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. 

The origins of tidyness.

Turns out that ~800,000 year old Neanderthal dwellings excavated in Israel show signs of separate "activity areas" such as hearths, stone-tool knapping areas, food preparation areas, sleeping areas, etc. (added note: this morning's NYTimes has an article on the work)

Editor's choice at the Journal of Behavioral and Brain Science

Back in the dark ages I had an article in a special issue of Behavioral and Brain Science (in an issue devoted to publishing the papers given at a meeting on vision - "Controversies in Neuroscience III: Signal Transduction in the Retina and Brain"). They put me on the mailing list of reviewers, which is how I can occasionally pass on interesting papers that are appearing in the journal.   A recent email offered a list of articles what the editors found most interesting.  I've enjoyed reading several of them.   Here is that list, with links:

Consciousness, accessibility, and the mesh between psychology and neuroscience -  Ned Block

The myth of language universals: Language diversity and its importance for cognitive science -  Nicholas Evans and Stephen C. Levinson

Understanding and sharing intentions: The origins of cultural cognition (a PDF download) - Michael Tomasello, Malinda Carpenter, Josep Call, Tanya Behne, and Henrike Moll

Consciousness without a cerebral cortex: A challenge for neuroscience and medicine Bjorn Merker

Resolving the paradox of common, harmful, heritable mental disorders: Which evolutionary genetic models work best?  - Matthew C. Keller and Geoffrey Miller

Précis of the book: "Principles of Brain Evolution" - Georg F. Striedter

Cruelty's rewards: The gratification of perpetrators and spectators  - Victor Nell

Monday, December 21, 2009

How to lie more skillfully

Just apply transcranial direct current stimulation (tDCS) to your anterior prefrontal cortex (aPFC). From Karim et al:
Recent neuroimaging studies have indicated a predominant role of the anterior prefrontal cortex (aPFC) in deception and moral cognition, yet the functional contribution of the aPFC to deceptive behavior remains unknown. We hypothesized that modulating the excitability of the aPFC by transcranial direct current stimulation (tDCS) could reveal its functional contribution in generating deceitful responses. Forty-four healthy volunteers participated in a thief role-play in which they were supposed to steal money and then to attend an interrogation with the Guilty Knowledge Test. During the interrogation, participants received cathodal, anodal, or sham tDCS. Remarkably, inhibition of the aPFC by cathodal tDCS did not lead to an impairment of deceptive behavior but rather to a significant improvement. This effect manifested in faster reaction times in telling lies, but not in telling the truth, a decrease in sympathetic skin-conductance response and feelings of guilt while deceiving the interrogator and a significantly higher lying quotient reflecting skillful lying. Increasing the excitability of the aPFC by anodal tDCS did not affect deceptive behavior, confirming the specificity of the stimulation polarity. These findings give causal support to recent correlative data obtained by functional magnetic resonance imaging studies indicating a pivotal role of the aPFC in deception.

Neuromarketing nonsense

A blog reader pointed out to me this nice popular press debunking, by Sally Satel (interestingly, a resident scholar at the American Enterprise Institute), of the headset marketed by EmSense to gauge consumer reactions to advertising and products. The company website is notably lacking in documentation of any studies supporting their claims.  Here are clips from Satel's piece:
Neuromarketers are becoming the next generation of Mad Men. They are working for companies like Google, Frito-Lay and Disney. But instead of directly asking consumers whether they like a product, neuromarketers are asking their brains....Using electroencephalography (EEG)--a technology typically used by neurologists to diagnose seizures--marketers measure brain wave activity in response to advertisements and products. Electrodes placed on the subject's scalp collect the data. The consumer herself doesn't say a thing.

And that's the point. In the new world of neuromarketing, it is the more immediate, unedited emotional brain-level reaction to a product or ad that presumably indicates what the consumer really wants, even if she doesn't really know it. The rational and deliberate responses elicited in focus groups are considered unreliable....No wonder EmSense, a San Francisco-based market research company, succeeded in raising $9 million in capital last month....EmSense tests products with a band-like EEG device called the Emband that goes across the consumer's forehead. As she shops, the four sensors contained in the Emband collect data that, according to the company Web site, "open a window into the mind of the consumer."

Brain activation detected through the band's sensors is believed to signal the consumer's emotional engagement with a product. Engagement, in turn, is essential to sustaining interest and in enhancing memorability, important for developing brand loyalty. Yet the practical dimensions of neuromarketing are far from well-established.

First, how well does EEG detect emotion? It can gauge alertness, yes, but the more subtle kinds of mental states that relate to purchasing decisions--such as attraction, disgust, nostalgia or aspirational fantasy--are not accessible via brain wave analysis....Second, the notion of a discrete "buy button in the brain," as marketers call the holy grail of marketing, is deeply naive. Response to the shape, smell and color of a product is the culmination of complex processes that engage many areas of the brain...there is nothing close to a direct path between brain activation and actual consumer behavior.

Third, and most important, we still don't know whether any measure of neural activity predicts actual market performance or sales better than existing methods. Right now the data that are trumpeted by neuromarketers as revelatory have not been published in peer-reviewed journals. Nor has testing occurred under real-world circumstances in which consumers juggle their pocketbooks, the foreseeable reaction from spouse (you bought what?!?), other purchases they have recently made and even their mood at the time they go shopping.

Companies don't sell to brains; they sell to people. And human actions are determined by an array of motives and impulses that come into play once the subject removes the EEG apparatus from her head....Until the EEG marketing paradigm can prove itself to independent scientists, consumer actions will always speak louder than brain activation. Nonetheless, the allure of neuromarketing is obvious: Traditional focus groups seem too fuzzy and subjective; brain technology is objective, measurable and scientific...Having raised an impressive $9 million, the least one can safely say about EmSense is that it surely knows how to market itself. But whether EmSense, or other neuromarketers for that matter, can deliver on their high-tech promises remains to be seen.

