Monday, January 04, 2010

The faith instinct

Schulevitz reviews Nicholas Wade's new book "The Faith Instinct - How it evolved and how it endures."
According to Wade, a New York Times science writer, religions are machines for manufacturing social solidarity. They bind us into groups. Long ago, codes requiring altruistic behavior, and the gods who enforced them, helped human society expand from families to bands of people who were not necessarily related. We didn’t become religious creatures because we became social; we became social creatures because we became religious. Or, to put it in Darwinian terms, being willing to live and die for their coreligionists gave our ancestors an advantage in the struggle for resources.
...Rituals take time; sacrifices take money or its equivalent. Individuals willing to lavish time and money on a particular group signal their commitment to it, and a high level of commitment makes each coreligionist less loath to ignore short-term self-interest and to act for the benefit of the whole. What are gods for? They’re the enforcers. Supernatural beings scare away cheaters and freeloaders and cow everyone into loyal, unselfish, dutiful and, when appropriate, warlike behavior.

...our innate piety has adapted to our changing needs. Hunter-gatherers were egalitarian and, shamans aside, had direct access to the divine. But when humans began to farm and to settle in cities and states, religion became hierarchical. Priests emerged, turning unwritten rules and chummy gods into opaque instruments of surveillance and power. Church bureaucracies created crucial social institutions but also suppressed the more ecstatic aspects of worship, especially music, dance and trance. Wade advances the delightfully explosive thesis that the periodic rise of exuberant mystery cults represent human nature rebelling against the institutionalization of worship: “A propensity to follow the ecstatic behaviors of dance and trance was built into people’s minds and provided consistently fertile ground for revolts against established religion,”

Friday, January 01, 2010

A gentle start to the new year...some Debussy

I offer the mellow romantic energy of this Debussy piece "Valse Romantique" to start the new year. I continue to be amazed at how many people listen to and comment on some of these piano pieces I have posted on YouTube.

Reward regions in the adolescent brain.

Van Leijenhorst et al examine brain activations associated with anticipation, receipt, and omission of reward in several different age groups:
The relation between brain development across adolescence and adolescent risky behavior has attracted increasing interest in recent years. It has been proposed that adolescents are hypersensitive to reward because of an imbalance in the developmental pattern followed by the striatum and prefrontal cortex. To date, it is unclear if adolescents engage in risky behavior because they overestimate potential rewards or respond more to received rewards and whether these effects occur in the absence of decisions. In this study, we used a functional magnetic resonance imaging paradigm that allowed us to dissociate effects of the anticipation, receipt, and omission of reward in 10- to 12-year-old, 14- to 15-year-old, and 18- to 23-year-old participants. We show that in anticipation of uncertain outcomes, the anterior insula is more active in adolescents compared with young adults and that the ventral striatum shows a reward-related peak in middle adolescence, whereas young adults show orbitofrontal cortex activation to omitted reward. These regions show distinct developmental trajectories. This study supports the hypothesis that adolescents are hypersensitive to reward and adds to the current literature in demonstrating that neural activation differs in adolescents even for small rewards in the absence of choice. These findings may have important implications for understanding adolescent risk-taking behavior.

Unconscious strategic recruitment of resources measured with pupil diameter.

Recent research suggests that reward cues, in the absence of awareness, can enhance people's investment of physical resources (for an example, see this previous post). Bijleveld et al. make the interesting observation that pupil dilation can reveal strategic recruitment of resources when subliminal reward cues are presented. They make use of the fact that our pupils dilate with sympathetic activity and constrict with parasympathetic activity so that their size can be an unobtrusive measure of the resources invested in a task. Their rationale:
If subliminal reward cues input into the strategic processes involved in resource recruitment, the effects of rewards on pupil dilation should occur when the task is demanding (here, recall of five digits), but not when the task is undemanding (recall of three digits), as undemanding tasks can be completed routinely and do not require many resources. It is important to note that this interactive effect of reward and demand on recruitment of resources is expected to occur regardless of whether the reward is processed consciously or nonconsciously.
Their results:
Pupil-dilation data indicated that valuable (compared with nonvaluable) rewards led to recruitment of more resources, but only when obtaining the reward required considerable mental effort. This pattern was identical for supraliminal and subliminal reward cues. This indicates that awareness of a reward is not a necessary condition for strategic resource recruitment to take place. These findings are in line with recent research suggesting that the unconscious has flexible and adaptive capabilities (Hassin, Uleman, & Bargh, 2005; Wilson, 2002). More generally, whereas analyses of costs (required effort) and benefits (value of rewards) are usually thought to require consciousness, our findings suggest that such strategic processes can occur outside of awareness—and these processes show in the eyes.

