Essential role of default mode network in higher cognitive processing.

The respective roles of attentional and default mode networks in our brains has been the subject of numerous MindBlog posts (enter 'default mode' in the search box in the left column). A summary article by Bola and Borchardt notes an important recent contribution by Vatansever et al., whose abstract is shown below, followed by a graphic from the summary article.  Their work changes the previous view that the default mode disengages during goal-directed tasks.

ABSTRACT

The default mode network (DMN) has been traditionally assumed to hinder behavioral performance in externally focused, goal-directed paradigms and to provide no active contribution to human cognition. However, recent evidence suggests greater DMN activity in an array of tasks, especially those that involve self-referential and memory-based processing. Although data that robustly demonstrate a comprehensive functional role for DMN remains relatively scarce, the global workspace framework, which implicates the DMN in global information integration for conscious processing, can potentially provide an explanation for the broad range of higher-order paradigms that report DMN involvement. We used graph theoretical measures to assess the contribution of the DMN to global functional connectivity dynamics in 22 healthy volunteers during an fMRI-based n-back working-memory paradigm with parametric increases in difficulty. Our predominant finding is that brain modularity decreases with greater task demands, thus adapting a more global workspace configuration, in direct relation to increases in reaction times to correct responses. Flexible default mode regions dynamically switch community memberships and display significant changes in their nodal participation coefficient and strength, which may reflect the observed whole-brain changes in functional connectivity architecture. These findings have important implications for our understanding of healthy brain function, as they suggest a central role for the DMN in higher cognitive processing.

SIGNIFICANCE STATEMENT

The default mode network (DMN) has been shown to increase its activity during the absence of external stimulation, and hence was historically assumed to disengage during goal-directed tasks. Recent evidence, however, implicates the DMN in self-referential and memory-based processing. We provide robust evidence for this network's active contribution to working memory by revealing dynamic reconfiguration in its interactions with other networks and offer an explanation within the global workspace theoretical framework. These promising findings may help redefine our understanding of the exact DMN role in human cognition.

Graphic from Review

Schematic representation of the main findings of Vatansever et al. Community representation and colors are in the style of Figures 1 and 3 in the article by Vatansever et al. (2015), and the DMN is represented by Community 4. In the low-demanding 0-back condition, the network was highly modular (high Q index) and was divided into four distinct modules. With the increasing cognitive load, the modularity of the network decreased, and three communities merged into one. Thus, while local segregation was prevalent in the low-demanding task, increasing cognitive effort was associated with more pronounced global integration.

How to attract others.

Well, Duh...... Interesting, but talk about showing the obvious!.. from Vacharkulksemsuka et al.:

Across two field studies of romantic attraction, we demonstrate that postural expansiveness makes humans more romantically appealing. In a field study (n = 144 speed-dates), we coded nonverbal behaviors associated with liking, love, and dominance. Postural expansiveness—expanding the body in physical space—was most predictive of attraction, with each one-unit increase in coded behavior from the video recordings nearly doubling a person’s odds of getting a “yes” response from one’s speed-dating partner. In a subsequent field experiment (n = 3,000), we tested the causality of postural expansion (vs. contraction) on attraction using a popular Global Positioning System-based online-dating application. Mate-seekers rapidly flipped through photographs of potential sexual/date partners, selecting those they desired to meet for a date. Mate-seekers were significantly more likely to select partners displaying an expansive (vs. contractive) nonverbal posture. Mediation analyses demonstrate one plausible mechanism through which expansiveness is appealing: Expansiveness makes the dating candidate appear more dominant. In a dating world in which success sometimes is determined by a split-second decision rendered after a brief interaction or exposure to a static photograph, single persons have very little time to make a good impression. Our research suggests that a nonverbal dominance display increases a person’s chances of being selected as a potential mate.

Impulsivity, sensation seeking, and substance use correlate with reduced brain cortical thickness.

From Holmes et al.:

Individuals vary widely in their tendency to seek stimulation and act impulsively, early developing traits with genetic origins. Failures to regulate these behaviors increase risk for maladaptive outcomes including substance abuse. Here, we explored the neuroanatomical correlates of sensation seeking and impulsivity in healthy young adults. Our analyses revealed links between sensation seeking and reduced cortical thickness that were preferentially localized to regions implicated in cognitive control, including anterior cingulate and middle frontal gyrus (n = 1015). These associations generalized to self-reported motor impulsivity, replicated in an independent group (n = 219), and correlated with heightened alcohol, tobacco, and caffeine use. Critically, the relations between sensation seeking and brain structure were evident in participants without a history of alcohol or tobacco use, suggesting that observed associations with anatomy are not solely a consequence of substance use. These results demonstrate that individual differences in the tendency to seek stimulation, act on impulse, and engage in substance use are correlated with the anatomical structure of cognitive control circuitry. Our findings suggest that, in healthy populations, covariation across these complex multidimensional behaviors may in part originate from a common underlying biology.

