How to qualify as a social partner.

Most theoretical models for human social interactions explore relatively simple scenarios to allow for analytical solutions. Rockenbacha and Milinski have now devised a more sophisticated social-dilemma game that come closer to modeling real world interactions. Here is how they pose the issue:

What is the benefit of watching someone? Observing a person's behavior in a social dilemma may provide information about her qualities as a social partner for potential collaboration in the future: Does she contribute to a public good? Does she punish free riders? Does she reward contributors? Do I want to collaborate with her? Direct observation is more reliable than trusting gossip. Being watched, however, is not neutral: An individual's behavior may change in the presence of an observer (the “audience effect”), and the observed may be tempted to behave as expected to manage her reputation. Watchful eyes may induce altruistic behavior in the observed. Even a mechanistic origin of recognizing watchful eyes in the brain has been described as cortical orienting circuits that mediate nuanced and context-dependent social attention. However, watching also may induce an “arms race” of signals between observers and the observed. The observer should take into account that the behavior of the observed may change in response to observation and therefore should conceal her watching; the observed should be very alert to faint signals of being watched but should avoid any sign of having recognized that watching is occurring. The interaction between observing and being observed has implications for the large body of recent research on human altruism. Especially when a conflict of interest exists between observers and observed, they may use a rich toolbox of sophisticated strategies both to manipulate signals and to uncover manipulations.

The authors observe that in deciding on social partners observed cooperativeness is decisive, and severe punishment is hidden. Here is their abstract:

Conflicts of interest between the community and its members are at the core of human social dilemmas. If observed selfishness has future costs, individuals may hide selfish acts but display altruistic ones, and peers aim at identifying the most selfish persons to avoid them as future social partners. An interaction involving hiding and seeking information may be inevitable. We staged an experimental social-dilemma game in which actors could pay to conceal information about their contribution, giving, and punishing decisions from an observer who selects her future social partners from the actors. The observer could pay to conceal her observation of the actors. We found sophisticated dynamic strategies on either side. Actors hide their severe punishment and low contributions but display high contributions. Observers select high contributors as social partners; remarkably, punishment behavior seems irrelevant for qualifying as a social partner. That actors nonetheless pay to conceal their severe punishment adds a further puzzle to the role of punishment in human social behavior. Competition between hiding and seeking information about social behavior may be even more relevant and elaborate in the real world but usually is hidden from our eyes.

Improve your motor memory!

Here is an bit of work Zhang et al. on consolidation of motor memory that more clearly confirms what I know from my own experience of trying to learn a new piano piece. If I watch a video of myself playing a passage where I have difficulty with the notes, I remember the notes better than if I actually play them several times - the actual movement appears to get in the way of forming a motor memory of it. (The same effects can happen with mentally visualizing the movements, a trick known to many athletes and performers).

Practicing a motor task can induce neuroplastic changes in the human primary motor cortex (M1) that are subsequently consolidated, leading to a stable memory trace. Currently, little is known whether early consolidation, tested several minutes after skill acquisition, can be improved by behavioral interventions. Here we test whether movement observation, known to evoke similar neural responses in M1 as movement execution, can benefit the early consolidation of new motor memories. We show that observing the same type of movement as that previously practiced (congruent movement stimuli) substantially improves performance on a retention test 30 min after training compared with observing either an incongruent movement type or control stimuli not showing biological motion. Differences in retention following observation of congruent, incongruent, and control stimuli were not found when observed 24 h after initial training and neural evidence further confirmed that, unlike motor practice, movement observation alone did not induce plastic changes in the motor cortex. This time-specific effect is critical to conclude that movement observation of congruent stimuli interacts with training-induced neuroplasticity and enhances early consolidation of motor memories. Our findings are not only of theoretical relevance for memory research, but also have great potential for application in clinical settings when neuroplasticity needs to be maximized.

MindBlog back in Fort Lauderdale, FL

I'm tired from three days driving with my two Abyssinian cats from Madison WI to my condo in Fort Lauderdale, FL (posts have been coming out on autopilot)... The picture is my work pod, just set up in my office here.

