The brain's fight against aging

Numerous studies have documented diminution in sensory and cognitive functions with aging, but very little is known about what is actually happening to cells in the brain. Knowing more about structural alterations as the brain ages is essential to understanding functional and cognitive changes. Richard et al.have used a simplified cortical model, the olfactory bulb in the mouse brain, to show, somewhat surprisingly, overall stability of structure and no neurodegeneration with aging. What they do observe is fine synaptic alterations that affect selected cellular compartments, and losses of synapses in specific layers. (The olfactory bulb sensory cortex is an appropriate model because it has well-known synaptic organization, and its normal and pathological aging is associated with impairment of food intake and reduced health.)

Little is known about how normal aging affects the brain. Recent evidence suggests that neuronal loss is not ubiquitous in aging neocortex. Instead, subtle and still controversial, region- and layer-specific alterations of neuron morphology and synapses are reported during aging, leading to the notion that discrete changes in neural circuitry may underlie age-related cognitive deficits. Although deficits in sensory function suggest that primary sensory cortices are affected by aging, our understanding of the age-related cellular and molecular changes is sparse. To assess the effect of aging on the organization of olfactory bulb (OB) circuitry, we carried out quantitative morphometric analyses in the mouse OB at 2, 6, 12, 18, and 24 mo. Our data establish that the volumes of the major OB layers do not change during aging. Parallel to this, we are unique in demonstrating that the stereotypic glomerular convergence of M72-GFP OSN axons in the OB is preserved during aging. We then provide unique evidence of the stability of projection neurons and interneurons subpopulations in the aging mouse OB, arguing against the notion of an age-dependent widespread loss of neurons. Finally, we show ultrastructurally a significant layer-specific loss of synapses; synaptic density is reduced in the glomerular layer but not the external plexiform layer, leading to an imbalance in OB circuitry. These results suggest that reduction of afferent synaptic input and local modulatory circuit synapses in OB glomeruli may contribute to specific age-related alterations of the olfactory function.

Seeking emotional support - effects of oxytocin gene and cultural variation.

Certain genotypes are expressed in different forms depending upon the harshness/beneficence of social conditions; examples include the serotonin transporter gene, the monoamine oxidase A gene, the dopamine receptor gene seven-repeat polymorphism, and the glucocorticoid receptor gene. Genetic variations in these can influence expression of depressive and antisocial behaviors.
Kim et al now show that an oxytocin receptor, depending on its specific genotype, is sensitive to social environment, specifically cultural norms regarding emotional social support seeking. Seeking emotional support in times of distress is normative in American culture but not in Korean culture. American participants with a GG/AG genotypes reported seeking more emotional social support than those with a AA genotype, but Korean participants did not differ by genotype. The abstract:

Research has demonstrated that certain genotypes are expressed in different forms, depending on input from the social environment. To examine sensitivity to cultural norms regarding emotional support seeking as a type of social environment, we explored the behavioral expression of oxytocin receptor polymorphism (OXTR) rs53576, a gene previously related to socio-emotional sensitivity. Seeking emotional support in times of distress is normative in American culture but not in Korean culture. Consequently, we predicted a three-way interaction of culture, distress, and OXTR genotype on emotional support seeking. Korean and American participants (n = 274) completed assessments of psychological distress and emotional support seeking and were genotyped for OXTR. We found the predicted three-way interaction: among distressed American participants, those with the GG/AG genotypes reported seeking more emotional social support, compared with those with the AA genotype, whereas Korean participants did not differ significantly by genotype; under conditions of low distress, OXTR groups did not differ significantly in either cultural group. These findings suggest that OXTR rs53576 is sensitive to input from the social environment, specifically cultural norms regarding emotional social support seeking. These findings also indicate that psychological distress and culture are important moderators that shape behavioral outcomes associated with OXTR genotypes.

Learning tricks

Benedict Carey does a nice summary of what we do and don't know about different approaches to enhancing learning.