Metaphorical conflict shapes social perception when spatial and ideological collide.

Kleiman et al. do some intriguing experiments. I give you their abstract first, which doesn't actually say how they did the experiments, and then give you some further description from their text. The abstract:

In the present article, we introduce the concept of metaphorical conflict—a conflict between the concrete and abstract aspects of a metaphor. We used the association between the concrete (spatial) and abstract (ideological) components of the political left-right metaphor to demonstrate that metaphorical conflict has marked implications for cognitive processing and social perception. Specifically, we showed that creating conflict between a spatial location and a metaphorically linked concept reduces perceived differences between the attitudes of partisans who are generally viewed as possessing fundamentally different worldviews (Democrats and Republicans). We further demonstrated that metaphorical conflict reduces perceived attitude differences by creating a mind-set in which categories are represented as possessing broader boundaries than when concepts are metaphorically compatible. These results suggest that metaphorical conflict shapes social perception by making members of distinct groups appear more similar than they are generally thought to be. These findings have important implications for research on conflict, embodied cognition, and social perception.

In the first experiment they asked subjects to categorize a series of pictures of Barack Obama and Mitt Romney. One group categorized the Romney pictures using their right hand (the P key)and Obama pictures with their left hand using the Q key - compatible with the right wing, left wing political metaphor. A second group was asked to identify Obama with their right hand and Romney with their left - in this case the physical action and the candidate's ideology were metaphorically incompatible. The interesting result was that:

...participants in the incompatible condition perceived the difference between the candidates’ ideologies as smaller than did participants in the compatible condition...Additionally, participants in the incompatible condition perceived the difference between the candidates’ stances on specific political issues as smaller than did participants in the compatible condition

A second experiment asked participants to estimate the ideology of the typical Democrat and Republican using a scale of 1 to 9 that was either compatible or incompatible with the metaphorical association linking spatial locations to political ideologies.

Participants assigned to the incompatible condition (n = 194) provided their response on a horizontally displayed scale with the values in the opposite sequence, that is, from 1 (extremely conservative) to 9 (extremely liberal). Note that this scale reversed the traditional spatial assignment and placed liberal views on the right and conservative views on the left, which metaphorically puts the physical location and ideology in conflict... consistent with predictions, participants who rated their perceptions on the incompatible scale perceived the typical Republican’s and typical Democrat’s attitudes as more similar than did participants who rated their perceptions on the compatible scale.

Two further control experiments were done.

Political polarization and prejudice.

Yesterday's post dealt with softening prejudicial attitudes towards transgender people. This is relevant to prejudice rising from the right versus left political polarization that continues to increase in this county. From a recent NYTimes OpEd piece by Arthur Brooks:

Thirty-eight percent of Democrats have a “very unfavorable” view of Republicans, and 43 percent of Republicans hold that view of Democrats. About half of “consistently liberal” Americans say most of their friends share their views, and about a third say it’s important to live in a place where that is so. For those who are “consistently conservative,” these preferences are even more pronounced.

...the average American is becoming more ideologically predictable. A Pew Research Center study from 2014 shows that the share of Americans with “consistently conservative” or “consistently liberal” views has more than doubled in the last two decades to 21 percent from 10 percent...In 1994, nearly 40 percent of Republicans were more liberal than the median Democrat, and 30 percent of Democrats were more conservative than the median Republican. Today, those numbers have plummeted to 8 percent and 6 percent.

This polarization has led to political discrimination that studies have shown to be stronger than racial discrimination

...Bigotry’s cousin is contempt...Watch and listen to politically polarized commentary today, and you will see that it is more contemptuous than angry, overflowing with sneering, mockery and disgust.

So what’s the antidote? I asked the Dalai Lama, one of the world’s experts on bringing people together. He made two points. First, the solution starts not with institutions, but with individuals. We look too much to political parties or Congress to make progress, but not nearly enough at our own behavior...You can’t single-handedly change the country, but you can change yourself. By declaring your independence from the bitterness washing over our nation, you can strike a small blow for greater national unity.

Second, each of us must aspire to what the Dalai Lama calls “warmheartedness” toward those with whom we disagree. This might sound squishy, but it is actually tough and practical advice. As he has stated, “I defeat my enemies when I make them my friends.” He is not advocating surrender to the views of those with whom we disagree. Liberals should be liberals and conservatives should be conservatives. But our duty is to be respectful, fair and friendly to all, even those with whom we have great differences.

Yesterday's post on changing prejudice suggests a further technique for reconciliation: active or analogic perspective taking. This is essentially imagining a situation in which you felt contempt from others, and also putting yourself in the shoes of others, imagining their concerns, etc.