Resonating with others: changes in motor cortex

Individual concepts of self, or self-construals, vary across cultures. In collectivist cultures such as Japan, individuals adopt an interdependent self-construal in which relationships with others are central, whereas in individualist cultures like the U.S., a more independent self-construal with less emphasis on relationships with others is more likely to be adopted. Obhi et al note some interesting brain correlates of shifting self construal from interdependent to independent. Their data suggest that motor resonance mediates nonconscious mimicry in social settings:

“Self-construal” refers to how individuals view and make meaning of the self, and at least two subtypes have been identified. Interdependent self-construal is a view of the self that includes relationships with others, and independent self-construal is a view of the self that does not include relations with others. It has been suggested that priming these two types of self-construal affects the cognitive processing style that an individual adopts, especially with regard to context sensitivity. Specifically, an interdependent self-construal is thought to promote attention to others and social context to a greater degree than an independent self-construal. To investigate this assertion, we elicited motor-evoked potentials with transcranial magnetic stimulation during an action observation task in which human participants were presented with either interdependent or independent self-construal prime words. Priming interdependent self-construal increased motor cortical output whereas priming independent self-construal did not, compared with a no-priming baseline condition. These effects, likely mediated by changes in the mirror system, essentially tune the individual to, or shield the individual from, social input. Interestingly, the pattern of these self-construal-induced changes in the motor system corroborates with previously observed self-construal effects on overt behavioral mimicry in social settings, and as such, our results provide strong evidence that motor resonance likely mediates nonconscious mimicry in social settings. Finally, these self-construal effects may lead to the development of interventions for disorders of deficient or excessive social influence, like certain autism spectrum and compulsive imitative disorders.

Brain areas that increase in size with social network size.

The number of individuals that a single person can keep close track of is generally taken to be roughly 150 ("Dunbar's number), which would be the size of a tightly knit social grouping. This estimate derives from a comparative analysis of primate neuroanatomy and behavior and has led to the corollary that the magnitude of the number is determined by the size of the neocortex. Sallet et al. have now made the interesting observation that the relationship between brain size and social group magnitude can be plastic, finding that that housing macaque monkeys in larger groups increases the amount of gray matter in several parts of the brain involved in social cognition. We know from many studies that requiring increased skill in perceptual or motor abilities correlates with increases in sensory and motor areas of the brain, so it makes sense that requiring exercise of "social muscles" increases the grey matter volume in temporal and frontal lobes areas that have been identified as potential contributors to social success in both humans and monkeys. Here is the abstract:

It has been suggested that variation in brain structure correlates with the sizes of individuals’ social networks. Whether variation in social network size causes variation in brain structure, however, is unknown. To address this question, we neuroimaged 23 monkeys that had been living in social groups set to different sizes. Subject comparison revealed that living in larger groups caused increases in gray matter in mid-superior temporal sulcus and rostral prefrontal cortex and increased coupling of activity in frontal and temporal cortex. Social network size, therefore, contributes to changes both in brain structure and function. The changes have potential implications for an animal’s success in a social context; gray matter differences in similar areas were also correlated with each animal’s dominance within its social network.

Synaptic switch to social status in medial prefrontal cortex.

Wang et al. have determined the social hierarchy within groups of mice by using multiple behavioral tests and find that the social hierarchical status of an individual correlates with the synaptic strength in medial prefrontal cortical neurons. Furthermore, the hierarchical status of mice can be changed from dominant to subordinate, or vice versa, by manipulating the strength of synapses in the medial prefrontal cortex. Here is the abstract, followed by a figure from the review by Maroteaux and Mamell:

Dominance hierarchy has a profound impact on animals’ survival, health, and reproductive success, but its neural circuit mechanism is virtually unknown. We found that dominance ranking in mice is transitive, relatively stable, and highly correlates among multiple behavior measures. Recording from layer V pyramidal neurons of the medial prefrontal cortex (mPFC) showed higher strength of excitatory synaptic inputs in mice with higher ranking, as compared with their subordinate cage mates. Furthermore, molecular manipulations that resulted in an increase and decrease in the synaptic efficacy in dorsal mPFC neurons caused an upward and downward movement in the social rank, respectively. These results provide direct evidence for mPFC’s involvement in social hierarchy and suggest that social rank is plastic and can be tuned by altering synaptic strength in mPFC pyramidal cells.

