Features of Einstein's brain.

Clips from Michael Balter's recent report:

The first anatomical study of Einstein's brain was published in 1999, by a team led by Sandra Witelson, a neurobiologist at McMaster University in Hamilton, Canada..Witelson's team found that Einstein's parietal lobes--which are implicated in mathematical, visual, and spatial cognition--were 15% wider than normal parietal lobes...One parameter that did not explain Einstein's mental prowess, however, was the size of his brain: At 1230 grams, it fell at the low end of average for modern humans. Now Dean Falk, an anthropologist at Florida State University in Tallahassee...claims to have identified a number of previously unrecognized unusual features in Einstein's brain. They include a pronounced knoblike structure in the part of the motor cortex that controls the left hand; in other studies, similar "knobs" have been associated with musical ability. (Einstein had played the violin avidly since childhood.)

Like Witelson's team, Falk found that Einstein's parietal lobes were larger; comparing the photographs of Einstein's brain with a second previously published set of 58 control brains, Falk also identified a very rare pattern of grooves and ridges in the parietal regions of both sides of the brain that she speculates might somehow be related to Einstein's superior ability to conceptualize physics problems. Indeed, during his lifetime, Einstein often claimed that he thought in images and sensations rather than in words. Falk speculates that Einstein's talent as "a synthetic thinker" may have arisen from the unusual anatomy of his parietal cortex.

Juicing up your brain

"Every era has its defining drug. Neuroenhancers are perfectly suited for our efficiency-obsessed, BlackBerry-equipped office culture." Margaret Talbot writes an interesting article on the underground world of performance enhancing drugs in the New Yorker, covering benefits and pitfalls. Given that chemicals enhancing our sex life and beauty are commonly taken, it is not surprising that there is growing use of drugs enhancing our smarts.

The emerging bottom-up world order?

Two interesting articles on the kind of world order (or disorder) that is likely to emerge in the 21st century. David Brooks notes that:

We face a series of decentralized, transnational threats: jihadi terrorism, a global financial crisis, global warming, energy scarcity, nuclear proliferation and...possible health pandemics like swine flu...Do we build centralized global institutions that are strong enough to respond to transnational threats? Or do we rely on diverse and decentralized communities and nation-states?..The response to swine flu suggests that a decentralized approach is best. This crisis is only days old, yet we’ve already seen a bottom-up, highly aggressive response.

First, the decentralized approach is much faster. Mexico responded unilaterally and aggressively to close schools and cancel events. The U.S. has responded with astonishing speed, considering there are still few illnesses and just one hospitalization...Second, the decentralized approach is more credible. It is a fact of human nature that in times of crisis, people like to feel protected by one of their own. They will only trust people who share their historical experience, who understand their cultural assumptions about disease and the threat of outsiders and who have the legitimacy to make brutal choices...Finally, the decentralized approach has coped reasonably well with uncertainty. It is clear from the response, so far, that there is an informal network of scientists who have met over the years and come to certain shared understandings about things like quarantining and rates of infection.

A single global response would produce a uniform approach. A decentralized response fosters experimentation...The correct response to these dynamic, decentralized, emergent problems is to create dynamic, decentralized, emergent authorities: chains of local officials, state agencies, national governments and international bodies that are as flexible as the problem itself.

Kakutani reviews "The Age of the Unthinkable" by J. C. Ramo. Ramo argues:

that today’s complex, interconnected, globalized world requires policy makers willing to toss out old assumptions (about cause and effect, deterrence and defense, nation states and balances of power) and embrace creative new approaches...The central image that Mr. Ramo uses to evoke what he calls this “age of surprise” is Per Bak’s sand pile — that is, a sand pile described some two decades ago by the Danish-American physicist Per Bak, who argued that if grains of sand were dropped on a pile one at a time, the pile, at some point, would enter a critical state in which another grain of sand could cause a large avalanche — or nothing at all. It’s a hypothesis that shows that a small event can have momentous consequences and that seemingly stable systems can behave in highly unpredictable ways...It’s also a hypothesis that Mr. Ramo employs as a metaphor for a complex world in which changes — in politics, ecosystems or financial markets — take place not in smooth, linear progressions but as sequences of fast, sometimes catastrophic events.

