Our brain connectivity predicts perceptual task performance.

An MRI scan may soon be part of the interview process for jobs requiring skill at learning and performing novel tasks...Baldassarre et al. do fMRI measurements showing that certain patterns of resting state functional connectivity within visual cortex, and between visual cortex and higher-order cortical regions - before exposure to a novel perceptual task - represent neural predictors of individual differences in performing that task. Further, the topography of the prior connectivity coincides with the areas subsequently recruited by task performance. Here is their abstract:

People differ in their ability to perform novel perceptual tasks, both during initial exposure and in the rate of improvement with practice. It is also known that regions of the brain recruited by particular tasks change their activity during learning. Here we investigate neural signals predictive of individual variability in performance. We used resting-state functional MRI to assess functional connectivity before training on a novel visual discrimination task. Subsequent task performance was related to functional connectivity measures within portions of visual cortex and between visual cortex and prefrontal association areas. Our results indicate that individual differences in performing novel perceptual tasks can be related to individual differences in spontaneous cortical activity.

Childhood maltreatment reduces brain volume.

Shortly after putting up this post on maternal nurturing correlating with larger hippocampal volumes, I can across the flip side of the story from Teicher et al. Comparing 193 subjects of average age 22 who showed high vs. low scores on the Childhood Trauma Questionnaire and Adverse Childhood Experience study showed volume reductions in several areas of the hippocampus:

Childhood maltreatment or abuse is a major risk factor for mood, anxiety, substance abuse, psychotic, and personality disorders, and it is associated with reduced adult hippocampal volume, particularly on the left side. Translational studies show that the key consequences of stress exposure on the hippocampus are suppression of neurogenesis in the dentate gyrus (DG) and dendritic remodeling in the cornu ammonis (CA), particularly the CA3 subfield... The sample consisted of 193 unmedicated right-handed subjects (38% male, 21.9 ± 2.1 y of age) selected from the community. Maltreatment was quantified using the Adverse Childhood Experience study and Childhood Trauma Questionnaire scores. The strongest associations between maltreatment and volume were observed in the left CA2-CA3 and CA4-DG subfields, and were not mediated by histories of major depression or posttraumatic stress disorder. Comparing subjects with high vs. low scores on the Childhood Trauma Questionnaire and Adverse Childhood Experience study showed an average volume reduction of 6.3% and 6.1% in the left CA2-CA3 and CA4-DG, respectively. Volume reductions in the CA1 and fimbria were 44% and 60% smaller than in the CA2-CA3. Interestingly, maltreatment was associated with 4.2% and 4.3% reductions in the left presubiculum and subiculum, respectively. These findings support the hypothesis that exposure to early stress in humans, as in other animals, affects hippocampal subfield development.

Added note: Relevant to the subject of this post, I just got an email from a children's metal health advocacy group, The Child Mind Institute, that is sponsoring an annual public education campaign called "Speak Up For Kids".

Dim minds and dark attitudes.

This study of Hodson and Busseri on a United Kingdom and U.S. datasets documents the (hardly surprising) correlation between lower cognitive ability and right-wing ideology. They suggest that right-wing ideologies which are socially conservative and authoritarian represent a mechanism through which cognitive ability is linked with prejudice.

Despite their important implications for interpersonal behaviors and relations, cognitive abilities have been largely ignored as explanations of prejudice. We proposed and tested mediation models in which lower cognitive ability predicts greater prejudice, an effect mediated through the endorsement of right-wing ideologies (social conservatism, right-wing authoritarianism) and low levels of contact with out-groups. In an analysis of two large-scale, nationally representative United Kingdom data sets (N = 15,874), we found that lower general intelligence (g) in childhood predicts greater racism in adulthood, and this effect was largely mediated via conservative ideology. A secondary analysis of a U.S. data set confirmed a predictive effect of poor abstract-reasoning skills on antihomosexual prejudice, a relation partially mediated by both authoritarianism and low levels of intergroup contact. All analyses controlled for education and socioeconomic status. Our results suggest that cognitive abilities play a critical, albeit underappreciated, role in prejudice. Consequently, we recommend a heightened focus on cognitive ability in research on prejudice and a better integration of cognitive ability into prejudice models.

