Aging - How alcohol is good for you

Numerous studies have shown that non-drinkers tend to die before moderate drinkers. Jonah Lehrer points to a striking (and reassuring to me) long term study that fills in more detail, finding over a period of twenty years that the death rate among non-drinkers is twice that of moderate drinkers. Chunks from the abstract:

The sample at baseline included 1,824 individuals between the ages of 55 and 65. The database at baseline included information on daily alcohol consumption, sociodemographic factors, former problem drinking status, health factors, and social-behavioral factors. Abstention was defined as abstaining from alcohol at baseline. Death across a 20-year follow-up period was confirmed primarily by death certificate.

Controlling only for age and gender, compared to moderate drinkers, abstainers had a more than 2 times increased mortality risk, heavy drinkers had 70% increased risk, and light drinkers had 23% increased risk. A model controlling for former problem drinking status, existing health problems, and key sociodemographic and social-behavioral factors, as well as for age and gender, substantially reduced the mortality effect for abstainers compared to moderate drinkers. However, even after adjusting for all covariates, abstainers and heavy drinkers continued to show increased mortality risks of 51 and 45%, respectively, compared to moderate drinkers.

Leher notes that apart from anti-aging antioxidant or cardiac and circulatory effects of alcohol, a correlation of alcohol and socializing and its chemical correlates (dopamine, oxytocin, etc.) should be considered.

A Dictionary of the Near Future

Douglas Coupland has produced a clever and alarming dictionary of the near future (which seems to actually be applying to the present moment). Here are just a few of his entries:

BELL’S LAW OF TELEPHONY No matter what technology is used, your monthly phone bill magically remains about the same size.
DENARRATION The process whereby one’s life stops feeling like a story.
DESELFING Willingly diluting one’s sense of self and ego by plastering the Internet with as much information as possible. (See also Omniscience Fatigue; Undeselfing)
DIMANCHOPHOBIA Fear of Sundays, a condition that reflects fear of unstructured time. Also known as acalendrical anxiety.
FICTIVE REST The inability of many people to fall asleep until after reading even the tiniest amount of fiction.
FRANKENTIME What time feels like when you realize that most of your life is spent working with and around a computer and the Internet.
INSTANT REINCARNATION The fact that most adults, no matter how great their life is, wish for radical change in their life. The urge to reincarnate while still alive is near universal.
INTRAVINCULAR FAMILIAL SILENCE We need to be around our families not because we have so many shared experiences to talk about, but because they know precisely which subjects to avoid.
INTERNAL VOICE BLINDNESS The near universal inability of people to articulate the tone and personality of the voice that forms their interior monologue.
MALFACTORY AVERSION The ability to figure out what it is in life you don’t do well, and then to stop doing it.
OMNISCIENCE FATIGUE The burnout that comes with being able to know the answer to almost anything online.
PROCELERATION The acceleration of acceleration.
PSEUDOALIENATION The inability of humans to create genuinely alienating situations. Anything made by humans is a de facto expression of humanity. Technology cannot be alienating because humans created it. Genuinely alien technologies can be created only by aliens. Technically, a situation one might describe as alienating is, in fact, “humanating.”
ROSENWALD’S THEOREM The belief that all the wrong people have self-esteem.
UNDESELFING The attempt, usually frantic and futile, to reverse the deselfing process.

(please ignore -technorati probe- YFTQH7ZAY5KS)

Men's dance moves that catch a woman's eyes.

A loyal mindblog follower who occasionally sends me stuff he finds interesting has just forwarded this gem,  the associated videos are here and here.   The abstract:

Male movements serve as courtship signals in many animal species, and may honestly reflect the genotypic and/or phenotypic quality of the individual. Attractive human dance moves, particularly those of males, have been reported to show associations with measures of physical strength, prenatal androgenization and symmetry. Here we use advanced three-dimensional motion-capture technology to identify possible biomechanical differences between women's perceptions of ‘good’ and ‘bad’ male dancers. Nineteen males were recorded using the ‘Vicon’ motion-capture system while dancing to a basic rhythm; controlled stimuli in the form of avatars were then created in the form of 15 s video clips, and rated by 39 females for dance quality. Initial analyses showed that 11 movement variables were significantly positively correlated with perceived dance quality. Linear regression subsequently revealed that three movement measures were key predictors of dance quality; these were variability and amplitude of movements of the neck and trunk, and speed of movements of the right knee. In summary, we have identified specific movements within men's dance that influence women's perceptions of dancing ability. We suggest that such movements may form honest signals of male quality in terms of health, vigour or strength, though this remains to be confirmed.