Take the notion that children have specific learning styles, that some are “visual learners” and others are auditory; some are “left-brain” students, others “right-brain.” In a recent review... in the journal Psychological Science in the Public Interest, a team of psychologists found almost zero support for such ideas...Ditto for teaching styles...Some excellent instructors caper in front of the blackboard like summer-theater Falstaffs; others are reserved to the point of shyness...the common threads between teachers who create a constructive learning atmosphere have not been determined

In recent years, cognitive scientists have shown that a few simple techniques can reliably improve what matters most: how much a student learns from studying…For instance, instead of sticking to one study location, simply alternating the room where a person studies improves retention. So does studying distinct but related skills or concepts in one sitting, rather than focusing intensely on a single thing.

Varying the type of material studied in a single sitting — alternating, for example, among vocabulary, reading and speaking in a new language — seems to leave a deeper impression on the brain than does concentrating on just one skill at a time. Musicians have known this for years, and their practice sessions often include a mix of scales, musical pieces and rhythmic work. Many athletes, too, routinely mix their workouts with strength, speed and skill drills.

When the neural suitcase is packed carefully and gradually, it holds its contents for far, far longer. An hour of study tonight, an hour on the weekend, another session a week from now: such so-called spacing improves later recall…cognitive scientists see testing itself — or practice tests and quizzes — as a powerful tool of learning, rather than merely assessment. The process of retrieving an idea is not like pulling a book from a shelf; it seems to fundamentally alter the way the information is subsequently stored, making it far more accessible in the future.

None of ... these techniques — alternating study environments, mixing content, spacing study sessions, self-testing or all the above — will turn a grade-A slacker into a grade-A student. Motivation matters.

The anxiolytic power of religion

Inzlicht and Tullett add a bit of information to the growing field of the cognitive science of religion (which examines religious beliefs as a natural by-product of the way human minds and brains work, meeting a number of people’s myriad needs.) They find that a brain activity related to defensive responses to error (a sort of cortical 'alarm bell') is lower in religious than in non-religious individuals:

The world is a vast and complex place that can sometimes generate feelings of uncertainty and distress for its inhabitants. Although religion is associated with a sense of meaning and order, it remains unclear whether religious belief can actually cause people to feel less anxiety and distress. To test the anxiolytic power of religion, we conducted two experiments focusing on the error-related negativity (ERN)—a neural signal that arises from the anterior cingulate cortex and is associated with defensive responses to errors. The results indicate that for believers, conscious and nonconscious religious primes cause a decrease in ERN amplitude. In contrast, priming nonbelievers with religious concepts causes an increase in ERN amplitude. Overall, examining basic neurophysiological processes reveals the power of religion to act as a buffer against anxious reactions to self-generated, generic errors—but only for individuals who believe.

Google’s Earth

Well known author William Gibson (Neuromancer, and its sequels) does a brief NYTimes Op-Ed essay in which he discusses Google. His starting point is a controversial interview with Eric Schmidt, Google's chief executive, in which Schmidt says:

…I ACTUALLY think most people don’t want Google to answer their questions. They want Google to tell them what they should be doing next.

Gibson notes that Google is:

...a distributed entity, a two-way membrane, a game-changing tool on the order of the equally handy flint hand ax, with which we chop our way through the very densest thickets of information…it makes everything in the world accessible to everyone, and everyone accessible to the world. But we see everyone looking in, and blame Google…Google is made of us, a sort of coral reef of human minds and their products. And still we balk at Mr. Schmidt’s claim that we want Google to tell us what to do next.

We never imagined that artificial intelligence would be like this. We imagined discrete entities. Genies. We also seldom imagined (in spite of ample evidence) that emergent technologies would leave legislation in the dust, yet they do. In a world characterized by technologically driven change, we necessarily legislate after the fact, perpetually scrambling to catch up, while the core architectures of the future, increasingly, are erected by entities like Google.