Friday, December 18, 2009

Transiently blocking our concern for our good reputation

A fascinating open access piece by Knoch et al shows that brief disruption of our right lateral prefrontal cortex with low-frequency repetitive transcranial magnetic stimulation diminishes our ability to build a favorable reputation (by increasing our tendency to defect in a game of trust), even though ability to recognize both the fairness standards necessary for acquiring a good reputation and its future benefits are intact. This may help explain why reputation formation remains less prominent in most other species with less developed prefrontal cortices.
Reputation formation pervades human social life. In fact, many people go to great lengths to acquire a good reputation, even though building a good reputation is costly in many cases. Little is known about the neural underpinnings of this important social mechanism, however. In the present study, we show that disruption of the right, but not the left, lateral prefrontal cortex (PFC) with low-frequency repetitive transcranial magnetic stimulation (rTMS) diminishes subjects' ability to build a favorable reputation. This effect occurs even though subjects' ability to behave altruistically in the absence of reputation incentives remains intact, and even though they are still able to recognize both the fairness standards necessary for acquiring and the future benefits of a good reputation. Thus, subjects with a disrupted right lateral PFC no longer seem to be able to resist the temptation to defect, even though they know that this has detrimental effects on their future reputation. This suggests an important dissociation between the knowledge about one's own best interests and the ability to act accordingly in social contexts. These results link findings on the neural underpinnings of self-control and temptation with the study of human social behavior, and they may help explain why reputation formation remains less prominent in most other species with less developed prefrontal cortices.

Eldest children are less cooperative, trusting, and reciprocating

In a brief review titled "Why your older brother didn't share" ScienceNow points to interesting work by Courtiol et al. Their abstract:
Explaining the behavioural variations observed between individuals is an important step for understanding the evolution of human cooperation and personality traits. Birth order is a potentially important variable that implies physical and cognitive differences between siblings and differential access to parental resources during childhood. These differences have been shown to influence several personality characteristics in adulthood. We tested the hypothesis that birth order can shape adult cooperative behaviours towards nonkin. An anonymous investment game was played by 510 unrelated students. The results of the game show that firstborns were less trustful and reciprocated less than others. No significant differences in trust or reciprocity were found among laterborn and only children based on birth order. Firstborn status was a better predictor of cooperativeness than age, sex, income or religion. These results constitute some of the first experimental evidence that birth order differences established within the family can persist in adult behaviour among nonkin. We discuss the implications of this finding for the evolution of human cooperation.

Thursday, December 17, 2009

Spoken language and symbolic gestures processed by same brain areas

Xu et al perform MRI measurements that suggest that anterior and posterior perisylvian areas identified since the mid-19th century as the core of the brain's language system (including Broca's and Wernicke's area) may in fact function as a modality-independent semiotic system that plays a broader role in human communication, linking meaning with symbols whether these are words, gestures, images, sounds, or objects.

Symbolic gestures, such as pantomimes that signify actions (e.g., threading a needle) or emblems that facilitate social transactions (e.g., finger to lips indicating “be quiet”), play an important role in human communication. They are autonomous, can fully take the place of words, and function as complete utterances in their own right. The relationship between these gestures and spoken language remains unclear. We used functional MRI to investigate whether these two forms of communication are processed by the same system in the human brain. Responses to symbolic gestures, to their spoken glosses (expressing the gestures' meaning in English), and to visually and acoustically matched control stimuli were compared in a randomized block design....esults support a model in which bilateral modality-specific areas in superior and inferior temporal cortices extract salient features from vocal-auditory and gestural-visual stimuli respectively. However, both classes of stimuli activate a common, left-lateralized network of inferior frontal and posterior temporal regions in which symbolic gestures and spoken words may be mapped onto common, corresponding conceptual representations. We suggest that these anterior and posterior perisylvian areas, identified since the mid-19th century as the core of the brain's language system, are not in fact committed to language processing, but may function as a modality-independent semiotic system that plays a broader role in human communication, linking meaning with symbols whether these are words, gestures, images, sounds, or objects.

Figure - Common areas of activation for processing symbolic gestures and spoken language minus their respective baselines, identified using a random effects conjunction analysis. The resultant t map is rendered on a single subject T1 image: 3D surface rendering above, axial slices with associated z axis coordinates, below.

When seeing outweighs feeling.

Anders et al. make an interesting observation on patients who are blind in part of their visual field due to damage of a portion of the visual cortex. They still register negative feelings and somatic changes when a threatening stimulus is presented to their blind area, presumably due to sub-cortical pathways. However, when the visual stimulus is visible and receives full cortical processing, the patients’ phenomenal experience of affect does not closely reflect somatic changes. This decoupling of phenomenal affective experience and somatic changes is associated with an increase of activity in the left ventrolateral prefrontal cortex and a decrease of affect-related somatosensory activity. Here is their abstract:
Affective neuroscience has been strongly influenced by the view that a ‘feeling’ is the perception of somatic changes and has consequently often neglected the neural mechanisms that underlie the integration of somatic and other information in affective experience. Here, we investigate affective processing by means of functional magnetic resonance imaging in nine cortically blind patients. In these patients, unilateral postgeniculate lesions prevent primary cortical visual processing in part of the visual field which, as a result, becomes subjectively blind. Residual subcortical processing of visual information, however, is assumed to occur in the entire visual field. As we have reported earlier, these patients show significant startle reflex potentiation when a threat-related visual stimulus is shown in their blind visual field. Critically, this was associated with an increase of brain activity in somatosensory-related areas, and an increase in experienced negative affect. Here, we investigated the patients’ response when the visual stimulus was shown in the sighted visual field, that is, when it was visible and cortically processed. Despite the fact that startle reflex potentiation was similar in the blind and sighted visual field, patients reported significantly less negative affect during stimulation of the sighted visual field. In other words, when the visual stimulus was visible and received full cortical processing, the patients’ phenomenal experience of affect did not closely reflect somatic changes. This decoupling of phenomenal affective experience and somatic changes was associated with an increase of activity in the left ventrolateral prefrontal cortex and a decrease of affect-related somatosensory activity. Moreover, patients who showed stronger left ventrolateral prefrontal cortex activity tended to show a stronger decrease of affect-related somatosensory activity. Our findings show that similar affective somatic changes can be associated with different phenomenal experiences of affect, depending on the depth of cortical processing. They are in line with a model in which the left ventrolateral prefrontal cortex is a relay station that integrates information about subcortically triggered somatic responses and information resulting from in-depth cortical stimulus processing. Tentatively, we suggest that the observed decoupling of somatic responses and experienced affect, and the reduction of negative phenomenal experience, can be explained by a left ventrolateral prefrontal cortex-mediated inhibition of affect-related somatosensory activity.