Thursday, December 31, 2009

Inhibited behavior and our right frontal cortex.

Another interesting piece of work from Richie Davidson and colleagues at the University of Wisconsin.  Continuing their general catalog of correlations of left versus right frontal lobe activation with outgoing versus protective behaviors they find  that individuals with greater tonic (resting) activity in right-posterior dorsolateral prefrontal cortex rate themselves as more behaviorally inhibited. (The authors point out some limitation of the study: It is done with only female subjects and self reports of inhibition, so this clearly needs to be expanded. Their conclusions rest on a model, not a direct measurement, of the cerebral sources underlying the EEG, and the study did not address the degree to which individual differences in behavioral inhibition reflect altered functional connectivity between right-posterior DLPFC and other structures thought to underlie the behavioral inhibition system - e.g., amygdala, PAG, or ACC). Here is their abstract followed by a graphic from the article:
Individuals show marked variation in their responses to threat. Such individual differences in behavioral inhibition play a profound role in mental and physical well-being. Behavioral inhibition is thought to reflect variation in the sensitivity of a distributed neural system responsible for generating anxiety and organizing defensive responses to threat and punishment. Although progress has been made in identifying the key constituents of this behavioral inhibition system in humans, the involvement of dorsolateral prefrontal cortex (DLPFC) remains unclear. Here, we acquired self-reported Behavioral Inhibition System Sensitivity scores and high-resolution electroencephalography from a large sample (n= 51). Using the enhanced spatial resolution afforded by source modeling techniques, we show that individuals with greater tonic (resting) activity in right-posterior DLPFC rate themselves as more behaviorally inhibited. This observation provides novel support for recent conceptualizations of behavioral inhibition and clues to the mechanisms that might underlie variation in threat-induced negative affect.



Figure - Relations between individual differences in behavioral inhibition and tonic activity in right-posterior dorsolateral prefrontal cortex (DLPFC). The images in (a) depict the results of the electroencephalography source modeling analyses. The cluster lies at the intersection of the precentral and inferior frontal sulci, encompassing the right-posterior midfrontal and inferior-frontal gyri and including the inferior frontal junction (cluster-corrected p= .02). The crosshair shows the location in right-posterior DLPFC of the peak correlation in the sagittal (green outline), coronal (cyan outline), and axial (yellow outline) planes. The magnitude of voxel-wise correlations is depicted using a red-yellow scale; lighter shades of yellow indicate stronger correlations. "L" and "R" indicate the left and right hemispheres, respectively. The scatter plot (b) depicts the peak correlation between scores on the Behavioral Inhibition System (BIS) scale and standardized activity in right-posterior DLPFC (area 9/46v), r(48) =−.37, uncorrected p= .003. Standardized activity is in units of z-transformed cortical current density, log10(A/m2). Lines depict the regression line and 95% confidence envelope.


The power of music

North and Hargreaves introduce a special issue of The Psychologist which looks at musical ability; how and why people let music into their lives, and the impact of musical proficiency. They focus on the power of music to do harm (Rock music and self-injurious behavior), its effects on animal welfare, and its ability to influence pain stress and immunity. Some clips regarding the latter:
The most convincing evidence comes from Standley’s (1995) meta-analysis of 55 studies concerning the effect of music on 129 medically related variables. Podiatric pain, paediatric respiration, pulse, blood pressure and use of analgesia (in dental patients), pain, medication in paediatric surgery patients and EMG all showed effect sizes over 2, and the mean effect size over all 129 variables was .88, meaning that the impact of music was almost one standard deviation greater than without music.