Cyberspace, not so long ago, was a specific elsewhere, one we visited periodically, peering into it from the familiar physical world. Now cyberspace has everted. Turned itself inside out. Colonized the physical. Making Google a central and evolving structural unit not only of the architecture of cyberspace, but of the world…We are part of a post-geographical, post-national super-state, one that handily says no to China. Or yes, depending on profit considerations and strategy. But we do not participate in Google on that level. We’re citizens, but without rights.

On the possibility of fresh identities for those who have exposed their private lives in the cloud:

I imagine that those who are indiscreet on the Web will continue to have to make the best of it, while sharper cookies, pocketing nyms and proxy cascades (as sharper cookies already do), slouch toward an ever more Googleable future, one in which Google, to some even greater extent than it does now, helps us decide what we’ll do next.

Laughter therapy

The August 30 issue of The New Yorker has an engaging article on Madan Kataria, "The Laughing Guru."  Research in the field of psychoneuroimmunology has by now provided abundant evident that the opposite of laughter or light-heartedness - depression, stress, fear, or social isolation - can diminish health and suppress the immune system.  Kataria's international Laughter Yoga movement is based on the premise that laughter boosts health and the immune system.  Norman Cousins, who was editor of Saturday Review, wrote an influential book "Anatomy of an Illness" that described how genuine belly laughter lessened his pain from a joint disease,  and several studies have shown that laughter therapy lessens pain in cancer patients.  Other work has suggested that laughter may cause transient decreases in cortisol (stress hormone) and increases in endorphin (analgesic) levels, but Robert Provine and others have carried out exhaustive scientific reviews on laughter, humor, and health that conclude that there is not enough evidence of conclude much of anything, other perhaps than laughter can briefly limit physical pain.

I'm inclined to believe that there might be more to it, given numerous example of our embodied cognition. An instruction to contract the facial muscles that form a smile (with no instructions on accompanying feelings) causes slight enhancement of left/right frontal brain activity associated with more positive affect (elevation of mood), and small Botox injections that temporarily immobilize parts of the face can limit one's ability to express or feel emotions.   These effects are transient,  but it seems plausible to me that repetition of mechanical smiling exercises might enhance mood for  extended periods of time,  just as repeated meditation practice can decrease brain noise.  

Language shaping cognition - a followup

Relevant to today's other post on this topic, a MindBlog reader has just pointed out another good article, from the Sept. 1 New Scientist, on how words shape and enhance our cognition. The article has several links to relevant research, such as this article I was about to do a mindblog post on next week, on how assigning nonsense labels facilitates the learning of novel categories.

How language shapes our thinking

Just after drafting Monday's post  on how cultural setting shapes our visual cognition,  I read an excellent article by Guy Deutscher in the Sunday NYTimes Magazine, on how language shapes our thinking.  He starts by reviewing the story of the rise and fall of "the Whorfian hypothesis,"  which maintained that if a language had no term for a concept (such as the future), then the speaker of that language would not be able to grasp the concept in the sense that we can.  Hard data crashed the hypothesis, and the counter reaction was so severe that for many years no limits of language on basic cognition have been admitted.  How it turns out that the baby may have been thrown out with the bathwater. Some clips from the article, starting with some fact about differences between languages pointed out 50 years ago by linguist Roman Jakobson:

Languages differ essentially in what they must convey and not in what they may convey...if different languages influence our minds in different ways, this is not because of what our language allows us to think but rather because of what it habitually obliges us to think about.

In recent years, various experiments have shown that grammatical genders can shape the feelings and associations of speakers toward objects around them. In the 1990s, for example, psychologists compared associations between speakers of German and Spanish. There are many inanimate nouns whose genders in the two languages are reversed. A German bridge is feminine (die Brücke), for instance, but el puente is masculine in Spanish; and the same goes for clocks, apartments, forks, newspapers, pockets, shoulders, stamps, tickets, violins, the sun, the world and love...When speakers were asked to grade various objects on a range of characteristics, Spanish speakers deemed bridges, clocks and violins to have more “manly properties” like strength, but Germans tended to think of them as more slender or elegant.