Psychological benefits of religiosity ride on cultural values.

Gebauer et al. at Humboldt-University in Berlin analyze profile data on the eDarling online-dating site from 187,957 individuals in 11 European countries. Their bottom line summary is:

The religiosity-as-social-value hypothesis posits that the psychological benefits of religiosity (benefits to social self-esteem and psychological adjustment) are culturally specific: They should be stronger in countries that tend to value religiosity more. Data from more than 180,000 individuals across 11 countries were consistent with this prediction.

Overall, believers claimed greater social self-esteem and psychological adjustment than nonbelievers did. However, culture qualified this effect. Believers enjoyed psychological benefits in countries that tended to value religiosity, but did not differ from nonbelievers in countries that did not tend to value religiosity. Replication of this pattern with non-self-report data would be desirable. Regardless, the results suggest that religiosity, albeit a potent force, confers benefits by riding on cultural values.

More on the discorrelation of happiness and material welfare

The economist has an interesting piece on a study of 19,000 adults in 24 different countries by the research company Ipsos measuring "degrees of happiness". It reaches several counter-intuitive conclusions:

Large, fast-growing emerging markets do not share rich industrialized countries’ pessimism. The already large “very happy” cohort rose 16 points in Turkey, ten points in Mexico and five points in India...thus the highest levels of self-reported happiness is not in rich countries, as one would expect, but in poor and middle-income ones, notably Indonesia, India and Mexico. In rich countries, happiness scores range from above-average—28% of Australians and Americans say they are very happy—to far below the mean. The figures for Italy and Spain were 13% and 11% (Greece was not in the sample). Most Europeans are gloomier than the world average. So levels of income are, if anything, inversely related to felicity. Perceived happiness depends on a lot more than material welfare.  

Neophily - Exuberance for Novelty predicts well being.

I've been meaning to point to John Tierney's interesting piece in the NYTimes that emphasizes the work of Robert Cloninger, the psychiatrist who developed personality tests for measuring the trait of novelty seeking:

...a trait long associated with trouble.. problems like attention deficit disorder, compulsive spending and gambling, alcoholism, drug abuse and criminal behavior...After extensively tracking novelty-seekers, researchers are seeing the upside. In the right combination with other traits, it’s a crucial predictor of well-being. Winifred Gallagher's new book “New: Understanding Our Need for Novelty and Change” ...argues that neophilia has always been the quintessential human survival skill, whether adapting to climate change on the ancestral African savanna or coping with the latest digital toy from Silicon Valley....she classifies people as neophobes, neophiles and, at the most extreme, neophiliacs...

...adventurous neophiliacs are more likely to possess a “migration gene,” a DNA mutation that occurred about 50,000 years ago, as humans were dispersing from Africa around the world, according to Robert Moyzis, a biochemist at the University of California, Irvine. The mutations are more prevalent in the most far-flung populations, like Indian tribes in South America descended from the neophiliacs who crossed the Bering Strait.

...These genetic variations affect the brain’s regulation of dopamine, the neurotransmitter associated with the processing of rewards and new stimuli (and drugs like cocaine). The variations have been linked to faster reaction times, attention deficit hyperactivity disorder and a higher penchant for novelty-seeking and risk-taking.

Cloninger...has.. tracked people using a personality test he developed..looking for traits in people..who reported the best health, most friends, fewest emotional problems and greatest satisfaction with life...they scored high in novelty-seeking as well in persistence and self-transcendence (which he describes as the capacity to get lost in the moment doing what you love to do, to feel a connection to nature and humanity and the universe).

Advice from Gallagher and Cloninger:

..both advise neophiles to be selective in their targets. (Neophilia spurs us to adjust and explore and create technology and art, but at the extreme it can fuel a chronic restlessness and distraction.).. Don’t go wide and shallow into useless trivia...Use your neophilia to go deep into subjects that are important to you.

The map in our head is oriented north.

