View a flickering stimulus before you try to read fine print…

A nice piece of work from Arnold et al.:

Significance

Distinct anatomical visual pathways can be traced through the human central nervous system. These have been linked to specialized functions, such as encoding information about spatial forms (like the human face and text) and stimulus dynamics (flicker or movement). Our experiments are inconsistent with this strict division. They show that mechanisms responsive to flicker can alter form perception, with vision transiently sharpened by weakening the influence of flicker-sensitive mechanisms by prolonged exposure to flicker. So, next time you are trying to read fine print, you might be well advised to first view a flickering stimulus!

Abstract

Human vision is surprisingly malleable. A static stimulus can seem to move after prolonged exposure to movement (the motion aftereffect), and exposure to tilted lines can make vertical lines seem oppositely tilted (the tilt aftereffect). The paradigm used to induce such distortions (adaptation) can provide powerful insights into the computations underlying human visual experience. Previously spatial form and stimulus dynamics were thought to be encoded independently, but here we show that adaptation to stimulus dynamics can sharpen form perception. We find that fast flicker adaptation (FFAd) shifts the tuning of face perception to higher spatial frequencies, enhances the acuity of spatial vision—allowing people to localize inputs with greater precision and to read finer scaled text, and it selectively reduces sensitivity to coarse-scale form signals. These findings are consistent with two interrelated influences: FFAd reduces the responsiveness of magnocellular neurons (which are important for encoding dynamics, but can have poor spatial resolution), and magnocellular responses contribute coarse spatial scale information when the visual system synthesizes form signals. Consequently, when magnocellular responses are mitigated via FFAd, human form perception is transiently sharpened because “blur” signals are mitigated.

Why do people in big cities move faster?

A number of studies have shown that people in big cities move faster. Why is this? Pontzer describes work by Ahmed et al. suggesting that our brains use metabolic energy cost to determine the speed with which we (and other animals) move towards a reward.

For many tasks, such as walking, the metabolic energy (i.e., calories) expended per distance traveled is a function of speed; moving faster requires more energy per meter. A reward’s value can be a function of speed as well. Under a temporal discounting model, a reward’s value decreases the longer it takes to obtain it; food might decay or be lost to competitors, the comfortable seats on the rush-hour train might be taken. Given the cost:speed function for a given task and the value:time function for a given reward, one can solve for the speed that maximizes net return for a given action.

Ahmed and colleagues tested their model in a series of reaching tasks with human subjects and found strong support for it...despite its simplicity the model makes reliable predictions across a variety of different tasks and even across species. Analyzing the behavior of finches reported in an experimental study of foraging behavior, Ahmed and colleagues showed that their model correctly predicts whether the birds chose to walk (which is slow but metabolically inexpensive) or fly (fast but costly) to acquire food. When the time to acquire the food increased, its value as estimated by the discounting model decreased, and as predicted the birds chose to walk. In a separate analysis of isometric force production in human subjects, their model correctly predicted subjects’ decreasing sensitivity to task duration as the force exerted decreased.

That the model’s predictions work well across species suggests it may reflect a common, evolved neurobiological mechanism that is shared across species. Ahmed and colleagues suggest, for example, that the neural circuits involved in generating actions should be strongly coupled to the circuits involved in deciding between actions. Such shared, evolved neurological mechanisms are powerful tools for research, as they present a common framework for comparing behavioral strategies across species, tasks, and environments.

Pontzer's final paragraph:

For my fellow New Yorkers, Ahmed and colleagues’ model suggests two, mutually compatible reasons that we habitually walk faster, and less efficiently, than our relaxed, rural comrades (see figure above). We may perceive greater rewards are at stake, and given the remarkable sums of money exchanged each day in the city, that assessment may well be accurate for some. Alternatively, with over 8 million fellow primates foraging for the same resources, we may sense that the rewards we seek are slipping away more quickly — something to ponder next time you’re running for the train.

The mathematical model developed by Ahmed et al. is a bit more complex than is appropriate for a description here, but can be found in their paper.

Social class and attentiveness to others.

More on “The rich are different from you and me.” (F. Scott Fitzgerald) “Yes, They have more money.” (Hemingway). Dietze and Knowles use eye movement measurements to show that people of higher social class are less attentive to other people and their faces. Their abstract, slightly edited:

We theorize that people’s social class affects their appraisals of others’ motivational relevance—the degree to which others are seen as potentially rewarding, threatening, or otherwise worth attending to. Supporting this account, three studies indicate that social classes differ in the amount of attention their members direct toward other human beings. In the first study, wearable technology was used to film the visual fields of pedestrians on city streets; higher-class participants looked less at other people than did lower-class participants. A second study tracked participants’ eye movements while they viewed street scenes; higher class was associated with reduced attention to people in the images. Finally a third study used a change-detection procedure to assess the degree to which human faces spontaneously attract visual attention; faces proved less effective at drawing the attention of high-class than low-class participants, which implies that class affects spontaneous relevance appraisals. The measurement and conceptualization of social class are discussed.