Wednesday, December 16, 2009

A biological rationale for musical scales

An interesting article from Gill and Purves on musical scales, and how humans use only a few of the enormous number of possible tone combinations to create music. I found the illustrations to be fascinating and very educational:
Scales are collections of tones that divide octaves into specific intervals used to create music. Since humans can distinguish about 240 different pitches over an octave in the mid-range of hearing, in principle a very large number of tone combinations could have been used for this purpose. Nonetheless, compositions in Western classical, folk and popular music as well as in many other musical traditions are based on a relatively small number of scales that typically comprise only five to seven tones. Why humans employ only a few of the enormous number of possible tone combinations to create music is not known. Here we show that the component intervals of the most widely used scales throughout history and across cultures are those with the greatest overall spectral similarity to a harmonic series. These findings suggest that humans prefer tone combinations that reflect the spectral characteristics of conspecific vocalizations. The analysis also highlights the spectral similarity among the scales used by different cultures.

Rapid amygdala activation by fearful objects in our peripheral vision

Bayle et al. use Magnetoencephalography (MEG) to show that fearful objects presented to our peripheral field of vision while we are consciously looking at a central object cause rapid (80 msec) activation of the amygdala. If the fearful stimulus is presented to our central field of view and processed by the classical occipito-temporal visual pathway, it takes between 140 and 190 ms to register. Some clips:
In ecological situations, threatening stimuli often come out from the peripheral vision. Such aggressive messages must trigger rapid attention to the periphery to allow a fast and adapted motor reaction... Fearful and neutral faces were briefly presented in the central or peripheral visual field, and were followed by target faces stimuli. An event-related beamformer source analysis model was applied in three time windows following the first face presentations: 80 to 130 ms, 140 to 190 ms, and 210 to 260 ms. The frontal lobe and the right internal temporal lobe part, including the amygdala, reacted as soon as 80 ms of latency to fear occurring in the peripheral vision. For central presentation, fearful faces evoked the classical neuronal activity along the occipito-temporal visual pathway between 140 and 190 ms...Thus, the high spatio-temporal resolution of MEG allowed disclosing a fast response of a network involving medial temporal and frontal structures in the processing of fear related stimuli occurring unconsciously in the peripheral visual field.
A related study is offered by Sabatinelli et al., who examine the timing of emotional discrimination in the amygdala and ventral visual cortex.

Tuesday, December 15, 2009

Sequence of presentation influences our choice between alternatives.

FromMantonakis et al.:
When several choice options are sampled one at a time in a sequence and a single choice of the best option is made at the end of the sequence, which location in the sequence is chosen most often? We report a large-scale experiment that assessed tasting preferences in choice sets of two, three, four, or five wines. We found a large primacy effect—the first wine had a large advantage in the end-of-sequence choice. We also found that participants who were knowledgeable about wines showed a recency effect in the longer sequences.
The model they propose to explain their findings is interesting:
We propose that two biases operated within that sequential competitive evaluation process. First, a first-is-best bias accounts for the consistent primacy effect. Second, a bias in favor of each new wine among high-knowledge participants accounts for the recency effect, and for an interesting reason: Compared with the low-knowledge participants, the high-knowledge participants were more persistent in looking for a better wine later in the sequence—a plausible result of greater expertise. Thus, high-knowledge participants were likelier to make a comparison between their current favorite and the new wine when each new wine was sampled. Thus, there was a substantial chance that each new wine would beat the current favorite, and this habit produced the pronounced recency effect in longer sequences, especially for high-knowledge participants. For example, suppose that each new wine has a .30 chance of beating the current favorite, and the current favorite remains the preferred choice with a .70 probability. Note that these values are consistent with the size of the observed primacy effects (e.g., the first wine was chosen with approximately .70 probability in the two-option sets) and with the recency effects for the high-knowledge participants (the last wine was chosen with approximately .30 probability in the four-option and five-option sets).
We account for the lack of recency effects among the low-knowledge participants by proposing that they followed the pair-wise competitive-evaluation strategy less vigorously than the high-knowledge participants, eliminating the potential recency advantage. We speculate that the low-knowledge participants were more likely to be overwhelmed by the cognitive demands of the pair-wise competitive strategy as memory load and interference increased across the sampling trials.
The pair-wise model provides an almost perfect fit to the data if we add one more assumption about the comparison process. Thus far, we have assumed that all current favorites have a .70-versus-.30 advantage in all pair-wise comparisons. But if we suppose that the current-favorite advantage increases for later favorites (e.g., if the third option wins its pair-wise competition, its advantage increases to .75 vs. .25; if the fourth wins, its advantage is .80 vs. .20), then the model fits the data almost perfectly. This pair-wise-competition process model is impressive; its one failing is that it predicts a small recency effect for the three-option set for high-knowledge participants.

Experiencing our causality warps our sense of time.

Buehner et al. make the interesting observation that two events we know to be causally related are experienced as closer in time than similar unrelated events.  Thus, expectation warps our sense of time. :
According to widely held views in cognitive science harking back to David Hume, causality cannot be perceived directly, but instead is inferred from patterns of sensory experience, and the quality of these inferences is determined by perceivable quantities such as contingency and contiguity. We report results that suggest a reversal of Hume's conjecture: People's sense of time is warped by the experience of causality. In a stimulus-anticipation task, participants' response behavior reflected a shortened experience of time in the case of target stimuli participants themselves had generated, relative to equidistant, equally predictable stimuli they had not caused. These findings suggest that causality in the mind leads to temporal binding of cause and effect, and extend and generalize beyond earlier claims of intentional binding between action and outcome.