Differences in brain connectivity drive cognitive differences

Forstmann et al. do some interesting work on examining pathways that regulate how readily we respond (i.e. decrease response thresholds) to decisions varying in their demands for speed versus accuracy. The figure showing the relevant structures (the striatum and subthalmic nucleus in the basal ganglia which are regulated by the cortex, click to enlarge) is taken from an academic website. Their abstract:

When people make decisions they often face opposing demands for response speed and response accuracy, a process likely mediated by response thresholds. According to the striatal hypothesis, people decrease response thresholds by increasing activation from cortex to striatum, releasing the brain from inhibition. According to the STN hypothesis, people decrease response thresholds by decreasing activation from cortex to subthalamic nucleus (STN); a decrease in STN activity is likewise thought to release the brain from inhibition and result in responses that are fast but error-prone. To test these hypotheses—both of which may be true—we conducted two experiments on perceptual decision making in which we used cues to vary the demands for speed vs. accuracy. In both experiments, behavioral data and mathematical model analyses confirmed that instruction from the cue selectively affected the setting of response thresholds. In the first experiment we used ultra-high-resolution 7T structural MRI to locate the STN precisely. We then used 3T structural MRI and probabilistic tractography to quantify the connectivity between the relevant brain areas. The results showed that participants who flexibly change response thresholds (as quantified by the mathematical model) have strong structural connections between presupplementary motor area and striatum. This result was confirmed in an independent second experiment. In general, these findings show that individual differences in elementary cognitive tasks are partly driven by structural differences in brain connectivity. Specifically, these findings support a cortico-striatal control account of how the brain implements adaptive switches between cautious and risky behavior.

The brain's fight against aging

Numerous studies have documented diminution in sensory and cognitive functions with aging, but very little is known about what is actually happening to cells in the brain. Knowing more about structural alterations as the brain ages is essential to understanding functional and cognitive changes. Richard et al.have used a simplified cortical model, the olfactory bulb in the mouse brain, to show, somewhat surprisingly, overall stability of structure and no neurodegeneration with aging. What they do observe is fine synaptic alterations that affect selected cellular compartments, and losses of synapses in specific layers. (The olfactory bulb sensory cortex is an appropriate model because it has well-known synaptic organization, and its normal and pathological aging is associated with impairment of food intake and reduced health.)

Little is known about how normal aging affects the brain. Recent evidence suggests that neuronal loss is not ubiquitous in aging neocortex. Instead, subtle and still controversial, region- and layer-specific alterations of neuron morphology and synapses are reported during aging, leading to the notion that discrete changes in neural circuitry may underlie age-related cognitive deficits. Although deficits in sensory function suggest that primary sensory cortices are affected by aging, our understanding of the age-related cellular and molecular changes is sparse. To assess the effect of aging on the organization of olfactory bulb (OB) circuitry, we carried out quantitative morphometric analyses in the mouse OB at 2, 6, 12, 18, and 24 mo. Our data establish that the volumes of the major OB layers do not change during aging. Parallel to this, we are unique in demonstrating that the stereotypic glomerular convergence of M72-GFP OSN axons in the OB is preserved during aging. We then provide unique evidence of the stability of projection neurons and interneurons subpopulations in the aging mouse OB, arguing against the notion of an age-dependent widespread loss of neurons. Finally, we show ultrastructurally a significant layer-specific loss of synapses; synaptic density is reduced in the glomerular layer but not the external plexiform layer, leading to an imbalance in OB circuitry. These results suggest that reduction of afferent synaptic input and local modulatory circuit synapses in OB glomeruli may contribute to specific age-related alterations of the olfactory function.