Explaining gender differences in anxiety.

Li et al. find that a set of oxytocin-responsive neurons in the medial prefrontal cortex (mPFC) look similar in both sexes, but in males they secrete a protein (CRHBP) that antagonizes the effect of the corticotropin-releasing hormone (CRH) associated with stress, thus causing an anti-anxiety effect with males that is not seen in females. This suggests the possibility of developing gender specific therapies for anxiety.

Highlights

•Activation of OxtrINs (oxytocin receptor interneurons) is anxiolytic in males and prosocial in females 

•OxtrINs specifically express CRHBP, an inhibitor of the stress hormone CRH 

•CRHBP blocks activation of layer 2/3 pyramidal cells by CRH only in males 

•OxtrINs in the mPFC (medial prefrontal cortex) coordinate sexually dimorphic social/emotional behaviors

Summary

The frequency of human social and emotional disorders varies significantly between males and females. We have recently reported that oxytocin receptor interneurons (OxtrINs) modulate female sociosexual behavior. Here, we show that, in male mice, OxtrINs regulate anxiety-related behaviors. We demonstrate that corticotropin-releasing-hormone-binding protein (CRHBP), an antagonist of the stress hormone CRH, is specifically expressed in OxtrINs. Production of CRHBP blocks the CRH-induced potentiation of postsynaptic layer 2/3 pyramidal cell activity of male, but not female, mice, thus producing an anxiolytic effect. Our data identify OxtrINs as critical for modulation of social and emotional behaviors in both females and males and reveal a molecular mechanism that acts on local medial prefrontal cortex (mPFC) circuits to coordinate responses to OXT and CRH. They suggest that additional studies of the impact of the OXT/OXTR and CRHBP/CRH pathways in males and females will be important in development of gender-specific therapies.

The presidential election has spawned an effusion of interesting essays - a sampling

A rich trove of Op-Ed pieces and essays has emerged during the recent presidential campaign. I’ve accumulated a list of links, thinking each article might merit an individual blog post, but the list has become overwhelming, like everything else in the campaign. Instead of letting the list entirely fade away, I thought I would pass on selected links, with a brief note on the content of each article:

Behind Our Anxiety, The Fear of Being Unneeded. An interesting collaboration between the conservative president of the American Enterprise Institute and the Dalai Lama. It's message is that our current anxiety and malaise stems not from material needs, but from the growing number of people who feel they are no longer useful, no longer needed, no longer one with their societies. What is needed is the building of a compassionate society that creates a wealth of opportunities for meaningful work in the service of others, so that everyone who is capable of contributing can do so.

Hillary Clinton’s Juggling Act. Hillary Clinton must juggle three competing interest groups: her party’s upscale pro-trade, globalist wing; its underdog minority wing; and organized labor. She is paying a price for her triple allegiance.

The Ethics of Globalism, Nationalism, and Patriotism. A thoughtful article noting a fundamental cause of the division between globalists and nationalists: their underlying theories of human nature, the “unconstrained vision” and the “constrained vision.” If you really believe that the world is “full of good people,” then why not lower the drawbridge and leave it down? But if you have a darker view of human nature and are inclined to see more threats in the world, then you’ll want to retain full control of the drawbridge, lower it selectively, and check people’s papers before you let them in. He quotes from a David Brooks essay "The way out of this debate is not to go nationalist or globalist. It’s to return to American nationalism—espoused by people like Walt Whitman—which combines an inclusive definition of who is Our Own with a fervent commitment to assimilate and Take Care of them."

The Price of Certainty. A piece, with a video, on the work of social psychologist Arie Kruglanski, and his theory of "cognitive closure." Closure is the moment that you make a decision or form a judgment. You literally close your mind to new information. If you have high need for closure, you tend to make decisions quickly and see the world in black and white. If you have a low need for closure, you tolerate ambiguity, but often have difficulty making decisions. All of us fall naturally somewhere on this spectrum...But during times of fear and anxiety — like, for example, right now — everybody’s need for closure increases. We tend to make judgments more quickly, regardless of the facts. We’re also drawn to leaders who are decisive and paint solutions in simple terms.

The Case Against Democracy. An interesting essay Caleb Crain in The New Yorker on the history of the idea of “epistocracy,” meaning “government by the knowledgeable.”

