Cross-species evidence that adaptive training diminishes distractibility in Aging.

Another fascinating study from Gazzaley's productive research group. A video clip is offered in the abstract. Here are the highlights and summary:

Highlights

•Adaptive distractor training selectively suppresses sensory distractor responses 

•Training enhances spectral and spatial tuning of sensory receptive fields in older rats 

•Top-down frontal theta is selectively restrained for distractors in trained humans 

•Training in older humans generalizes to enhanced aspects of cognitive control

Summary

Aging is associated with deficits in the ability to ignore distractions, which has not yet been remediated by any neurotherapeutic approach. Here, in parallel auditory experiments with older rats and humans, we evaluated a targeted cognitive training approach that adaptively manipulated distractor challenge. Training resulted in enhanced discrimination abilities in the setting of irrelevant information in both species that was driven by selectively diminished distraction-related errors. Neural responses to distractors in auditory cortex were selectively reduced in both species, mimicking the behavioral effects. Sensory receptive fields in trained rats exhibited improved spectral and spatial selectivity. Frontal theta measures of top-down engagement with distractors were selectively restrained in trained humans. Finally, training gains generalized to group and individual level benefits in aspects of working memory and sustained attention. Thus, we demonstrate converging cross-species evidence for training-induced selective plasticity of distractor processing at multiple neural scales, benefitting distractor suppression and cognitive control.

How to bridge the respective bubbles of our ideological tribes?

A number of recent mindblog posts have engaged the issue of the individual versus the collective good (for example, here, here, and here), a creative tension that has been central in human evolution. This has led me to mull a bit about the current apparent drift in the direction of more extreme individualism and rejection of the state’s concern for common interests.

I sometimes feel guilty for not being more evangelistic about promoting a rational scientific ideology that encompasses creationists, conservatives, and libertarians in a more broad evolutionary view, I wonder how it might be possible to induce these groups to admit a broader swath of reality than they currently seem willing to engage.

Concrete personal steps I might take? The expression of my ideas or those of others in writing is relatively easy, that is what this blog is about.

The problem is that MindBlog exists as one instance in the array of similarly minded sites that largely mirror each other’s views. I suspect that it is quite invisible to those following websites that deal with Creationism , conservatism, the libertarian or tea party movements that extoll individualism, etc. Those sites, in turn, are unlikely to be viewed by followers of atheist, agnostic, skeptic, or humanist sites more sympathetic to collective views of the individual in society.

I am a person who is timid about robust personal visceral engagement with those of opposing religious or political views, so I quail at the prospect of showing up at meetings of evangelical or ultra-conservative groups to ask questions like “you say you want the government off our backs...do you accept your social security or medicare payments? If so, do you see any inconsistency in your beliefs and actual practices?” Or, “You indicate you believe the biblical account that earth was created about 6,000 years ago. Do you accept the validity of the physical laws that permit your computer and iPhone to function? If so, how do you account for the fact that these same laws governing the physical properties of atoms prove that life on this planet began 3-4 billion years ago?”

I do hope that the a devout creationist or extreme individualist who occasionally stumbles on to a MindBlog post has his or her mental horizons slightly expanded.

Critique of the Nature paper on dishonest bankers,

I wanted to pass on to MindBlog readers this item analyzing the paper noted in my recent post "Banking - a culture of dishonesty", Statistician Salil Mehta argues that the article is misleading, missing data, and mathematically inaccurate.

Several nuggets on the individual vs. the collective.

Following yesterday's post on the evolution of prosocial religions, I pass on a random set of links to articles also relevant to the individual and the collective.

Terrell notes that the current political schism between Republicans and Democrats has a foundation in different views about the whether an individual's primary purpose is to look out for communal or self interests.

...modern evolutionary research, anthropology, cognitive psychology and neuroscience have come down on the side of the philosophers who have argued that the basic unit of human social life is not and never has been the selfish, self-serving individual. Contrary to libertarian and Tea Party rhetoric, evolution has made us a powerfully social species, so much so that the essential precondition of human survival is and always has been the individual plus his or her relationships with others.

Luhrman does a piece "Wheat people versus rice people" which references the same work mentioned in MindBlog's May 21st post, and notes several other studies on individualistic versus collective cultures.