So how should leaders cope with the sand-pile world? How can they learn to “ride the earthquake” and protect their countries from the worst fallout of such tremors? Mr. Ramo suggests that they must learn to build resilient societies with strong immune systems: instead of undertaking the impossible task of trying to prepare for every possible contingency, they ought to focus on things like national health care, construction of a better transport infrastructure and investment in education...leaders should develop ways of looking at problems that focus more on context than on reductive answers. And he talks about people learning to become gardeners instead of architects, of embracing Eastern ideas of indirection instead of Western patterns of confrontation, of seeing “threats as systems, not objects.”

Born to be Good

I have just thoroughly enjoyed a reading of Dacher Keltner's book "Born to be Good." Keltner, a former student of Paul Ekman, starts with Darwin's acute observations on human emotions, describes Ekman's pioneering work on innate human facial communication, and then proceeds through chapters on embarassment, smiling, laughing, teasing, touching, compassion and awe. He documents work of his own and others that demonstrates evolved stereotyped facial and body movement patterns characteristic of each of these behaviors. The video is a brief promo of the book.

The quest for compassion

Greg Miller writes (PDF here) on the establishment of a new institute at Stanford University for the scientific study of compassion.

Enlightenment therapy?

I found myself disappointed by what at first appeared to be a promising article in this past Sunday’s NY Times magazine: “Enlightenment Therapy” by Chip Brown. It relates the interaction of a 63-year old professor who renounced a tenured professorship in philosophy to become a Zen Buddhist monk 35 years ago and a psychotherapist who has published a series of books on psychotherapy and Buddhism. A detailed account of the professor’s childhood traumas, and their effect on his adult life, is given, but it seems a pity that the article is almost completely lacking in any broader reference to other religious figures and psychiatrists (Alan Wallace and Mark Epstein come to mind) who have been very influential in integrating Buddhist and Psychoanalytic insights. Even more puzzling is the absence of reference to discoveries in cognitive neuroscience that validate the insights of both traditions (noted by integrative writers such as philosopher Thomas Metzinger and trade writer Alan Nisker).

Econophysics - a model that explains the crash

I thought I would pass on this report by Cho, slightly edited, on a model that shows leverage to be the root of the current financial turmoil:

During the 1990s, physicists flocked to Wall Street and other financial hubs, eager to turn their analytical skills and phenomenological mindset to the problem of making a killing. Now that the world's stock markets are in retreat, they've turned to explaining why markets crash. According to one new analysis, leverage—the practice by hedge funds and other investors of borrowing money to buy investments—is the root of many nettlesome properties of financial markets that classical economics cannot explain, including a propensity to crash.

Given that in the buildup to the recent global economic meltdown hedge funds had been leveraging their deals by ratios of 30-to-1 (that is, borrowing $30 for every $1 of their own that they put in), it may seem obvious that massive leverage leads to trouble. But Stefan Thurner, an econophysicist and director of the complex systems research group at the Medical University of Vienna, Austria, and colleagues say their model shows that many of the distinctive statistical properties of financial markets emerge together as rates of leverage climb.

Financial markets behave in ways that... classical economic theory cannot explain. Classical economics assumes that the fluctuations in stock prices conform to a so-called Gaussian distribution—a bell curve that gives little probability to large swings. In reality, the distribution has "fat tails" that make big changes more likely, and the shapes of those tails conform to a mathematical formula known as a power law. Classical economics assumes that the fluctuations are uncorrelated from one moment to the next, whereas big swings in prices tend to come together in the so-called clustering of volatility.

To try to explain those characteristics, over the past 5 years Thurner and colleagues have developed an "agent-based model" of a market. In such a computer model, virtual agents of various types interact according to certain rules, like robots playing a game. The researchers included hedge funds that could borrow to make their investments; banks to loan the money; "noise investors" who, like day traders, simply react to the market and have no other insight into the value of assets; and general investors who played the role of, for example, state pension funds.