How to change prejudice...for real this time

John Bohannon summarizes the interesting story of two researchers, who after finding that a study on reversing homophobia was based on fake data, went ahead to find that the effect claimed by the fraudulent study was real after all. Broockman and Kalla used a technique developed by the Los Angeles LGBT center:

...the LGBT Center has its canvassers follow one called “analogic perspective taking.” By inviting someone to discuss an experience in which that person was perceived as different and treated unfairly, a canvasser tries to generate sympathy for the suffering of another group—such as gay or transgender people.

Here is the abstract:

Existing research depicts intergroup prejudices as deeply ingrained, requiring intense intervention to lastingly reduce. Here, we show that a single approximately 10-minute conversation encouraging actively taking the perspective of others can markedly reduce prejudice for at least 3 months. We illustrate this potential with a door-to-door canvassing intervention in South Florida targeting antitransgender prejudice. Despite declines in homophobia, transphobia remains pervasive. For the intervention, 56 canvassers went door to door encouraging active perspective-taking with 501 voters at voters’ doorsteps. A randomized trial found that these conversations substantially reduced transphobia, with decreases greater than Americans’ average decrease in homophobia from 1998 to 2012. These effects persisted for 3 months, and both transgender and nontransgender canvassers were effective. The intervention also increased support for a nondiscrimination law, even after exposing voters to counterarguments.

Brain correlates of how the risk taking of others influences our own risk taking

From Suzuki et al., another upstairs/downstairs story. Risk is represented in the caudate nucleus (downstairs), the risk activity of others is represented in the dorsolateral prefrontal cortex (upstairs). The strength of the connections between these areas determines how susceptible our behavior is to influence by others.

Our attitude toward risk plays a crucial role in influencing our everyday decision-making. Despite its importance, little is known about how human risk-preference can be modulated by observing risky behavior in other agents at either the behavioral or the neural level. Using fMRI combined with computational modeling of behavioral data, we show that human risk-preference can be systematically altered by the act of observing and learning from others’ risk-related decisions. The contagion is driven specifically by brain regions involved in the assessment of risk: the behavioral shift is implemented via a neural representation of risk in the caudate nucleus, whereas the representations of other decision-related variables such as expected value are not affected. Furthermore, we uncover neural computations underlying learning about others’ risk-preferences and describe how these signals interact with the neural representation of risk in the caudate. Updating of the belief about others’ preferences is associated with neural activity in the dorsolateral prefrontal cortex (dlPFC). Functional coupling between the dlPFC and the caudate correlates with the degree of susceptibility to the contagion effect, suggesting that a frontal–subcortical loop, the so-called dorsolateral prefrontal–striatal circuit, underlies the modulation of risk-preference. Taken together, these findings provide a mechanistic account for how observation of others’ risky behavior can modulate an individual’s own risk-preference.

Aging brains - more physical activity, more gray matter, less Alzheimers.

I like to pass on any work I see relevant to exercise, aging, and the brain. The following is from Raji et al.

BACKGROUND: Physical activity (PA) can be neuroprotective and reduce the risk for Alzheimer's disease (AD). In assessing physical activity, caloric expenditure is a proxy marker reflecting the sum total of multiple physical activity types conducted by an individual. 

OBJECTIVE: To assess caloric expenditure, as a proxy marker of PA, as a predictive measure of gray matter (GM) volumes in the normal and cognitively impaired elderly persons. 

METHODS: All subjects in this study were recruited from the Institutional Review Board approved Cardiovascular Health Study (CHS), a multisite population-based longitudinal study in persons aged 65 and older. We analyzed a sub-sample of CHS participants 876 subjects (mean age 78.3, 57.5% F, 42.5% M) who had i) energy output assessed as kilocalories (kcal) per week using the standardized Minnesota Leisure-Time Activities questionnaire, ii) cognitive assessments for clinical classification of normal cognition, mild cognitive impairment (MCI), and AD, and iii) volumetric MR imaging of the brain. Voxel-based morphometry modeled the relationship between kcal/week and GM volumes while accounting for standard covariates including head size, age, sex, white matter hyperintensity lesions, MCI or AD status, and site. Multiple comparisons were controlled using a False Discovery Rate of 5 percent. 

RESULTS: Higher energy output, from a variety of physical activity types, was associated with larger GM volumes in frontal, temporal, and parietal lobes, as well as hippocampus, thalamus, and basal ganglia. High levels of caloric expenditure moderated neurodegeneration-associated volume loss in the precuneus, posterior cingulate, and cerebellar vermis. 

CONCLUSION: Increasing energy output from a variety of physical activities is related to larger gray matter volumes in the elderly, regardless of cognitive status.

Distraction in the digital era….what about since 1710?

I want to pass on some clips from an interesting essay by Frank Furedi, "The Ages of Distraction."