Monday, December 14, 2009

The year in ideas

The New York Times Magazine has just done its annual issue on what it selects, from A to Z, to be the most clever, important, silly or just plain weird innovations from all corners of the thinking world. Here are links to a few items that hooked me:

Drunken Ultimatums

Glow-in-the-dark dog

Good enough is the new great.

Google algorithm as an extinction model.

Guilty robots

Infant sleep is destiny

Literary Alzheimers 

The genius of crowds - massively collaborative mathematics

Random promotions 

This year's patents - a great humorous graphic

Modulation of our pain by emotions - cerebral and spinal sites

Our response to painful stimulation can be modulated by the emotional impact of viewing a pleasant or an unpleasant picture.  In an open access article, Roy et. al.  view the multiple sites associated with this effect - noting the central role of the right insula - by doing brain imaging of participants who received painful electric shocks while they viewed blocks of pleasant, unpleasant, or neutral pictures.:
Emotions have powerful effects on pain perception. However, the brain mechanisms underlying these effects remain largely unknown. In this study, we combined functional cerebral imaging with psychophysiological methods to explore the neural mechanisms involved in the emotional modulation of spinal nociceptive responses (RIII-reflex) and pain perception in healthy participants. Emotions induced by pleasant or unpleasant pictures modulated the responses to painful electrical stimulations in the right insula, paracentral lobule, parahippocampal gyrus, thalamus, and amygdala. Right insula activation covaried with the modulation of pain perception, consistent with a key role of this structure in the integration of pain signals with the ongoing emotion. In contrast, activity in the thalamus, amygdala, and several prefrontal areas was associated with the modulation of spinal reflex responses. Last, connectivity analyses suggested an involvement of prefrontal, parahippocampal, and brainstem structures in the cerebral and cerebrospinal modulation of pain by emotions. This multiplicity of mechanisms underlying the emotional modulation of pain is reflective of the strong interrelations between pain and emotions, and emphasizes the powerful effects that emotions can have on pain.

Friday, December 11, 2009

Why exercise makes you less anxious.

An article by Gretchen Reynolds summarizes work showing that exercise stimulates the synthesis of new brain cells that appear to be specifically buffered from exposure to stressful experience. Exercise also appears to cause beneficial changes in dopamine and serotonin regulation and the vulnerability to oxidative stress.

Stop me if I've told you this before......

Benedict Carey does a nice summary of work from Gopie and McCloud. Here is the Psychological Science Abstract of the work:
Everyone has recounted a story or joke to someone only to experience a nagging feeling that they may already have told this person this information. Remembering to whom one has told what, an ability that we term destination memory, has been overlooked by researchers despite its important social ramifications. Using a novel paradigm, we demonstrate that destination memory is more fallible than source memory—remembering the person from whom one has received information. In two experiments we increased and decreased self-focus, obtaining support for a theoretical framework that explains relatively poor destination memory performance as being the result of focusing attention on oneself and on the processes required to transmit information. Along with source memory, destination memory is an important component of episodic memory that plays a critical role in social interactions.

Thursday, December 10, 2009

Why mindblog spends in the winter in Ft. Lauderdale...

View from the living room window of my Middleton, WI. home, just outside Madison, WI.  Seventeen inches of snow in Madison yesterday, today wind chill of -10 to -20 degrees fahrenheit. Getting to my Univ. of Wisconsin office would not be all that pleasant. Fort Lauderdale is sunny today with an unseasonable high of 87 degrees.

Political partisanship and perception of skin color tone

Interesting...from Caruso et al.:
People tend to view members of their own political group more positively than members of a competing political group. In this article, we demonstrate that political partisanship influences people's visual representations of a biracial political candidate's skin tone. In three studies, participants rated the representativeness of photographs of a hypothetical (Study 1) or real (Barack Obama; Studies 2 and 3) biracial political candidate. Unbeknownst to participants, some of the photographs had been altered to make the candidate's skin tone either lighter or darker than it was in the original photograph. Participants whose partisanship matched that of the candidate they were evaluating consistently rated the lightened photographs as more representative of the candidate than the darkened photographs, whereas participants whose partisanship did not match that of the candidate showed the opposite pattern. For evaluations of Barack Obama, the extent to which people rated lightened photographs as representative of him was positively correlated with their stated voting intentions and reported voting behavior in the 2008 Presidential election. This effect persisted when controlling for political ideology and racial attitudes. These results suggest that people's visual representations of others are related to their own preexisting beliefs and to the decisions they make in a consequential context.

Social isolation and inflammatory gene expression

My thanks to mindblog reader Ian for pointing out this article demonstrating how social isolation correlates with the expression of a large array of genes that elevate the risk of inflammatory disease. They did a DNA microarray analysis that identified 209 genes that were differentially expressed in circulating leukocytes from 14 high- versus low-lonely individuals, noting impaired transcription of glucocorticoid response genes and increased activity of pro-inflammatory transcription control pathways.

Wednesday, December 09, 2009

Men do everything they do to get laid?

Ted Maxwell of Intelligence Squared asks that I pass on this notice of a live online debate on evolutionary psychology at 18:45 GMT on Dec. 10.
Can it really be true that men do everything they do to get laid? Yes, argue the proponents of evolutionary psychology - because in their view the largely unconscious motive of human behaviour is to maximize reproductive success, which in men's case means getting sexual access to as many fertile women as possible. And so men - without necessarily being aware of it - do everything they do in order to get laid, and they are evolutionarily designed to behave in this way, because if they (and their ancestors) weren't, they wouldn't be here today. Women, on the other hand, have to be rather more careful about who they sleep with.
This, according to the theory, is why most millionaires, criminals and creative geniuses are men, why Intelligence Squared has such trouble finding good women speakers for its debates, and why middle-aged men tend to leave their wives for younger women. But what about the 50% of men who stick with their first marriage? And are we really saying that every creative endeavour - from the Sistine Chapel to the splitting of the atom - is nothing more than the manifestation of an underlying psychological impulse to copulate as much as possible?

My symbiosis with Google.