Seeking emotional support - effects of oxytocin gene and cultural variation.

Certain genotypes are expressed in different forms depending upon the harshness/beneficence of social conditions; examples include the serotonin transporter gene, the monoamine oxidase A gene, the dopamine receptor gene seven-repeat polymorphism, and the glucocorticoid receptor gene. Genetic variations in these can influence expression of depressive and antisocial behaviors.
Kim et al now show that an oxytocin receptor, depending on its specific genotype, is sensitive to social environment, specifically cultural norms regarding emotional social support seeking. Seeking emotional support in times of distress is normative in American culture but not in Korean culture. American participants with a GG/AG genotypes reported seeking more emotional social support than those with a AA genotype, but Korean participants did not differ by genotype. The abstract:

Research has demonstrated that certain genotypes are expressed in different forms, depending on input from the social environment. To examine sensitivity to cultural norms regarding emotional support seeking as a type of social environment, we explored the behavioral expression of oxytocin receptor polymorphism (OXTR) rs53576, a gene previously related to socio-emotional sensitivity. Seeking emotional support in times of distress is normative in American culture but not in Korean culture. Consequently, we predicted a three-way interaction of culture, distress, and OXTR genotype on emotional support seeking. Korean and American participants (n = 274) completed assessments of psychological distress and emotional support seeking and were genotyped for OXTR. We found the predicted three-way interaction: among distressed American participants, those with the GG/AG genotypes reported seeking more emotional social support, compared with those with the AA genotype, whereas Korean participants did not differ significantly by genotype; under conditions of low distress, OXTR groups did not differ significantly in either cultural group. These findings suggest that OXTR rs53576 is sensitive to input from the social environment, specifically cultural norms regarding emotional social support seeking. These findings also indicate that psychological distress and culture are important moderators that shape behavioral outcomes associated with OXTR genotypes.

Learning tricks

Benedict Carey does a nice summary of what we do and don't know about different approaches to enhancing learning.

Take the notion that children have specific learning styles, that some are “visual learners” and others are auditory; some are “left-brain” students, others “right-brain.” In a recent review... in the journal Psychological Science in the Public Interest, a team of psychologists found almost zero support for such ideas...Ditto for teaching styles...Some excellent instructors caper in front of the blackboard like summer-theater Falstaffs; others are reserved to the point of shyness...the common threads between teachers who create a constructive learning atmosphere have not been determined

In recent years, cognitive scientists have shown that a few simple techniques can reliably improve what matters most: how much a student learns from studying…For instance, instead of sticking to one study location, simply alternating the room where a person studies improves retention. So does studying distinct but related skills or concepts in one sitting, rather than focusing intensely on a single thing.

Varying the type of material studied in a single sitting — alternating, for example, among vocabulary, reading and speaking in a new language — seems to leave a deeper impression on the brain than does concentrating on just one skill at a time. Musicians have known this for years, and their practice sessions often include a mix of scales, musical pieces and rhythmic work. Many athletes, too, routinely mix their workouts with strength, speed and skill drills.

When the neural suitcase is packed carefully and gradually, it holds its contents for far, far longer. An hour of study tonight, an hour on the weekend, another session a week from now: such so-called spacing improves later recall…cognitive scientists see testing itself — or practice tests and quizzes — as a powerful tool of learning, rather than merely assessment. The process of retrieving an idea is not like pulling a book from a shelf; it seems to fundamentally alter the way the information is subsequently stored, making it far more accessible in the future.

None of ... these techniques — alternating study environments, mixing content, spacing study sessions, self-testing or all the above — will turn a grade-A slacker into a grade-A student. Motivation matters.