Of course, all this does not mean that speakers of Spanish or French or German fail to understand that inanimate objects do not really have biological sex — a German woman rarely mistakes her husband for a hat, and Spanish men are not known to confuse a bed with what might be lying in it...Did the opposite genders of “bridge” in German and Spanish, for example, have an effect on the design of bridges in Spain and Germany? Do the emotional maps imposed by a gender system have higher-level behavioral consequences for our everyday life?

The area where the most striking evidence for the influence of language on thought has come to light is the language of space — how we describe the orientation of the world around us...egocentric coordinates...depend on our own bodies: a left-right axis and a front-back axis orthogonal to it. The second system uses fixed geographic directions, which do not rotate with us wherever we turn... a remote Australian aboriginal tongue, Guugu Yimithirr, doesn’t make any use of egocentric coordinates at all...Guugu Yimithirr does not use words like “left” or “right,” “in front of” or “behind,” to describe the position of objects. Whenever we would use the egocentric system, the Guugu Yimithirr rely on cardinal directions. If they want you to move over on the car seat to make room, they’ll say “move a bit to the east.” To tell you where exactly they left something in your house, they’ll say, “I left it on the southern edge of the western table.”...languages that rely primarily on geographical coordinates are scattered around the world, from Polynesia to Mexico, from Namibia to Bali.

How does this work? The convention of communicating with geographic coordinates compels speakers from the youngest age to pay attention to the clues from the physical environment (the position of the sun, wind and so on) every second of their lives..This habit of constant awareness to the geographic direction is inculcated almost from infancy...When Guugu Yimithirr speakers were asked how they knew where north is, they couldn’t explain it any more than you can explain how you know where “behind” is.

Recently, it has been demonstrated in a series of ingenious experiments that we even perceive colors through the lens of our mother tongue. There are radical variations in the way languages carve up the spectrum of visible light; for example, green and blue are distinct colors in English but are considered shades of the same color in many languages. And it turns out that the colors that our language routinely obliges us to treat as distinct can refine our purely visual sensitivity to certain color differences in reality, so that our brains are trained to exaggerate the distance between shades of color if these have different names in our language. As strange as it may sound, our experience of a Chagall painting actually depends to some extent on whether our language has a word for blue.

Sealing the emotions genie

Need to put out of mind an unpleasant memory or unfulfilled desire? By offering yet another example of embodied cognition and metaphorical thinking Li et al. may have just the trick for you:

This research investigated whether the physical act of enclosing an emotionally laden stimulus can help alleviate the associated negative emotions. Four experiments found support for this claim. In the first two experiments, emotional negativity was reduced for participants who placed a written recollection of a regretted past decision or unsatisfied strong desire inside an envelope. A further experiment showed that enclosing a stimulus unrelated to the emotional experience did not have the same effect. Finally, we showed that the effect was not driven by participants simply doing something extra with the materials, and that the effect of physical enclosure was mediated by the psychological closure that participants felt toward the event.

Robbed of lasting pleasures by drugs

Friedman does a nice summary of the course of drug addiction and withdrawal,  noting work on brain correlates of the craving that persists after drug highs have ceased and drug usage has stopped. 

Money looms larger to the powerless.

DuBois et al. make observations on an accentuation bias. They explore:

...how people’s place in a power hierarchy alters their representations of valued objects. The authors hypothesized that powerlessness produces an accentuation bias by altering the physical representation of monetary objects in a manner consistent with the size-to-value relationship. In the first three experiments, powerless participants, induced through episodic priming or role manipulations, systematically overestimated the size of objects associated with monetary value (i.e., quarters, poker chips) compared to powerful and baseline participants. However, when value was inversely associated with size (i.e., smaller objects were more valuable), the powerless drew these valued objects smaller, not larger. In addition, the accentuation bias by the powerless was more pronounced when the monetary value associated with the object was greater, increased when the object was physically present, and was mediated by differences in subjective value. These findings suggest that powerlessness fosters compensatory processes that guide representations of valued objects.