Yesterday's article by Brad Stone on Google in the NYTimes made me pause, yet again, to reflect on how utterly my professional and personal life have been altered by the 'free' services of this behemoth and 'the cloud,' most notably google search, Blogger, YouTube, gmail, Calendar and Contact synch of my iPhone and all my computers, etc. I have not filed away the hard copy of a scientific article in years, instead putting the PDF of any article of interest in the images file that supports this blog. I've just switched to their Chrome web browser which has blazing saddles speed compared with Firefox, Safari, Explorer, etc. (By the way, Kakutani has a review in the same NYTimes issue of "GOOGLED - The End of the World as We Know It" by Ken Auletta. titled "Still Counting the Ways to Infiltrate Daily Lives.")

The Brad Stone article describes partnerships with Twitter, Facebook and MySpace to bring updates from those services into its search index within seconds, so for example, you can see comments on the Copenhagen climate conference scrolling past as they are made. A new feature called Google Goggles, allows people to send Google a cellphone photograph of, say, a landmark or a book, and have information about the contents of the image returned to them instantly.

From Kakutani's review:
Because Google “enjoys a well-deserved reputation for earning the trust of users,” Mr. Auletta says, it is “hard to imagine an issue that could imperil the trust Google has achieved as quickly as could privacy.” He adds: “One Google executive whispers, ‘Privacy is an atomic bomb. Our success is based on trust.’ ”...If users, Mr. Auletta writes, “lost trust in Google, believed their private data was being exploited and shared with advertisers (or governments), the company regularly judged one of the world’s most trusted brands would commit suicide.”
“Google appears to be well positioned for the foreseeable future,” Mr. Auletta concludes, “but it is worth remembering that few companies maintain their dominance. At one point, few thought the Big Three auto companies would ever falter — or the three television networks or AT&T, IBM or AOL. For companies with histories of serious missteps — Apple, IBM — it was difficult to imagine that they’d rebound, until they did.”...In short, one of the few things it is impossible to Google is the future of Google.

The "Name-Ease" effect...

Interesting material from Labroo et al.:
We demonstrate that merely naming a research finding elicits feelings of ease (a "name-ease" effect). These feelings of ease can reduce or enhance the finding's perceived importance depending on whether people are making inferences about how understandable or how memorable the finding is. When people assess their understanding of a finding, feelings of ease reduce the finding's perceived importance. This is because people usually invest effort to understand important information but also mistakenly infer the reverse—namely, that information that requires effort to be understood is important. In contrast, when people assess the memorability of a finding, feelings of ease increase the finding's perceived importance. Because people usually recall important information easily, in this case they equate ease with importance. Psychological effects, economic principles, math theorems, jury cases, and decisions to fund medical research can all show these effects.

Primitive syntax in a monkey language?

Nicholas Wade points to some interesting work on the Campbell’s monkey in Tai Forest, Ivory Coast. (Later note: here is the link to the subsequent PNAS article.)

Tuesday, December 08, 2009

Our cooperative behavior is innate.

Nicholas Wade notes Tomasello's new book "Why We Cooperate." Helping behavior is observed in children and seems to be innate because it appears very early and before many parents start teaching children the rules of polite behavior. (The pictures shows a young child responding when an adult has dropped something.) Helping behavior can also be seen in infant chimpanzees under the right experimental conditions. Some clips:
Shared intentionality, in Dr. Tomasello’s view, is close to the essence of what distinguishes people from chimpanzees. A group of human children will use all kinds of words and gestures to form goals and coordinate activities, but young chimps seem to have little interest in what may be their companions’ minds...The shared intentionality lies at the basis of human society, Dr. Tomasello argues. From it flow ideas of norms, of punishing those who violate the norms and of shame and guilt for punishing oneself. Shared intentionality evolved very early in the human lineage, he believes, and its probable purpose was for cooperation in gathering food. Anthropologists report that when men cooperate in hunting, they can take down large game, which single hunters generally cannot do. Chimpanzees gather to hunt colobus monkeys, but Dr. Tomasello argues this is far less of a cooperative endeavor because the participants act on an ad hoc basis and do not really share their catch.

An interesting bodily reflection of humans’ shared intentionality is the sclera, or whites, of the eyes. All 200 or so species of primates have dark eyes and a barely visible sclera. All, that is, except humans, whose sclera is three times as large, a feature that makes it much easier to follow the direction of someone else’s gaze. Chimps will follow a person’s gaze, but by looking at his head, even if his eyes are closed. Babies follow a person’s eyes, even if the experimenter keeps his head still...Advertising what one is looking at could be a risk. Dr. Tomasello argues that the behavior evolved “in cooperative social groups in which monitoring one another’s focus was to everyone’s benefit in completing joint tasks.”..This could have happened at some point early in human evolution, when in order to survive, people were forced to cooperate in hunting game or gathering fruit. The path to obligatory cooperation — one that other primates did not take — led to social rules and their enforcement, to human altruism and to language.

Pre-natal androgens and risk taking...

Coates and Page follow up on a study I mentioned in an earlier post, this time examining risk taking as well as long-term profitability of traders in the City of London exchange:
Traders in the financial world are assessed by the amount of money they make and, increasingly, by the amount of money they make per unit of risk taken, a measure known as the Sharpe Ratio. Little is known about the average Sharpe Ratio among traders, but the Efficient Market Hypothesis suggests that traders, like asset managers, should not outperform the broad market. Here we report the findings of a study conducted in the City of London which shows that a population of experienced traders attain Sharpe Ratios significantly higher than the broad market. To explain this anomaly we examine a surrogate marker of prenatal androgen exposure, the second-to-fourth finger length ratio (2D:4D), which has previously been identified as predicting a trader's long term profitability. We find that it predicts the amount of risk taken by traders but not their Sharpe Ratios. We do, however, find that the traders' Sharpe Ratios increase markedly with the number of years they have traded, a result suggesting that learning plays a role in increasing the returns of traders. Our findings present anomalous data for the Efficient Markets Hypothesis.

Monday, December 07, 2009

How fear versus disgust regulate our attention.