The rise of the internet and the widespread availability of digital technology has surrounded us with endless sources of distraction: texts, emails and Instagrams from friends, streaming music and videos, ever-changing stock quotes, news and more news. To get our work done, we could try to turn off the digital stream, but that’s difficult to do when we’re plagued by FOMO, the modern fear of missing out. Some people think that our willpower is so weak because our brains have been damaged by digital noise. But blaming technology for the rise in inattention is misplaced. History shows that the disquiet is fueled not by the next new thing but by the threat this thing – whatever it might be – poses to the moral authority of the day.

The first time inattention emerged as a social threat was in 18th-century Europe, during the Enlightenment, just as logic and science were pushing against religion and myth. The Oxford English Dictionary cites a 1710 entry from Tatler as its first reference to this word, coupling inattention with indolence; both are represented as moral vices of serious public concern.

The recent decades have seen a dramatic reversal in the conceptualization of inattention. Unlike in the 18th century when it was perceived as abnormal, today inattention is often presented as the normal state. The current era is frequently characterized as the Age of Distraction, and inattention is no longer depicted as a condition that afflicts a few. Nowadays, the erosion of humanity’s capacity for attention is portrayed as an existential problem, linked with the allegedly corrosive effects of digitally driven streams of information relentlessly flowing our way.

The perception of an Age of Distraction is related to our uncertainty about the answer to the question of ‘attention to what or to whom’. The sublimation of anxieties about moral authority through the fetish of technologically driven distraction has acquired pathological proportions in relation to children and young people. Yet as most sensible observers understand, children who are inattentive to their teachers are often obsessively attentive to the text messages that they receive. The constant lament about inattentive youth in the Anglo-American world could be interpreted as a symptom of problems related to the exercise of adult authority.

Often the failure to inspire and capture the imagination of young people is blamed on their inattentive state of minds. Too often educators have responded to this condition by adopting a fatalistic approach of accommodating to the supposed inattentive reading practices of digital natives. This pattern is evident in higher education where the assumption that college students can no longer be expected to read long and challenging texts or pay attention to serious lectures has led to the adaptation of course material to the inattentive mentality of the digital native. Calls to change the educational environment to ‘fit the student’ have become widespread in higher education.

How different from the reaction of moral philosophers such as Dugald Stewart, also concerned with the problem of the inattentive student. Author of Outlines of Moral Philosophy: For the Use of Students in the University of Edinburgh (1793), Stewart believed that the problem of inattention could be overcome through moral education. Unlike some contemporary academics, he regarded the ‘early habit of inattention’ a problem to be solved rather than an unalterable fact of existence. Helvétius fervently believed that everyone had the potential to acquire ‘continued attention’ and ‘triumph over indolence’.

Regrettably, the optimism of Helvétius has given way to a mood of resignation. Attention is still seen as desirable but almost impossible to achieve. As one alarmist account warns, ‘an epidemic erosion of attention is a sure sign of an impending dark age’. Helvétius would have been distressed by the fatalism expressed in this lament.

The evolutionary origins of smiles, laughter, and tears.

Graziano suggests that our smile originated in the defensive reaction of monkeys to other monkeys moving into their personal space. He then proceeds to make just-so stories about simian origins of our laughing and crying. To begin, imagine Monkey B steps into the personal space of Monkey A.

Monkey A squints, protecting his eyes. His upper lip pulls up. This does expose the teeth, but only as a side-effect: in a defensive reaction, the point of the curled lip is not to prepare for a biting attack so much as it is to bunch the facial skin upward, further padding the eyes in folds of skin...The head pulls down and the shoulders pull up to protect the vulnerable throat and jugular....The torso curves forward to protect the abdomen...Monkey B can learn a lot by watching the reaction of Monkey A...And so the stage is set for a social signal to evolve: natural selection will favour monkeys that can read the cringe reactions of their peers and adjust their behaviour accordingly...If Monkey B can glean useful information by watching Monkey A, then it’s useful for Monkey A to manipulate that information and influence Monkey B. Evolution therefore favours monkeys that can, in the right circumstances, pantomime a defensive reaction. It helps to convince others that you’re non-threatening. Finally we see the origin of the smile: a briefly flashed imitation of a defensive stance.

In people, the smile has been pared down to little more than its facial components — the lifting of the upper lip, the upward bunching of the cheeks, the squint. These days we use it mainly to communicate a friendly lack of aggression rather than outright subservience...We can’t help feeling warmer towards someone who beams that Duchenne smile.

On laughing:

...chimps have something like laughter: they open their mouths and make short exhalations during play fights, or if someone tickles them. Gorillas and orangutans do the same. The psychologist Marina Ross compared the noises made by different species of ape and found that it was the sound of bonobos at play that comes closest to human laughter, again, when play-fighting or tickling. All of which makes it seem quite likely that the original type of human laughter also emerged from, yes, play-fighting and tickling.