Illustration (click to enlarge) - Synapses and rank - Excitatory synaptic drive onto cortical pyramidal neurons in the mouse brain is stronger in dominant individuals than subordinates. Modulating synaptic strength by increasing or decreasing AMPA receptor–mediated transmission switches the initial social ranking.

On understanding our brains...

I thought I would pass on some chunks of the lead editorial in the Nov. 4 Science Magazine, written by two senior establishment neuroscientists, Sidney Brenner and Terrence Sejnowski:

Like most fields in biology, neuroscience is succumbing to an “epidomic” of data collecting. There are major projects under way to completely characterize the proteomic, metabolomic, genomic, and methylomic signatures for all of the different types of neurons and glial cells in the human brain. In addition, “connectomics” plans to provide the complete network structure of brains, and “synaptomics” aims to uncover all molecules and their interactions at synapses. This is a good time to pause and ask ourselves what we expect to find at the end of this immense omic brainbow.

Linnaeus's catalog of species and the classifications he imposed on them turned data into knowledge, but it did not lead to an understanding of why they were all there. That had to wait for Darwin's theory of evolution and the development of genetics. All the lists that we will accumulate about the brain, although necessary, will be far from sufficient for understanding. The human brain contains an estimated 86 billion neurons and an equal number of glial cells. The complete structure of the enormously simpler 302-neuron network of the nematode worm Caenorhabditis elegans was published in 1986. But without the activities of neurons and their synapses, it was far from a complete “wiring diagram.” Today, with genetically encoded calcium sensors, with better knowledge of the molecules present at synapses, and by integrating the omic catalogs with developmental and dynamical data, we may finally be in sight of completing the worm wiring diagram, as required for a full understanding of this one relatively simple nervous system.

…Since the 1980s, neuroscience has received visionary financial support from private foundations, jump-starting new fields including cognitive neuroscience and computational neuroscience based on new techniques for imaging and modeling the human brain. The global view of human brain activity thus far obtained from imaging experiments has changed the way we think about ourselves. Homo neuroeconomicus has replaced the rational-agent model of human behavior, neuroeducators want to make children better learners, and neuroethicists have been inspired by the discovery of biological links to aggression, trust, and affi liation. However, individual differences often dominate. Although expensive bets are being placed on explaining the diversity of human behavior and mental disorders with genetic polymorphisms, gene mutations, and chromosomal rearrangements, the results so far have been modest

The Internet is making neuroscience more accessible to the public. The Society for Neuroscience, which convenes its annual meeting next week, will soon launch BrainFacts.org, a reliable source of information about the brain. In-depth interviews with neuroscientists can be found online at thesciencenetwork.org. And a Neuroeducation X Prize is being planned to encourage innovation in online computer games that enhance cognitive skills. Let us celebrate what our brains have discovered and what they can tell us about themselves.

Where in the brain does 'negative surprise' happen?

Egner points to an article by Alexander and Brown that provides an integrated model of how the brain deals with the non-occurrence of an expected event, such as George Bush and the famous non-opening Chinese door, suggesting this type of negative surprise drives neural responses in the dorsal anterior cingulate cortex and adjacent medial prefrontal cortex (dACC/mPFC), regions whose functions have been disputed in recent years. Their model provides a common denominator for a wide range of dACC/mPFC responses that have previously been attributed to diverse cognitive computations, making it a promising candidate for an integrative theory of this region's function. Their predicted response–outcome (PRO) model attempts to reconcile diverse finding, by suggesting that individual neurons generate signals reflecting a learned prediction of the probability and timing of the various possible outcomes of an action. These prediction signals are inhibited when the corresponding predicted outcome actually occurs. The resulting activity is therefore maximal when an expected outcome fails to occur, which suggests that what mPFC signals, in part, is the unexpected non-occurrence of a predicted outcome. Here is their abstract:

The medial prefrontal cortex (mPFC) and especially anterior cingulate cortex is central to higher cognitive function and many clinical disorders, yet its basic function remains in dispute. Various competing theories of mPFC have treated effects of errors, conflict, error likelihood, volatility and reward, using findings from neuroimaging and neurophysiology in humans and monkeys. No single theory has been able to reconcile and account for the variety of findings. Here we show that a simple model based on standard learning rules can simulate and unify an unprecedented range of known effects in mPFC. The model reinterprets many known effects and suggests a new view of mPFC, as a region concerned with learning and predicting the likely outcomes of actions, whether good or bad. Cognitive control at the neural level is then seen as a result of evaluating the probable and actual outcomes of one's actions.

Insensitivity to social reputation in autism.

Further characterization of how social cognition is changed by the autism disorder - evidence for distinctive brain systems that mediate the effects of social reputation:

People act more prosocially when they know they are watched by others, an everyday observation borne out by studies from behavioral economics, social psychology, and cognitive neuroscience. This effect is thought to be mediated by the incentive to improve one's social reputation, a specific and possibly uniquely human motivation that depends on our ability to represent what other people think of us. Here we tested the hypothesis that social reputation effects are selectively impaired in autism, a developmental disorder characterized in part by impairments in reciprocal social interactions but whose underlying cognitive causes remain elusive. When asked to make real charitable donations in the presence or absence of an observer, matched healthy controls donated significantly more in the observer's presence than absence, replicating prior work. By contrast, people with high-functioning autism were not influenced by the presence of an observer at all in this task. However, both groups performed significantly better on a continuous performance task in the presence of an observer, suggesting intact general social facilitation in autism. The results argue that people with autism lack the ability to take into consideration what others think of them and provide further support for specialized neural systems mediating the effects of social reputation.

Our resting brain networks can be formed by multiple architectures.

There has been a lot of interest lately (see Jonah's Lehrer's nice summary) in the resting, default, or 'mind wandering' state of our brains. It recruits functional networks with rich endogenous dynamics which typically distributed over both cerebral cortices. An interdisciplinary collaboration involving Ralph Adolphs, whose experiments were carried out by Michael Tyszka, asked the question of whether these resting states, as one might suppose, require the presence of the corpus callosum, the large bundle of fibers connecting the two hemispheres. What they found is that a normal complement of resting-state networks and intact functional coupling between the hemispheres can emerge in the absence of the corpus callosum, suggesting that resting brain networks can be formed by multiple architectures. Their abstract:

Temporal correlations between different brain regions in the resting-state BOLD signal are thought to reflect intrinsic functional brain connectivity. The functional networks identified are typically bilaterally distributed across the cerebral hemispheres, show similarity to known white matter connections, and are seen even in anesthetized monkeys. Yet it remains unclear how they arise. Here we tested two distinct possibilities: (1) functional networks arise largely from structural connectivity constraints, and generally require direct interactions between functionally coupled regions mediated by white-matter tracts; and (2) functional networks emerge flexibly with the development of normal cognition and behavior and can be realized in multiple structural architectures. We conducted resting-state fMRI in eight adult humans with complete agenesis of the corpus callosum (AgCC) and normal intelligence, and compared their data to those from eight healthy matched controls. We performed three main analyses: anatomical region-of-interest-based correlations to test homotopic functional connectivity, independent component analysis (ICA) to reveal functional networks with a data-driven approach, and ICA-based interhemispheric correlation analysis. Both groups showed equivalently strong homotopic BOLD correlation. Surprisingly, almost all of the group-level independent components identified in controls were observed in AgCC and were predominantly bilaterally symmetric. The results argue that a normal complement of resting-state networks and intact functional coupling between the hemispheres can emerge in the absence of the corpus callosum, favoring the second over the first possibility listed above.

When it's an error to mirror...