Vermeulen et al. do a nice experiment demonstrating emotional effects on our attention, using the attentional blink to show that our noticing a rapidly presented second irrelevant input after seeing a fearful face is inhibited more than after we have seen a disgusting face.
It is well known that facial expressions represent important social cues. In humans expressing facial emotion, fear may be configured to maximize sensory exposure (e.g., increases visual input) whereas disgust can reduce sensory exposure (e.g., decreases visual input). To investigate whether such effects also extend to the attentional system, we used the “attentional blink” (AB) paradigm. Many studies have documented that the second target (T2) of a pair is typically missed when presented within a time window of about 200–500 ms from the first to-be-detected target (T1; i.e., the AB effect). It has recently been proposed that the AB effect depends on the efficiency of a gating system which facilitates the entrance of relevant input into working memory, while inhibiting irrelevant input. Following the inhibitory response on post T1 distractors, prolonged inhibition of the subsequent T2 is observed. We hypothesized that processing facial expressions of emotion would influence this attentional gating. Fearful faces would increase but disgust faces would decrease inhibition of the second target...We found that processing fear faces impaired the detection of T2 to a greater extent than did the processing disgust faces. This finding implies emotion-specific modulation of attention.

A dopamine receptor gene and emotional control

Blasi et al. note that variation of the Dopamine D2 receptor gene is associated with emotional control as well as brain activity and connectivity during human emotion processing:
Personality traits related to emotion processing are, at least in part, heritable and genetically determined. Dopamine D2 receptor signaling is involved in modulation of emotional behavior and activity of associated brain regions such as the amygdala and the prefrontal cortex. An intronic single nucleotide polymorphism within the D2 receptor gene (DRD2) (rs1076560, guanine > thymine or G > T) shifts splicing of the two protein isoforms (D2 short, mainly presynaptic, and D2 long) and has been associated with modulation of memory performance and brain activity. Here, our aim was to investigate the association of DRD2 rs1076560 genotype with personality traits of emotional stability and with brain physiology during processing of emotionally relevant stimuli. DRD2 genotype and Big Five Questionnaire scores were evaluated in 134 healthy subjects demonstrating that GG subjects have reduced "emotion control" compared with GT subjects. Functional magnetic resonance imaging in a sample of 24 individuals indicated greater amygdala activity during implicit processing and greater dorsolateral prefrontal cortex (DLPFC) response during explicit processing of facial emotional stimuli in GG subjects compared with GT. Other results also demonstrate an interaction between DRD2 genotype and facial emotional expression on functional connectivity of both amygdala and dorsolateral prefrontal regions with overlapping medial prefrontal areas. Moreover, rs1076560 genotype is associated with differential relationships between amygdala/DLPFC functional connectivity and emotion control scores. These results suggest that genetically determined D2 signaling may explain part of personality traits related to emotion processing and individual variability in specific brain responses to emotionally relevant inputs.

Psyche is back.

I've been meaning to mention that the official journal of the ASSC ( the Association for the Scientific Study of Consciousness), Psyche, is now back in a new form with its articles available for free PDF download.

Friday, December 04, 2009

Ongoing Victim Suffering Increases Prejudice

Imhoff and Banse empirically test the secondary-anti-Semitism theory, which suggests that every reminder of the German atrocities and the victims' suffering still evokes aversive feelings of guilt and thus increases a defensive anti-Semitism—even in Germans born decades after 1945. (Hence the famous quip from Israeli psychoanalyst Zvi Rex that "The Germans will never forgive the Jews for Auschwitz.") The bogus pipeline (BPL) mentioned is a classic approach for revealing socially undesirable attitudes or behavior in which participants are led to believe that they are being monitored by a psychophysiological apparatus that can detect untruthful responses. Previous research has shown that individuals disclose more socially undesirable behaviors and attitudes under BPL conditions than when the BPL is not employed. Here is the abstract:
Some people have postulated that the perception of Jews' ongoing suffering from past atrocities can result in an increase in anti-Semitism. This postulated secondary anti-Semitism is compatible with a number of psychological theories, but until now there has been no empirical evidence in support of this notion. The present study provides the first evidence that ongoing suffering evokes an increase in prejudice against the victims. However, this effect became apparent only if respondents felt obliged to respond truthfully because of a bogus pipeline (BPL); without this constraint, the perception of ongoing victim suffering led to a socially desirable reduction in self-reported prejudice. The validity of the BPL manipulation was confirmed by the finding that it moderated the relation between explicit and implicit anti-Semitism, as measured with an affect misattribution procedure.

Universality in distinguishing natural from artificial, and in color naming.

Interesting observations by Biederman et al.:
Many of the phenomena underlying shape recognition can be derived from the greater sensitivity to nonaccidental properties of an image (e.g., whether a contour is straight or curved), which are invariant to orientation in depth, than to the metric properties of an image (e.g., a contour's degree of curvature), which can vary with orientation. What enables this sensitivity? One explanation is that it derives from people's immersion in a manufactured world in which simple, regular shapes distinguished by nonaccidental properties abound (e.g., a can, a brick), and toddlers are encouraged to play with toy shape sorters. This report provides evidence against this explanation. The Himba, a seminomadic people living in a remote region of northwestern Namibia where there is little exposure to regular, simple artifacts, were virtually identical to Western observers in their greater sensitivity to nonaccidental properties than to metric properties of simple shapes.
Also, on the subject of human universals, Lindsey and Brown note universal motifs in color naming.

Thursday, December 03, 2009

Obama, Afganistan, and the emotional brain

David Eagleman does a nice essay on how Obama's withdrawal timetable decisions relate to the psychology of uncertainty, expectation, and reward.

Watch the live dissection of a famous brain.

See Benedict's Carey's article on Henry Molaison — known during his lifetime only as H.M., to protect his privacy — who lost the ability to form new memories after a brain operation in 1953, and over the next half century became the most studied patient in brain science. Here is the dissection in progress:
We have reached the corpus callosum. The team is resting for the night. The brain will be safe surrounded by our chillers until tomorrow morning. The cutting will resume again at 8AM PST.

Tomorrow will be a big day - We will try to cover the medial temporal lobes and the area surrounding the hippocampus.