The anxiolytic power of religion

Inzlicht and Tullett add a bit of information to the growing field of the cognitive science of religion (which examines religious beliefs as a natural by-product of the way human minds and brains work, meeting a number of people’s myriad needs.) They find that a brain activity related to defensive responses to error (a sort of cortical 'alarm bell') is lower in religious than in non-religious individuals:

The world is a vast and complex place that can sometimes generate feelings of uncertainty and distress for its inhabitants. Although religion is associated with a sense of meaning and order, it remains unclear whether religious belief can actually cause people to feel less anxiety and distress. To test the anxiolytic power of religion, we conducted two experiments focusing on the error-related negativity (ERN)—a neural signal that arises from the anterior cingulate cortex and is associated with defensive responses to errors. The results indicate that for believers, conscious and nonconscious religious primes cause a decrease in ERN amplitude. In contrast, priming nonbelievers with religious concepts causes an increase in ERN amplitude. Overall, examining basic neurophysiological processes reveals the power of religion to act as a buffer against anxious reactions to self-generated, generic errors—but only for individuals who believe.

Google’s Earth

Well known author William Gibson (Neuromancer, and its sequels) does a brief NYTimes Op-Ed essay in which he discusses Google. His starting point is a controversial interview with Eric Schmidt, Google's chief executive, in which Schmidt says:

…I ACTUALLY think most people don’t want Google to answer their questions. They want Google to tell them what they should be doing next.

Gibson notes that Google is:

...a distributed entity, a two-way membrane, a game-changing tool on the order of the equally handy flint hand ax, with which we chop our way through the very densest thickets of information…it makes everything in the world accessible to everyone, and everyone accessible to the world. But we see everyone looking in, and blame Google…Google is made of us, a sort of coral reef of human minds and their products. And still we balk at Mr. Schmidt’s claim that we want Google to tell us what to do next.

We never imagined that artificial intelligence would be like this. We imagined discrete entities. Genies. We also seldom imagined (in spite of ample evidence) that emergent technologies would leave legislation in the dust, yet they do. In a world characterized by technologically driven change, we necessarily legislate after the fact, perpetually scrambling to catch up, while the core architectures of the future, increasingly, are erected by entities like Google.

Cyberspace, not so long ago, was a specific elsewhere, one we visited periodically, peering into it from the familiar physical world. Now cyberspace has everted. Turned itself inside out. Colonized the physical. Making Google a central and evolving structural unit not only of the architecture of cyberspace, but of the world…We are part of a post-geographical, post-national super-state, one that handily says no to China. Or yes, depending on profit considerations and strategy. But we do not participate in Google on that level. We’re citizens, but without rights.

On the possibility of fresh identities for those who have exposed their private lives in the cloud:

I imagine that those who are indiscreet on the Web will continue to have to make the best of it, while sharper cookies, pocketing nyms and proxy cascades (as sharper cookies already do), slouch toward an ever more Googleable future, one in which Google, to some even greater extent than it does now, helps us decide what we’ll do next.

Laughter therapy

The August 30 issue of The New Yorker has an engaging article on Madan Kataria, "The Laughing Guru."  Research in the field of psychoneuroimmunology has by now provided abundant evident that the opposite of laughter or light-heartedness - depression, stress, fear, or social isolation - can diminish health and suppress the immune system.  Kataria's international Laughter Yoga movement is based on the premise that laughter boosts health and the immune system.  Norman Cousins, who was editor of Saturday Review, wrote an influential book "Anatomy of an Illness" that described how genuine belly laughter lessened his pain from a joint disease,  and several studies have shown that laughter therapy lessens pain in cancer patients.  Other work has suggested that laughter may cause transient decreases in cortisol (stress hormone) and increases in endorphin (analgesic) levels, but Robert Provine and others have carried out exhaustive scientific reviews on laughter, humor, and health that conclude that there is not enough evidence of conclude much of anything, other perhaps than laughter can briefly limit physical pain.

I'm inclined to believe that there might be more to it, given numerous example of our embodied cognition. An instruction to contract the facial muscles that form a smile (with no instructions on accompanying feelings) causes slight enhancement of left/right frontal brain activity associated with more positive affect (elevation of mood), and small Botox injections that temporarily immobilize parts of the face can limit one's ability to express or feel emotions.   These effects are transient,  but it seems plausible to me that repetition of mechanical smiling exercises might enhance mood for  extended periods of time,  just as repeated meditation practice can decrease brain noise.  