On crying:

My best guess, strange as it might sound, is that our ancestors were in the habit of punching each other on the nose. Such injuries would have resulted in copious tear production...According to recent analysis by David Carrier and Michael Morgan from Utah University, the shape of human facial bones might well have evolved to withstand the physical trauma of frequent punching. Thickly buttressed facial bones are first seen in fossils of Australopithecus, which appeared following our split with chimpanzees...the reason we weep now may well be that our ancestors discussed their differences by hitting each other in the face. Some of us still do, I suppose.

In any event, the entire behavioural display that we call crying – the tear production, the squinting, the raised upper lip, the repeated alarm calls – makes for a useful signifier. Evolution would have favoured animals that reacted to it with an emotional desire to dispense comfort.

Graziano's speculative summary:

An age-old defensive mechanism, a mechanism that monitors bubbles of space around the body and organises protective movements, suddenly takes flight in the hyper-social world of primates, spinning into smiles and laughter and crying and cringeing. Each one of those behaviours then splits further, branching into a whole codebook of signals for use in different social circumstances. Not all of human expression can be explained in this way, but much of it can. A Duchenne smile, a cold smile, laughter at a joke, laughter that acknowledges a clever witticism, cruel laughter, a cringe to show servility, standing straight to show confidence, the arms-crossed expression of suspicion, the arms-open expression of welcome, tilting your head as a sign of surrender to a lover, the fleeting crinkling of the face that hints at crying as we show sympathy for some sad story, or a full blown sobbing jag: this whole vast range of expression could well have emerged from a protective sensory-motor loop that has nothing to do with communication. Evolution is bizarre.

Another list - "Keys to happiness"

The New York Times has done a simple list of pointers to basic articles and research on well being. I'm passing on a few of the items from a condensed version of that list, rearranging the list in almost reverse order to reflect not importance, but items that seem to me to be less commonly acted on. So, keys of happiness:

Don't obsess about it, and don't overdo it.

If all else fails, fake it.

Gratitude helps.

Make friends, family, and weekends a priority

Be healthy

A succinct list of some of our common psychological errors.

I want to point to Belsky's article on why we think we are better decision makers under uncertainty than we really are. He summarizes several common errors:

The sunk cost fallacy - hanging on to a decision, or an investment, in an unconscious desire to justify it.

Loss aversion - reacting more strongly to loss of a resource (time, goods, or money) than to a similar gain.

Overconfidence - overrating our abilities, knowledge, and skill (two thirds of investors rate their financial sophistication as advanced, but barely pass a financial literacy exam.)

Optimism bias - which seems to be hard-wired into our brains because it has evolutionarily useful, driving humans to strive in the face of long odds.

Hindsight bias - rewriting history to make ourselves look good, as in misremembering our forecasts in a way that makes us look smarter.

Attribution bias - attributing good outcomes to our own skills, but bad outcomes to causes over which we had no control.

Confirmation bias - giving too much weight to information that supports our existing beliefs and discounting that which does not.

Muscle mass and nerve control enhanced in octogenarian athletes.

Power et al. expand their earlier studies on active runners ~65 years old to find ~14% greater muscle mass and ~28% more functioning motor nerve units in octogenarian masters athletes than in healthy age-matched controls.

Our group has shown a greater number of functioning motor units (MU) in a cohort of highly-active older(~65y) masters runners relative to age-matched controls. Owing to the precipitous loss in the number of functioning MUs in the 8th and 9th decade of life it is unknown whether older world class octogenarian masters athletes (MA) would also have greater numbers of functioning MUs (MUNE) compared with age-matched controls. We measured MU numbers and neuromuscular transmission stability in the tibialis anterior of world champion MAs (~80y), and compared the values to healthy age-matched controls (~80y). Decomposition-enhanced spike-triggered averaging was used to collect surface and intramuscular electromyography signals during dorsiflexion at ~25% of maximum voluntary isometric contraction(MVC). Near fibre (NF) MU potential analysis was used to assess neuromuscular transmission stability. For the MAs as compared with age-matched controls; the amount of excitable muscle mass (CMAP) was 14% greater (p less than 0.05), there was a trend (p=0.07) towards a 27% smaller surface detected motor unit potential - representative of less collateral reinnervation, and 28% more functioning MUs (p less than 0.05). Additionally, the MAs had greater MU neuromuscular stability than the controls as indicated by lower NF jitter and jiggle values (p less than 0.05). These results demonstrate that high performing octogenarians better maintain neuromuscular stability of the MU and mitigate the loss of MUs associated with aging well into the later decades of life during which time the loss of muscle mass and strength become functionally relevant. Future studies need to identify the concomitant roles genetics and exercise play in neuroprotection.

Why sad music can make us feel good.