Rand et al. offer economic game experiments to illustrate how static network structure stabilizes human cooperation

Finally Crockett et al. do an experiment relevant to social cohesion, showing that harm to others outweighs harm to self in moral decision making - most people sacrifice more money to reduce a stranger’s pain than their own pain (the pain being delivered by electric shocks).

The Cultural Evolution of Prosocial Religions

Having been an author in an issue of "Behavioral and Brain Biology" published by Cambridge University Press, I receive notice of forthcoming articles inviting reviewers comments. The articles are then published with the reviewer's comments and authors' responses to the comments.

As a followup to my recent MindBlog post on E.O. Wilson's new book, I am passing on this interesting abstract of such a forthcoming article by Norenzayan et al.  (Motivated readers can email me if they wish to obtain a PDF of this article.)

We develop a cultural evolutionary theory of the origins of prosocial religions, and apply it to resolve two puzzles in human psychology and cultural history: 1) the rise of large-scale cooperation among strangers in the last twelve millennia, and 2) the spread of prosocial religions during the same period. We argue that these two developments were importantly linked. We explain how a package of culturally evolved religious beliefs and practices characterized by increasingly potent, moralizing supernatural agents, credible displays of faith, and other psychologically active elements conducive to social solidarity promoted internal harmony, large-scale cooperation, and high fertility, often leading to success in intergroup competition. In turn, prosocial religious beliefs and practices spread and aggregated as these successful groups expanded, or were copied by less successful groups. This synthesis is grounded in the idea that although religious beliefs and practices originally arose as non-adaptive byproducts of innate cognitive functions, particular cultural variants were then selected for their prosocial effects in a long-term cultural evolutionary process. This framework (1) reconciles key aspects of the adaptationist and byproduct approaches to the origins of religion, (2) explains a variety of empirical observations that have not received adequate attention, and (3) generates novel predictions. Converging lines of evidence drawn from diverse disciplines provide empirical support while at the same time encouraging new research directions and opening up new questions for exploration and debate.

The new surveillance state and our robotic future.

Isreal et al. examine one of the many uses to which individual credit scores are being put - to determine our cardiovascular risk (useful information for health insurance companies). They also note that credit scores are also used by employers, utility companies, and automobile insurers to index high-risk behavior; and by life insurance companies that incorporate credit scores into actuarial models.) Here is the abstract:

Credit scores are the most widely used instruments to assess whether or not a person is a financial risk. Credit scoring has been so successful that it has expanded beyond lending and into our everyday lives, even to inform how insurers evaluate our health. The pervasive application of credit scoring has outpaced knowledge about why credit scores are such useful indicators of individual behavior. Here we test if the same factors that lead to poor credit scores also lead to poor health. Following the Dunedin (New Zealand) Longitudinal Study cohort of 1,037 study members, we examined the association between credit scores and cardiovascular disease risk and the underlying factors that account for this association. We find that credit scores are negatively correlated with cardiovascular disease risk. Variation in household income was not sufficient to account for this association. Rather, individual differences in human capital factors—educational attainment, cognitive ability, and self-control—predicted both credit scores and cardiovascular disease risk and accounted for ∼45% of the correlation between credit scores and cardiovascular disease risk. Tracing human capital factors back to their childhood antecedents revealed that the characteristic attitudes, behaviors, and competencies children develop in their first decade of life account for a significant portion (∼22%) of the link between credit scores and cardiovascular disease risk at midlife. We discuss the implications of these findings for policy debates about data privacy, financial literacy, and early childhood interventions.

Also, the well known futuristic author Margaret Atwood offers an essay, well worth giving a read, on our growing efforts to craft a robotic future. One clip:

Why do we dream up such things? Because, deep down, we desire them...If we were technologically capable mice, we’d be perfecting deadly cat harpoons, or bird-exploding rockets, or cheese-on-demand molecular assemblers...To understand Homo sapiens’ primary wish list, go back to mythology. We endowed the gods with the abilities we wished we had ourselves: immortality and eternal youth, flight, resplendent beauty, total power, climate control, ultimate weapons, delicious banquets minus the cooking and washing up — and artificial creatures at our beck and call.