Hearing with both your skin and your ears

Gick and Derrick offer a fascinating example of cross modal sensory perception, demonstrating 'aero-tactile' integration in speech perception:
...we show that perceivers integrate naturalistic tactile information during auditory speech perception without previous training. Drawing on the observation that some speech sounds produce tiny bursts of aspiration (such as English 'p'), we applied slight, inaudible air puffs on participants' skin at one of two locations: the right hand or the neck. Syllables heard simultaneously with cutaneous air puffs were more likely to be heard as aspirated (for example, causing participants to mishear 'b' as 'p'). These results demonstrate that perceivers integrate event-relevant tactile information in auditory perception in much the same way as they do visual information.
The syllables included “pa” and “ta,” which produce a brief puff from the mouth when spoken, and “da” and “ba,” which do not produce puffs. When listeners heard “da” or “ba” while a puff of air was blown onto their skin, they perceived the sound as “ta” or “pa.” It seems likely that this integration of different sensory cues is innate, for subjects were completely unaware that they were doing it.

Buttress self esteem - reduce aggression

Here is a fascinating study from Thomaes et al. They conducted a randomized field trial in the Netherlands to assess the efficacy of a brief affirmation exercise designed to buttress self-esteem. Before the intervention, aggressive behavior was prevalent among the individuals who scored high on the narcissism scale and low on self-esteem. Afterward, acts of aggression decreased even though the individual levels of self-esteem (both high and low) were unchanged. Here is the abstract:
Narcissistic individuals are prone to become aggressive when their egos are threatened. We report a randomized field experiment that tested whether a social-psychological intervention designed to lessen the impact of ego threat reduces narcissistic aggression. A sample of 405 young adolescents (mean age = 13.9 years) were randomly assigned to complete either a short self-affirmation writing assignment (which allowed them to reflect on their personally important values) or a control writing assignment. We expected that the self-affirmation would temporarily attenuate the ego-protective motivations that normally drive narcissists' aggression. As expected, the self-affirmation writing assignment reduced narcissistic aggression for a period of a school week, that is, for a period up to 400 times the duration of the intervention itself. These results provide the first empirical demonstration that buttressing self-esteem (as opposed to boosting self-esteem) can be effective at reducing aggression in at-risk youth.

Wednesday, December 02, 2009

How's Your Gaydar?

From the random samples section of the Nov. 27 issue of Science:
Can you guess a woman's sexual orientation just from her face? Surprisingly, your guess would be better than flipping a coin....Psychologist Nicholas Rule of Tufts University in Medford, Massachusetts, and colleagues asked 21 college students the same question about 192 photos—cropped to eliminate hair and ears—of gay and straight women from dating Web sites. The undergraduates guessed right 64% of the time and scored better than chance—53%—even when they saw only the women's eyes, the researchers report this month in the Journal of Experimental Social Psychology. In 2008, Rule reported similar results with male faces.

The process appears to be unconscious, Rule says. Subjects were more accurate when told to make snap judgments than when they pondered their decisions. Rule believes subtle differences in facial muscles caused by habitual expressions may be the clue. Previous work has shown that homosexuals tend to adopt facial expressions more typical of the opposite sex. The results show that we know much more about others from snippets of information than we realize, says psychologist David Kenny of the University of Connecticut, Storrs.
Here is the abstract from Rule et al.
Whereas previous work has shown that male sexual orientation can be accurately and rapidly perceived from the human face and its individual features, no study has examined the judgment of female sexual orientation. To fill this gap, the current work examined the accuracy, speed, and automaticity of judgments of female sexual orientation from the face and from facial features. Study 1 showed that female sexual orientation could be accurately judged from the face and from just eyes without brows and limited to the outer canthi. Study 2 then examined the speed and efficiency of these judgments, showing that judgments of the faces following very brief, near subliminal (40 ms) exposures were significantly better than chance guessing. Finally, Study 3 tested the automaticity of judgments of female sexual orientation by examining the effects of deliberation on accuracy. Participants who made snap judgments of female sexual orientation were significantly more accurate than participants who made thoughtful and deliberated judgments. These data therefore evidence a robust, reliable, and automatic capacity for extracting information about female sexual orientation from nonverbal cues in the face.

Dietary specialization: man-eating lions

I thought this fascinating bit of work was a hoot. Two famous man-eating lions in the Tsavo region of Kenya were identified and shot in 1989, and these guys analyzed their diet from studies of the isotopes in their bones:
Cooperation is the cornerstone of lion social behavior. In a notorious case, a coalition of two adult male lions from Tsavo, southern Kenya, cooperatively killed dozens of railway workers in 1898. The “man-eaters of Tsavo” have since become the subject of numerous popular accounts, including three Hollywood films. Yet the full extent of the lions' man-eating behavior is unknown; estimates range widely from 28 to 135 victims. Here we use stable isotope ratios to quantify increasing dietary specialization on novel prey during a time of food limitation. For one lion, the δ13C and δ15N values of bone collagen and hair keratin (which reflect dietary inputs over years and months, respectively) reveal isotopic changes that are consistent with a progressive dietary specialization on humans. These findings not only support the hypothesis that prey scarcity drives individual dietary specialization, but also demonstrate that sustained dietary individuality can exist within a cooperative framework. The intensity of human predation (up to 30% reliance during the final months of 1898) is also associated with severe craniodental infirmities, which may have further promoted the inclusion of unconventional prey under perturbed environmental conditions.

The man-eaters of Tsavo and a Taita ancestral shrine. (A) Lieutenant Colonel J. H. Patterson and lion FMNH 23970 shot December 9, 1898 (16) (FMNH photo archives no. z93658, Field Museum of Natural History). (B) Articulated jaws of FMNH 23970 revealing a fractured lower right canine (and subsequent root-tip abscess), missing lower incisors, supererupted upper right incisors, and rotation and malocclusion of the upper right canine. Cranial asymmetry of 23970 occurred after injury and before death. (C) Lion FMNH 23969 shot December 29, 1898. (D) Articulated jaws of FMNH 23969, revealing a fractured upper left carnassial with a double pulp exposure. (E) A Taita ancestral shrine photographed in 1929 by L. S. B. Leakey. Such a shrine results from the unusual funerary practices of the Taita; after approximately 1 year of burial in a seated position, skulls are exhumed, severed, and enshrined in ancestral caves or rock shelters.