Political ideology and pathogen avoidance across 30 nations

Tyber et al. (a huge number of collaborators) show from a survey across 30 nations that the relatively higher conservatism of people and nations with greater pathogen stress is based more on intragroup norms than on avoidance of contact with outgroups (who might pose great infectious disease threats than ingroup members):

People who are more avoidant of pathogens are more politically conservative, as are nations with greater parasite stress. In the current research, we test two prominent hypotheses that have been proposed as explanations for these relationships. The first, which is an intragroup account, holds that these relationships between pathogens and politics are based on motivations to adhere to local norms, which are sometimes shaped by cultural evolution to have pathogen-neutralizing properties. The second, which is an intergroup account, holds that these same relationships are based on motivations to avoid contact with outgroups, who might pose greater infectious disease threats than ingroup members. Results from a study surveying 11,501 participants across 30 nations are more consistent with the intragroup account than with the intergroup account. National parasite stress relates to traditionalism (an aspect of conservatism especially related to adherence to group norms) but not to social dominance orientation (SDO; an aspect of conservatism especially related to endorsements of intergroup barriers and negativity toward ethnic and racial outgroups). Further, individual differences in pathogen-avoidance motives (i.e., disgust sensitivity) relate more strongly to traditionalism than to SDO within the 30 nations.

How to get beyond our tribal politics.

Haidt and Iyer offer an essay in The Wall Street Journal that tries to see a way past the tribal animosities that have been dominating our political discourse. Some edited clips:

Nearly half the country will ...wake up deeply disappointed on the morning of Nov. 9, and many members of the losing side will think that America is doomed..many will be shocked and disgusted that nearly half of their fellow citizens voted for the moral equivalent of the devil.

Is it possible for Americans to forgive, accept and carry on working and living together? We think that it is. After all, civility doesn't require consensus or the suspension of criticism.. If we understand better the psychological causes of our current animosity, we can all take some simple steps to turn it down...Three time honored quotations can serve as guides.

"Me against my brother, my brothers and me against my cousins, then my cousins and me against strangers." - Bedouin saying... Human nature is tribal. We form teams easily, most likely because we have evolved for violent intergroup conflict...The tribal mind is adept at changing alliances to face shifting threats, as the Bedouin saying indicates...we saw it happen after the 9/11 attacks, when the country came together to support the president and the military in the invasion of Afghanistan...So what will happen the next time there is a major terrorist attack? Will we come together again? Or will the attack become a partisan football within hours, as happened after the various lone-wolf attacks of the past year? Something is broken in American tribalism. It is now "my brothers and me against my cousins" all the time, even when we are threatened by strangers...We must find a way to see citizens on the other side as cousins who are sometimes opponents but who share most of our values and interest and are never our mortal enemies.

"Why do you see the speck in your neighbor's eye, but do not notice the log in your own eye?... You hypocrite, first take the log out of your own eye, and then you will see clearly to take the speck out of your neighbor's eye." - Jesus, in Matthew 7:3-5. Our tribal minds are equipped with a powerful tool: shameless and clueless hypocrisy...We think with a particular purpose in mind..psychologists call this "motivated reasoning."...This is why partisans find it so easy to dismiss scandalous revelations about their own candidate while focusing so intently on scandalous revelations about the other candidate...Motivated reasoning has interacted with tribalism and new media technologies since the 1990s in unfortunate ways. Social media, hackers and Google search now help us to find hundreds of specks in our opponents' eyes, but no technology can force us to acknowledge the logs in our own.

"Nature has so formed us that a certain tie unites us all, but...this tie becomes stronger from proximity." - Cicero, "On Friendship". Tribalism...exists in tension with our extraordinary ability to develop bonds with other human beings...French, British and German soldiers came out of their trences in World War I to exchange food, cigarettes and Christmas greetings...Pople who have at least one friend from the other political party are less likely to hate the supporters of that party... but tragically, americans are losing their proximity to those on the other side and are spending more time in politically purified settings. Sine the 1980s, Democrats have been packling into the cities while the rural areas and exurbs have been getting more Republican..ever more of our social life is spent online, in ..networks that are politically homogeneous...will the polarizing trends identified by Pew just keep going until the country splits in two? .... we have lasted 240 years so far, and both sides agree that American is worth fighting for. We just have to see that the fight isn't always against each other...

Here is some advice, adapted from ancient wisdom and modern research:

First, separate your feelings about Donald Trump and Hillary Clinton from your feelings their supporters... don't assume that most people on the other side like or even agree with their candidate on any particular issue...if you knew their stories, you might well empathize with them.

Second, step back and think about your goals. In the long run, would you rather change people or hate them? If you actually want to persuade or otherwise influence people, you should know that it is nearly impossible to change people's minds by arguing with them. When there is mutual antipathy, there is mutual motivated reasoning, defensiveness, and hypocrisy.