The model contains more than a dozen adjustable parameters. However, Thurner and colleagues found that the maximum level of leverage exerts a curious, unifying effect. If they forbade leverage, the market behaved largely as classical economics would predict. But as they increased the maximum leverage, the characteristics of real markets emerged together. "We can explain the fat tails, the right [power law], the clustering of volatility, all this," Thurner says. And when the leverage limit climbed to levels of 5-to-1 and beyond, the market became unstable and hedge funds went bust much more often.

Thurner, who managed a hedge fund that tanked, says that limiting leverage should help prevent crashes. He admits, however, that he would not have embraced that idea when the market was still going strong.

Childhood poverty, chronic stress, and adult working memory

Sobering observations from Evans and Schaumberg presented in an open access article in PNAS:

The income–achievement gap is a formidable societal problem, but little is known about either neurocognitive or biological mechanisms that might account for income-related deficits in academic achievement. We show that childhood poverty is inversely related to working memory in young adults. Furthermore, this prospective relationship is mediated by elevated chronic stress during childhood. Chronic stress is measured by allostatic load, a biological marker of cumulative wear and tear on the body that is caused by the mobilization of multiple physiological systems in response to chronic environmental demands.

Failure to find effect of estrogen or testosterone on economic behavior.

Zethraeus et al.(open access) obtain a result that is contrary to expectations generated by previous studies:

Existing correlative evidence suggests that sex hormones may affect economic behavior such as risk taking and reciprocal fairness. To test this hypothesis we conducted a double-blind randomized study. Two-hundred healthy postmenopausal women aged 50–65 years were randomly allocated to 4 weeks of treatment with estrogen, testosterone, or placebo. At the end of the treatment period, the subjects participated in a series of economic experiments that measure altruism, reciprocal fairness, trust, trustworthiness, and risk attitudes. There was no significant effect of estrogen or testosterone on any of the studied behaviors.

The sapient paradox

Merlin Donald has written a series of fascinating books on the emergence of modern humans, one of which I used extensively as a reference in my "Biology of Mind" book. He now reviews a special issue of the Proceedings of the Royal Society devoted to a conference at the Univ. of Cambridge titled ‘Archaeology meets neuroscience’. His review (PDF here) is well worth reading.

A major link between archaeology and neuroscience is provided by cognitive science, which has a foot in both camps. Some aspects of cognition, such as literacy, mathematics and music are obviously cultural in origin. Others, such as attention, perception and action stem directly from the design of the central nervous system. These two influences, brain and culture, work together in forming human cognition, and cognitive scientists find themselves in the position of having to explain many of the higher cognitive capabilities of human beings in terms of hybrid brain-culture mechanisms. Evolutionary models are one important way of ordering the evidence on hybrid mechanisms, and epigenetic factors may prove to be paramount in this process.

The ‘sapient paradox’ refers to a puzzle that has been a thorn in the side of prehistory researchers for some time. There seems to have been a long — in fact, inordinately long — delay between the emergence of anatomically modern humans and our later cultural flowering. Both genetic and archaeological evidence converge on the conclusion that the ‘speciation’ phase of sapient humans occurred in Africa at least 70 000–100 000 years BP, and possibly earlier, and all modern humans are descended from those original populations...a later period, extending from 10 000 years ago to the present, is referred to as the ‘tectonic’ phase. This has been a period of greatly accelerated change, stepping relatively quickly through several different levels of social and material culture, including the domestication of plants and animals, sedentary societies, cities and advanced metallurgy. It has culminated in many recent changes, giving us dramatic innovations, such as skyscrapers, atomic energy and the internet. The paradox is that there was a gap of well over 50 000 years between the speciation and tectonic phases. The acceleration of recent cultural change is especially puzzling when viewed in the light of the hundreds of thousands of years it took our ancestors to master fire, stone tool making and coordinated seasonal hunting.

Merlin's review succinctly summarizes the views of conference contributors on these issues.