As an update to a previous MindBlog post on why we like sad music, I want to note Ojiaku's brief mention of several articles on this subject.

Sad music might make people feel vicarious unpleasant emotions, found a study published last year in Frontiers in Psychology. But this experience can ultimately be pleasurable because it allows a negative emotion to exist indirectly, and at a safe distance. Instead of feeling the depths of despair, people can feel nostalgia for a time when they were in a similar emotional state: a non-threatening way to remember a sadness.

People who are very empathetic are more likely to take pleasure in the emotional experience of sad music, according to another study in Frontiers of Psychology. Others enjoy sad songs because they help them return to an emotionally balanced state, according to a review in Frontiers in Human Neuroscience, published in 2015. And those more open to varied experiences might enjoy the songs because the unique emotions that come up when listening to the music fulfill their need for novelty in thoughts and feelings.

From the Frontiers in Neurosciences abstract:

We offer a framework to account for how listening to sad music can lead to positive feelings, contending that this effect hinges on correcting an ongoing homeostatic imbalance. Sadness evoked by music is found pleasurable: (1) when it is perceived as non-threatening; (2) when it is aesthetically pleasing; and (3) when it produces psychological benefits such as mood regulation, and empathic feelings, caused, for example, by recollection of and reflection on past events.

The Social Gene

I want to pass on some clips from Joseph's Swift's review of a book, "The Society of Genes" by Yanai and Lercher that updates Richard Dawkins's classic "The Selfish Gene" publised 40 years ago. (Their title reminds me of "Society of Mind," a classic book published in 1986 by Marvin Minsky, who recently died at age 88.)

Genetic research has moved rapidly since the publication of Richard Dawkins's The Selfish Gene 40 years ago. In the intervening years, we have come to realize that many of the most interesting and important phenomena in human biology are not caused by any single gene. Processes like the immune system's ability to recognize infection, or the timing of our sleep-wake cycle, for example, are the product of many genes working together in a highly integrated way. Citing a wealth of recent research that explores the ways genes work together to produce complex biological processes, Itai Yanai and Martin Lercher argue that it is time to embrace a new, more holistic, metaphor in their book, The Society of Genes.

Rather than focus on any one gene, Yanai and Lercher invite the reader to step back and observe how genes assemble together to make a global genetic system, or genome. From here, one can see that the labor within the genome is not divided equally. Whereas many genes encode for proteins that perform a single monotonous task, such as breaking down a certain type of sugar or producing a specific skin pigment, there are others that serve such fundamental roles that their removal would lead to the crumbling of the genomic society altogether. Among the latter group are genes that manage the behavior of a host of other genes.

When genes are mismanaged by their masters, organisms can be transformed in dramatic ways. For example, in humans, when SOX9 fails to direct its wide range of subordinates succinctly, sex reversal and skeletal malformations can occur.

Given that catastrophic things tend to happen when genes don't work together properly, changes to how the genomic society is run are a rare occurrence. When genes with new abilities evolve, Darwinian selection determines whether they will join the ranks as productive members of society. Our ancestors obtained genes that could interpret light as color and a gene for a more efficient oxygen-carrying hemoglobin in this very way.

And then there are the genes that don't contribute to society at all. Instead, they secure their position by hijacking the system. The LINE1 gene, for example, encodes only for its own dispersal, copying and pasting itself throughout our genome while providing the society with no clear benefit. The “bad behavior” of genes amounts to scandal in the genomic society, and learning about their exploits is one of the most enjoyable elements of reading the book.

There are even genes that work to ensure the survival of individual cells within an organism by wreaking havoc on others. In fruit flies, for example, a pair of genes involved in sperm production work in concert to produce both a poison and its antidote. The toxic compound is released from the cell, while the antidote is retained. In this way, surrounding sperm cells without the gene pair are killed. On reading about such systems, one begins to realize that it's not quite right to imagine our genome as some idealized republic. This is a society that is easily compromised from within its own ranks.

In the years since The Selfish Gene was published, the human genome has been sequenced, along with the genomes of many other species. Indeed, probing one's own genes is beginning to become routine. Thus, The Society of Genes represents a timely and welcome handbook for navigating this postgenomic era.

Pterostilbene anti-aging supplement - undesirable side effects

In a January 15 MindBlog post, I noted the start of my most recent foray into supplements meant to have salutary effects on energy, mind, body, longevity, etc., giving some references to work on pterostilbene, a resveratrol cousin whose added methyl groups allow more rapid absorption after ingestion and slow down its removal by the liver. I’m wanting to report now on my experience of trying Elysium’s pills containing 125 mg pterostilbene and 25 mg nicotinamide riboside, (one per day, instead of the two recommended). I emphasize that this is a single report, people doubtless vary in their sensitivity.

