The Righteous Mind

I want to point to two reviews of Jonathan Haidt's new book, which has the title of this post. It brings exceptional clarity to the definition of contemporary liberals and conservatives, and argues that it is the liberals who are not getting the point. First, some clips from Kristof's comments:

Jonathan Haidt, a University of Virginia psychology professor, argues that, for liberals, morality is largely a matter of three values: caring for the weak, fairness and liberty. Conservatives share those concerns (although they think of fairness and liberty differently) and add three others: loyalty, respect for authority and sanctity...Those latter values bind groups together with a shared respect for symbols and institutions such as the flag or the military...This year’s Republican primaries have been a kaleidoscope of loyalty, authority and sanctity issues...Americans speak about values in six languages, from care to sanctity. Conservatives speak all six, but liberals are fluent in only three...Moral psychology can help to explain why the Democratic Party has had so much difficulty connecting with voters.

From Saletan's review:

Haidt argues that people are fundamentally intuitive, not rational. If you want to persuade others, you have to appeal to their sentiments...We were never designed to listen to reason. When you ask people moral questions, time their responses and scan their brains, their answers and brain activation patterns indicate that they reach conclusions quickly and produce reasons later only to justify what they’ve decided...The problem isn’t that people don’t reason. They do reason. But their arguments aim to support their conclusions, not yours. Reason doesn’t work like a judge or teacher, impartially weighing evidence or guiding us to wisdom. It works more like a lawyer or press secretary, justifying our acts and judgments to others...Haidt invokes an evolutionary hypothesis: We compete for social status, and the key advantage in this struggle is the ability to influence others. Reason, in this view, evolved to help us spin, not to help us learn. So if you want to change people’s minds, Haidt concludes, don’t appeal to their reason. Appeal to reason’s boss: the underlying moral intuitions whose conclusions reason defends.

We acquire morality the same way we acquire food preferences: we start with what we’re given. If it tastes good, we stick with it. If it doesn’t, we reject it. People accept God, authority and karma because these ideas suit their moral taste buds. Haidt points to research showing that people punish cheaters, accept many hierarchies and don’t support equal distribution of benefits when contributions are unequal...You don’t have to go abroad to see these ideas. You can find them in the Republican Party. Social conservatives see welfare and feminism as threats to responsibility and family stability. The Tea Party hates redistribution because it interferes with letting people reap what they earn. Faith, patriotism, valor, chastity, law and order — these Republican themes touch all six moral foundations, whereas Democrats, in Haidt’s analysis, focus almost entirely on care and fighting oppression. This is Haidt’s startling message to the left: When it comes to morality, conservatives are more broad-minded than liberals. They serve a more varied diet.

Is income inequality immoral? Should government favor religion? Can we tolerate cultures of female subjugation? And how far should we trust our instincts? Should people who find homosexuality repugnant overcome that reaction?..Haidt’s faith in moral taste receptors may not survive this scrutiny. Our taste for sanctity or authority, like our taste for sugar, could turn out to be a dangerous relic. But Haidt is right that we must learn what we have been, even if our nature is to transcend it.

Haidt's book references a number of experiments noted in MindBlog posts, on differences in the psychologies and autonomic nervous system reactivities of conservatives and liberals.

By the way, in this same vein, I might point to Chris Money's comments on his book "The Republican Brain," which he almost called "The Science of Truthiness," which asks why very intelligent Republicans deny scientific realities such as evolution and climate change.

Everything Is The Way It Is Because It Got That Way

An interesting summary of some core ideas in developmental psychology by Paul Bloom:

This aphorism is attributed to the biologist and classicist D'Arcy Thompson, and it's an elegant summary of how Thompson sought to explain the shapes of things, from jellyfish to sand dunes to elephant tusks....this insight applies to explanation more generally—all sciences are, to at least some extent, historical sciences. 

I think it's a perfect motto for my own field of developmental psychology. Every adult mind has two histories. There is evolution. Few would doubt that some of the most elegant and persuasive explanations in psychology appeal to the constructive process of natural selection. And there is development—how our minds unfold over time, the processes of maturation and learning. 

While evolutionary explanations work best for explaining what humans share, development can sometimes capture how we differ. This can be obvious: Nobody is surprised to hear that adults who are fluent in Korean have usually been exposed to Korean when they were children or that adults who practice Judaism have usually been raised as Jews. But other developmental explanations are rather interesting.