Mimicry and imitation can facilitate cultural learning, maintenance of culture, and group cohesion, and individuals must competently select the appropriate models and actions to imitate. Mimicry and imitation also play an important role in dyadic social interactions. People mimic their partners’ mannerisms, which increases rapport and the partners’ liking of the mimickersA collaboration between psychologists and philosophers at the Univ. of California, San Diego asks whether and how mimicry unconsciously influences evaluations made by third-party observers of dyadic interactions. Their results indicate that third-party observers make judgments about individuals’ competence on the basis of their decisions concerning whether and whom to mimic. Contrary to the notion that mimicry is uniformly beneficial to the mimicker, people who mimicked an unfriendly model were rated as less competent than nonmimics. Thus, a positive reputation depends not only on the ability to mimic, but also on the ability to discriminate when not to mimic. Here is their experimental setup (click on figure to enlarge):

Figure: Illustration of the experimental paradigm and experimental results. Subjects watched two videos, in each of which an interviewer (model) interacted with an interviewee. After each video, subjects rated the interviewee’s competence, trustworthiness, and likeability. For each subject, one video showed a mimicking interviewee, and the other showed a nonmimicking interviewee. In Experiment 1, video frames were uncropped, so subjects could see the interviewer; in Experiment 2, video frames were cropped, so subjects could not see the interviewer, and mimicry was obscured. The interviewer’s attitude varied between subjects; some subjects saw videos with a cordial interviewer, and other subjects saw videos with a condescending interviewer. The graph shows the difference in average competence ratings between the cordial- and condescending-model conditions as a function of whether or not the interviewee mimicked the interviewer, separately for Experiments 1 and 2. Error bars represent standard errors of the difference between conditions.

Booze and our brains.

This is all I needed!..... yet another reason to chill on my happy hour Martini. I keep reminding myself that, in addition to yielding a pleasant ‘buzz’, a modest amount of alcohol is supposed to have overall health benefits. There is a growing body of evidence that alcohol triggers rapid changes in the immune system in the brain as well as neuronal changes. This immune response lies behind some of the well-known alcohol-related behavioral changes, such as difficulty controlling the muscles involved in walking and talking. Wu et al. find in experiments on mice that a receptor on immune cells (TLR4) that controls expression of genes related to the inflammatory response to pathogens is involved in alcohol-induced sedation and impaired motor activity. If the receptor’s action is blocked either by a drug (naloxone) or by the receptor’s genetic removal, the effects of alcohol are reduced. This suggests that drugs specifically targeting the TLR4 receptor might be useful in treating alcohol dependence and acute overdoses.

Dynamnic views of MindBlog

Some time ago I put a link you can see at the right top of this MindBlog home page to "DYNAMIC VIEWS OF MINDBLOG."  A reminder email from Google's Blogger News prompted me to click on the link for the first time in quite a while.  They have obviously been refining these views.  Give it a try....you can click through some very interesting ways of presenting posts in various arrays, many quite appealing visually.

Economic inequality is linked to biased self-perception

A common view is that westerners are more likely to be individualists who seek personal success and uniqueness, and thus self-enhance - (i.e. emphasize or exaggerate one’s desirable qualities relative to other people’s) - more than do Easterners, who are more likely to be collectivists seeking interpersonal harmony and belonging. An international group of collaborators proposes an alternative explanation that favors socioeconomic differences over cultural dimensions. They suggest that the extent to which people engage in biased self-perception is influenced by the economic structure of their society, specifically its level of economic inequality. They gathered data from 1,625 participants in five continents and 15 nations: Europe (Belgium, Estonia, Germany, Hungary, Italy, Spain), the Americas (Peru, the United States, Venezuela), Asia (China, Japan, Singapore, South Korea), Africa (South Africa), and Oceania (Australia). Participants completed a standard questionnaire assessing self-enhancement. The bottom line is that people in societies with more income inequality tend to view themselves as superior to others, and people in societies with less income inequality tend to see themselves as more similar to their peers.
Their abstract:

People’s self-perception biases often lead them to see themselves as better than the average person (a phenomenon known as self-enhancement). This bias varies across cultures, and variations are typically explained using cultural variables, such as individualism versus collectivism. We propose that socioeconomic differences among societies—specifically, relative levels of economic inequality—play an important but unrecognized role in how people evaluate themselves. Evidence for self-enhancement was found in 15 diverse nations, but the magnitude of the bias varied. Greater self-enhancement was found in societies with more income inequality, and income inequality predicted cross-cultural differences in self-enhancement better than did individualism/collectivism. These results indicate that macrosocial differences in the distribution of economic goods are linked to microsocial processes of perceiving the self.