Language shaping cognition - a followup

Relevant to today's other post on this topic, a MindBlog reader has just pointed out another good article, from the Sept. 1 New Scientist, on how words shape and enhance our cognition. The article has several links to relevant research, such as this article I was about to do a mindblog post on next week, on how assigning nonsense labels facilitates the learning of novel categories.

How language shapes our thinking

Just after drafting Monday's post  on how cultural setting shapes our visual cognition,  I read an excellent article by Guy Deutscher in the Sunday NYTimes Magazine, on how language shapes our thinking.  He starts by reviewing the story of the rise and fall of "the Whorfian hypothesis,"  which maintained that if a language had no term for a concept (such as the future), then the speaker of that language would not be able to grasp the concept in the sense that we can.  Hard data crashed the hypothesis, and the counter reaction was so severe that for many years no limits of language on basic cognition have been admitted.  How it turns out that the baby may have been thrown out with the bathwater. Some clips from the article, starting with some fact about differences between languages pointed out 50 years ago by linguist Roman Jakobson:

Languages differ essentially in what they must convey and not in what they may convey...if different languages influence our minds in different ways, this is not because of what our language allows us to think but rather because of what it habitually obliges us to think about.

In recent years, various experiments have shown that grammatical genders can shape the feelings and associations of speakers toward objects around them. In the 1990s, for example, psychologists compared associations between speakers of German and Spanish. There are many inanimate nouns whose genders in the two languages are reversed. A German bridge is feminine (die Brücke), for instance, but el puente is masculine in Spanish; and the same goes for clocks, apartments, forks, newspapers, pockets, shoulders, stamps, tickets, violins, the sun, the world and love...When speakers were asked to grade various objects on a range of characteristics, Spanish speakers deemed bridges, clocks and violins to have more “manly properties” like strength, but Germans tended to think of them as more slender or elegant.

Of course, all this does not mean that speakers of Spanish or French or German fail to understand that inanimate objects do not really have biological sex — a German woman rarely mistakes her husband for a hat, and Spanish men are not known to confuse a bed with what might be lying in it...Did the opposite genders of “bridge” in German and Spanish, for example, have an effect on the design of bridges in Spain and Germany? Do the emotional maps imposed by a gender system have higher-level behavioral consequences for our everyday life?

The area where the most striking evidence for the influence of language on thought has come to light is the language of space — how we describe the orientation of the world around us...egocentric coordinates...depend on our own bodies: a left-right axis and a front-back axis orthogonal to it. The second system uses fixed geographic directions, which do not rotate with us wherever we turn... a remote Australian aboriginal tongue, Guugu Yimithirr, doesn’t make any use of egocentric coordinates at all...Guugu Yimithirr does not use words like “left” or “right,” “in front of” or “behind,” to describe the position of objects. Whenever we would use the egocentric system, the Guugu Yimithirr rely on cardinal directions. If they want you to move over on the car seat to make room, they’ll say “move a bit to the east.” To tell you where exactly they left something in your house, they’ll say, “I left it on the southern edge of the western table.”...languages that rely primarily on geographical coordinates are scattered around the world, from Polynesia to Mexico, from Namibia to Bali.

How does this work? The convention of communicating with geographic coordinates compels speakers from the youngest age to pay attention to the clues from the physical environment (the position of the sun, wind and so on) every second of their lives..This habit of constant awareness to the geographic direction is inculcated almost from infancy...When Guugu Yimithirr speakers were asked how they knew where north is, they couldn’t explain it any more than you can explain how you know where “behind” is.

Recently, it has been demonstrated in a series of ingenious experiments that we even perceive colors through the lens of our mother tongue. There are radical variations in the way languages carve up the spectrum of visible light; for example, green and blue are distinct colors in English but are considered shades of the same color in many languages. And it turns out that the colors that our language routinely obliges us to treat as distinct can refine our purely visual sensitivity to certain color differences in reality, so that our brains are trained to exaggerate the distance between shades of color if these have different names in our language. As strange as it may sound, our experience of a Chagall painting actually depends to some extent on whether our language has a word for blue.

