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.
This blog reports new ideas and work on mind, brain, behavior, psychology, and politics - as well as random curious stuff. (Try the Dynamic Views at top of right column.)
Wednesday, December 30, 2009
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:
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.
From Siegal et al's abstract:
...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.
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.
Blog Categories:
attention/perception,
memory/learning
Thursday, December 24, 2009
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
'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
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.
Blog Categories:
acting/choosing,
culture/politics,
technology
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.
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