Interesting observations from Julia Frankenstein et al.:

We examined how a highly familiar environmental space—one’s city of residence—is represented in memory. Twenty-six participants faced a photo-realistic virtual model of their hometown and completed a task in which they pointed to familiar target locations from various orientations. Each participant’s performance was most accurate when he or she was facing north, and errors increased as participants’ deviation from a north-facing orientation increased. Pointing errors and latencies were not related to the distance between participants’ initial locations and the target locations. Our results are inconsistent with accounts of orientation-free memory and with theories assuming that the storage of spatial knowledge depends on local reference frames. Although participants recognized familiar local views in their initial locations, their strategy for pointing relied on a single, north-oriented reference frame that was likely acquired from maps rather than experience from daily exploration. Even though participants had spent significantly more time navigating the city than looking at maps, their pointing behavior seemed to rely on a north-oriented mental map.

Added note: Check out this nice summary by Frankenstein in the NYTimes.

Early maternal support predicts larger brain volumes at school age.

Luby et al. offer a compelling study showing the importance of maternal nuturing in young humans.Maternal support is predictive of hippocampus volume measured at school age. From their introduction:

Animal studies have shown that maternal nurturance...promotes adaptive programming of the hypothalamic–pituitary–adrenal axis stress response and hippocampal development. Improvements in the capacity for stress modulation have been shown to be related to epigenetic modifications whereby methylation of multiple genes results in changes in gene expression for glucocorticoid and mineralcorticoid receptors. These changes are associated with increases in dendritic branching and neurogenesis and related increases in hippocampal volumes. Consistent with this phenomenon and conversely, the stress of early maternal deprivation has been shown to have negative effects on this cascade. A similar relationship between early nurturance and stress modulation has also been reported in nonhuman primates.

Their abstract:

Early maternal support has been shown to promote specific gene expression, neurogenesis, adaptive stress responses, and larger hippocampal volumes in developing animals. In humans, a relationship between psychosocial factors in early childhood and later amygdala volumes based on prospective data has been demonstrated, providing a key link between early experience and brain development. Although much retrospective data suggests a link between early psychosocial factors and hippocampal volumes in humans, to date there has been no prospective data to inform this potentially important public health issue. In a longitudinal study of depressed and healthy preschool children who underwent neuroimaging at school age, we investigated whether early maternal support predicted later hippocampal volumes. Maternal support observed in early childhood was strongly predictive of hippocampal volume measured at school age. The positive effect of maternal support on hippocampal volumes was greater in nondepressed children. These findings provide prospective evidence in humans of the positive effect of early supportive parenting on healthy hippocampal development, a brain region key to memory and stress modulation.

How to get the rich to share their marbles.

Jonathan Haidt does a nice job of bringing contemporary relevance to Tomasello and colleagues' work comparing and contrasting the social behaviors of young humans and chimpanzees. (As these two previous MindBlog posts show (1,2), this laboratory has been carpet bombing the journals with articles in this vein.)

Pretend you’re a three-year-old, exploring an exciting new room full of toys. You and another child come up to a large machine that has some marbles inside, which you can see. There’s a rope running through the machine and the two ends of the rope hang out of the front, five feet apart. If you or your partner pulls on the rope alone, you just get more rope. But if you both pull at the same time, the rope dislodges some marbles, which you each get to keep. The marbles roll down a chute, and then they divide: one rolls into the cup in front of you, three roll into the cup in front of your partner...In this situation, where both kids have to pull for anyone to get marbles, the children equalize the wealth about 75% of the time, with hardly any conflict. Either the “rich” kid hands over one marble spontaneously or else the “poor” kid asks for one and his request is immediately granted. (Chimpanzees doing tasks similar to this one do not share the spoils, in any of the conditions. They just grab what they can, regardless of who did what.)

A slight variation ..reveals a deep truth. Things start off just as in the first condition: you and your partner see two ropes hanging out of the machine. But as you start tugging it becomes clear that they are two separate ropes. You pull yours, and one marble rolls out into your cup. Your partner pulls the other rope, and is rewarded with three marbles...What happens next?...For the most part, it’s pullers-keepers. Even though you and your partner each did the same work (rope pulling) at more or less the same time, you both know that you didn’t really collaborate to produce the wealth. Only about 30% of the time did the kids work out an equal split. In other words, the “share-the-spoils” button is not pressed by the mere existence of inequality. It is pressed when two or more people collaborated to produce a gain. Once the button is pressed in both brains, both parties willingly and effortlessly share.