...anything that opens the heart opens the mind as well, so do what you can to cultivate personal relationships with those on the other side..let the proximity recommended by Cicero strengthen ties..if you find a way to have a real conversation with someone on the other side, approach it skillfully. One powerful opener is to point to a log in your own eye - to admit right up front that you or your side were wrong about something...this signals that you aren't in combat mode.... Another powerful depolarizing move is praise, as we saw in the second Clinton-Trump debate in their response to a final question "would either of you name one positive thing that you respect in one another?"

...The true test of our democracy - and our love of country - will come on the day after the election...each of us must decide what kind of person we want to be and what kind of relationship we want to have with our politically estranged cousins.

Facebook use associated with a longer life?

From Hobbs et al., with the usual caution that correlations are not causes:

Significance

People who have stronger social networks live longer. However, can we say the same about online social networks? Here, we conduct such a study. Using public California vital records, we compare 12 million Facebook users to nonusers. More importantly, we also look within Facebook users to explore how online social interactions—reflecting both online and offline social activity—are associated with longevity. We find that Facebook users who accept more friendships have a lower risk of mortality, but there is no relationship for those who initiate more friendships. Mortality risk is lowest for those with high levels of offline social interaction and moderate levels of online social interaction.

Abstract

Social interactions increasingly take place online. Friendships and other offline social ties have been repeatedly associated with human longevity, but online interactions might have different properties. Here, we reference 12 million social media profiles against California Department of Public Health vital records and use longitudinal statistical models to assess whether social media use is associated with longer life. The results show that receiving requests to connect as friends online is associated with reduced mortality but initiating friendships is not. Additionally, online behaviors that indicate face-to-face social activity (like posting photos) are associated with reduced mortality, but online-only behaviors (like sending messages) have a nonlinear relationship, where moderate use is associated with the lowest mortality. These results suggest that online social integration is linked to lower risk for a wide variety of critical health problems. Although this is an associational study, it may be an important step in understanding how, on a global scale, online social networks might be adapted to improve modern populations’ social and physical health.

Social motion, social bonds, and exercise.

Davis et al. note how bodies moving in synchrony perform beyond the sum of their individual parts.

In two experimental studies, we investigated mechanisms hypothesized to underpin two pervasive and interrelated phenomena: that certain forms of group movement and exercise lead to social bonding and that social bonding can lead to enhanced exercise performance. In Study 1, we manipulated synchrony and exercise intensity among rowers and found that, compared with low intensity exercise, moderate intensity exercise led to significantly higher levels of cooperation in an economic game; no effect of synchrony vs. non-synchrony was found. In Study 2, we investigated the effects of bonding on performance, using synchrony as a cue of existing supportive social bonds among participants. An elite, highly bonded team of rugby players participated in solo, synchronized, and non-synchronized warm-up sessions; participants' anaerobic performance significantly improved after the brief synchronous warm-up relative to the non-synchronous warm-up. The findings substantiate claims concerning the reciprocal links between group exercise and social bonding, and may help to explain the ubiquity of collective physical activity across cultural domains as varied as play, ritual, sport, and dance.

Wikipedia - a possible antidote for the pathologies of the internet?

This interesting article by Jeff Guo is worth a read. The early hope that the instant communication offered by the internet would knit society together has been dashed...just the opposite has happened. Echo chambers of like-minded people have reinforced political polarization and striking increases in abusive comments. Guo notes:

It’s downright startling, then, to observe what happens behind the scenes at Wikipedia. Go to any article and visit the “talk” tab. More often than not, you'll find a somewhat orderly debate, even on contentious topics like Hillary Clinton's e-mails or Donald Trump's sexual abuse allegations.

He cites research showing that Wikipedia appears to exert a moderating influence on its contributors:

An analysis of political articles shows that the site was once heavily biased toward the left, but has steadily drifted toward the center, to the point that many entries are now about as neutral as their counterparts in the Encyclopedia Britannica...over the years, individuals who edit political articles on Wikipedia seem to grow less biased — their contributions start to contain noticeably fewer ideologically-charged statements...researchers analyzed over 70,000 different articles related to American politics, tallying the different changes made by each of the 2.9 million people who edited those pages between 2001 and 2011...As the researchers followed the contributors over time, they realized that contributors were becoming much less partisan — at least, they were sounding a lot less partisan. Many started their Wikipedia careers using a lot of left-leaning or right-leaning language, but after a few years, most of them began to favor more neutral language...The researchers believe this is evidence that Wikipedia helps break people out of their ideological echo chambers.