Sealing the emotions genie

Need to put out of mind an unpleasant memory or unfulfilled desire? By offering yet another example of embodied cognition and metaphorical thinking Li et al. may have just the trick for you:

This research investigated whether the physical act of enclosing an emotionally laden stimulus can help alleviate the associated negative emotions. Four experiments found support for this claim. In the first two experiments, emotional negativity was reduced for participants who placed a written recollection of a regretted past decision or unsatisfied strong desire inside an envelope. A further experiment showed that enclosing a stimulus unrelated to the emotional experience did not have the same effect. Finally, we showed that the effect was not driven by participants simply doing something extra with the materials, and that the effect of physical enclosure was mediated by the psychological closure that participants felt toward the event.

Robbed of lasting pleasures by drugs

Friedman does a nice summary of the course of drug addiction and withdrawal,  noting work on brain correlates of the craving that persists after drug highs have ceased and drug usage has stopped. 

Money looms larger to the powerless.

DuBois et al. make observations on an accentuation bias. They explore:

...how people’s place in a power hierarchy alters their representations of valued objects. The authors hypothesized that powerlessness produces an accentuation bias by altering the physical representation of monetary objects in a manner consistent with the size-to-value relationship. In the first three experiments, powerless participants, induced through episodic priming or role manipulations, systematically overestimated the size of objects associated with monetary value (i.e., quarters, poker chips) compared to powerful and baseline participants. However, when value was inversely associated with size (i.e., smaller objects were more valuable), the powerless drew these valued objects smaller, not larger. In addition, the accentuation bias by the powerless was more pronounced when the monetary value associated with the object was greater, increased when the object was physically present, and was mediated by differences in subjective value. These findings suggest that powerlessness fosters compensatory processes that guide representations of valued objects.

Social learning - The importance of copying others

In the August 24 issue of Current Biology Grüter et al. offer a description of experiments on social learning carried out by Rendell et al. that enhance the description given in the abstract of the original paper:

In humans, learning by observing or asking others can save time and effort. For example, a traveler can bypass the need to check out the numerous available restaurants in an unknown city by asking the residents where there is a good place to eat. However, relying on others can be a risky strategy. The person you rely on might have a different taste, a bad memory, or not have visited a restaurant for years. An inability to avoid out-of-date or unreliable information is considered a major pitfall of social learning. As a consequence, theory has predicted that both individuals and populations should usually employ a mixture of both social and individual learning. A new study by Rendell et al. challenges this view and argues that social learning is usually superior.... Inspired by a classic evolutionary tournament that investigated the evolution of cooperation, Rendell et al. organised a computer tournament in which social learning strategies, submitted by entrants, competed in a game of natural selection for a 10,000 Euro prize. Each strategy specified when an individual should copy another, when it should gather its own information, and when it should simply use the information it had already acquired. They found that the strategies that performed best relied almost exclusively on social learning. Because ‘demonstrators’ have information about the expected pay-off of different behaviours, they selectively perform those that are most beneficial for themselves. By doing so, they inadvertently filter information for all other individuals in the population. As a result, individuals relying mostly on copying acquire high-payoff behaviours as well.

Here is the Rendell et al abstract:

Social learning (learning through observation or interaction with other individuals) is widespread in nature and is central to the remarkable success of humanity, yet it remains unclear why copying is profitable and how to copy most effectively. To address these questions, we organized a computer tournament in which entrants submitted strategies specifying how to use social learning and its asocial alternative (for example, trial-and-error learning) to acquire adaptive behavior in a complex environment. Most current theory predicts the emergence of mixed strategies that rely on some combination of the two types of learning. In the tournament, however, strategies that relied heavily on social learning were found to be remarkably successful, even when asocial information was no more costly than social information. Social learning proved advantageous because individuals frequently demonstrated the highest-payoff behavior in their repertoire, inadvertently filtering information for copiers. The winning strategy (discountmachine) relied nearly exclusively on social learning and weighted information according to the time since acquisition.

