to be a common body representation supporting all types of motor actions, and previous studies have considered only a single motor action. Although we often execute multiple motor actions, how the body schema operates during such actions is unknown. To address this issue, I developed a technique to measure the body schema during multiple motor actions. Participants made simultaneous eye and reach movements to the same location of 10 landmarks on their hand. By analyzing the internal configuration of the locations of these points for each of the eye and reach movements, I produced maps of the mental representation of hand shape. Despite these two movements being simultaneously directed to the same bodily location, the resulting hand map (i.e., a part of the body schema) was much more distorted for reach movements than for eye movements. Furthermore, the weighting of visual and proprioceptive bodily cues to build up this part of the body schema differed for each effector. These results demonstrate that the body schema is organized as multiple effector-specific body representations. I propose that the choice of effector toward one’s body can determine which body representation in the brain is observed and that this visualization approach may offer a new way to understand patients’ body schema.
Tuesday, January 25, 2022
Using big data to track major shifts in human cognition
Scheffer et al.’s (1) exciting new work reports an historic rearrangement, occurring in the late 20th century, of the balance between reason and emotion. Its approach is part of a new trend in the psychological sciences that uses extremely large volumes of text to study basic patterns of human cognition. Recent work in this vein has included studies of the universal properties of gender representations (2), the rise of causal thinking (3), and a cognitive bias towards positivity in language itself (4). The goal of going “from text to thought” (5) is an attractive one, and the promise of the machine learning era is that we will only get better at extracting the imprints left, in text, by the mechanisms of the mind.
To establish their claims, Scheffer et al. (1) use principal component analysis to identify two major polarities of correlated vocabulary words in the Google Books corpus (6). The first polarity (PC1) tracks a shift from archaic to modern, in both material life (“iron” is archaic, “computer” is modern) and culture (“liberty” is archaic, “privacy” is modern). The second polarity (PC2) that emerges is the intriguing one, and forms the basis of their paper: Its two poles, the authors argue, correspond to the distinction between “rational” and “intuitive” language.
Their main finding then has two pieces: a shift from the intuitive pole to the rational pole (the “rise” of rationality) and then back (the “fall”) (1). The rise has begun by the start of their data in 1850, and unfolds over the course of a century or more. They attribute it to a society increasingly concerned with quantifying, and justifying, the world through scientific and impersonal language—a gradual tightening of Max Weber’s famous “iron cage” of collectivized, rationalized bureaucracy in service of the capitalist profit motive (7). The fall, meaning a shift from the rational back to the intuitive, begins in 1980, and is more rapid than the rise: By 2020, the balance is similar to that seen in the early 1900s. The fall appears to accelerate in the early 2000s, which leads the authors to associate it with social media use and a “post-truth era” where “feelings trump facts.” Both these interpretations are supported by accompanying shifts toward “collective” pronouns (we, our, and they) in the Weberian period, and then toward the “individualistic” ones (I, my, he, and she) after.
The raw effect sizes the authors report are extraordinarily large (1). At the peak in 1980, rationality words outnumbered intuition words, on average, three to one. Forty years later (and 100 y earlier), however, the balance was roughly one to one. If these represent changes in actual language use, let alone the time devoted to the underlying cognitive processes, they are enormous shifts in the nature of human experience.
1. M. Scheffer, I. van de Leemput, E. Weinans, J. Bollen, The rise and fall of rationality in language. Proc. Natl. Acad. Sci. U.S.A. 118, e2107848118 (2021).
2. T. E. S. Charlesworth, V. Yang, T. C. Mann, B. Kurdi, M. R. Banaji, Gender stereotypes in natural language: Word embeddings show robust consistency across child and adult language corpora of more than 65 million words. Psychol. Sci. 32, 218–240 (2021).
3. R. Iliev, R. Axelrod, Does causality matter more now? Increase in the proportion of causal language in English texts. Psychol. Sci. 27, 635–643 (2016).
4. P. S. Dodds et al, Human language reveals a universal positivity bias. Proc. Natl. Acad. Sci. U.S.A. 112, 2389–2394 (2015).
5. J. C. Jackson et al, From text to thought: How analyzing language can advance psychological science. Perspect. Psychol. Sci., 10.117/17456916211004899 (2021).