Unlike, say, the comments section on most websites, Wikipedia has an extensive manual instructing contributors how to behave. One of the key guidelines is to “assume good faith.” The site also insists that every fact must be backed up by a reliable source. When people seek to change a controversial article, they often to have provide a persuasive argument and extensive citations to make their edits stick.

Paradoxical thinking intervention can moderate attitudes in violent times

Hameiri et al. show how attitudes of those participating in one of the most intractable conflicts in the world can be moderated. I pass on their description of the paradoxical thinking technique employed, and then their abstract:

Paradoxical thinking is “the attempt to change attitudes using new information, which is consistent with the held societal beliefs, but of extreme content that is intended to lead an individual to paradoxically perceive his/her currently held societal beliefs or the current situation as irrational and senseless”. It is based on the classic debating technique, reductio ad absurdum, as well as on practical knowledge accumulated in clinical psychological treatments. These treatments suggest that the extreme content can range from blatant extremity to more subtle exaggerations, or amplifications, of held attitudes and beliefs and extrapolating from them absurd conclusions.

The authors did a large-scale study examining a multichanneled large-scale intervention targeting an entire city in the center of Israel.

...it was intentionally designed to be completely unobtrusive. Specifically, participants did not receive any external motivation to be exposed to the campaign materials and were completely unaware of the connection between the surveys they were requested to answer and the campaign, which took place in their home city. Second, to boost statistical power, our initial samples were quite large. Finally, during the intervention campaign (September–October 2015), the Knife Intifada erupted, with assaults taking place in major cities all over Israel, East Jerusalem, and the West Bank. This violent escalation provided us with the unfortunate context needed to test whether the paradoxical thinking intervention would also be effective in the face of highly negative conflict-related developments that sparked fear and constant threat.

They used multichannel intervention, online video clips, video banners, billboards, posters balloons, and brochures in a six week campaign in a small city in the center of Israel with ~25,000 inhabitants. For example,

During the 6 wk of the campaign, the campaign included the following five short 20-s video clips: 

i) “For the heroes,” see https://www.youtube.com/watch?v=xWoMSv3eXCc (text translates to “Without it we wouldn’t have had heroes ... For the heroes, we probably need the conflict”). 

ii) “For the army,” see https://www.youtube.com/watch?v=xIfXYu60LJE (text translates to “Without it we wouldn’t have had the strongest army in the world ... For the army, we probably need the conflict”). 

iii) “For unity,” see https://www.youtube.com/watch?v=i-HEWpDhMYg (text translates to “Without it we wouldn’t have united against a common enemy ... For unity, we probably need the conflict”). 

iv) “For justice,” https://www.youtube.com/watch?v=NWSJARJk7Q8 (text translates to “Without it we would never be just ... For justice, we probably need the conflict”). 

v) “For morality,” see https://www.youtube.com/watch?v=OTpn5aVBHbI (text translates to “Without it we would never be moral ... For morality, we probably need the conflict”).

Messages on "The Conflict" t-shirts, balloons, and 4,000 brochures:

Imagine for a second
our life here without the conflict:
Without the myths we grew up on,
without a strong army and heroic soldiers,
without “The Peace Party” and “The National Party”…
Impossible!
How will we be “just” without the rockets
that they fire at us from their schools?
How will we be “united”
if we don’t have a common enemy
that gathers us all
in the stairway hall when there’s an alarm?
What would the “leftists” and “rightists” do?
What would Roni Daniel (an Israeli TV military correspondent) do?
Will he cover the story about a young hippo
that was born in the Ramat Gan safari? [in Hebrew the last sentence rhymes]
The Conflict (Logo)
We all want peace.
But more than we want peace,
We probably
Need the conflict

Finally, here is the article's abstract:

In the current paper, we report a large-scale randomized field experiment, conducted among Jewish Israelis during widespread violence. The study examines the effectiveness of a “real world,” multichanneled paradoxical thinking intervention, with messages disseminated through various means of communication (i.e., online, billboards, flyers). Over the course of 6 wk, we targeted a small city in the center of Israel whose population is largely rightwing and religious. Based on the paradoxical thinking principles, the intervention involved transmission of messages that are extreme but congruent with the shared Israeli ethos of conflict. To examine the intervention’s effectiveness, we conducted a large-scale field experiment (prepost design) in which we sampled participants from the city population (n = 215) and compared them to a control condition (from different places of residence) with similar demographic and political characteristics (n = 320). Importantly, participants were not aware that the intervention was related to the questionnaires they answered. Results showed that even in the midst of a cycle of ongoing violence within the context of one of the most intractable conflicts in the world, the intervention led hawkish participants to decrease their adherence to conflict-supporting attitudes across time. Furthermore, compared with the control condition, hawkish participants that were exposed to the paradoxical thinking intervention expressed less support for aggressive policies that the government should consider as a result of the escalation in violence and more support for conciliatory policies to end the violence and promote a long-lasting agreement.