Facial plus vocal emotion - watching the brain's enhanced response

From Hagan et al:
An influential neural model of face perception suggests that the posterior superior temporal sulcus (STS) is sensitive to those aspects of faces that produce transient visual changes, including facial expression. Other researchers note that recognition of expression involves multiple sensory modalities and suggest that the STS also may respond to crossmodal facial signals that change transiently. Indeed, many studies of audiovisual (AV) speech perception show STS involvement in AV speech integration. Here we examine whether these findings extend to AV emotion. We used magnetoencephalography to measure the neural responses of participants as they viewed and heard emotionally congruent fear and minimally congruent neutral face and voice stimuli. We demonstrate significant supra-additive responses (i.e., where AV > [unimodal auditory + unimodal visual]) in the posterior STS within the first 250 ms for emotionally congruent AV stimuli. These findings show a role for the STS in processing crossmodal emotive signals.

Tuesday, December 01, 2009

Dieting, compulsive eating, and brain stress.

An interesting piece from Cottone et al:
Dieting to control body weight involves cycles of deprivation from palatable food that can promote compulsive eating. The present study shows that rats withdrawn from intermittent access to palatable food exhibit overeating of palatable food upon renewed access and an affective withdrawal-like state characterized by corticotropin-releasing factor-1 (CRF1) receptor antagonist-reversible behaviors, including hypophagia, motivational deficits to obtain less palatable food, and anxiogenic-like behavior. Withdrawal was accompanied by increased CRF expression and CRF1 electrophysiological responsiveness in the central nucleus of the amygdala. We propose that recruitment of anti-reward extrahypothalamic CRF-CRF1 systems during withdrawal from palatable food, analogous to abstinence from abused drugs, may promote compulsive selection of palatable food, undereating of healthier alternatives, and a negative emotional state when intake of palatable food is prevented.

Neural architecture of music-evoked autobiographical memories

Interesting work (open access article) from Janata:
The medial prefrontal cortex (MPFC) is regarded as a region of the brain that supports self-referential processes, including the integration of sensory information with self-knowledge and the retrieval of autobiographical information. I used functional magnetic resonance imaging and a novel procedure for eliciting autobiographical memories with excerpts of popular music dating to one's extended childhood to test the hypothesis that music and autobiographical memories are integrated in the MPFC. Dorsal regions of the MPFC (Brodmann area 8/9) were shown to respond parametrically to the degree of autobiographical salience experienced over the course of individual 30 s excerpts. Moreover, the dorsal MPFC also responded on a second, faster timescale corresponding to the signature movements of the musical excerpts through tonal space. These results suggest that the dorsal MPFC associates music and memories when we experience emotionally salient episodic memories that are triggered by familiar songs from our personal past. MPFC acted in concert with lateral prefrontal and posterior cortices both in terms of tonality tracking and overall responsiveness to familiar and autobiographically salient songs. These findings extend the results of previous autobiographical memory research by demonstrating the spontaneous activation of an autobiographical memory network in a naturalistic task with low retrieval demands.

Neural correlates of detecting wrong notes in advance.

I'm always fascinating by studies on the brains of pianists (like myself). This from Ruiz et al:
Music performance is an extremely rapid process with low incidence of errors even at the fast rates of production required. This is possible only due to the fast functioning of the self-monitoring system. Surprisingly, no specific data about error monitoring have been published in the music domain. Consequently, the present study investigated the electrophysiological correlates of executive control mechanisms, in particular error detection, during piano performance. Our target was to extend the previous research efforts on understanding of the human action-monitoring system by selecting a highly skilled multimodal task. Pianists had to retrieve memorized music pieces at a fast tempo in the presence or absence of auditory feedback. Our main interest was to study the interplay between auditory and sensorimotor information in the processes triggered by an erroneous action, considering only wrong pitches as errors. We found that around 70 ms prior to errors a negative component is elicited in the event-related potentials and is generated by the anterior cingulate cortex. Interestingly, this component was independent of the auditory feedback. However, the auditory information did modulate the processing of the errors after their execution, as reflected in a larger error positivity (Pe). Our data are interpreted within the context of feedforward models and the auditory–motor coupling.

Monday, November 30, 2009

Nutrition, brain aging, and neurodegeneration

Joseph et al. offer a review of recent work showing that dietary changes favoring berry fruit, nut, fish oil, and curcumin intake, as well as and caloric restriction mimetics (such as resveratrol) may provide beneficial effects in aging and prevent or delay the onset of neurodegenerative diseases such as Alzheimer disease. While many of the mechanisms for the beneficial effects of these nutritional interventions have yet to be discerned, it is clear that they involve decreases in oxidative/inflammatory stress signaling, increases in protective signaling, and may even involve hormetic effects to protect against the two major villains of aging, oxidative and inflammatory stressors. (Hormetic is a term used to describe generally-favorable biological responses to low exposures to toxins and other stressors.)

The fMRI of understanding others' regret.

Rizzolatti and colleagues carry the mirror neuron story to an even higher level in a study of regret:
Previous studies showed that the understanding of others' basic emotional experiences is based on a “resonant” mechanism, i.e., on the reactivation, in the observer's brain, of the cerebral areas associated with those experiences. The present study aimed to investigate whether the same neural mechanism is activated both when experiencing and attending complex, cognitively-generated, emotions. A gambling task and functional-Magnetic-Resonance-Imaging (fMRI) were used to test this hypothesis using regret, the negative cognitively-based emotion resulting from an unfavorable counterfactual comparison between the outcomes of chosen and discarded options. Do the same brain structures that mediate the experience of regret become active in the observation of situations eliciting regret in another individual? Here we show that observing the regretful outcomes of someone else's choices activates the same regions that are activated during a first-person experience of regret, i.e. the ventromedial prefrontal cortex, anterior cingulate cortex and hippocampus. These results extend the possible role of a mirror-like mechanism beyond basic emotions.