I used the half dose because my previous 2008 experiment with resveratrol was terminated after 19 days because of increasing arthritic symptoms, especially in hands, which disappeared with a week after stopping the supplement. The MindBlog post reporting this result received 33 comments noting side effects of arthritic symptoms, foot and finger soreness and stiffness, sleep disturbance, joint pain, etc. All of these effects are consistent with possible immune system activation and inflammation. 

On starting one pill a day, I thought I noticed after a few days a subtle increase in body energy, a slightly more benign and positive temperament (there are a few reports of anxiolytic effects of low doses of pterostilbene), and most interesting to me, a decrease in rumination or mind wandering versus focused attention . By day 30 increasing stiffness in fingers and body movement was obvious. I terminated the pills, and stiffness disappeared over the next few days. After seven days off, I started one pill a day again. After four days, stiffness and arthritic symptoms had clearly increased in my hands. On stopping the pills again, stiffness disappeared over the next few days.

So, I guess that’s it for me on the resveratrol or pterostilbene trip. Pity… chemical studies noting their desirable effects are quite compelling. I do think Elysium and other vendors of these products should state their possible side effects.

Are we all sexists and racists?

I want to point to Miller's review of work of Levanon et al., as well as other studies, showing that that when women have moved into occupations in large numbers, those jobs have begun paying less even after controlling for education, work experience, skills, race and geography.

A striking example is to be found in the field of recreation — working in parks or leading camps — which went from predominantly male to female from 1950 to 2000. Median hourly wages in this field declined 57 percentage points, accounting for the change in the value of the dollar, according to a complex formula used by Professor Levanon. The job of ticket agent also went from mainly male to female during this period, and wages dropped 43 percentage points...The same thing happened when women in large numbers became designers (wages fell 34 percentage points), housekeepers (wages fell 21 percentage points) and biologists (wages fell 18 percentage points). The reverse was true when a job attracted more men. Computer programming, for instance, used to be a relatively menial role done by women. But when male programmers began to outnumber female ones, the job began paying more and gained prestige.

In the vein of work described in a previous MindBlog post, an excellent article by Ojiaku, a former Neuroscience Graduate Student at the University of Wisconsin, gives extensive references to work demonstrating that our unconscious racism starts early, and creates a deadly empathy gap. The studies Ojiaku cites:

...showed racially biased differences in cognitive and emotion-related brain regions, including the anterior cingulate cortex (ACC). One of the ACC’s functions is registering when you experience your own pain or empathy for another person’s pain. In the study, Chinese and Caucasian college students were shown video clips of both Chinese and Caucasian faces either in pain or not in pain as scientists conducted brain scans. The researchers measured increased ACC activity in the brains of those viewing painful expressions on the faces belonging to their own race, but decreased ACC activity when viewing pain in another race, uncovering a racially biased difference in empathetic response to pain in the brain.

Another study:

...asked participants to view video images of white, black, and violet-illuminated (for racially neutral) hands being pricked with a needle. While watching the prick, the volunteers were tested for their empathetic response via transcranial magnetic stimulation (TMS); the greater the reaction to the stimulation, the higher the empathetic response to the pain...Interestingly enough, both black and white participants had an adequately empathetic response to seeing the violet hand being pricked. However, all of the participants – both black and white – failed to react as strongly to the pain of someone who was outside their racial group. The study also found that people who scored higher in racial bias on the IAT (implicit association test) – meaning that they showed more implicit preferences for faces belonging to their own race – also showed less reactivity to pain experienced by someone from another race.

The last straw:

...is a study from the University of Iowa published in Psychological Science in February 2016. Incredibly, the researchers found that when white test subjects were primed with photos of five-year-old black boys, they were far more likely to mistake objects such as toys for guns – or even to claim to see guns when there were none. In sharp contrast, when subjects were primed with photos of five-year-old white boys before seeing the objects, the effect reserved, as they were more likely to mistake guns for toys. These findings are ominous for black children, because it shows that youth does not mitigate their potential to become targets of racist events, as in the case of the 12-year-old Tamir Rice, a young black boy carrying a toy ‘BB gun’ in a park in Cleveland, Ohio, whom the police shot in less than two seconds after arriving on the scene.

Another social science, Economics, looks at itself.

Mindblog recently noted a large study that tested the replicability of studies in psychology journals. Only 36% of the findings were repeated. The quality of results has also been questioned in many fields such as medicine, neuroscience, and genetics. Camerer et al. have now tested the replicability of experiments published in top-tier economics journals, finding that two-thirds of the 18 studies examined yielded replicable estimates of effect size and direction. Their abstract:

The replicability of some scientific findings has recently been called into question. To contribute data about replicability in economics, we replicated 18 studies published in the American Economic Review and the Quarterly Journal of Economics between 2011 and 2014. All of these replications followed predefined analysis plans that were made publicly available beforehand, and they all have a statistical power of at least 90% to detect the original effect size at the 5% significance level. We found a significant effect in the same direction as in the original study for 11 replications (61%); on average, the replicated effect size is 66% of the original. The replicability rate varies between 67% and 78% for four additional replicability indicators, including a prediction market measure of peer beliefs.