6. J. B. Michel et al.; Google Books Team, Quantitative analysis of culture using millions of digitized books. Science 331, 176–182 (2011).
Friday, January 21, 2022
What is working for you and what is not?
This post passes on to MindBlog readers the discussion topic for a Feb 6 2:00 p.m. (CST) Zoom meeting of The Austin Rainbow Forum, which I coordinate along with fellow Austinites Darrell Laremore and Charles Curry. If you are interested in attending the session please email forumaustin@gmail.com.
What is working for you and what is not? Are things as bad as most of the media suggest? We are freer, richer, safer than we have ever been before, yet anxiety and suicides are at all-time highs. What sets our ratio of hopelessness to hopefulness? Do we have overactive fear, negativity, and blame biases? Below is a selection of background reading relevant to optimism versus pessimism.
Maybe things are not as bad as we think
Most People are Good
Social Media isn’t the problem…We are.
Antidotes to anxiety and hopelessness
How to stay optimistic when everything seems wrong.
How to be more optimistic
The Compassionate Instinct
What can go wrong - the tide of bad news from our media
America Is Falling Apart at the Seams
The Mental Health Toll of Trump-Era Politics
Going Bananas in the Age of Anxiety
More optimistic long term views
Hans Rosling: Factfulness: Ten Reasons We’re Wrong About the World - and Why Things are Better Than you Think. (10 psychological instincts that mislead us, for example to excess fear, negativity, blame, etc. - The link takes you to the first of a series of four blog posts abstracting the main points of the book)
Steven Pinker: Enlightenment Now: The Case for Reason, Science, Humanism, and Progress (The link takes you to a series of posts abstracting the main points of the book).
Nicholas A. Christakis: Blueprint: The Evolutionary Origins of a Good Society
Can monitoring brain waves boost mental health?
Well-heeled investors, including the former secretary of education, Betsy DeVos, continue to pour millions into neurofeedback companies that promise dramatic improvements to the ways our brains function...However, neurofeedback is still not accepted as a mainstream treatment within mental health circles — and the most robust research into the intervention so far suggests it is no more effective than a placebo.
Practitioners across the country use neurofeedback to treat conditions like attention deficit hyperactivity disorder, major depressive disorder, anxiety disorder, epilepsy and traumatic brain injuries. The Food and Drug Administration has cleared a wide range of neurofeedback devices to treat these and other conditions, and the Centers for Disease Control and Prevention list it as an option in cases of ADHD in children, though they stop short of endorsing it.
Robert Thibault, a postdoctoral scholar at the Meta-Research Innovation Center at Stanford University, notes that neurofeedback advocates point to peer-reviewed research that have “impressive results,” but most are not rigorous double-blind, placebo-controlled trials. Of the dozen or so such trials, all but one concluded that fake neurofeedback works just as well as real neurofeedback...neurofeedback therapy success stories are likely caused by the placebo effect and not the treatment. He suggested that the therapy’s success may have something to do with the “healing environment” that practitioners create in their clinics or the allure of using sophisticated brain-monitoring technology.
In many instances, an online course is all that is needed to earn the certificate required to operate one of the dozens of neurofeedback devices on the market...Some companies skip the practitioner entirely by selling pricey neurofeedback devices directly to consumers...While its effectiveness is still debated, neurofeedback is generally thought to be safe. Even critics admit there are few side effects or downsides for those who have the time and money.
Wednesday, January 19, 2022
C.E.O.s are our heroes, at least according to them.
His philanthropic efforts have been directed at easing homelessness in San Francisco, while expanding health care for children. He and Salesforce collectively contributed $7 million toward a successful 2018 campaign for a local ballot measure that levied fresh taxes on San Francisco companies to finance expanded programs. The new taxes were likely to cost Salesforce $10 million a year.
That sounded like a lot of money, ostensible evidence of a socially conscious C.E.O. sacrificing the bottom line in the interest of catering to societal needs. But it was less than a trifle alongside the money that Salesforce withheld from the government through legal tax subterfuge.
The same year that Mr. Benioff backed the ballot measure, his company recorded revenues exceeding $13 billion while paying the modest sum of zero in federal taxes. Salesforce deployed 14 tax subsidiaries scattered from Singapore to Switzerland, moving its money and assets around in a masterful display of accounting hocus-pocus that made its taxable income vanish..Salesforce repeated the trick in 2020, paying no federal taxes despite reporting $2.6 billion in profit.