Risk and reward processing in different prefrontal areas

More information from Bechara and collaborators on how decisions are parceled out within the prefrontal cortex:

Making a risky decision is a complex process that involves evaluation of both the value of the options and the associated risk level. Yet the neural processes underlying these processes have not so far been clearly identified. Using functional magnetic resonance imaging and a task that simulates risky decisions, we found that the dorsal region of the medial prefrontal cortex (MPFC) was activated whenever a risky decision was made, but the degree of this activity across subjects was negatively correlated with their risk preference. In contrast, the ventral MPFC was parametrically modulated by the received gain/loss, and the activation in this region was positively correlated with an individual's risk preference. These results extend existing neurological evidence by showing that the dorsal and ventral MPFC convey different decision signals (i.e., aversion to uncertainty vs. approach to rewarding outcomes), where the relative strengths of these signals determine behavioral decisions involving risk and uncertainty.

Can evolution explain how minds work?

Some clips from an essay in Nature Magazine by Bolhuis and Wynne:

....biologists have tended to assume that species with shared ancestry will have similar cognitive abilities, and that the evolutionary history of traits can be used to reveal how we and other animals perform certain mental tasks. A closer analysis suggests things aren't so simple.

...Over the past two decades, researchers have reported that chimpanzees can empathize with other members of their species, and that they reconcile and even console each other after conflicts. Monkeys and apes have been credited with a sense of fairness and aversion to inequity and, in the case of apes, an awareness of the mental states of others — in other words, a theory of mind. A closer look at many of these studies reveals, however, that appropriate control conditions have often been lacking, and simpler explanations overlooked in a flurry of anthropomorphic overinterpretation. For instance, capuchin monkeys were thought to have a sense of fairness because they reject a slice of cucumber if they see another monkey in an adjacent cage, performing the same task, rewarded with a more-sought-after grape. Researchers interpreted a monkey's refusal to eat the cucumber as evidence of 'inequity aversion' prompted by seeing another monkey being more generously rewarded. Yet, closer analysis has revealed that a monkey will still refuse cucumber when a grape is placed in a nearby empty cage. This suggests that the monkeys simply reject lesser rewards when better ones are available.

...Laboratory studies of a number of species performing a wide range of tasks indicate that different species may have arrived at similar solutions to cognitive problems because they have experienced similar selection pressures, not because they are closely related. In other words, evolutionary convergence may be more important than common descent in accounting for similar cognitive outcomes in different animal groups.

...For example, we now know that birds are capable of feats that match or even exceed those reported in monkeys and apes. Rooks, for example, rub their bills together after one of them has been involved in a confrontation with another bird. Equivalent stroking and embracing in chimpanzees would be labelled 'consolation'. The self-directed pecking that magpies show when they are put in front of a mirror after a mark has been placed on their body is similar to the reactions seen in apes given the same treatment. In magpies, this behaviour has been interpreted as evidence for some degree of self-recognition. But in apes, the same behaviour has been thought to indicate a deeper level of self-consciousness. Caledonian crows outperform monkeys in their ability to retrieve food from a trap tube — from which food can be accessed only at one end. The crows can also work out how to use one tool to obtain a second with which they can retrieve food, a skill that monkeys and apes struggle to master.

...Researchers have tried for decades to teach apes some form of language, be it by using visual symbols or gestures. But linguists generally agree that the resulting efforts made by chimps and bonobos don't qualify as language. One of the prerequisites for language is being able to imitate sounds that are created by someone else. Our primate cousins show no inclination to do this. Yet many parrots and songbirds are striking vocal mimics. Furthermore, the way that they learn to sing is not unlike how human infants learn to speak. Both children and the chicks of parrots and songbirds learn many of their vocalizations during a sensitive period early in life. They also undergo a transitional period during which their attempts to speak or sing increasingly come to resemble those of adults. Recent studies even suggest that starlings can identify certain syntactic features of sound patterns that non-human primates miss.

The appearance of similar abilities in distantly related species, but not necessarily in closely related ones, illustrates that cognitive traits cannot be neatly arranged on an evolutionary scale of relatedness.