There is evidence that an adult's inability to see in stereo is due to poor vision during a critical period in childhood. Some have argued that the self-confidence of adult males is influenced by how young they were when they reached puberty (because of the boost in status caused by being bigger, even if temporarily, than their peers). It's been claimed that smarter adults are more likely to be firstborns (because later children find themselves in environments that are, on average, less intellectually sophisticated). Creative adults are more likely to be later-borns (because they were forced to find their own distinctive niches.) Romantic attachments in adults are influenced by their relationships as children with their parents. A man's pain-sensitivity later in life is influenced by whether or not he was circumcised as a baby.

With the exception of the stereo-vision example, I don't know if any of these explanations are true. But they are elegant and non-obvious, and some of them verge on beautiful.

Handedness affects the coding of affective information.

Interesting correlates from Brunyé et al.:

The body specificity hypothesis posits that the way in which people interact with the world affects their mental representation of information. For instance, right- versus left-handedness affects the mental representation of affective valence, with right-handers categorically associating good with rightward areas and bad with leftward areas, and left-handers doing the opposite. In two experiments we have tested whether this hypothesis can: extend to spatial memory, be measured in a continuous manner, be predicted by extent of handedness, and how the application of such a heuristic might vary as a function of informational specificity. A first experiment demonstrated systematic and continuous spatial location memory biases as a function of associated affective information; right-handed individuals misremembered positively- and negatively-valenced locations as further right and left, respectively, relative to their original locations. Left-handed individuals did the opposite, and in general those with stronger right- or left-handedness showed greater spatial memory biases. A second experiment tested whether participants would show similar effects when studying a map with high visual specificity (i.e., zoomed in); they did not. Overall we support the hypothesis that handedness affects the coding of affective information, and better specify the scope and nature of body-specific effects on spatial memory.

Emotion in Eastern and Western Music Mirrors Vocalization

Further interesting work from Purves and his colleagues:

In Western music, the major mode is typically used to convey excited, happy, bright or martial emotions, whereas the minor mode typically conveys subdued, sad or dark emotions. Recent studies indicate that the differences between these modes parallel differences between the prosodic and spectral characteristics of voiced speech sounds uttered in corresponding emotional states. Here we ask whether tonality and emotion are similarly linked in an Eastern musical tradition. The results show that the tonal relationships used to express positive/excited and negative/subdued emotions in classical South Indian music are much the same as those used in Western music. Moreover, tonal variations in the prosody of English and Tamil speech uttered in different emotional states are parallel to the tonal trends in music. These results are consistent with the hypothesis that the association between musical tonality and emotion is based on universal vocal characteristics of different affective states.

Eyes as location of the self.

Starmans and Bloom do an interesting nugget of work showing how children and adults see the eyes as the location of the self. In three experiments they:

...explore preschoolers’ and adults’ intuitions about the location of the self using a novel method that asks when an object is closet to a person. Children and adults judge objects near a person’s eyes to be closer to her than objects near other parts of her body. This holds even when considering an alien character whose eyes are located on its chest. Objects located near the eyes but out of sight are also judged to be close, suggesting that participants are not using what a person can see as a proxy for what is close to her. These findings suggest that children and adults intuitively think of the self as occupying a precise location within the body, at or near the eyes.

The importance of epigenetics in understanding nature/nurture interactions

I'm vaguely aware of the vast new field of epigenetics, defined in various ways, but all definitions are based in the central concept that environmental forces can affect gene behavior, either turning genes on or off. I thought this recent summary by Helen Fisher was a nice statement of the importance of this new field:

..two basic mechanisms are known: one involves molecules known as methyl-groups that latch on to DNA to suppress and silence gene expression; the other involves molecules known as acetyl-groups which activate and enhance gene expression...Moroccan Amazighs or Berbers, people with highly similar genetic profiles reside in three different environments: some roam the deserts as nomads; some farm the mountain slopes; some live in the towns and cities along the Moroccan coast. Depending on where they live, up to one-third of their genes are differentially expressed.