Figure: Scatter plot (with best-fitting regression line) showing self-enhancement (as indexed by beta weights from a two-level model) as a function of economic inequality (as indexed by the Gini coefficient) across nations. The data points for Australia and Italy are very close and overlap on the graph.

A bit from their discussion:

It is unlikely that economic inequality directly leads to biased self-perception. It seems more likely that there are intervening factors that result from socioeconomic differences. One possibility ... is perceived competition. When benefits and costs are polarized by inequality, people may compete for social superiority. One manifestation of this drive may be the presentation of the self as superior through self-enhancement. Thus, it may be the competitiveness triggered by economic inequality that drives biased self-perception. It is interesting to note that competitiveness may be related to differences in individualism as well, with more individualistic societies also fostering greater competition. Both individualism and economic inequality may work in concert to foster a perception of competition that results in cultural differences in levels of self-enhancement.1 Likewise, both individualism and economic inequality may undermine the norm of modesty. Modesty norms play an important role in reducing self-enhancement, and when they are compromised, self-enhancement increases. In societies with more income equality, people may not only have more-equal incomes, but they may also feel a pressure to seem more similar to others. This may manifest as a modesty norm, whereby people are discouraged from voicing both real and perceived superiority. Understanding the relationship between socioeconomic structure and individual psychology can help bridge the gulf between large-scale sociological studies of societies and individual social and psychological functioning.

An important limitation of the study was that, except for the United States, participants were drawn from university populations, and university students might often find themselves in situations in which their social standing is actually better than the average person’s, an effect which would be more pronounced in societies with more income inequality.

Climate change and human crisis

In case you need anything further to depress you about our impending climate changes, Zhang et al. do a more fine-grained analysis of the effect of past episodes of climate catastrophe by bringing more quantitative scrutiny to try to confirm what scholars have qualitatively noted: that massive social disturbance, societal collapse, and population collapse often coincided with great climate change in America, the Middle East, China, and many other countries in preindustrial times.

Recent studies have shown strong temporal correlations between past climate changes and societal crises. However, the specific causal mechanisms underlying this relation have not been addressed. We explored quantitative responses of 14 fine-grained agro-ecological, socioeconomic, and demographic variables to climate fluctuations from A.D. 1500–1800 in Europe (a period that contained both periods of harmony and times of crisis). Results show that cooling from A.D. 1560–1660 caused successive agro-ecological, socioeconomic, and demographic catastrophes, leading to the General Crisis of the Seventeenth Century. We identified a set of causal linkages between climate change and human crisis. Using temperature data and climate-driven economic variables, we simulated the alternation of defined “golden” and “dark” ages in Europe and the Northern Hemisphere during the past millennium. Our findings indicate that climate change was the ultimate cause, and climate-driven economic downturn was the direct cause, of large-scale human crises in preindustrial Europe and the Northern Hemisphere.

Their data support the causal links shown in this figure:

Figure - Set of causal linkages from climate change to large-scale human crisis in preindustrial Europe. The terms in bold black type are sectors, and terms in red type within parentheses are variables that represent the sector. The thickness of the arrow indicates the degree of average correlation

Narcissistic Leaders and Group Performance

Nevica et al. point to yet another case where reality is at odds with perceptions:

Although narcissistic individuals are generally perceived as arrogant and overly dominant, they are particularly skilled at radiating an image of a prototypically effective leader. As a result, they tend to emerge as leaders in group settings. Despite people’s positive perceptions of narcissists as leaders, it was previously unknown if and how leaders’ narcissism is related to the performance of the people they lead. In this study, we used a hidden-profile paradigm to investigate this question and found evidence for discordance between the positive image of narcissists as leaders and the reality of group performance. We hypothesized and found that although narcissistic leaders are perceived as effective because of their displays of authority, a leader’s narcissism actually inhibits information exchange between group members and thereby negatively affects group performance. Our findings thus indicate that perceptions and reality can be at odds and have important practical and theoretical implications.