During President Bill Clinton’s administration, the Treasury Department opened up a loophole that enabled executives at multinational corporations to set up subsidiaries in foreign countries that beckoned with low taxes — Ireland was a popular choice — and then legally transfer their intellectual property there. Their new international outposts charged the rest of the corporation exorbitant licensing fees to use the intellectual property.
The net effect: On their American earnings statements, the wealthiest corporations looked like money losers, paying taxes accordingly.
Monday, January 17, 2022
Different circuits in the brain for reward seeking and novelty seeking.
Novelty seeking is a key feature of intelligent behavior and adaptive cognition. However, we know little about the circuits that regulate our attraction to novel objects for novelty’s sake. Ogasawara et al. discovered that a brain nucleus called the zona incerta was causally related to novelty seeking. A region in the anterior medial temporal lobe projected to the zona incerta and sent motivational signals required to control novelty seeking through the zona incerta circuit. A novelty-seeking task, in which monkeys were motivated by the receipt of novel objects, showed that this behavior was not regulated by the dopamine reward-seeking circuitry. This work provides evidence for a clear dissociation in the brain circuitry between reward seeking and novelty seeking.
Friday, January 14, 2022
Unlocking adults’ implicit statistical learning by cognitive depletion
Smalle et al. make the fascinating observation that inhibition of our adult cognitive control system by non-invasive brain stimulation can unleash some of our infant implicit statistical learning abilities - the learning of novel words embedded in a string of spoken syllables. This suggests that adult language learning is antagonized by higher cognitive mechanisms.
Significance
Statistical learning mechanisms enable extraction of patterns in the environment from infancy to adulthood. For example, they enable segmentation of continuous speech streams into novel words. Adults typically become aware of the hidden words even when passively listening to speech streams. It remains poorly understood how cognitive development and brain maturation affect implicit statistical learning (i.e., infant-like learning without awareness). Here, we show that the depletion of the cognitive control system by noninvasive brain stimulation or by demanding cognitive tasks boosts adults’ implicit but not explicit word-segmentation abilities. These findings suggest that the adult cognitive architecture constrains statistical learning mechanisms that are likely to contribute to early language acquisition and opens avenues to enhance language-learning abilities in adults.Abstract
Human learning is supported by multiple neural mechanisms that maturate at different rates and interact in mostly cooperative but also sometimes competitive ways. We tested the hypothesis that mature cognitive mechanisms constrain implicit statistical learning mechanisms that contribute to early language acquisition. Specifically, we tested the prediction that depleting cognitive control mechanisms in adults enhances their implicit, auditory word-segmentation abilities. Young adults were exposed to continuous streams of syllables that repeated into hidden novel words while watching a silent film. Afterward, learning was measured in a forced-choice test that contrasted hidden words with nonwords. The participants also had to indicate whether they explicitly recalled the word or not in order to dissociate explicit versus implicit knowledge. We additionally measured electroencephalography during exposure to measure neural entrainment to the repeating words. Engagement of the cognitive mechanisms was manipulated by using two methods. In experiment 1 (n = 36), inhibitory theta-burst stimulation (TBS) was applied to the left dorsolateral prefrontal cortex or to a control region. In experiment 2 (n = 60), participants performed a dual working-memory task that induced high or low levels of cognitive fatigue. In both experiments, cognitive depletion enhanced word recognition, especially when participants reported low confidence in remembering the words (i.e., when their knowledge was implicit). TBS additionally modulated neural entrainment to the words and syllables. These findings suggest that cognitive depletion improves the acquisition of linguistic knowledge in adults by unlocking implicit statistical learning mechanisms and support the hypothesis that adult language learning is antagonized by higher cognitive mechanisms.