...Genes hold the instructions; epigenetic factors direct how those instructions are carried out. As we age, these epigenetic processes continue to modify and build who we are. Fifty-year-old twins, for example, show three times more epigenetic modifications than do three-year-old twins; and twins reared apart show more epigenetic alterations than those who grow up together. Genes are not destiny; but neither is the environment...some epigenetic instructions are passed from one generation to the next. Trans-generational epigenetic modifications are now documented in plants and fungi, and have been suggested in mice.

The 18^th century philosopher, John Locke, was convinced that the human mind is an empty slate upon which the environment inscribes personality. With equal self-assurance, others have been convinced that genes orchestrate our development, illnesses and life styles. Yet social scientists had failed for decades to explain the mechanisms governing behavioral variations between twins, family members and culture groups. And biological scientists had failed to pinpoint the genetic foundations of many mental illnesses and complex diseases. The central mechanism to explain these complex issues has been found...to me as an anthropologist long trying to take a middle road in a scientific discipline intractably immersed in nature-versus-nurture warfare, epigenetics is the missing link. 

Belief in and memory for an event can be independent constructs.

From Clark et al.:

Recent studies have shown that many people spontaneously report vivid memories of events that they do not believe to have occurred. In the present experiment we tested for the first time whether, after powerful false memories have been created, debriefing might leave behind nonbelieved memories for the fake events. In a first session participants imitated simple actions, and in Session two they saw doctored video-recordings containing clips that falsely suggested they had performed additional (fake) actions. As in earlier studies, this procedure created powerful false memories. Finally, participants were debriefed and told that specific actions in the video were not truly performed. Beliefs and memories for all critical actions were tested before and after the debriefing. Results showed that debriefing undermined participants' beliefs in fake actions, but left behind residual memory-like content. These results indicate that debriefing can leave behind vivid false memories which are no longer believed, and thus we demonstrate for the first time that the memory of an event can be experimentally dissociated from the belief in the event's occurrence. These results also confirm that belief in and memory for an event can be independently-occurring constructs.

Beyond mirror neurons - the neuroscience of real social encounters

A recent draft manuscript by Schilbach et al (PDF) has a nice summary of what a second-person neuroscience would be like, moving beyond spectator theories of knowledge:

Two neuroanatomically distinct large-scale networks have gained center stage as the neural substrates of social cognition: the so-called “mirror neuron system” and the “mentalizing network” . both of these paradigms are investigating actual, but limited domains of social cognition. Both are, in effect, committed to spectator theories of knowledge. They have focused on the use of isolation paradigms in which participants are required to merely observe others or think about their mental states rather than participate in social interaction with them. Consequently, it has remained unclear whether and how activity in the large-scale neural networks described above is modulated by the degree to which a person does or does not feel actively involved in an ongoing interaction and whether the networks might subserve complementary or mutually exclusive roles in this case

The article outlines work from his and other laboratories on brain imaging done during real time human interactions, noting in particular a ground-breaking study by Saito et al., who have devised a setup in which they not only use hyper-scanning, but also allow participants to interact in real-time by exchanging gaze behavior. Two MRI scanners were equipped with infrared eyetracking systems and video cameras. A live video image of the respective interaction partner’s face could be broadcast into the respective other scanner to generate a mediated face-to-face situation.

Here is the summary from Saito et al.:

Eye contact provides a communicative link between humans, prompting joint attention. As spontaneous brain activity might have an important role in the coordination of neuronal processing within the brain, their inter-subject synchronization might occur during eye contact. To test this, we conducted simultaneous functional MRI in pairs of adults. Eye contact was maintained at baseline while the subjects engaged in real-time gaze exchange in a joint attention task. Averted gaze activated the bilateral occipital pole extending to the right posterior superior temporal sulcus, the dorso-medial prefrontal cortex, and the bilateral inferior frontal gyrus. Following a partner’s gaze toward an object activated the left intraparietal sulcus. After all the task-related effects were modeled out, inter-individual correlation analysis of residual time-courses was performed. Paired subjects showed more prominent correlations than non-paired subjects in the right inferior frontal gyrus, suggesting that this region is involved in sharing intention during eye contact that provides the context for joint attention.

Our brains lengthen perceptions of biological motions.

Wang and Jiang show that the inherent temporal properties of life motion signals spontaneously engage more intricate brain processings compared with those of nonbiological motions, and consequentially induce subjective time dilation. They thus suggest that the temporal encoding of biological motions relies upon a specialized brain mechanism intrinsically tuned to life motion signals irrespective of their configurations, and is essentially an automatic process operating without a person's awareness.