And just one more:

...people are dreaming up robotic prostitutes, complete with sanitary self-flushing features. Will there be a voice feature, and, if so, what will it say?...If the prospect of getting painfully stuck due to a malfunction keeps you from test-driving a full-body prostibot, you may soon be able to avail yourself of a remote kissing device that transmits the sensation of your sweetie’s kiss to your lips via haptic feedback and an apparatus that resembles a Silly Putty egg. (Just close your eyes.) Or you could venture all the way into the emerging world of “teledildonics” — essentially, remote-controlled vibrators. Push the game-controller levers, watch the effect on screen. Germ-free! Wait for Google or Skype to snatch this up.

Why elders smile, and wisdom in social signals.

Two articles relevant to becoming a senior person:
From Rijsbergen et al. (open access), a piece of work that reminds me of the book recently read by my book group here in Fort Lauderdale, the classic John Rechy novel about male hustlers, "City of Night", in which two age classes existed - 'young man' and 'old man.' Their abstract:

In an increasingly aging society, age has become a foundational dimension of social grouping broadly targeted by advertising and governmental policies. However, perception of old age induces mainly strong negative social biases. To characterize their cognitive and perceptual foundations, we modeled the mental representations of faces associated with three age groups (young age, middle age, and old age), in younger and older participants. We then validated the accuracy of each mental representation of age with independent validators. Using statistical image processing, we identified the features of mental representations that predict perceived age. Here, we show that whereas younger people mentally dichotomize aging into two groups, themselves (younger) and others (older), older participants faithfully represent the features of young age, middle age, and old age, with richer representations of all considered ages. Our results demonstrate that, contrary to popular public belief, older minds depict socially relevant information more accurately than their younger counterparts.

Also, David Brooks cites several books on the practical wisdom that comes with aging, and notes on the famous U-curve experiments in which people generally assess their own well being as high in their 20's and decreasing until about age 50 and then rising again until people rate themselve most happy at ages 82 to 85. A sample clip:

...experienced heads have intuitive awareness of the landscape of reality, a feel for what other people are thinking and feeling, an instinct for how events will flow. In “The Wisdom Paradox,” Elkhonon Goldberg details the many ways the brain deteriorates with age: brain cells die, mental operations slow. But a lifetime of intellectual effort can lead to empathy and pattern awareness. “What I have lost with age in my capacity for hard mental work,” Goldberg writes, “I seem to have gained in my capacity for instantaneous, almost unfairly easy insight.”

Physics, Emergence, and the Connectome - From the connectome to brain function

A special issue of Neuron on connectomics has a special open source section of articles with different views of the problems we face in relating details of brain structure to brain function. I would in particular recommend, Robert B. Laughlin's rather deep article on Physics, Emergence, and the Connectome, whose final paragraphs I copy in below:

It is not controversial that neurons do playful things. They deploy themselves somewhat haphazardly in glial matter, exhibiting no lateral crystalline order. They arborize with each other in ways that resemble tree branches and roots. They possess on-board memory that responds to incoming signals in an agent-based way and changes the signals they themselves generate.

What Might Be Missing

If we suspend disbelief for a moment and consider the possibility that play might be a design principle rather than a higher emergent phenomenon, a simple idea presents itself as to why making sense of the connectome might be so difficult. The latter includes things like obtaining the entire map of C. elegans and finding that it still doesn’t make any sense, and that it even has no action potentials. It is a small step from systems that play without direction to systems that play with rules, and from there to systems that play games with each other. Were that to happen, it could easily account for something as complicated as the brain, for it is well known from the study of automata that simple systems playing games can create enormously complex structures with very sophisticated functions. It is also known that small changes in the rule base can make enormous changes in the structures that develop. There is also the obvious example of the human economy, a thing that grows out of simple rules of money exchange that transcends anyone’s attempt to understand and manage it. One of the economy’s physical manifestations is a great network of highways with mighty cities at its hubs. It would obviously be a fool’s errand to try understanding the economy by mapping its roads.

There is nothing supernatural or unscientific in the concept of gaming making a brain, or for that matter an entire organism. All that is required is an intermediate stage of organization that is unstable, like the weather. Physical science tells us that unstable development can be perfectly deterministic yet difficult, if not impossible, to follow by experiment, among other reasons because unstable evolution is functionally the same thing as cryptography. Thus the scientific resolution of the whole mystery might simply be that the genome instructs the system to go wild and generate a bag of tools and parts it might need to construct something interesting, and then sends a subsequent instruction to go out and play. Emergent self-organization then finishes the job.