Wednesday, January 12, 2022
Children universally across societies enforce conventional norms but in culturally variable ways
Humans, as compared with other animals, create and follow conventional norms that determine how we greet each other, dress, or play certain games. Conventional norms are universal in all human societies, but it is an open question whether individuals in all societies also actively enforce conventional norms when others in their group break them. We investigated third-party enforcement of conventional norms in 5- to 8-y-old children (n = 376) from eight diverse small-scale and large-scale societies. Children learned the rules for playing a new sorting game and then, observed a peer who was apparently breaking them. Across societies, observer children intervened frequently to correct their misguided peer (i.e., more frequently than when the peer was following the rules). However, both the magnitude and the style of interventions varied across societies. Detailed analyses of children’s interactions revealed societal differences in children’s verbal protest styles as well as in their use of actions, gestures, and nonverbal expressions to intervene. Observers’ interventions predicted whether their peer adopted the observer’s sorting rule. Enforcement of conventional norms appears to be an early emerging human universal that comes to be expressed in culturally variable ways.
Monday, January 10, 2022
Transcranial stimulation of alpha oscillations up-regulates the default mode network
In the brain’s functional organization, the default mode network (DMN) represents a key architecture, whose dysregulation is involved in a host of major neuropsychiatric disorders. However, insights into the regulation of the DMN remain scarce. Through neural synchrony, the alpha-frequency oscillation represents another key underpinning of the brain’s organization and is thought to share an inherent interdependence with the DMN. Here, we demonstrated that transcranial alternating current stimulation of alpha oscillations (α-tACS) not only augmented alpha activity but also strengthened connectivity of the DMN, with the former serving as a mediator of the latter. These findings reveal that alpha oscillations can support DMN functioning. In addition, they identify an effective noninvasive approach to regulate the DMN via α-tACS.Abstract
The default mode network (DMN) is the most-prominent intrinsic connectivity network, serving as a key architecture of the brain’s functional organization. Conversely, dysregulated DMN is characteristic of major neuropsychiatric disorders. However, the field still lacks mechanistic insights into the regulation of the DMN and effective interventions for DMN dysregulation. The current study approached this problem by manipulating neural synchrony, particularly alpha (8 to 12 Hz) oscillations, a dominant intrinsic oscillatory activity that has been increasingly associated with the DMN in both function and physiology. Using high-definition alpha-frequency transcranial alternating current stimulation (α-tACS) to stimulate the cortical source of alpha oscillations, in combination with simultaneous electroencephalography and functional MRI (EEG-fMRI), we demonstrated that α-tACS (versus Sham control) not only augmented EEG alpha oscillations but also strengthened fMRI and (source-level) alpha connectivity within the core of the DMN. Importantly, increase in alpha oscillations mediated the DMN connectivity enhancement. These findings thus identify a mechanistic link between alpha oscillations and DMN functioning. That transcranial alpha modulation can up-regulate the DMN further highlights an effective noninvasive intervention to normalize DMN functioning in various disorders.
Friday, January 07, 2022
Twitter amplifies the political right more than the political left
Significance
The role of social media in political discourse has been the topic of intense scholarly and public debate. Politicians and commentators from all sides allege that Twitter’s algorithms amplify their opponents’ voices, or silence theirs. Policy makers and researchers have thus called for increased transparency on how algorithms influence exposure to political content on the platform. Based on a massive-scale experiment involving millions of Twitter users, a fine-grained analysis of political parties in seven countries, and 6.2 million news articles shared in the United States, this study carries out the most comprehensive audit of an algorithmic recommender system and its effects on political content. Results unveil that the political right enjoys higher amplification compared to the political left.
Abstract
Content on Twitter’s home timeline is selected and ordered by personalization algorithms. By consistently ranking certain content higher, these algorithms may amplify some messages while reducing the visibility of others. There’s been intense public and scholarly debate about the possibility that some political groups benefit more from algorithmic amplification than others. We provide quantitative evidence from a long-running, massive-scale randomized experiment on the Twitter platform that committed a randomized control group including nearly 2 million daily active accounts to a reverse-chronological content feed free of algorithmic personalization. We present two sets of findings. First, we studied tweets by elected legislators from major political parties in seven countries. Our results reveal a remarkably consistent trend: In six out of seven countries studied, the mainstream political right enjoys higher algorithmic amplification than the mainstream political left. Consistent with this overall trend, our second set of findings studying the US media landscape revealed that algorithmic amplification favors right-leaning news sources. We further looked at whether algorithms amplify far-left and far-right political groups more than moderate ones; contrary to prevailing public belief, we did not find evidence to support this hypothesis. We hope our findings will contribute to an evidence-based debate on the role personalization algorithms play in shaping political content consumption.