Point-light biological motions, conveying various different attributes of biological entities, have particular spatiotemporal properties that enable them to be processed with remarkable efficiency in the human visual system. Here we demonstrate that such signals automatically lengthen their perceived temporal duration independent of global configuration and without observers’ subjective awareness of their biological nature. By using a duration discrimination paradigm, we showed that an upright biological motion sequence was perceived significantly longer than an inverted but otherwise identical sequence of the same duration. Furthermore, this temporal dilation effect could be extended to spatially scrambled biological motion signals, whose global configurations were completely disrupted, regardless of whether observers were aware of the nature of the stimuli. However, such an effect completely disappeared when critical biological characteristics were removed. Taken together, our findings suggest a special mechanism of time perception tuned to life motion signals and shed new light on the temporal encoding of biological motion.

Meditation practice increases brain size and gyrification

Luders and her colleagues (PDF here) have examined 44 people — 22 control subjects and 22 who had practiced various forms of meditation, including Zazen, Samatha and Vipassana, among others. The amount of time they had practiced ranged from five to 46 years, with an average of 24 years. More than half of all the meditators said that deep concentration was an essential part of their practice, and most meditated between 10 and 90 minutes every day. The MRI measurements found significantly larger cerebral measurements in meditators compared with controls: larger volumes of the right hippocampus and increased gray matter in the right orbito-frontal cortex, the right thalamus and the left inferior temporal lobe. Increases in the left and right anterior dorsal insula - which is a hub for internal autonomic, affective, and cognitive integration - were most pronounced. There were no regions where controls had significantly larger volumes or more gray matter than meditators. The enlarged brain areas are linked to emotions, making one wonder whether this reflects the increased 'emotional muscles' of meditators,i.e. their ability to regulate their emotions.

 Cortical Surface Shown is the lateral view of the right cortical surface. The red circle indicates where the maximum effect occurred. Top: Larger gyrification in 50 long-term meditators compared to 50 well-matched controls. Bottom: Positive correlations between gyrification and the number of meditation years within the 50 meditators. (Credit: Image courtesy of University of California - Los Angeles)

Serotonin and reaction to unfairness.

How should one deal with line cutters? Or, more generally, what would you do if you faced unfair or wrong behavior? Studies have shown that machiavellian individuals accept unfair offers more often in ultimatum games (UG), using realism and opportunism to maximize their self-interest. 5-HT (serotonin) transmission, for which the dorsal raphe nucleus (DRN) is a major source, is important in brain regions such as the dorsal lateral prefrontal cortex that are recruited for this kind of cognitive control. Honest and trustful persons who cannot easily separate themselves from moral precepts tend to adhere to a norm of fairness and thus show lower tolerance of unfairness. Takahashi et al. have now used positron emission tomography to directly measure 5-HT transporters (5-HTT) and 5-HT1A receptors and find that low 5-HTT in the DRN is associated with straightforwardness and trust personality traits and predicts higher rejection rates of unfair offers in the ultimatum game. Here is their abstract:

How does one deal with unfair behaviors? This subject has long been investigated by various disciplines including philosophy, psychology, economics, and biology. However, our reactions to unfairness differ from one individual to another. Experimental economics studies using the ultimatum game (UG), in which players must decide whether to accept or reject fair or unfair offers, have also shown that there are substantial individual differences in reaction to unfairness. However, little is known about psychological as well as neurobiological mechanisms of this observation. We combined a molecular imaging technique, an economics game, and a personality inventory to elucidate the neurobiological mechanism of heterogeneous reactions to unfairness. Contrary to the common belief that aggressive personalities (impulsivity or hostility) are related to the high rejection rate of unfair offers in UG, we found that individuals with apparently peaceful personalities (straightforwardness and trust) rejected more often and were engaged in personally costly forms of retaliation. Furthermore, individuals with a low level of serotonin transporters in the dorsal raphe nucleus (DRN) are honest and trustful, and thus cannot tolerate unfairness, being candid in expressing their frustrations. In other words, higher central serotonin transmission might allow us to behave adroitly and opportunistically, being good at playing games while pursuing self-interest. We provide unique neurobiological evidence to account for individual differences of reaction to unfairness.