Psilocybin changes brain connectivity.

Petri et al. show that "the brain's functional patterns undergoes a dramatic change post-psilocybin, characterized by the appearance of many transient structures of low stability and of a small number of persistent ones that are not observed in the case of placebo." A simple reading of their results is that the effect of psilocybin is to relax constraints on brain function, ascribing cognition a more flexible quality. This may account for the transient synesthesia reported by many with psilocybin, hearing colors or seeing sounds.

Simplified visualization of the persistence homological scaffolds. a.) placebo baseline b.) with psilocybin

A review of the work by Bone notes:

When ingested, psilocybin metabolizes to psilocin, which resembles the chemical structure of serotonin — a neurotransmitter that regulates mood, appetite, sleep, cognitive functions like memory and learning and feelings of pleasure. Psilocin may simulate serotonin, and stimulate serotonin receptors in the brain...psilocybin therapy could be useful in treating disorders like depression, in which people get stuck in a spiral of negative thoughts. Like electric shock therapy, psilocybin might act like tripping a circuit breaker or rebooting your computer.

The Bone review also give links to studies on psilocybin effects on other psychological syndromes.

We search for meaning at the start of each chronological decade.

Recent soulful introspection by my husband, who moves from age 59 to 60 in late December, motivates me to point to this study by Alter and Hershfield, who perform six cross cultural studies to show the same thing I recall from my own experience when I was 49, 59 and 69: that people renew their search for meaning as they face a new decade. The studies aggregated data available on several major survey data websites relevant to values, search for meaning, extramarital affairs, suicide rates, and marathon sign-ups and performance. The summary from their significance and abstract sections:

...people audit the meaningfulness of their lives as they approach a new decade in chronological age, further suggesting that people across dozens of countries and cultures are prone to making significant decisions as they approach each new decade...Six studies show that adults undertake a search for existential meaning when they approach a new decade in age (e.g., at ages 29, 39, 49, etc.) or imagine entering a new epoch, which leads them to behave in ways that suggest an ongoing or failed search for meaning (e.g., by exercising more vigorously, seeking extramarital affairs, or choosing to end their lives).

Banking - a culture of dishonesty

Kelland points to work by Cohn et al., who have studied bank workers and other professionals in experiments in which they won more money if they cheated. They found that bankers were more dishonest when they were made particularly aware of their professional role. Employees in other sectors - manufacturing, telecoms, pharmaceuticals - did not show more dishonest behavior when their professional identity or banking-related information was emphasized. Honesty was tested by having participants toss a coin 10 times, unobserved, and report the results, knowing whether heads or tails would yield a $20 reward. They were told they could keep their winnings if they were more than or equal to those of a randomly selected subject from a pilot study. The control group reported ~50% winning tosses, and bankers who banking identity had been emphasized to them reported ~58% as wins. The authors conclude that the prevailing business culture in the banking industry weakens and undermines the honesty norm, suggesting a need for measures that re-establish an honest culture.

The ecology of religious beliefs

Botero et al. do a fascinating survey of 583 societies to show that religions with moralizing high gods that promote cooperation between humans are more prevalent among societies that inhabit poorer environments and are more prone to ecological duress:

Although ecological forces are known to shape the expression of sociality across a broad range of biological taxa, their role in shaping human behavior is currently disputed. Both comparative and experimental evidence indicate that beliefs in moralizing high gods promote cooperation among humans, a behavioral attribute known to correlate with environmental harshness in nonhuman animals. Here we combine fine-grained bioclimatic data with the latest statistical tools from ecology and the social sciences to evaluate the potential effects of environmental forces, language history, and culture on the global distribution of belief in moralizing high gods (n = 583 societies). After simultaneously accounting for potential nonindependence among societies because of shared ancestry and cultural diffusion, we find that these beliefs are more prevalent among societies that inhabit poorer environments and are more prone to ecological duress. In addition, we find that these beliefs are more likely in politically complex societies that recognize rights to movable property. Overall, our multimodel inference approach predicts the global distribution of beliefs in moralizing high gods with an accuracy of 91%, and estimates the relative importance of different potential mechanisms by which this spatial pattern may have arisen. The emerging picture is neither one of pure cultural transmission nor of simple ecological determinism, but rather a complex mixture of social, cultural, and environmental influences. Our methods and findings provide a blueprint for how the increasing wealth of ecological, linguistic, and historical data can be leveraged to understand the forces that have shaped the behavior of our own species.