The largest single body of literature concerns the impact of music on chronic pain, pain experienced during and after treatment, and pain experienced specifically by cancer patients and those undergoing palliative care. Research suggests that music can mediate pain in these cases by distracting the patient’s attention from it and/or by increasing their perceived control over the pain (since if patients believe that they have access to music as a means of pain control, then this belief itself decreases the aversiveness of pain). Similar research on stress has yielded the not entirely unsurprising conclusion that it may be reduced by music; but also that the amount of stress reduction varies according to age, the stressor, the listener’s musical preference, and their prior level of musical experience. More interestingly still, this reduction in stress manifests itself through physical measures, such as reduced levels of cortisol, and this has a very provocative further implication. Lower levels of stress are associated with greater immunity to illness of course, and several studies have indicated effects of music listening on physical measures of immune system strength, such as salivary immunoglobulin A. Although the mechanism by which this occurs is not well understood, the implication is clear: music contributes directly to physical health.

Wednesday, December 30, 2009

Changes in our brain connectivities as a funcion of age and sex

From Gong et al. one of those studies I take personally (i.e. describing my aging male brain):
Neuroanatomical differences attributable to aging and gender have been well documented, and these differences may be associated with differences in behaviors and cognitive performance. However, little is known about the dynamic organization of anatomical connectivity within the cerebral cortex, which may underlie population differences in brain function. In this study, we investigated age and sex effects on the anatomical connectivity patterns of 95 normal subjects ranging in age from 19 to 85 years. Using the connectivity probability derived from diffusion magnetic resonance imaging tractography, we characterized the cerebral cortex as a weighted network of connected regions. This approach captures the underlying organization of anatomical connectivity for each subject at a regional level. Advanced graph theoretical analysis revealed that the resulting cortical networks exhibited "small-world" character (i.e., efficient information transfer both at local and global scale). In particular, the precuneus and posterior cingulate gyrus were consistently observed as centrally connected regions, independent of age and sex. Additional analysis revealed a reduction in overall cortical connectivity with age. There were also changes in the underlying network organization that resulted in decreased local efficiency, and also a shift of regional efficiency from the parietal and occipital to frontal and temporal neocortex in older brains. In addition, women showed greater overall cortical connectivity and the underlying organization of their cortical networks was more efficient, both locally and globally. There were also distributed regional differences in efficiency between sexes. Our results provide new insights into the substrates that underlie behavioral and cognitive differences in aging and sex.



Figure- The spatial distribution of cortical regions showing significant age effect (p less than 0.05, corrected) on the integrated regional efficiency. The color represents t statistic of the age effect that was calculated from the general linear model. Each identified region was marked out. Notably, negative age effect was mainly distributed in the parietal and occipital cortex, whereas the positive age effect was localized only in the frontal and temporal cortex.

Subtle transmission of race bias by televised nonverbal behavior

It is well known that whites who appear nonprejudiced on self-report measures tend to display negative nonverbal behaviors as a function of unconscious, automatically activated racial bias. Weisbuch et al. illustrate how racial prejudice can be covertly spread and reinforced by noting uncover racial bias in actors' nonverbal displays despite the highly scripted nature of prime-time television shows, which generally minimizes expressions of racial bias. They obtain their findings with samples of white college undergraduates, who are more favorable toward outgroups (individuals whom the white students consider outside their group) and more inclined to conceal negative responses toward outgroups than the "average" white American. Here is their abstract:
Compared with more explicit racial slurs and statements, biased facial expressions and body language may resist conscious identification and thus produce a hidden social influence. In four studies, we show that race biases can be subtly transmitted via televised nonverbal behavior. Characters on 11 popular television shows exhibited more negative nonverbal behavior toward black than toward status-matched white characters. Critically, exposure to prowhite (versus problack) nonverbal bias increased viewers’ bias even though patterns of nonverbal behavior could not be consciously reported. These findings suggest that hidden patterns of televised nonverbal behavior influence bias among viewers.