Correlation between rejection rate of unfair offers in UG and 5-HTT binding in DRN. (A) SPM image showing regions of negative correlation between rejection rate of unfair offers and 5-HTT binding in DRN. (B) Plots and regression line of correlation between rejection rate of unfair offers and 5-HTT binding in DRN (R = −0.50, P = 0.026). Dashed lines are 95% confidence interval boundaries.

Elegance of our brain lies in its inelegance.

I want to pass on this nice brief essay by David Eagleman:

For centuries, neuroscience attempted to neatly assign labels to the various parts of the brain: this is the area for language, this one for morality, this for tool use, color detection, face recognition, and so on. This search for an orderly brain map started off as a viable endeavor, but turned out to be misguided.

The deep and beautiful trick of the brain is more interesting: it possesses multiple, overlapping ways of dealing with the world. It is a machine built of conflicting parts. It is a representative democracy that functions by competition among parties who all believe they know the right way to solve the problem.

As a result, we can get mad at ourselves, argue with ourselves, curse at ourselves and contract with ourselves. We can feel conflicted. These sorts of neural battles lie behind marital infidelity, relapses into addiction, cheating on diets, breaking of New Year's resolutions—all situations in which some parts of a person want one thing and other parts another.

These are things which modern machines simply do not do. Your car cannot be conflicted about which way to turn: it has one steering wheel commanded by only one driver, and it follows directions without complaint. Brains, on the other hand, can be of two minds, and often many more. We don't know whether to turn toward the cake or away from it, because there are several sets of hands on the steering wheel of behavior.

Take memory. Under normal circumstances, memories of daily events are consolidated by an area of the brain called the hippocampus. But in frightening situations—such as a car accident or a robbery—another area, the amygdala, also lays down memories along an independent, secondary memory track. Amygdala memories have a different quality to them: they are difficult to erase and they can return in "flash-bulb" fashion—a common description of rape victims and war veterans. In other words, there is more than one way to lay down memory. We're not talking about memories of different events, but different memories of the same event. The unfolding story appears to be that there may be even more than two factions involved, all writing down information and later competing to tell the story. The unity of memory is an illusion.

And consider the different systems involved in decision making: some are fast, automatic and below the surface of conscious awareness; others are slow, cognitive, and conscious. And there's no reason to assume there are only two systems; there may well be a spectrum. Some networks in the brain are implicated in long-term decisions, others in short-term impulses (and there may be a fleet of medium-term biases as well).

Attention, also, has also recently come to be understood as the end result of multiple, competing networks, some for focused, dedicated attention to a specific task, and others for monitoring broadly (vigilance). They are always locked in competition to steer the actions of the organism.

Even basic sensory functions—like the detection of motion—appear now to have been reinvented multiple times by evolution. This provides the perfect substrate for a neural democracy.

On a larger anatomical scale, the two hemispheres of the brain, left and right, can be understood as overlapping systems that compete. We know this from patients whose hemispheres are disconnected: they essentially function with two independent brains. For example, put a pencil in each hand, and they can simultaneously draw incompatible figures such as a circle and a triangle. The two hemispheres function differently in the domains of language, abstract thinking, story construction, inference, memory, gambling strategies, and so on. The two halves constitute a team of rivals: agents with the same goals but slightly different ways of going about it.

To my mind, this elegant solution to the mysteries of the brain should change the goal for aspiring neuroscientists. Instead of spending years advocating for one's favorite solution, the mission should evolve into elucidating the different overlapping solutions: how they compete, how the union is held together, and what happens when things fall apart.
Part of the importance of discovering elegant solutions is capitalizing on them. The neural democracy model may be just the thing to dislodge artificial intelligence. We human programmers still approach a problem by assuming there's a best way to solve it, or that there's a way it should be solved. But evolution does not solve a problem and then check it off the list. Instead, it ceaselessly reinvents programs, each with overlapping and competing approaches. The lesson is to abandon the question "what's the most clever way to solve that problem?" in favor of "are there multiple, overlapping ways to solve that problem?" This will be the starting point in ushering in a fruitful new age of elegantly inelegant computational devices.

Cognitive enhancement is in our futures.