Overkill in techno-aids for 'Mens Sana in Corpore Sano'

None of us would argue with the 'sound mind in a sound body' injunction from Juvenal’s Latin satires (~100 AD), a goal that can be accomplished by diligent pursuit of a few simple activities. Two NYTimes articles note how modern technology manages, for a profit, to vastly encumber that pursuit.

With regard to 'sound mind,' Gelles notes:

The other morning, I woke up and brewed a cup of Mindful Lotus tea ($6 for 20 bags). On the subway, I loaded the Headspace app on my iPhone and followed a guided mindfulness exercise ($13 a month for premium content). Later in the day, I dropped by Mndfl, a meditation studio in Greenwich Village ($20 for a 30-minute class)...There are more than two dozen mindfulness apps for smartphones, some offering $400 lifetime subscriptions. The Great Courses has two mindfulness packages, each with a couple of dozen DVDs for $250. For an enterprising contemplative, it’s never been easier to make a buck...On a recent trip to Whole Foods, near the kombucha, I came across a new product from the health food maker Earth Balance: a dairy-free mayonnaise substitute called Mindful Mayo ($4.50 a jar). Then, in line, I picked up a copy of Mindful magazine ($6)....With so many mindful goods and services for sale, it can be easy to forget that mindfulness is a quality of being, not a piece of merchandise

...with so many cashing in on the meditation craze, it’s hard not to wonder whether something essential is being lost...Increasingly, mindfulness is being packaged as a one-minute reprieve, an interlude between checking Instagram and starting the next episode of “House of Cards.” One company proclaims it has found the “minimum effective dose” of meditation that will change your life. On Amazon, you can pick up “One-Minute Mindfulness: 50 Simple Ways to Find Peace, Clarity, and New Possibilities in a Stressed-Out World.” Dubious courses promise to help people “master mindfulness” in a few weeks.

More often than not, however, the people I know who take time to meditate — carefully observing thoughts, emotions and sensations — are sincere in their aspirations to become less stressed, more accepting and at least a little happier.

Hutchinson discusses the greater than billion dollar market for body fitness aids (which are not used by more than half their buyers six months after their purchase) suggesting:

...a more fundamental question about our rapid adoption of wearable fitness tech: Is the data we collect with these devices actually useful?...Last September, in The British Journal of Sports Medicine, Australian researchers published a review of studies that compared subjective and objective measures of “athlete well-being” during training. The objective measures included state-of-the-art monitoring of heart rate, blood, hormones and more; the subjective measure boiled down to asking the athletes how they felt. The results were striking: The researchers found that as the athletes worked out, their own perception registered changes in training stress with “superior sensitivity and consistency” to the high tech measures...running with a GPS watch “slackens the bond between perception and action.” In other words, when you’re running, instead of speeding up or slowing down based on immediate and intuitive feedback from your body and environment, you’re inserting an unwieldy extra cognitive step that relies on checking your device as you go.

On the positive side:

Health researchers also want to use your tracked data to figure out what works in the real world to improve health and fitness, rather than testing theories in the artificial conditions of the lab. An analysis of in-the-wild data from 4.2 million MyFitnessPal users, for example, recently yielded unexpected insights into the habits of successful weight-losers compared with unsuccessful ones: They ate nearly a third more fiber, and 11 percent less meat. And the dietary changes the successful dieters made between 2014 and 2015 bucked broader trends: They consumed more grains, cereal and raw fruit, but fewer eggs.

As prosaic as it sounds, this is the greatest promise of the wearables revolution. Once the novelty of tracking your exercise habits wears off, knowing how many steps you took today or what your resting heart rate was yesterday soon loses its interest. But together, 100 million of us wearing wristbands could uncover some truly valuable insights into what works to make us healthier and fitter.

Perhaps the most effective and simple way to increase aerobic fitness: use a jump rope!

Storing long term emotional memories.

A Journal of Neuroscience precis of an article by Cambiaghi et al., slightly edited:

When we remember events, we often also remember what we were feeling at the time. Cambiaghi et al. asked where in the brain we store such connections. To answer this, they conditioned rats to associate a tone with an unpleasant experience. They then simultaneously recorded from two brain regions, the higher-order auditory cortex and the amygdala, 1 day and 1 month after the conditioning. Animals displayed fearful behavior at both time points, and both areas showed learning-evoked changes. However, the two brain regions only interacted significantly after 1 month had passed (The cue increased the synchrony of their firing.) The degree of interaction predicted the animals' ability to recognize the tone as unpleasant.