Tuesday, December 29, 2009

Culture modulate eye movement responses to visual novelty

Goh et al. find a robust cultural bias in visual processing even when external stimuli draw attention in an opposite manner to the cultural bias.:
When viewing complex scenes, East Asians attend more to contexts whereas Westerners attend more to objects, reflecting cultural differences in holistic and analytic visual processing styles respectively. This eye-tracking study investigated more specific mechanisms and the robustness of these cultural biases in visual processing when salient changes in the objects and backgrounds occur in complex pictures.

Chinese Singaporean (East Asian) and Caucasian US (Western) participants passively viewed pictures containing selectively changing objects and background scenes that strongly captured participants' attention in a data-driven manner. We found that although participants from both groups responded to object changes in the pictures, there was still evidence for cultural divergence in eye-movements. The number of object fixations in the US participants was more affected by object change than in the Singapore participants. Additionally, despite the picture manipulations, US participants consistently maintained longer durations for both object and background fixations, with eye-movements that generally remained within the focal objects. In contrast, Singapore participants had shorter fixation durations with eye-movements that alternated more between objects and backgrounds.

Indirect reward and punishment - their payoff

Ule et al. examine indirect reciprocity, which in widespread in human culture - rewarding those we know have been kind to others or punishing those we know have been unkind to others. They devise a game to show that cooperation is enhanced best by a system in which both indirect rewards and indirect punishment can occur. Here is their experimental setup, followed by their abstract:
Our experimental design builds on the so-called "indirect helping game". In total, 140 participants are repeatedly (100 rounds), anonymously, and randomly matched into donor-recipient pairs. Because roles are determined randomly, participants will typically be the donor in approximately half of the rounds. In the indirect helping game, only donors make decisions. In any round, each donor first observes the recipient’s recent behavior in the role of donor and then decides whether to "help" the recipient or to "pass." Helping is costly for the donor and beneficial for the recipient, with the benefits exceeding the costs. In earlier experiments, indirect punishment was not available as an option, a restriction that is arguably not a realistic feature of human interactions. In our experiment, the donor can choose to "hurt" the recipient instead of passing or helping. Hurting is costly for the donor, but we vary its impact on the receiver. We conducted two treatments that differ only in this impact, which allows us to isolate the effect of indirect punishment on the payoff performance of different types of behavior. In our main treatment [harmful punishment (HP)], a hurt recipient loses 250 units of our experimental money, "francs." In the control treatment [symbolic punishment (SP)], a hurt recipient loses or earns no francs. We say that punishment is harmful in HP but only symbolic in SP. In both treatments, the donor loses 50 francs for hurting or 200 francs for helping, and the recipient earns 250 francs when he or she receives help. Passing does not affect either player’s payoff. In both treatments the recipient observes the donor’s action. Treatment SP is a control for HP, because it identifies differences in behavior between environments where indirect punishment has material consequences for the recipient and where it does not, while holding all other parameters constant across treatments.
the final conclusions, from the abstract:
We find that if unkind strangers cannot be punished, defection earns most. If they can be punished, however, then indirect rewarding earns most. Indirect punishment plays this important role, even if it gives a low payoff and is rarely implemented.

Monday, December 28, 2009

Describing our inner experience...

Hoffman writes an article describing the work of Russell T. Hurlburt, who tries to record the mental life of individuals by fitting them with a beeper that randomly prompts them to record whatever is in their awareness several times a day. The resulting mental freeze-frames are remarkably diverse. His research indicates:
...that there are a lot of people who don’t ever naturally form images, and then there are other people who form very florid, high-fidelity, Technicolor, moving images,...Some people have inner lives dominated by speech, body sensations or emotions, and yet others by “unsymbolized thinking” that can take the form of wordless questions.
Their is the point that:
...after-the-fact interviews should be treated with caution: one cannot assume the subjects will be honest, or that they are not twisting their answers to conform with their own biases, or telling the experimenter what they think he wants to hear, or simply filling in details they forgot.
Stephen Kosslyn, a professor of psychology at Harvard notes:
The experience sampling work is a reasonable first step, but only that; the claims need to be followed up and backed up by objective studies.