Cortical thinning in people with familial risk for major depression

From Peterson et al:

The brain disturbances that place a person at risk for developing depression are unknown. We imaged the brains of 131 individuals, ages 6 to 54 years, who were biological descendants (children or grandchildren) of individuals identified as having either moderate to severe, recurrent, and functionally debilitating depression or as having no lifetime history of depression. We compared cortical thickness across high- and low-risk groups, detecting large expanses of cortical thinning across the lateral surface of the right cerebral hemisphere in persons at high risk. Thinning correlated with measures of current symptom severity, inattention, and visual memory for social and emotional stimuli. Mediator analyses indicated that cortical thickness mediated the associations of familial risk with inattention, visual memory, and clinical symptoms. These findings suggest that cortical thinning in the right hemisphere produces disturbances in arousal, attention, and memory for social stimuli, which in turn may increase the risk of developing depressive illness.

The Green Brain

I would recommend reading Jon Gertner's article "Why isn't the Brain Green?" (In the same issue of the New York Times Magazine, Paul Bloom's article is also worth a look). I give just a few clips below, in which Gertner writes on the psychology of environmentalism, starting by noting a meeting at the Center for Research on Environmental Decisions.

A branch of behavioral research situated at the intersection of psychology and economics, decision science focuses on the mental proces­ses that shape our choices, behaviors and attitudes. The field’s origins grew mostly out of the work, beginning in the 1970s, of Daniel Kahneman and Amos Tversky, two psychologists whose experiments have demonstrated that people can behave unexpectedly when confronted with simple choices. We have many automatic biases — we’re more averse to losses than we are interested in gains, for instance — and we make repeated errors in judgment based on our tendency to use shorthand rules to solve problems. We can also be extremely susceptible to how questions are posed. Would you undergo surgery if it had a 20 percent mortality rate? What if it had an 80 percent survival rate? It’s the same procedure, of course, but in various experiments, responses from patients can differ markedly.

...where nearly all dollars for climate investigation are directed toward physical or biological projects, the notion that vital environmental solutions will be attained through social-science research — instead of improved climate models or innovative technologies — is an aggressively insurgent view.

But in fact,

...climate change is anthropogenic...More or less, people have agreed on that. That means it’s caused by human behavior. That’s not to say that engineering solutions aren’t important. But if it’s caused by human behavior, then the solution probably also lies in changing human behavior.

...Cognitive psychologists now broadly accept that we have different systems for processing risks. One system works analytically, often involving a careful consideration of costs and benefits. The other experiences risk as a feeling: a primitive and urgent reaction to danger, usually based on a personal experience, that can prove invaluable when (for example) we wake at night to the smell of smoke.

There are some unfortunate implications here. In analytical mode, we are not always adept at long-term thinking; experiments have shown a frequent dislike for delayed benefits, so we undervalue promised future outcomes. (Given a choice, we usually take $10 now as opposed to, say, $20 two years from now.) Environmentally speaking, this means we are far less likely to make lifestyle changes in order to ensure a safer future climate. Letting emotions determine how we assess risk presents its own problems. Almost certainly, we underestimate the danger of rising sea levels or epic droughts or other events that we’ve never experienced and seem far away in time and place.

...we have a “finite pool of worry,” which means we’re unable to maintain our fear of climate change when a different problem — a plunging stock market, a personal emergency — comes along. We simply move one fear into the worry bin and one fear out. And even if we could remain persistently concerned about a warmer world? We have a “single-action bias.” Prompted by a distressing emotional signal, we buy a more efficient furnace or insulate our attic or vote for a green candidate — a single action that effectively diminishes global warming as a motivating factor.

...Increasing personal evidence of global warming and its potentially devastating consequences can be counted on to be an extremely effective teacher and motivator...emotional and experiential feelings of risk are superb drivers of action. Unfortunately, such lessons may arrive too late for corrective action.