E.O. Wilson and "The Meaning of Human Existence"

I've just read through E.O. Wilson's new and admirably brief and terse book (~200 pages) that gives a distillation of his previous writings on our human condition, and in particular the relationship between the sciences and the humanities. I pass on here a few clips from the first section of the book, but start with his statement in the final section where he gives his version of what the meaning of human existence is. (It conforms to my own opinion that experiencing ourselves as part of biological evolution suffices as a complete spiritual path.)

So, what is the meaning of human existence? I suggest that it is the epic of the species, begun in biological evolution and prehistory, passed into recorded history, and urgently now, day by day, faster and faster into the indefinite future, it is also what we will choose to become.

From Section I "The Reason We Exist":

In ordinary usage the word “meaning” implies intention, intention implies design, and design implies a designer. Any entity, any process, or definition of any word itself is put into play as a result of an intended consequence in the mind of the designer. This is the heart of the philosophical worldview of organized religions, and in particular their creation stories. Humanity, it assumes, exists for a purpose. Individuals have a purpose in being on Earth. Both humanity and individuals have meaning.

There is a second, broader way the word “meaning” is used and a very different worldview implied. It is that the accidents of history, not the intentions of a designer, are the source of meaning. There is no advance design, but instead overlapping networks of physical cause and effect. The unfolding of history is obedient only to the general laws of the Universe. Each event is random yet alters the probability of later events. During organic evolution, for example, the origin of one adaptation by natural selection makes the origin of certain other adaptations more likely. This concept of meaning, insofar as it illuminates humanity and the rest of life, is the worldview of science.

We are about to abandon natural selection , the process that created us, in order to direct our own evolution by volitional selection— the process of redesigning our biology and human nature as we wish them to be.

Humanity, I argue, arose entirely on its own through an accumulated series of events during evolution. We are not predestined to reach any goal, nor are we answerable to any power but our own. Only wisdom based on self-understanding, not piety, will save us.

...the grand master is multilevel selection . This formulation recognizes two levels at which natural selection operates: individual selection based on competition and cooperation among members of the same group, and group selection, which arises from competition and cooperation between groups. Group selection can occur through violent conflict or by competition between groups in the finding and harvesting of new resources.

Probably ... during the habiline period, a conflict ensued between individual-level selection, with individuals competing with other individuals in the same group, on the one side, and group-level selection , with competition among groups, on the other. The latter force promoted altruism and cooperation among all the group members. It led to innate group-wide morality and a sense of conscience and honor. The competition between the two forces can be succinctly expressed as follows: Within groups selfish individuals beat altruistic individuals, but groups of altruists beat groups of selfish individuals. Or, risking oversimplification, individual selection promoted sin, while group selection promoted virtue.

So it came to pass that humans are forever conflicted by their prehistory of multilevel selection. They are suspended in unstable and constantly changing positions between the two extreme forces that created us. We are unlikely to yield completely to either force as the ideal solution to our social and political turmoil. To give in completely to the instinctual urgings born from individual selection would be to dissolve society. At the opposite extreme, to surrender to the urgings from group selection would turn us into angelic robots— the outsized equivalents of ants.

Varieties of poverty - money, time, and bandwidth

We usually think of money when the word poverty is employed. But, just like getting caught in a high interest loan cycle, we can get in trouble by borrowing too much time, having a list of deadlines we continually fall behind on, forcing us to focus on the immediate next deadline, just like the next loan payment due. Konnikova points to the consequence of situations like these, bandwidth poverty:

If I’m focused on the immediate deadline, I don’t have the cognitive resources to spend on mundane tasks or later deadlines. If I’m short on money, I can’t stop thinking about today’s expenses — never mind those in the future. In both cases, I end up making decisions that leave me worse off because I lack the ability to focus properly on anything other than what’s staring me in the face right now, at this exact moment... 

She quotes a Princeton psychologist:

Under scarcity, you devote a lot of resources to the thing you’re lacking...When people are juggling time, they are doing something very similar to when they’re juggling finances. It is all scarcity juggling. You borrow from tomorrow, and tomorrow you have less time than you have today, and tomorrow becomes more costly. It’s a very costly loan.