I want to point to three articles on brain enhancement that have accumulated in my queue of potential items for posting:

Benedict Carey discusses work showing that deep brain stimulation delivered through electrodes inserted into the brains of epilepsy patients being prepared for surgery sharply improved performance on a virtual driving game that tests spatial memory, the neural mapping ability that allows people to navigate a new city without a GPS:

Ross Andersen does an article in The Atlantic that describes ethical debates that have risen over the use of transcranial direct current stimulation (TDCS) to improve cognition in human beings.

Recent years have seen some encouraging, if preliminary, lab results involving TDCS, a deep brain stimulation technique that uses electrodes placed outside the head to direct tiny painless currents across the brain. The currents are thought to increase neuroplasticity, making it easier for neurons to fire and form the connections that enable learning. There are signs that the technology could improve language acumen, math ability, and even memory.

Finally in PloS Biology Knafo et al. note that a pharmacological cognitive enhancer that improves spatial learning and memory (in rats) by enhancing synaptic transmission in the hippocampus.

The debate over the evolution of altruism.

Jonah Lehrer does a fascinating article in the March 5 issue of The New Yorker titled "Kind and Kind - a fight about the genetics of altruism". He gives the history of that debate starting by describing the work of William Hamilton and his successors, but centers on the contributions of E.O. Wilson. The last few paragraphs of Lehrer's article, which outline Wilson's current views, are a nice summary that I want to pass on here:

Wilson's current explanation for altruism has returned to a hypothesis first proposed by Darwin.. that human generosity might have evolved as an emergent property not of the individual but of the group…While acts of altruism can be costly for the individual, Darwin argued that they helped sustain the colony, which made individuals within the colony more likely to survive.

The idea is know as group selection, and it's an explanation that most evolutionary biologists now dismiss [inserted note: with the exception of David Sloan Wilson, not mentioned by Lehrer, but whose work is referenced in about 6 mindblog posts.], because the advantages of generosity are much less tangible than the benefits of selfishness. A tribe full of nice guys would be easy prey for a cheater, who would quickly spread his genes through the population. But Wilson believes that it may hold the key to understanding altruism. To make his case, he cites recent studies of "cooperating" microbes, plants, and even female lions. In all these studies, many of which have been conducted in the controlled conditions of the lab, clumps of cooperators thrive and replicate, while selfish groups wither and die. In a 2007 paper that he co-authored, he summarizes his new view in three terse sentences: "selfishness beats altruism within groups. Altruistic groups beat selfish groups. Everything else is commentary."

Wilson's larger point is that, to the extent that altruism exists, is isn't an illusion. Instead, goodness might actually be an adaptive trait, allowing more cooperative groups to outcompete their conniving cousins. In a field defined by the cruel logic of natural selection, group selection appears to be the rare hint of virtue, the one biological force pushing back against the obvious advantages of greed and deceit. "I see human nature as hung in the balance between these two extremes," Wilson says. "If our behavior was driven entirely by group selection, then we'd be robotic cooperators, like ants. But, if individual-level selection was the only thing that mattered, then we'd be entirely selfish. What makes us human is that our history has been shaped by both forces. We're stuck in between."

Why humans made it, and chimps didn’t

Fascinating work on the comparative cognitive and social behavior of humans and chimpanzees continues to pour out, highlighting behaviors that made us human. Yamamoto et al. show that Chimpanzees can understand conspecifics’ goals and demonstrate cognitively advanced targeted helping as long as they are able to visually evaluate their conspecifics’ predicament. However, they will seldom help others without direct request for help. And, Dean et al. compare higher-level problem solving behaviors in Capuchin Monkeys, Chimpanzees, and human infants, finding that a package of sociocognitive processes are found only in humans:

The remarkable ecological and demographic success of humanity is largely attributed to our capacity for cumulative culture, with knowledge and technology accumulating over time, yet the social and cognitive capabilities that have enabled cumulative culture remain unclear. In a comparative study of sequential problem solving, we provided groups of capuchin monkeys, chimpanzees, and children with an experimental puzzlebox that could be solved in three stages to retrieve rewards of increasing desirability. The success of the children, but not of the chimpanzees or capuchins, in reaching higher-level solutions was strongly associated with a package of sociocognitive processes—including teaching through verbal instruction, imitation, and prosociality—that were observed only in the children and covaried with performance.