Music and the brain - rhythm and pleasure

Two PNAS articles I have been meaning to mention deal with an apparently innate sense of rhythm in infants, and how pleasing music activates brain regions implicated in reward. First, an open access article from Winkler et al on infants:

To shed light on how humans can learn to understand music, we need to discover what the perceptual capabilities with which infants are born. Beat induction, the detection of a regular pulse in an auditory signal, is considered a fundamental human trait that, arguably, played a decisive role in the origin of music. Theorists are divided on the issue whether this ability is innate or learned. We show that newborn infants develop expectation for the onset of rhythmic cycles (the downbeat), even when it is not marked by stress or other distinguishing spectral features. Omitting the downbeat elicits brain activity associated with violating sensory expectations. Thus, our results strongly support the view that beat perception is innate.

Also, Blood and Zatorre on brain imaging during experiencing pleasurable music:

We used positron emission tomography to study neural mechanisms underlying intensely pleasant emotional responses to music. Cerebral blood flow changes were measured in response to subject-selected music that elicited the highly pleasurable experience of “shivers-down-the-spine” or “chills.” Subjective reports of chills were accompanied by changes in heart rate, electromyogram, and respiration. As intensity of these chills increased, cerebral blood flow increases and decreases were observed in brain regions thought to be involved in reward/motivation, emotion, and arousal, including ventral striatum, midbrain, amygdala, orbitofrontal cortex, and ventral medial prefrontal cortex. These brain structures are known to be active in response to other euphoria-inducing stimuli, such as food, sex, and drugs of abuse. This finding links music with biologically relevant, survival-related stimuli via their common recruitment of brain circuitry involved in pleasure and reward.

A bird that follows human eye movements.

Interesting observations from von Bayern and Emery. They offered food to hand-raised jackdaws. The birds took longer to nab a proffered nibble if the food was the subject of a stranger's stare, and they seemed to be watching the eyes rather than the direction of the head (see variations of head and eye attitudes, pictured). In a separate experiment, the birds needed moving, rather than static, eye signals from a familiar person to understand communication about the location of hidden food. They speculate that jackdaws evolved this eye-following ability to interact with one another. However, they add that the birds followed by the study have spent their whole lives with humans.:

Humans communicate their intentions and disposition using their eyes, whereas the communicative function of eyes in animals is less clear. Many species show aversive reactions to eyes, and several species gain information from conspecifics' gaze direction by automatically co-orienting with them. However, most species show little sensitivity to more subtle indicators of attention than head orientation and have difficulties using such cues in a cooperative context. Recently, some species have been found responsive to gaze direction in competitive situations. We investigated the sensitivity of jackdaws, pair-bonded social corvids that exhibit an analogous eye morphology to humans, to subtle attentional and communicative cues in two contexts and paradigms. In a conflict paradigm, we measured the birds' latency to retrieve food in front of an unfamiliar or familiar human, depending on the state and orientation of their eyes toward food. In a cooperative paradigm, we tested whether the jackdaws used familiar human's attentional or communicative cues to locate hidden food. Jackdaws were sensitive to human attentional states in the conflict situation but only responded to communicative cues in the cooperative situation. These findings may be the result of a natural tendency to attend to conspecifics' eyes or the effect of intense human contact during socialization.

Chimps exchange meat for sex

Evolutionary origin of the upscale date at Ruths' Chris Steakhouse meant to impress your girlfriend? From Gomes and Boesch:

Humans and chimpanzees are unusual among primates in that they frequently perform group hunts of mammalian prey and share meat with conspecifics. Especially interesting are cases in which males give meat to unrelated females. The meat-for-sex hypothesis aims at explaining these cases by proposing that males and females exchange meat for sex, which would result in males increasing their mating success and females increasing their caloric intake without suffering the energetic costs and potential risk of injury related to hunting. Although chimpanzees have been shown to share meat extensively with females, there has not been much direct evidence in this species to support the meat-for-sex hypothesis. Here we show that female wild chimpanzees copulate more frequently with those males who, over a period of 22 months, share meat with them. We excluded other alternative hypotheses to exchanging meat for sex, by statistically controlling for rank of the male, age, rank and gregariousness of the female, association patterns of each male-female dyad and meat begging frequency of each female. Although males were more likely to share meat with estrous than anestrous females given their proportional representation in hunting parties, the relationship between mating success and sharing meat remained significant after excluding from the analysis sharing episodes with estrous females. These results strongly suggest that wild chimpanzees exchange meat for sex, and do so on a long-term basis. Similar studies on humans will determine if the direct nutritional benefits that women receive from hunters in foraging societies could also be driving the relationship between reproductive success and good hunting skills.