Haidt argues that Obama's prescription for curing the economy fails to press the "share-the-spoils", which might happen if he could frame his statements to make Americans perceive the economy as a giant collaborative project, as happened for the generations that went through the great depression and the second world war (share-the-sacrifice). Instead,

Obama promised he would not raise taxes on anyone but the rich. He and other Democrats have also vowed to “protect seniors” from cuts, even though seniors receive the vast majority of entitlement dollars. The president is therefore in the unenviable position of arguing that we’re in big trouble and so a small percentage of people will have to give more, but most people will be protected from sacrifice. This appeal misses the shared-sacrifice button completely. It also fails to push the share-the-spoils button. When people feel that they’re all pulling on different ropes, they don’t feel entitled to a share of other people’s wealth, even when that wealth was acquired by luck.

Cognitive dissonance reduction in conservative and liberal Christians

Ross et al. offer an interesting study showing how the answers of conservative and liberal Christians to the question "What would a contemporary Jesus do?" reduces the cognitive dissonance of their own opinions:

The present study explores the dramatic projection of one's own views onto those of Jesus among conservative and liberal American Christians. In a large-scale survey, the relevant views that each group attributed to a contemporary Jesus differed almost as much as their own views. Despite such dissonance-reducing projection, however, conservatives acknowledged the relevant discrepancy with regard to “fellowship” issues (e.g., taxation to reduce economic inequality and treatment of immigrants) and liberals acknowledged the relevant discrepancy with regard to “morality” issues (e.g., abortion and gay marriage). However, conservatives also claimed that a contemporary Jesus would be even more conservative than themselves on the former issues whereas liberals claimed that Jesus would be even more liberal than themselves on the latter issues. Further reducing potential dissonance, liberal and conservative Christians differed markedly in the types of issues they claimed to be more central to their faith. A concluding discussion considers the relationship between individual motivational processes and more social processes that may underlie the present findings, as well as implications for contemporary social and political conflict.

Desperately seeking simplicity.

The Harvard Business Review blog network has an article by Chris Zook, who is co-head of the Global Strategy Practice at Bain & Company (Now why does that name sound familiar, I wonder!!). I thought it worthwhile to abstract and paraphrase his thoughts - his comments derive from a theme that was omnipresent at the recent World Economic Forum in Davos:

that while events are unfolding in the world at an accelerating pace, increasingly complex institutions are less and less able to deal with them.

The problem seems

...not so much identifying what needed to be done as the lack of a plan for making the changes quickly enough.

In a survey, hundreds of leaders and executives...

...say that they do not face inadequate opportunities. Rather, their biggest barrier by far (about 85% of the time) relates to the internal complexity of their organizations and the management of their energy against that...a multi-year study of the root causes of enduring success...found an increasing premium to simplicity in the world of today — not just simplicity of organization, but more fundamentally to an essential simplicity at the heart of strategy itself...an inherent advantage in dealing with... faster moving markets and increased internal complexity due to ability to keep things simpler and more transparent than their rivals...companies who seemed best at creating enduring competitive advantage seemed to be able to maintain a simplicity at their core (think of companies like IKEA, Nike, or Vanguard for instance — very large in size, but with a clarity of strategy and purpose that jumps out at you).

This has its own parallel in the three attributes of great leaders of the future outlined in a talk by Daniel Goleman (Author of Emotional Intelligence):

1) authenticity and sharp clarity of purpose, 2) empathy and the ability to relate to people at the "front line" levels, and 3) self-awareness and humility to constantly question and adapt.

An App for your anxiety...

Continuing in the thread of yesterdays post about a science App, I should mention the blip of interest (and controversy) over the putative appearance of an array of 'therapists in your iPhone or Android phone." Benedict Carey offers a recent review. My first reaction is one of complete aversion, thinking that therapy is best cast in a social web of narrative, but as Carey notes:

The upside is that well-designed apps could reach millions of people who lack the means or interest to engage in traditional therapy and need more than the pop mysticism, soothing thoughts or confidence boosters now in use.