I can't resist passing this on..... Trump Sandwich

Sent by a friend:

Questioning the universality of a facial emotional expression.

Crivelli et al. question the universality of at least one facial expression that has been thought to be the same across all cultures. This challenges the conclusions of classic experiments by Paul Ekman, largely unquestioned for the past 50 years, that facial expression from anger to happiness to sadness to surprise seem to be universally understood around the world, a biologically innate response to emotion. They find the fear gasping face of most cultures is taken as a threat display in a Melanesian society:

Significance

Humans interpret others’ facial behavior, such as frowns and smiles, and guide their behavior accordingly, but whether such interpretations are pancultural or culturally specific is unknown. In a society with a great degree of cultural and visual isolation from the West—Trobrianders of Papua New Guinea—adolescents interpreted a gasping face (seen by Western samples as conveying fear and submission) as conveying anger and threat. This finding is important not only in supporting behavioral ecology and the ethological approach to facial behavior, as well as challenging psychology’s approach of allegedly pancultural “basic emotions,” but also in applications such as emotional intelligence tests and border security.

Abstract

Theory and research show that humans attribute both emotions and intentions to others on the basis of facial behavior: A gasping face can be seen as showing “fear” and intent to submit. The assumption that such interpretations are pancultural derives largely from Western societies. Here, we report two studies conducted in an indigenous, small-scale Melanesian society with considerable cultural and visual isolation from the West: the Trobrianders of Papua New Guinea. Our multidisciplinary research team spoke the vernacular and had extensive prior fieldwork experience. In study 1, Trobriand adolescents were asked to attribute emotions, social motives, or both to a set of facial displays. Trobrianders showed a mixed and variable attribution pattern, although with much lower agreement than studies of Western samples. Remarkably, the gasping face (traditionally considered a display of fear and submission in the West) was consistently matched to two unpredicted categories: anger and threat. In study 2, adolescents were asked to select the face that was threatening; Trobrianders chose the “fear” gasping face whereas Spaniards chose an “angry” scowling face. Our findings, consistent with functional approaches to animal communication and observations made on threat displays in small-scale societies, challenge the Western assumption that “fear” gasping faces uniformly express fear or signal submission across cultures.

Added note: My thanks to the commenter below who forwarded this relevant 2009 article: Spontaneous Facial Expressions of Emotion of Congenitally and Noncongenitally Blind Individuals

Lifespan adversity and later adulthood telomere length.

From Puterman et al. (Note...telomeres are protective caps of tandem repeats of nucleotides at the end of DNA strands, whose shortening is involved in cellular aging):

Stress over the lifespan is thought to promote accelerated aging and early disease. Telomere length is a marker of cell aging that appears to be one mediator of this relationship. Telomere length is associated with early adversity and with chronic stressors in adulthood in many studies. Although cumulative lifespan adversity should have bigger impacts than single events, it is also possible that adversity in childhood has larger effects on later life health than adult stressors, as suggested by models of biological embedding in early life. No studies have examined the individual vs. cumulative effects of childhood and adulthood adversities on adult telomere length. Here, we examined the relationship between cumulative childhood and adulthood adversity, adding up a range of severe financial, traumatic, and social exposures, as well as comparing them to each other, in relation to salivary telomere length. We examined 4,598 men and women from the US Health and Retirement Study. Single adversities tended to have nonsignificant relations with telomere length. In adjusted models, lifetime cumulative adversity predicted 6% greater odds of shorter telomere length. This result was mainly due to childhood adversity. In adjusted models for cumulative childhood adversity, the occurrence of each additional childhood event predicted 11% increased odds of having short telomeres. This result appeared mainly because of social/traumatic exposures rather than financial exposures. This study suggests that the shadow of childhood adversity may reach far into later adulthood in part through cellular aging.

More evidence on exercise delaying later life dementia

Suo et al. examine changes in brain anatomy that occur during exercise, the only known antidote to later life dementia. They compare brain changes after 6 months of progressive resistance training (PRT), computerized cognitive training (CCT) or combined intervention:

Physical and cognitive exercise may prevent or delay dementia in later life but the neural mechanisms underlying these therapeutic benefits are largely unknown. We examined structural and functional magnetic resonance imaging (MRI) brain changes after 6 months of progressive resistance training (PRT), computerized cognitive training (CCT) or combined intervention. A total of 100 older individuals (68 females, average age=70.1, s.d.±6.7, 55–87 years) with dementia prodrome mild cognitive impairment were recruited in the SMART (Study of Mental Activity and Resistance Training) Trial. Participants were randomly assigned into four intervention groups: PRT+CCT, PRT+SHAM CCT, CCT+SHAM PRT and double SHAM. Multimodal MRI was conducted at baseline and at 6 months of follow-up (immediately after training) to measure structural and spontaneous functional changes in the brain, with a focus on the hippocampus and posterior cingulate regions. Participants’ cognitive changes were also assessed before and after training. We found that PRT but not CCT significantly improved global cognition (F(90)=4.1, P less than 0.05) as well as expanded gray matter in the posterior cingulate (P_corrected less than 0.05), and these changes were related to each other (r=0.25, P=0.03). PRT also reversed progression of white matter hyperintensities, a biomarker of cerebrovascular disease, in several brain areas. In contrast, CCT but not PRT attenuated decline in overall memory performance (F(90)=5.7, P less than 0.02), mediated by enhanced functional connectivity between the hippocampus and superior frontal cortex. Our findings indicate that physical and cognitive training depend on discrete neuronal mechanisms for their therapeutic efficacy, information that may help develop targeted lifestyle-based preventative strategies.

Men are more friendly after conflict than women.

Interesting stuff from Benenson and Wrangham, whose findings suggest the deep evolutionary history of male bonding. Men affiliate more after one-on-one conflicts than women, which facilitates future intragroup cooperation.

Highlights

•After sports matches, male opponents engage in friendly touches longer than females •Male winners and losers make more friendly touches than their female counterparts

Summary

The nature of ancestral human social structure and the circumstances in which men or women tend to be more cooperative are subjects of intense debate. The male warrior hypothesis proposes that success in intergroup contests has been vital in human evolution and that men therefore must engage in maximally effective intragroup cooperation. Post-conflict affiliation between opponents is further proposed to facilitate future cooperation, which has been demonstrated in non-human primates and humans. The sex that invests more in post-conflict affiliation, therefore, should cooperate more. Supportive evidence comes from chimpanzees, a close genetic relative to humans that also engages in male intergroup aggression. Here we apply this principle to humans by testing the hypothesis that among members of a large community, following a conflict, males are predisposed to be more ready than females to repair their relationship via friendly contact. We took high-level sports matches as a proxy for intragroup conflict, because they occur within a large organization and constitute semi-naturalistic, standardized, aggressive, and intense confrontations. Duration or frequency of peaceful physical contacts served as the measure of post-conflict affiliation because they are strongly associated with pro-social intentions. Across tennis, table tennis, badminton, and boxing, with participants from 44 countries, duration of post-conflict affiliation was longer for males than females. Our results indicate that unrelated human males are more predisposed than females to invest in a behavior, post-conflict affiliation, that is expected to facilitate future intragroup cooperation.

Issues or Identity? Cognitive foundations of voter choice.

This open source article in Trends in Cognitive Sciences by Jenki and Huette is worth a look. I pass on the summary and one figure.

Voter choice is one of the most important problems in political science. The most common models assume that voting is a rational choice based on policy positions (e.g., key issues) and nonpolicy information (e.g., social identity, personality). Though such models explain macroscopic features of elections, they also reveal important anomalies that have been resistant to explanation. We argue for a new approach that builds upon recent research in cognitive science and neuroscience; specifically, we contend that policy positions and social identities do not combine in merely an additive manner, but compete to determine voter preferences. This model not only explains several key anomalies in voter choice, but also suggests new directions for research in both political science and cognitive science.

Key Figure: Voter Choice Reflects a Competition between Policy and Identity

Building on recent work in neuroscience and cognitive science, we argue that voter choice can be modeled as a competition between policy and identity. Significant evidence now supports the idea that a domain-general neural system (including the ventromedial prefrontal cortex, shown at top left) tracks the values of economic outcomes (left column). Such values can enter into rational choice models, in economics as well as political science, as variables that are weighted according to their importance (i.e., decision weights, W). Yet, many decisions also involve tracking social information like how one's actions reinforce social categories relative to one's identity (e.g., community involvement, veteran status), a process for which social cognitive regions (e.g., the temporal-parietal junction, TPJ, shown at upper right) play a key role (right column). We develop a simple model in which policy variables and identity variables compete to determine voter choice. Policy variables provide utility according to the importance of the underlying issue; for example, a given voter might prioritize affordable healthcare and a strong national defense. Identity variables provide utility through the act of voting itself, such as by strengthening one's ties to a social group (e.g., pride in one's state) or by signaling one's civic responsibility (e.g., ‘I voted’). Whether policy or identity exerts a dominant influence on choice is determined by a single trade-off parameter (δ).

What kind of exercise is best for the brain?