Social learning - The importance of copying others

In the August 24 issue of Current Biology Grüter et al. offer a description of experiments on social learning carried out by Rendell et al. that enhance the description given in the abstract of the original paper:

In humans, learning by observing or asking others can save time and effort. For example, a traveler can bypass the need to check out the numerous available restaurants in an unknown city by asking the residents where there is a good place to eat. However, relying on others can be a risky strategy. The person you rely on might have a different taste, a bad memory, or not have visited a restaurant for years. An inability to avoid out-of-date or unreliable information is considered a major pitfall of social learning. As a consequence, theory has predicted that both individuals and populations should usually employ a mixture of both social and individual learning. A new study by Rendell et al. challenges this view and argues that social learning is usually superior.... Inspired by a classic evolutionary tournament that investigated the evolution of cooperation, Rendell et al. organised a computer tournament in which social learning strategies, submitted by entrants, competed in a game of natural selection for a 10,000 Euro prize. Each strategy specified when an individual should copy another, when it should gather its own information, and when it should simply use the information it had already acquired. They found that the strategies that performed best relied almost exclusively on social learning. Because ‘demonstrators’ have information about the expected pay-off of different behaviours, they selectively perform those that are most beneficial for themselves. By doing so, they inadvertently filter information for all other individuals in the population. As a result, individuals relying mostly on copying acquire high-payoff behaviours as well.

Here is the Rendell et al abstract:

Social learning (learning through observation or interaction with other individuals) is widespread in nature and is central to the remarkable success of humanity, yet it remains unclear why copying is profitable and how to copy most effectively. To address these questions, we organized a computer tournament in which entrants submitted strategies specifying how to use social learning and its asocial alternative (for example, trial-and-error learning) to acquire adaptive behavior in a complex environment. Most current theory predicts the emergence of mixed strategies that rely on some combination of the two types of learning. In the tournament, however, strategies that relied heavily on social learning were found to be remarkably successful, even when asocial information was no more costly than social information. Social learning proved advantageous because individuals frequently demonstrated the highest-payoff behavior in their repertoire, inadvertently filtering information for copiers. The winning strategy (discountmachine) relied nearly exclusively on social learning and weighted information according to the time since acquisition.

Doing good (or evil) increases physical strength

Kurt Gray offers some interesting observations on the embodyment of moral typecasting:

Moral transformation is the hypothesis that doing good or evil increases agency—the capacity for self-control, tenacity, and personal strength. Three experiments provide support for this hypothesis, finding that those who do good or evil become physically more powerful. In Experiment 1, people hold a 5 lb. weight longer after donating to charity. In Experiment 2, people hold a weight longer when writing about themselves helping or harming another. In Experiment 3, people hold a hand grip longer after donating to charity. The transformative power of good and evil is not accounted for by affect. Moral transformation is explained as the embodiment of moral typecasting, the tendency to “typecast” good- and evildoers as more capable of agency and less sensitive to experience. This has implications for power, aging, self-control, and recovery.

Making decisions: Optimally interacting minds

Bahrami et al. find conditions under which two heads are - and are not - better than one. Science Magazine gives a nice summary:

When two people peer into the distance and try to figure out if a faint number is a three or an eight, classical signal detection theory states that the joint decision can only be as good as that of the person with higher visual acuity. Bahrami et al. propose that a discussion not only of what each person perceives but also of the degree of confidence in those assignments can improve the overall sensitivity of the decision. Using a traditional contrast-detection task, they showed that, when the individuals did not differ too much in their powers of visual discrimination, collective decision-making significantly improved sensitivity. The model offered here formalizes debates held since the Enlightenment about whether collective thinking can outperform that of elite individuals.