Further clips:

When you get overloaded and you feel this deadline is overwhelming, you can say, I’ll take a vacation, I’ll focus on work-life balance...Poor people can’t say, ‘I’ll take a vacation from being poor.’ It’s the same mental process, but a different feedback loop.The poor are under a deadline that never lifts, pressure that can’t be relieved. If I am poor, I work or I churn until decisions like buying lottery tickets begin to seem like attractive alternatives. I lack the time to calculate the odds and think of alternative uses for my money...the mental bandwidth tax is powerful enough to make the overall problem run deeper. The poor... are so taxed they don’t even realize they have a problem...AND of course how much money you have affects how much time you have. If you keep busyness constant, the rich have it much easier...they can buy nannies and drivers and lawyers and the like. It’s easy to give yourself time if you have money.

If poverty is about time and mental bandwidth as well as money, how does this change how we combat its effects? When we think about programs for the poor, we don’t ever think, hey, let’s give them programs that don’t use a lot of bandwidth...Instead, we fault people for failing to sign up for programs that are ostensibly available, even though we don’t factor in the time and cognitive capacity they need to get past even the first step...Take something like the Fafsa” — the Free Application for Federal Student Aid — Why is pickup for the low-income families less than 30 percent? People are already overwhelmed, and you go and give them an incredibly complicated form...One study found that if you offer help with filling out the Fafsa form, pickup goes up significantly.

My iPad is masturbating!

As I have read the New York Times or Kindle Apps on my iPad over the past few weeks, the tablet has seemed to take on a mind of its own, opening articles or turning pages when I haven't touched it. Going by a techie store I am asked whether the screen has ever been broken and replaced, and indeed, this happened several months ago. It appears that if the job isn't done properly, or the screen is a poor quality one, it can start spontaneous touching or stroking in the absence of a human finger. To turn pages I am now gingerly stroking parts of the screen that don't seem to get its g-spots excited..... (I don't want to buy a new iPad because I am waiting for the larger one to come out, it will be more useful for displaying musical scores.)

The peripheral immune system and stress susceptibility.

Using a social stress model in mice, Hoades et al. find preexisting individual differences in the sensitivity of the peripheral immune system that predict and promote vulnerability to social stress. Finding that the emotional response to stress can be generated or blocked outside the brain suggest a new route for treating stress disorders, perhaps by controlling the peripheral level of the cytokine IL-6.

Significance

Depression and anxiety have been linked to increased inflammation. However, we do not know if inflammatory status predates onset of disease or whether it contributes to depression symptomatology. We report preexisting individual differences in the peripheral immune system that predict and promote stress susceptibility. Replacing a stress-naive animal’s peripheral immune system with that of a stressed animal increases susceptibility to social stress including repeated social defeat stress (RSDS) and witness defeat (a purely emotional form of social stress). Depleting the cytokine IL-6 from the whole body or just from leukocytes promotes resilience, as does sequestering IL-6 outside of the brain. These studies demonstrate that the emotional response to stress can be generated or blocked in the periphery, and offer a potential new form of treatment for stress disorders.

Abstract

Depression and anxiety disorders are associated with increased release of peripheral cytokines; however, their functional relevance remains unknown. Using a social stress model in mice, we find preexisting individual differences in the sensitivity of the peripheral immune system that predict and promote vulnerability to social stress. Cytokine profiles were obtained 20 min after the first social stress exposure. Of the cytokines regulated by stress, IL-6 was most highly up-regulated only in mice that ultimately developed a susceptible behavioral phenotype following a subsequent chronic stress, and levels remained elevated for at least 1 mo. We confirmed a similar elevation of serum IL-6 in two separate cohorts of patients with treatment-resistant major depressive disorder. Before any physical contact in mice, we observed individual differences in IL-6 levels from ex vivo stimulated leukocytes that predict susceptibility versus resilience to a subsequent stressor. To shift the sensitivity of the peripheral immune system to a pro- or antidepressant state, bone marrow (BM) chimeras were generated by transplanting hematopoietic progenitor cells from stress-susceptible mice releasing high IL-6 or from IL-6 knockout (IL-6−/−) mice. Stress-susceptible BM chimeras exhibited increased social avoidance behavior after exposure to either subthreshold repeated social defeat stress (RSDS) or a purely emotional stressor termed witness defeat. IL-6−/− BM chimeric and IL-6−/− mice, as well as those treated with a systemic IL-6 monoclonal antibody, were resilient to social stress. These data establish that preexisting differences in stress-responsive IL-6 release from BM-derived leukocytes functionally contribute to social stress-induced behavioral abnormalities.