Reynolds points to work by Nokia et al. asking what kind of exercise is most effective in stimulating the generation of new brain cells in the hippocampus, important in learning and memory. They devised, for rats, tasks analogous to the human exercise practices of weight training, high-intensity interval training, or sustained aerobic activity (like running or biking). Many more new nerve cells appeared in the brains of rats doing sustained activity (which may generate more B.D.N.F - Brain Derived Neurotrophic Factor) than in those doing high-intensity interval training, and weight training had no effect. Here is the abstract:

Aerobic exercise, such as running, has positive effects on brain structure and function, such as adult hippocampal neurogenesis (AHN) and learning. Whether high-intensity interval training (HIT), referring to alternating short bouts of very intense anaerobic exercise with recovery periods, or anaerobic resistance training (RT) has similar effects on AHN is unclear. In addition, individual genetic variation in the overall response to physical exercise is likely to play a part in the effects of exercise on AHN but is less well studied. Recently, we developed polygenic rat models that gain differentially for running capacity in response to aerobic treadmill training. Here, we subjected these low-response trainer (LRT) and high-response trainer (HRT) adult male rats to various forms of physical exercise for 6–8 weeks and examined the effects on AHN. Compared with sedentary animals, the highest number of doublecortin-positive hippocampal cells was observed in HRT rats that ran voluntarily on a running wheel, whereas HIT on the treadmill had a smaller, statistically non-significant effect on AHN. Adult hippocampal neurogenesis was elevated in both LRT and HRT rats that underwent endurance training on a treadmill compared with those that performed RT by climbing a vertical ladder with weights, despite their significant gain in strength. Furthermore, RT had no effect on proliferation (Ki67), maturation (doublecortin) or survival (bromodeoxyuridine) of new adult-born hippocampal neurons in adult male Sprague–Dawley rats. Our results suggest that physical exercise promotes AHN most effectively if the exercise is aerobic and sustained, especially when accompanied by a heightened genetic predisposition for response to physical exercise.

Most effective learning?... sleep between two practice sessions

From Mazza et al.:

Both repeated practice and sleep improve long-term retention of information. The assumed common mechanism underlying these effects is memory reactivation, either on-line and effortful or off-line and effortless. In the study reported here, we investigated whether sleep-dependent memory consolidation could help to save practice time during relearning. During two sessions occurring 12 hr apart, 40 participants practiced foreign vocabulary until they reached a perfect level of performance. Half of them learned in the morning and relearned in the evening of a single day. The other half learned in the evening of one day, slept, and then relearned in the morning of the next day. Their retention was assessed 1 week later and 6 months later. We found that interleaving sleep between learning sessions not only reduced the amount of practice needed by half but also ensured much better long-term retention. Sleeping after learning is definitely a good strategy, but sleeping between two learning sessions is a better strategy.

You're gonna die....

I live in Fort Lauderdale, an epicenter of life extension companies peddling life extending elixirs. I've tried a few of them, and reported on my experiences in this MindBlog. It is good to see the occasional breath of sanity offered by articles like this one from Dong et al. (I'm passing along their abstract and two figures):

Driven by technological progress, human life expectancy has increased greatly since the nineteenth century. Demographic evidence has revealed an ongoing reduction in old-age mortality and a rise of the maximum age at death, which may gradually extend human longevity. Together with observations that lifespan in various animal species is flexible and can be increased by genetic or pharmaceutical intervention, these results have led to suggestions that longevity may not be subject to strict, species-specific genetic constraints. Here, by analysing global demographic data, we show that improvements in survival with age tend to decline after age 100, and that the age at death of the world’s oldest person has not increased since the 1990s. Our results strongly suggest that the maximum lifespan of humans is fixed and subject to natural constraints.

a, Life expectancy at birth for the population in each given year. Life expectancy in France has increased over the course of the 20th and early 21st centuries. b, Regressions of the fraction of people surviving to old age demonstrate that survival has increased since 1900, but the rate of increase appears to be slower for ages over 100. c, Plotting the rate of change (coefficients resulting from regression of log-transformed data) reveals that gains in survival peak around 100 years of age and then rapidly decline. d, Relationship between calendar year and the age that experiences the most rapid gains in survival over the past 100 years. The age with most rapid gains has increased over the century, but its rise has been slowing and it appears to have reached a plateau.

All data were collected from the IDL database (France, Japan, UK and US, 1968–2006). a, The yearly maximum reported age at death (MRAD). The lines represent the functions of linear regressions. b, The annual 1st to 5th highest reported ages at death (RAD). The dashed lines are estimates of the RAD using cubic smoothing splines. The red dots represent the MRAD. c, Annual average age at death of supercentenarians (110 years plus, n = 534). The solid line is the estimate of the annual average age at death of supercentenarians, using a cubic smoothing spline.