It may be that turning introspection into a science is as impractical as “trying to turn up the gas quickly enough to see how the darkness looks,” as William James wrote in 1890.

Diminutive digits discern delicate details.

Peters et al. show that tactile perception improves with decreasing finger size, and that this correlation fully explains the better perception of women, who on average have smaller fingers than men.
We have observed that passive tactile spatial acuity, the ability to resolve the spatial structure of surfaces pressed upon the skin, differs subtly but consistently between the sexes, with women able to perceive finer surface detail than men. Eschewing complex central explanations, we hypothesized that this sex difference in somatosensory perception might result from simple physical differences between the fingers of women and men. To investigate, we tested 50 women and 50 men on a tactile grating orientation task and measured the surface area of the participants' index fingertips. In subsets of participants, we additionally measured finger skin compliance and optically imaged the fingerprint microstructure to count sweat pores. We show here that tactile perception improves with decreasing finger size, and that this correlation fully explains the better perception of women, who on average have smaller fingers than men. Indeed, when sex and finger size are both considered in statistical analyses, only finger size predicts tactile acuity. Thus, a man and a woman with fingers of equal size will, on average, enjoy equal tactile acuity. We further show that sweat pores, and presumably the Merkel receptors beneath them, are packed more densely in smaller fingers.

Friday, December 25, 2009

From the Bach Collegium Munchen....

The emotional resonance of this magnificent high church music pierces right through my materialistic rationalist armor. The setting of this performance reminds me of my week in Munich this summer, and visits to several of its Baroque churches.

How our brains keep multiple things in mind.

Siegel et al. have made a fundamental advance in revealing how the brain manages to keep multiple things in mind in our working (short term) memory system. A review by Vogel and Fukada in the same issue of PNAS gives a nice description of the context and nature of the experiments:
...brain oscillations are thought to provide a vehicle for coordinating and sharing information within a given cortical region as well as a means of communicating signals between different brain areas. Oscillations can occur across a number of different frequency bands, ranging from very slow cycles (4–7 Hz, theta band) to very fast cycles (25–100 Hz, gamma band). In the context of working memory, oscillations in the gamma band have been proposed to play a fundamental role in linking up the various attributes of the memoranda (e.g., position, shape, color, etc.) across numerous individual neurons into a unified working memory representation. However, if working memories are all represented in the same gamma oscillation, how do we manage to keep from blurring all of the active memories together? One solution that has been proposed in a number of computational models has been to keep the memories separated by positioning each one in a different phase within the oscillation. That is, individual memories can be kept segregated, so long as they are “out of phase” with one another in the oscillation.

...the study by Siegel et al. appears to provide the first demonstration of such a phase-coding scheme in the brain for working memory. To do this, they recorded the local field potential over the prefrontal cortex while monkeys performed a sequential short-term memory task. In this task, monkeys are shown two pictures, one at a time, that they had to remember. After a short delay, memory was tested by presenting three pictures simultaneously; two of which were the pictures they had seen earlier in the trial, and one was a novel picture. To perform correctly, the monkey responded by initially looking at the first picture in the original sequence, then looking at the second picture, but not the novel picture. This task requires them to actively remember both of the pictures from the sequence and the order of presentation. By examining the gamma oscillation over prefrontal cortex during the blank delay period while these memories were being maintained in mind, Siegel et al. found that the two remembered objects were represented in distinct phase orientations of the oscillation depending on the order of presentation. That is, the first object of the sequence was preferentially coded in one phase orientation, and the second object was always in a separate phase orientation. Thus, they found direct evidence that the brain kept these two active memories separated by keeping them out of phase.
From Siegal et al's abstract:
We recorded neuronal activity from the prefrontal cortices of monkeys remembering two visual objects over a brief interval. We found that during this memory interval prefrontal population activity was rhythmically synchronized at frequencies around 32 and 3 Hz and that spikes carried the most information about the memorized objects at specific phases. Further, according to their order of presentation, optimal encoding of the first presented object was significantly earlier in the 32 Hz cycle than that for the second object. Our results suggest that oscillatory neuronal synchronization mediates a phase-dependent coding of memorized objects in the prefrontal cortex. Encoding at distinct phases may play a role for disambiguating information about multiple objects in short-term memory.