Does exercise really make us smarter?

A NYTimes Well piece by Gretchen Reynolds points to an interesting study by Stothart et al., who decided to address a basic deficiency in most studies of the effects of aerobic training on cognition, they don't control for a possible placebo effect. If we expect to be smarter after training, our brains might just respond correspondingly. Stothart et al. found that people queried in an online survey expected a muscle stretching and toning program to have a greater effect on measures of thinking than a regular walking program. In actual experiments, stretching and toning regimens generally have been shown to have little if any impact on people’s cognitive skills. Walking, on the other hand, seems to substantially improve thinking ability. This lack of correlation between expectations and actual outcome suggests that a placebo effect does not explain the improved cognition observed after exercise.

The usefulness of spite.

Angier reviews a number of studies suggesting that the evolution of human cooperation can be assisted by spite, a certain degree of "altruistic" punishment, when some individuals are willing to punish rule breakers even when the infraction does not directly affect them. From Forber and Smead:

The presence of apparently irrational fair play in the ultimatum game remains a focal point for studies in the evolution of social behaviour. We investigate the role of negative assortment in the evolution of fair play in the ultimatum game. Spite-social behaviour that inflicts harm with no direct benefit to the actor-can evolve when it is disproportionally directed at individuals playing different strategies. The introduction of negative assortment alters the dynamics in a way that increases the chance fairness evolves, but at a cost: spite also evolves. Fairness is usually linked to cooperation and prosocial behaviour, but this study shows that it may have evolutionary links to harmful antisocial behaviour.

And, from Marlowe et al.:

We analyse generosity, second-party ('spiteful') punishment (2PP), and third-party ('altruistic') punishment (3PP) in a cross-cultural experimental economics project. We show that smaller societies are less generous in the Dictator Game but no less prone to 2PP in the Ultimatum Game. We might assume people everywhere would be more willing to punish someone who hurt them directly (2PP) than someone who hurt an anonymous third person (3PP). While this is true of small societies, people in large societies are actually more likely to engage in 3PP than 2PP. Strong reciprocity, including generous offers and 3PP, exists mostly in large, complex societies that face numerous challenging collective action problems. We argue that 'spiteful' 2PP, motivated by the basic emotion of anger, is more universal than 3PP and sufficient to explain the origins of human cooperation.

Brain's inflammatory response may contribute to brain disorders.

This post is just a pointer to a press release from the Society for Neuroscience meetings in Washington, DC. It outlines several studies on the link between brain inflammation and the progression of many common brain illnesses and disorders, suggesting possible targets for future treatments.

In older people, moderate alcohol intake improves memory.

Articles like this work from Downer et al. make me worry less about the possible deleterious effects of the happy hour cocktail that is part of my daily ritual. Several studies have shown that light and moderate alcohol consumption during late life is associated with higher cognitive functioning among older adults and a decreased risk of dementia, and they now document relevant correlations with the volume of the hippocampus, which is important in memory. Their abstract, slightly edited:

This study utilized data from the Framingham Heart Study Offspring Cohort to examine the relationship between midlife and late-life alcohol consumption, cognitive functioning, and regional brain volumes among older adults without dementia or a history of abusing alcohol. The results from multiple linear regression models indicate that late life, but not midlife, alcohol consumption status is associated with episodic memory and hippocampal volume. Compared to late life abstainers, moderate consumers had larger hippocampal volume, and light consumers had higher episodic memory. The differences in episodic memory according to late life alcohol consumption status were no longer significant when hippocampal volume was included in the regression model (This suggests that the observed relationship between alcohol consumption and episodic memory and alcohol consumption during old age may be due to larger hippocampal volume.) The findings from this study provide new evidence that hippocampal volume may contribute to the observed differences in episodic memory among older adults and late life alcohol consumption status.

The authors note that findings from animal studies suggest that moderate alcohol consumption may contribute to preserved hippocampal volume by promoting the generation of new neurons in the hippocampus. In addition, exposing the brain to moderate amounts of alcohol may increase the release of acetylcholine and other neurotransmitters that are involved in cognitive functioning.