The evolution of cognition

It is now commonly recognized that high-level cognitive function is not limited to primate lineages and like many other traits, is shaped by selection imposed by ecological and environmental demands. MacClean et al. (PDF here) propose that a merger of the fields of comparative psychology and phylogenetics would greatly improve our ability to understand the forces that drive cognitive evolution:

Now more than ever animal studies have the potential to test hypotheses regarding how cognition evolves. Comparative psychologists have developed new techniques to probe the cognitive mechanisms underlying animal behavior, and they have become increasingly skillful at adapting methodologies to test multiple species. Meanwhile, evolutionary biologists have generated quantitative approaches to investigate the phylogenetic distribution and function of phenotypic traits, including cognition. In particular, phylogenetic methods can quantitatively (1) test whether specific cognitive abilities are correlated with life history (e.g., lifespan), morphology (e.g., brain size), or socio-ecological variables (e.g., social system), (2) measure how strongly phylogenetic relatedness predicts the distribution of cognitive skills across species, and (3) estimate the ancestral state of a given cognitive trait using measures of cognitive performance from extant species. Phylogenetic methods can also be used to guide the selection of species comparisons that offer the strongest tests of a priori predictions of cognitive evolutionary hypotheses (i.e., phylogenetic targeting). Here, we explain how an integration of comparative psychology and evolutionary biology will answer a host of questions regarding the phylogenetic distribution and history of cognitive traits, as well as the evolutionary processes that drove their evolution.

Very brief meditation training produces brain changes associated with positive emotions.

It is known that the ratio of left frontal to right frontal lobe activation is relatively higher in individuals with higher positive affect - this effect can be monitored by e.e.g. electrodes placed on the head. (In light of Gilbert's recent observation that "A wandering mind is an unhappy mind," I wonder if resting frontal asymmetry correlates with mind wandering....) Davidson and colleagues have shown that a fairly rigorous 8-week meditation training program can cause a significant increase the left-sided anterior activation associated with positive affect. Now Moyer et al. at the Univ. of Wisconsin, Stout, claim that a much briefer intervention can be effective. Participants..

...who did not differ in frontal EEG asymmetry before training, were randomly assigned to the meditation training (MT; n = 11) or waiting-list (WL; n = 10) group. MT participants were told that nine 30-min sessions of meditation instruction were available to them and were encouraged to attend as many sessions as possible. A standard protocol was used to measure positive and negative affect before and after 15 min of attempted focused-attention meditation according to provided instructions (“relax with your eyes closed, and focus on the flow of your breath at the tip of your nose; if a random thought arises, acknowledge the thought and then simply let it go by gently bringing your attention back to the flow of your breath”).

Some results from the paper:

MT and WL participants did not differ in frontal EEG asymmetry before training, paired t(13) = 0.16, r = −.01, p = .88, d = 0.06 (see Figure, click to enlarge). During training, MT participants attended an average of 6.73 (SD = 1.35, range = 4−8) instruction sessions and reported engaging in independent 15-min intervals of meditation an average of 2.24 (SD = 1.01, range = 1−5) times per week. MT participants averaged 6 hr 13 min of training (SD = 1 hr 35 min, range = 3 hr 15 min to 9 hr 8 min) across the 5 weeks. After training, MT participants had significantly greater leftward shift in frontal EEG asymmetry than WL participants did across all time points, paired t(13) = 10.80, r = .40, p less than .001, d = 3.18 (see Figure).

Comparison with the control group (WL) seems somewhat shakey. They were doing nothing except knowing they would be offered training after the first group? What about being given an amount for some other kind of 'instruction' (religious, philosophical, whatever) for the same intervals?