Thursday, December 24, 2009

One more light show...


Amazing Grace Techno - Computer Controlled Christmas Lights from Richard Holdman on Vimeo.

The "protocol society"

In a recent Op-Ed piece Brooks makes some points about the new economy:
In the 19th and 20th centuries we made stuff: corn and steel and trucks. Now, we make protocols: sets of instructions. A software program is a protocol for organizing information. A new drug is a protocol for organizing chemicals. Wal-Mart produces protocols for moving and marketing consumer goods. Even when you are buying a car, you are mostly paying for the knowledge embedded in its design, not the metal and glass...Physical stuff is subject to the laws of scarcity: you can use up your timber. But it’s hard to use up a good idea. Prices for material goods tend toward equilibrium, depending on supply and demand. Equilibrium doesn’t really apply to the market for new ideas.

A protocol economy tends toward inequality because some societies and subcultures have norms, attitudes and customs that increase the velocity of new recipes while other subcultures retard it. Some nations are blessed with self-reliant families, social trust and fairly enforced regulations, while others are cursed by distrust, corruption and fatalistic attitudes about the future. It is very hard to transfer the protocols of one culture onto those of another...When the economy was about stuff, economics resembled physics. When it’s about ideas, economics comes to resemble psychology.

Wednesday, December 23, 2009

For the season...

Can't let the holiday pass without a light show:

'Tis the season to be generous'...but watch the testosterone

A nice nugget from Zak et al:
How do human beings decide when to be selfish or selfless? In this study, we gave testosterone to 25 men to establish its impact on prosocial behaviors in a double-blind within-subjects design. We also confirmed participants' testosterone levels before and after treatment through blood draws. Using the Ultimatum Game from behavioral economics, we find that men with artificially raised T, compared to themselves on placebo, were 27% less generous towards strangers with money they controlled. This effect scales with a man's level of total-, free-, and dihydro-testosterone (DHT). Men in the lowest decile of DHT were 560% more generous than men in the highest decile of DHT. We also found that men with elevated testosterone were more likely to use their own money punish those who were ungenerous toward them. Our results continue to hold after controlling for altruism. We conclude that elevated testosterone causes men to behave antisocially.

More on the psychology of Liberals and Conservatives

Michael Shermer does an interesting column on this topic in the December Scientific American. It focuses mainly on the work of Jonathan Haidt, who explains liberal and conservative stereotypes in terms of his Moral Foundations Theory...
Haidt proposes that the foundations of our sense of right and wrong rest within “ ve innate and universally available psychological systems” that might be summarized as follows:
1. Harm/care: Evolved mammalian attachment systems mean we can feel the pain of others, giving rise to the virtues of kindness, gentleness and nurturance.
2. Fairness/reciprocity: Evolved reciprocal altruism generates a sense of justice.
3. Ingroup/loyalty: Evolved in-group tribalism leads to patriotism.
4. Authority/respect: Evolved hierarchical social structures translate to respect for authority and tradition.
5. Purity/sanctity: Evolved emotion of disgust related to disease and contamination underlies our sense of bodily purity.

Over the years Haidt and his University of Virginia colleague Jesse Graham have surveyed the moral opinions of more than 110,000 people from dozens of countries and have found this consistent difference: self-reported liberals are high on 1 and 2 (harm/ care and fairness/reciprocity) but are low on 3, 4 and 5 (ingroup/loyalty, authority/respect and purity/sanctity), whereas selfreported conservatives are roughly equal on all five dimensions, although they place slightly less emphasis on 1 and 2 than liberals do. (Take the survey yourself.)

Tuesday, December 22, 2009

Clever octopus, using tools.

No sooner do I get back from a restaurant in which I had a marvelous octopus ceviche, than I come across this video.