It is a fact that some cognitive missteps are of a very mechanical nature, reflecting glitches in stimulus-response matching. Here is a nice example of the app approach:

..cognitive bias modification...seeks to break some of the brain’s bad habits...and is straightforward. Consider people with social anxiety, a kind of extreme shyness that can leave people breathless with dread...many who struggle with such anxiety fixate subconsciously on hostile faces in a crowd of people with mostly relaxed expressions, as if they see only the bad apples in a bushel of mostly good ones...Modifying that bias — that is, reducing it — can interrupt the cascade of thoughts and feelings that normally follow, short-circuiting anxiety, lab studies suggest. In one commonly used program, for instance, people see two faces on the screen, one with a neutral expression and one looking hostile. The faces are stacked one atop the other, and a split-second later they disappear, and a single letter flashes on the screen, in either the top half or the bottom....Users push a button to identify the letter, but this is meaningless; the object is to snap the eyes away from the part of the screen that showed the hostile face, conditioning the brain to ignore those bad apples. That’s all there is to it. Repeated practice, the researchers say, may train the eyes to automatically look away, or the frontal areas of the brain to exercise more top-down control.

Some studies claim positive results with these simple games equivalent to normal therapy, other find no effect. There are the usual issues of whether positive outcomes are a placebo effort or undue attention is being paid to positive data, while negative results are rationalized or downplayed. The strongest claims seem to be for anxiety disorders, not depression.

Science of minus 10 Biology iPad App

I've been cruising the annual best science and engineering visualization competition sponsored every year by Science Magazine and the National Science Foundation (see also Wired Magazine account.). I find especially compelling the game "Powers of Ten", which allows players to zoom into a person’s hand, explore the world at different magnifications and learn about the human body:

Our brains as prediction machines - a unified view of mind and action

Anything Andy Clark writes is totally worth reading (I used his charming essay "I am John's brain" when I first began teaching my "Biology of Mind Course" at the University of Wisconsin in the 1990's), and so I pass on this manuscript of an article on which comments are currently being solicited.  It is a fascinating read, lucidly and clearly written. 

"Whatever Next? Predictive Brains, Situated Agents, and the Future of Cognitive Science"

Abstract: Brains, it has recently been argued, are essentially prediction machines. They are bundles of cells that support perception and action by constantly attempting to match incoming sensory inputs with top-down expectations or predictions. This is achieved using a hierarchical generative model that aims to minimize prediction error within a bidirectional cascade of cortical processing.  Such accounts offer a unifying model of perception and action, illuminate the functional role of attention, and may neatly capture the special contribution of cortical processing to adaptive success. The paper critically examines this 'hierarchical prediction machine' approach, concluding that it offers the best clue yet to the shape of a unified science of mind and action. Sections 1 and 2 lay out the key elements and implications of the approach. Section 3 explores a variety of pitfalls and challenges, spanning the evidential, the methodological, and the more properly conceptual. The paper ends (sections 4 and 5) by asking how such approaches might impact our more general vision of mind, experience, and agency. 

Our brain's grasp of metaphors grounded in perception?

Theories of grounded cognition suggest that knowledge is represented in modal systems derived from perception (rather than abstract brain codes) and that cognition depends on perceptual simulations. Conceptual metaphor theory is one approach to grounded cognition which suggests that knowledge is structured by metaphorical mappings from sensory experience. Sathian and colleagues do a interesting experiment in which they find that textural metaphors — phrases like "soft-hearted"— turn on a part of the brain (the parietal operculum) that's important to the sense of touch. This doesn't happen with literal counterparts: "he is wet behind the ears" versus "he is naïve," for example, or "it was a hairy situation" versus "it was a precarious situation."

Figure - Touching actives areas shown in yellow and red. Textural metaphors also trigger a reaction (shown in green and, where overlapping, brown) in the parietal operculum.

It would be interesting to see if a subject's appreciation of a tactile metaphor was compromised by transcranial magnetic stimulation that disrupted activity of the parietal operculum.

Negative social interactions and body inflammation.