Recurring patterns in music from Bach to Scott Joplin

More amazing stuff from Daniel Levitan on music...first an except from the introduction to his latest paper in PNAS:

Musical behaviors—singing, dancing, and playing instruments—date back to Neanderthals, and have been a part of every human culture as far back as we know. People experience great enjoyment and pleasure from music, and music theorists have argued that this enjoyment stems in part from the structural features of music, such as the generation and violation of expectations... Mathematics has often been used to characterize, model, and understand music, from Schenkerian analysis to neural topography; and geometric models of tonality. One particular mathematical relation that has received attention in music is the 1/f distribution, which Mandelbrot termed “fractal.” 1/f distributions have been found to be a key feature of a number of natural and sensory phenomena. Analyzing the frequency of several natural disasters, including earthquakes, landslides, floods, and terrestrial meteor impacts,  reveals an inverse log-log linear (fractal) relation between the frequency and the intensity of the events.

Here is the abstract:

Much of our enjoyment of music comes from its balance of predictability and surprise. Musical pitch fluctuations follow a 1/f power law that precisely achieves this balance. Musical rhythms, especially those of Western classical music, are considered highly regular and predictable, and this predictability has been hypothesized to underlie rhythm's contribution to our enjoyment of music. Are musical rhythms indeed entirely predictable and how do they vary with genre and composer? To answer this question, we analyzed the rhythm spectra of 1,788 movements from 558 compositions of Western classical music. We found that an overwhelming majority of rhythms obeyed a 1/f^β power law across 16 subgenres and 40 composers, with β ranging from ∼0.5–1. Notably, classical composers, whose compositions are known to exhibit nearly identical 1/f pitch spectra, demonstrated distinctive 1/f rhythm spectra: Beethoven's rhythms were among the most predictable, and Mozart's among the least. Our finding of the ubiquity of 1/f rhythm spectra in compositions spanning nearly four centuries demonstrates that, as with musical pitch, musical rhythms also exhibit a balance of predictability and surprise that could contribute in a fundamental way to our aesthetic experience of music. Although music compositions are intended to be performed, the fact that the notated rhythms follow a 1/f spectrum indicates that such structure is no mere artifact of performance or perception, but rather, exists within the written composition before the music is performed. Furthermore, composers systematically manipulate (consciously or otherwise) the predictability in 1/f rhythms to give their compositions unique identities. 

The rich behaving badly

No big surprise, I guess, but here is a gem from Piff et al. that shows in a variety of different experimental settings that higher social class predicts increased unethical behavior. The authors agree with Plato and Aristotle, who deemed greed to be at the root of personal immorality.

Seven studies using experimental and naturalistic methods reveal that upper-class individuals behave more unethically than lower-class individuals. In studies 1 and 2, upper-class individuals were more likely to break the law while driving, relative to lower-class individuals. In follow-up laboratory studies, upper-class individuals were more likely to exhibit unethical decision-making tendencies (study 3), take valued goods from others (study 4), lie in a negotiation (study 5), cheat to increase their chances of winning a prize (study 6), and endorse unethical behavior at work (study 7) than were lower-class individuals. Mediator and moderator data demonstrated that upper-class individuals’ unethical tendencies are accounted for, in part, by their more favorable attitudes toward greed.

Some details on the first four studies: Studies 1 and 2 were naturalistic field studies that used observers’ codes of vehicle status (make, age, and appearance,known to be reliable indicators of a person’s social rank and wealth) to index drivers’ social class. Observers stood near the intersection, coded the status of approaching vehicles, and recorded whether the driver cut off other vehicles by crossing the intersection before waiting their turn, a behavior that defies the California Vehicle Code. In study 3 participants who reported their social class using the MacArthur scale of subjective socioeconomic status read eight different scenarios that implicated an actor in unrightfully taking or benefiting from something, and reported the likelihood that they would engage in the behavior described. In study 4 participants were primed to activate higher or lower social-class mindsets. The experimenter then presented participants with a jar of individually wrapped candies, ostensibly for children in a nearby laboratory, but informed them that they could take some if they wanted. This task was adapted from prior research on entitlement, and served as our measure of unethical behavior because taking candy would reduce the amount that would otherwise be given to children. Participants completed unrelated tasks and then reported the number of candies they had taken.

Our brain connectivity predicts perceptual task performance.

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

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

Childhood maltreatment reduces brain volume.

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

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

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

Dim minds and dark attitudes.

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

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