The Bahrami et al. abstract:

In everyday life, many people believe that two heads are better than one. Our ability to solve problems together appears to be fundamental to the current dominance and future survival of the human species. But are two heads really better than one? We addressed this question in the context of a collective low-level perceptual decision-making task. For two observers of nearly equal visual sensitivity, two heads were definitely better than one, provided they were given the opportunity to communicate freely, even in the absence of any feedback about decision outcomes. But for observers with very different visual sensitivities, two heads were actually worse than the better one. These seemingly discrepant patterns of group behavior can be explained by a model in which two heads are Bayes optimal under the assumption that individuals accurately communicate their level of confidence on every trial.

Religion and spatial cognition

The latest Science Magazine 'Editor's choice' points to an interesting bit of work. It is well known that East Asians see visual scenes via a holistic mindset in contrast to the Western style of focusing on salient objects. Variation within these cultural categories (between Chinese and Japanese, for example) can be shown. Colzato et al. have looked at the linkage between religious upbringing and visual perception in three somewhat less heterogeneous populations—neo-Calvinists in the Netherlands, Roman Catholics in Italy, and Orthodox Jews in Israel—and found that adherents of each of these religions differed from atheists of the same cultural background. The Calvinists, whose tradition emphasizes the role of the individual, showed greater visual attentiveness to local features, whereas the big picture perspective was favored by Catholics and Jews, whose traditions stress social togetherness. The abstract:

Religion is commonly defined as a set of rules, developed as part of a culture. Here we provide evidence that practice in following these rules systematically changes the way people attend to visual stimuli, as indicated by the individual sizes of the global precedence effect (better performance to global than to local features). We show that this effect is significantly reduced in Calvinism, a religion emphasizing individual responsibility, and increased in Catholicism and Judaism, religions emphasizing social solidarity. We also show that this effect is long-lasting (still affecting baptized atheists) and that its size systematically varies as a function of the amount and strictness of religious practices. These findings suggest that religious practice induces particular cognitive-control styles that induce chronic, directional biases in the control of visual attention.

More trusting people are better lie detectors

Carter and Weber make the interesting counter-intuitive observation that being a pollyanna does not make one more gullible (cf. with my Aug. 24 post). Their research:

...used a job interview context to investigate the relationship between peoples’ degrees of generalized trust—their default assessments of the likely trustworthiness of others—and their ability to detect lies. Participants watched videos of eight simulated job interviews: Half of the interviewees were completely truthful; half told a variety of lies to make themselves more attractive job candidates. Contrary to lay wisdom, high trusters were significantly better than low trusters were at detecting lies. This finding extends a growing body of theoretical and empirical work suggesting that high trusters are far from foolish Pollyannas and that low trusters’ defensiveness incurs significant costs.

Upstairs-Downstairs pathways regulating our cravings.

Kober et al. provide yet another "upstairs/downstairs" story of how it takes increased activity in our frontal cortex to override addictions and cravings fueled by the deeper structures in our old mammalian brain:

The ability to control craving for substances that offer immediate rewards but whose long-term consumption may pose serious risks lies at the root of substance use disorders and is critical for mental and physical health. Despite its importance, the neural systems supporting this ability remain unclear. Here, we investigated this issue using functional imaging to examine neural activity in cigarette smokers, the most prevalent substance-dependent population in the United States, as they used cognitive strategies to regulate craving for cigarettes and food. We found that the cognitive down-regulation of craving was associated with (i) activity in regions previously associated with regulating emotion in particular and cognitive control in general, including dorsomedial, dorsolateral, and ventrolateral prefrontal cortices, and (ii) decreased activity in regions previously associated with craving, including the ventral striatum, subgenual cingulate, amygdala, and ventral tegmental area. Decreases in craving correlated with decreases in ventral striatum activity and increases in dorsolateral prefrontal cortex activity, with ventral striatal activity fully mediating the relationship between lateral prefrontal cortex and reported craving. These results provide insight into the mechanisms that enable cognitive strategies to effectively regulate craving, suggesting that it involves neural dynamics parallel to those involved in regulating other emotions. In so doing, this study provides a methodological tool and conceptual foundation for studying this ability across substance using populations and developing more effective treatments for substance use disorders.