Many studies have proven that social relationships influence our physical health. People who are more socially integrated live longer, and are less likely to have medical problems such as heart attacks and upper respiratory illness. (Cytokines are small protein molecules - peptides - that regulate our inflammatory immune response. While transient inflammatory response due to tissue insult are adaptive and trigger needed immune responses, chronic increases in proinflammatory cytokines IL-6 and TNF-α are linked hypertension, atherosclerosis, coronary heart disease, depression, diabetes, and some cancers.) Chiang et al. now show that these cytokines promoting tissue inflammation appear when we are in socially stressful situations:

Research has consistently documented that social relationships influence physical health, a link that may implicate systemic inflammation. We examined whether daily social interactions predict levels of proinflammatory cytokines IL-6 and the soluble receptor for tumor necrosis factor-α (sTNFαRII) and their reactivity to a social stressor. One-hundred twenty-two healthy young adults completed daily diaries for 8 d that assessed positive, negative, and competitive social interactions. Participants then engaged in laboratory stress challenges, and IL-6 and sTNFαRII were collected at baseline and at 25- and 80-min poststressor, from oral mucosal transudate. Negative social interactions predicted elevated sTNFαRII at baseline, and IL-6 and sTNFαRII 25-min poststressor, as well as total output of sTNFαRII. Competitive social interactions predicted elevated baseline levels of IL-6 and sTNFαRII and total output of both cytokines. These findings suggest that daily social interactions that are negative and competitive are associated prospectively with heightened proinflammatory cytokine activity.

How psychedelics affect our brain - unconstrained cognition

Carhart-Harris et al. have done an interesting study showing that psilocybin decreases surrogate markers for neuronal activity [cerebral blood flow and blood oxygen level-dependent (BOLD) signals] in key brain regions implicated in psychedelic drug actions. They also report that psilocybin appears to decrease brain “connectivity” as measured by pharmaco-physiological interaction. Their results imply that "the subjective effects of psychedelic drugs are caused by decreased activity and connectivity in the brain's key connector hubs, enabling a state of unconstrained cognition."

Psychedelic drugs have a long history of use in healing ceremonies, but despite renewed interest in their therapeutic potential, we continue to know very little about how they work in the brain. Here we used psilocybin, a classic psychedelic found in magic mushrooms, and a task-free functional MRI (fMRI) protocol designed to capture the transition from normal waking consciousness to the psychedelic state. Arterial spin labeling perfusion and blood-oxygen level-dependent (BOLD) fMRI were used to map cerebral blood flow and changes in venous oxygenation before and after intravenous infusions of placebo and psilocybin. Fifteen healthy volunteers were scanned with arterial spin labeling and a separate 15 with BOLD. As predicted, profound changes in consciousness were observed after psilocybin, but surprisingly, only decreases in cerebral blood flow and BOLD signal were seen, and these were maximal in hub regions, such as the thalamus and anterior and posterior cingulate cortex (ACC and PCC). Decreased activity in the ACC/medial prefrontal cortex (mPFC) was a consistent finding and the magnitude of this decrease predicted the intensity of the subjective effects. Based on these results, a seed-based pharmaco-physiological interaction/functional connectivity analysis was performed using a medial prefrontal seed. Psilocybin caused a significant decrease in the positive coupling between the mPFC and PCC. These results strongly imply that the subjective effects of psychedelic drugs are caused by decreased activity and connectivity in the brain's key connector hubs, enabling a state of unconstrained cognition.

Brain deactivations after psilocybin. (Upper) Regions where there was a significant decrease in the BOLD signal after psilocybin versus after placebo. (Lower) Regions where there was a consistent decrease in CBF (cerebral blood flow) and BOLD after psilocybin. We observed no increases in CBF or BOLD signal in any region.

Life is a digital code.

Here is a nicely done precis of a crucial bit of our intellectual history from science written by Matt Ridley, his answer to "What is your favorite deep, elegant or beautiful explanation.":

It's hard now to recall just how mysterious life was on the morning of 28 February and just how much that had changed by lunchtime. Look back at all the answers to the question "what is life?" from before that and you get a taste of just how we, as a species, floundered. Life consisted of three-dimensional objects of specificity and complexity (mainly proteins). And it copied itself with accuracy. How? How do you set about making a copy of a three-dimensional object? How to do you grow it and develop it in a predictable way? This is the one scientific question where absolutely nobody came close to guessing the answer. Erwin Schrodinger had a stab, but fell back on quantum mechanics, which was irrelevant. True, he used the phrase "aperiodic crystal" and if you are generous you can see that as a prediction of a linear code, but I think that's stretching generosity.