Link between brain anatomy, personality, and the placebo analgesic response

As a companion to today's first post, on motivation, a note that Schweinhardt et al. provide some interesting correlations between personality traits related to dopaminergic neurotransmission (novelty seeking, harm avoidance (inversely related), behavioral drive, fun seeking, and reward responsiveness.), size of the mesolimbic reward system, and the effectiveness of the placebo effect:

The anticipation of clinical benefit, a crucial component of placebo analgesia, has been suggested to be a special case of reward anticipation. Since reward processing is closely linked to the ventral striatum and the neurotransmitter dopamine, we examined the relationships between brain gray matter, placebo analgesic response, and personality traits associated with dopaminergic neurotransmission. We report that dopamine-related traits predict a substantial portion of the pain relief an individual gains from a sham treatment. Voxel-based morphometry of magnetic resonance images shows that the magnitude of placebo analgesia is related to gray matter density (GMD) in several brain regions, including the ventral striatum, insula, and prefrontal cortex. Similarly, GMD in ventral striatum and prefrontal cortex is related to dopamine-related personality traits. Our findings highlight the relationship between placebo and reward and potentially offer ways of identifying subjects who are likely to show large placebo analgesic responses.

The shoplifting "high"

I pass on this tidbit from the random samples section of science magazine:

For compulsive shoplifters, covertly pinching a lipstick or a blouse brings a rush "similar to a cocaine or heroin high," says Jon Grant, a psychiatrist at the University of Minnesota School of Medicine in Minneapolis. That's why some psychiatrists prescribe naltrexone, a drug used to treat addicts, for the problem.

Naltrexone blocks the same brain receptors used by opioids, but there's little published evidence about its effectiveness in treating kleptomania. Now, in the April issue of Biological Psychiatry, Grant and colleagues report the first placebo-controlled trial of any drug against the disorder.

Subjects were 25 kleptomaniacs aged 17 to 65, 18 of them women. Almost all had been arrested for shoplifting at least once. For 8 weeks, half were given naltrexone daily and the rest a placebo. "Two-thirds of those on naltrexone had complete remission of their symptoms," says Grant. Psychiatrist Samuel Chamberlain of the University of Cambridge in the U.K. says the results "suggest that the brain circuits involved in compulsive stealing overlap with those involved in addictions more broadly." Grant hopes to get funding for a larger study.

The power of positive thinking.

Following up on experiments I mentioned in a previous post in 2006, Cohen et al. provide an example of how recursive positive feedback cycles can generate a self-perpetuating pattern of behavior. They performed a multiyear field experiment in which three cohorts of 7th-grade students were given seemingly gentle interventions--a brief writing assignment on personal values--several times throughout their 7th- and 8th-grade school years. Poorly performing African American students who had been assigned to write about self-affirmation displayed significantly smaller declines in their grades than those who had written about someone else's values; the intervention had no effect on the grade trends of highly performing African American or European American students. The intervention appeared to help to prevent the poorly performing group from falling into a cycle of negativity. Their abstract:

A subtle intervention to lessen minority students' psychological threat related to being negatively stereotyped in school was tested in an experiment conducted three times with three independent cohorts (N = 133, 149, and 134). The intervention, a series of brief but structured writing assignments focusing students on a self-affirming value, reduced the racial achievement gap. Over 2 years, the grade point average (GPA) of African Americans was, on average, raised by 0.24 grade points. Low-achieving African Americans were particularly benefited. Their GPA improved, on average, 0.41 points, and their rate of remediation or grade repetition was less (5% versus 18%). Additionally, treated students' self-perceptions showed long-term benefits. Findings suggest that because initial psychological states and performance determine later outcomes by providing a baseline and initial trajectory for a recursive process, apparently small but early alterations in trajectory can have long-term effects. Implications for psychological theory and educational practice are discussed.