Some clips from the discussion:

With training, focused-attention meditation shifts frontal EEG asymmetry toward a pattern associated with positive, approach-oriented emotions. Further, this shift does not require hundreds or even dozens of hours of practice. Individual MT participants in this study averaged only 5 to 16 min of active training (i.e., instruction, independent practice) per day across 5 weeks, but still exhibited a strong change in EEG asymmetry compared with the WL group. Our results suggest that the benefits of meditation may be more accessible than was previously believed. However, this study does not indicate if such asymmetry is pervasive or is limited to the time of meditation and the brief intervals that immediately surround it...We suggest two explanations for the increase in EEG asymmetry that emerged after so little training. First, our MT participants were able to decide when to practice, and for how long; this flexibility allowed them to determine for themselves when they would be most receptive to meditation, and choosing advantageous times may have heightened the efficacy of the meditation. Second, the small amount of active practice participants reported may have enabled a larger amount of passive practice to occur spontaneously, without a conscious decision to meditate; such passive practice may have strengthened the effects of meditation. This latter explanation is consistent with reports from some MT participants that they occasionally found themselves focusing their attention in the way they had been taught, even without having set out to do so.

Adolescent brain changes while viewing media violence

Strenziok et al. (open access) note a habituation and desensitization of adolescent emotional network brain responses to TV violence, which raises the obvious concern that diminishing the linking of the consequences of aggression with an emotional response might promote aggressive attitudes and behavior.

Adolescents spend a significant part of their leisure time watching TV programs and movies that portray violence. It is unknown, however, how the extent of violent media use and the severity of aggression displayed affect adolescents’ brain function. We investigated skin conductance responses, brain activation and functional brain connectivity to media violence in healthy adolescents. In an event-related functional magnetic resonance imaging experiment, subjects repeatedly viewed normed videos that displayed different degrees of aggressive behavior. We found a downward linear adaptation in skin conductance responses with increasing aggression and desensitization towards more aggressive videos. Our results further revealed adaptation in a fronto-parietal network including the left lateral orbitofrontal cortex (lOFC), right precuneus and bilateral inferior parietal lobules, again showing downward linear adaptations and desensitization towards more aggressive videos. Granger causality mapping analyses revealed attenuation in the left lOFC, indicating that activation during viewing aggressive media is driven by input from parietal regions that decreased over time, for more aggressive videos. We conclude that aggressive media activates an emotion–attention network that has the capability to blunt emotional responses through reduced attention with repeated viewing of aggressive media contents, which may restrict the linking of the consequences of aggression with an emotional response, and therefore potentially promotes aggressive attitudes and behavior.

A Fauré Nocturne - new born chicks would like it....

I'm finding some of the Gabriel Fauré Noctures very pleasant. Here is Nocturne no. 3, op. 33. And, the abstract following the video is relevant to the debate over whether our preference of consonant music of this sort is rooted in acoustic properties important to the auditory system or is acquired through enculturation. Italian researchers find newly hatched domestic chicks show a spontaneous preference for a visual imprinting object associated with consonant sound intervals over an identical object associated with dissonant sound intervals. This suggests that preference for harmonic relationships between frequency components may be related to the prominence of harmonic spectra in biological sounds in natural environments.



Here is the abstract from Chiandetti and
Vallortigara1:

The question of whether preference for consonance is rooted in acoustic properties important to the auditory system or is acquired through enculturation has not yet been resolved. Two-month-old infants prefer consonant over dissonant intervals, but it is possible that this preference is rapidly acquired through exposure to music soon after birth or in utero. Controlled-rearing studies with animals can help shed light on this question because such studies allow researchers to distinguish between biological predispositions and learned preferences. In the research reported here, we found that newly hatched domestic chicks show a spontaneous preference for a visual imprinting object associated with consonant sound intervals over an identical object associated with dissonant sound intervals. We propose that preference for harmonic relationships between frequency components may be related to the prominence of harmonic spectra in biological sounds in natural environments.