Figure - Regions active during or modulated by the cognitive regulation of craving. (A) Medial (Left) and lateral (Right) views of brain regions that showed greater activation when participants used a cognitive strategy to reduce their craving. Highlighted activations are shown in regions previously implicated in regulation of aversive emotion. (B) Medial (Left) and coronal (Right) views of brain regions that showed reduced activation. Highlighted reductions are shown in regions previously reported in studies of cue-induced craving or emotion. corr, Corrected for multiple comparisons; uncorr, uncorrected for multiple comparisons.

Delusions of Gender.

Katherine Bouton reviews what looks like a very interesting book by cognitive neuroscientist Cordelia Fine which has the title of this post. The book:

takes on that tricky question, Why exactly are men from Mars and women from Venus?, and eviscerates both the neuroscientists who claim to have found the answers and the popularizers who take their findings and run with them...Summarizing the research, she writes, “Nonexistent sex differences in language lateralization, mediated by nonexistent sex differences in corpus callosum structure, are widely believed to explain nonexistent sex differences in language skills.”...What all this adds up to, she says, is neurosexism. It’s all in the brain....But Dr. Fine persuasively argues that it is, in fact, all in the mind. Jan Morris, the historian, travel writer and male-to-female transsexual, saw this implicit stereotyping firsthand: “The more I was treated as a woman, the more woman I became. ”

Metacognitive deficits in public political discourse

Some interesting chunks from a recent David Brooks column in the NYTimes, on what he takes to be the underlying problem facing this country. He starts by describing the decay in the 19th and early 20th century emphasis on moral character,

...when people were more conscious of the fallen nature of men and women. People were held to be inherently sinful, and to be a decent person one had to struggle against one’s weakness...This emphasis on mental character lasted for a time, but it has abated. There’s less talk of sin and frailty these days...In the media competition for eyeballs, everyone is rewarded for producing enjoyable and affirming content. Output is measured by ratings and page views, so much of the media, and even the academy, is more geared toward pleasuring consumers, not putting them on some arduous character-building regime.

...we’re all less conscious of our severe mental shortcomings and less inclined to be skeptical of our own opinions...We have confirmation bias; we pick out evidence that supports our views. We are cognitive misers; we try to think as little as possible. We are herd thinkers and conform our perceptions to fit in with the group...The ensuing mental flabbiness is most evident in politics. Many conservatives declare that Barack Obama is a Muslim because it feels so good to say so...a seller’s market in ideologies...gives people a chance to feel victimized. There’s a rigidity to political debate. Issues like tax cuts and the size of government, which should be shaped by circumstances (often it’s good to cut taxes; sometimes it’s necessary to raise them), are now treated as inflexible tests of tribal purity.

To use a fancy word, there’s a metacognition deficit. Very few in public life habitually step back and think about the weakness in their own thinking and what they should do to compensate.

Inflammatory and neural responses to social rejection.

Slavich et al. measure changes in both brain activity and inflammatory chemical activity in response to social rejection:

Although stress-induced increases in inflammation have been implicated in several major disorders, including cardiovascular disease and depression, the neurocognitive pathways that underlie inflammatory responses to stress remain largely unknown. To examine these processes, we recruited 124 healthy young adult participants to complete a laboratory-based social stressor while markers of inflammatory activity were obtained from oral fluids. A subset of participants (n = 31) later completed an fMRI session in which their neural responses to social rejection were assessed. As predicted, exposure to the laboratory-based social stressor was associated with significant increases in two markers of inflammatory activity, namely a soluble receptor for tumor necrosis factor-α (sTNFαRII) and interleukin-6 (IL-6). In the neuroimaging subsample, greater increases in sTNFαRII (but not IL-6) were associated with greater activity in the dorsal anterior cingulate cortex and anterior insula, brain regions that have previously been associated with processing rejection-related distress and negative affect. These data thus elucidate a neurocognitive pathway that may be involved in potentiated inflammatory responses to acute social stress. As such, they have implications for understanding how social stressors may promote susceptibility to diseases with an inflammatory component.