Indeed, the problem had just got even more baffling thanks to the realization that DNA played a crucial role—and DNA was monotonously simple. All the explanations of life before 28 Feb 1953 are hand-waving waffle and might as well speak of protoplasm and vital sparks for all the insights they gave.

Then came the double helix and the immediate understanding that, as Crick wrote to his son a few weeks later, "some sort of code"—digital, linear two-dimensional, combinatorially infinite and instantly self-replicating—was all the explanation you needed. Here's part of Francis Crick's letter, 17 March 1953:

"My Dear Michael,

Jim Watson and I have probably made a most important discovery...Now we believe that the DNA is a code. That is, the order of the bases (the letters) makes one gene different from another gene (just as one page pf print is different from another). You can see how Nature makes copies of the genes. Because if the two chains unwind into two separate chains, and if each chain makes another chain come together on it, then because A always goes with T, and G with C, we shall get two copies where we had one before. In other words, we think we have found the basic copying mechanismby which life comes from life...You can understand we are excited."

Never has a mystery seemed more baffling in the morning and an explanation more obvious in the afternoon.

Testosterone, digit ratio, and abstract reasoning ability

Brañas-Garza and Aldo Rustichini suggest that perhaps higher testosterone market traders are more successful not only because they are greater risk takers, but also because their abstract reasoning abilities are superior:

Recent literature emphasizes the role that testosterone, as well as markers indicating early exposure to T and its organizing effect on the brain (such as the ratio of second to fourth finger, ), have on performance in financial markets. These results may suggest that the main effect of T, either circulating or in fetal exposure, on economic behavior occurs through the increased willingness to take risks. However, these findings indicate that traders with a low digit ratio are not only more profitable, but more able to survive in the long run, thus the effect might consist of more than just lower risk aversion. In addition, recent literature suggests a positive correlation between abstract reasoning ability and higher willingness to take risks. To test the two hypotheses of testosterone on performance in financial activities (effect on risk attitude versus a complex effect involving risk attitude and reasoning ability), we gather data on the three variables in a sample of 188 ethnically homogeneous college students (Caucasians). We measure a digit ratio, abstract reasoning ability with the Raven Progressive Matrices task, and risk attitude with choice among lotteries. Low digit ratio in men is associated with higher risk taking and higher scores in abstract reasoning ability when a combined measure of risk aversion over different tasks is used. This explains both the higher performance and higher survival rate observed in traders, as well as the observed correlation between abstract reasoning ability and risk taking. We also analyze how much of the total effect of digit ratio on risk attitude is direct, and how much is mediated. Mediation analysis shows that a substantial part of the effect of T on attitude to risk is mediated by abstract reasoning ability.

Us vs. them in context.

As I scan the tables of contexts of journals for items that might be appropriate for MindBlog, I am majorly influenced by a catchy title and relative brevity, the old brain doesn’t have to work as hard. (In this vein, see the recent essay on "Bite Size" Science.) Gilbert Chin of Science Magazine notes that a plain title I passed over points to an interesting piece of work, showing that our attitude towards pluralism and tolerance can depend very much on whether we are in the majority or minority of the relevant social group. From Chin's summary:

Us versus Them is both an enduring view of the world and a malleable one. It is enduring in the sense that groups form naturally even where there are no preexisting differences and malleable in the sense that the group that one identifies with can change over time or between situations. Theoretical and empirical evidence justifies the generalization that members of a majority group tend to favor the assimilation of immigrants into the native culture, whereas immigrants are more likely to vote for pluralistic policies that acknowledge the distinctiveness of minority cultures.

The abstract of the article:

This research examined preferences for national- and campus-level assimilative and pluralistic policies among Black and White students under different contexts, as majority- and minority-group members. We targeted attitudes at two universities, one where 85% of the student body is White, and another where 76% of students are Black. The results revealed that when a group constituted the majority, its members generally preferred assimilationist policies, and when a group constituted the minority, its members generally preferred pluralistic policies. The results support a functional perspective: Both majority and minority groups seek to protect and enhance their collective identities.