Doing good (or evil) increases physical strength

Kurt Gray offers some interesting observations on the embodyment of moral typecasting:

Moral transformation is the hypothesis that doing good or evil increases agency—the capacity for self-control, tenacity, and personal strength. Three experiments provide support for this hypothesis, finding that those who do good or evil become physically more powerful. In Experiment 1, people hold a 5 lb. weight longer after donating to charity. In Experiment 2, people hold a weight longer when writing about themselves helping or harming another. In Experiment 3, people hold a hand grip longer after donating to charity. The transformative power of good and evil is not accounted for by affect. Moral transformation is explained as the embodiment of moral typecasting, the tendency to “typecast” good- and evildoers as more capable of agency and less sensitive to experience. This has implications for power, aging, self-control, and recovery.

Making decisions: Optimally interacting minds

Bahrami et al. find conditions under which two heads are - and are not - better than one. Science Magazine gives a nice summary:

When two people peer into the distance and try to figure out if a faint number is a three or an eight, classical signal detection theory states that the joint decision can only be as good as that of the person with higher visual acuity. Bahrami et al. propose that a discussion not only of what each person perceives but also of the degree of confidence in those assignments can improve the overall sensitivity of the decision. Using a traditional contrast-detection task, they showed that, when the individuals did not differ too much in their powers of visual discrimination, collective decision-making significantly improved sensitivity. The model offered here formalizes debates held since the Enlightenment about whether collective thinking can outperform that of elite individuals.

The Bahrami et al. abstract:

In everyday life, many people believe that two heads are better than one. Our ability to solve problems together appears to be fundamental to the current dominance and future survival of the human species. But are two heads really better than one? We addressed this question in the context of a collective low-level perceptual decision-making task. For two observers of nearly equal visual sensitivity, two heads were definitely better than one, provided they were given the opportunity to communicate freely, even in the absence of any feedback about decision outcomes. But for observers with very different visual sensitivities, two heads were actually worse than the better one. These seemingly discrepant patterns of group behavior can be explained by a model in which two heads are Bayes optimal under the assumption that individuals accurately communicate their level of confidence on every trial.

Religion and spatial cognition

The latest Science Magazine 'Editor's choice' points to an interesting bit of work. It is well known that East Asians see visual scenes via a holistic mindset in contrast to the Western style of focusing on salient objects. Variation within these cultural categories (between Chinese and Japanese, for example) can be shown. Colzato et al. have looked at the linkage between religious upbringing and visual perception in three somewhat less heterogeneous populations—neo-Calvinists in the Netherlands, Roman Catholics in Italy, and Orthodox Jews in Israel—and found that adherents of each of these religions differed from atheists of the same cultural background. The Calvinists, whose tradition emphasizes the role of the individual, showed greater visual attentiveness to local features, whereas the big picture perspective was favored by Catholics and Jews, whose traditions stress social togetherness. The abstract:

Religion is commonly defined as a set of rules, developed as part of a culture. Here we provide evidence that practice in following these rules systematically changes the way people attend to visual stimuli, as indicated by the individual sizes of the global precedence effect (better performance to global than to local features). We show that this effect is significantly reduced in Calvinism, a religion emphasizing individual responsibility, and increased in Catholicism and Judaism, religions emphasizing social solidarity. We also show that this effect is long-lasting (still affecting baptized atheists) and that its size systematically varies as a function of the amount and strictness of religious practices. These findings suggest that religious practice induces particular cognitive-control styles that induce chronic, directional biases in the control of visual attention.

More trusting people are better lie detectors

Carter and Weber make the interesting counter-intuitive observation that being a pollyanna does not make one more gullible (cf. with my Aug. 24 post). Their research:

...used a job interview context to investigate the relationship between peoples’ degrees of generalized trust—their default assessments of the likely trustworthiness of others—and their ability to detect lies. Participants watched videos of eight simulated job interviews: Half of the interviewees were completely truthful; half told a variety of lies to make themselves more attractive job candidates. Contrary to lay wisdom, high trusters were significantly better than low trusters were at detecting lies. This finding extends a growing body of theoretical and empirical work suggesting that high trusters are far from foolish Pollyannas and that low trusters’ defensiveness incurs significant costs.