Friday, September 04, 2009

Happiness and unhappiness in East and West

From Uchida et al.:
Cultural folk models of happiness and unhappiness are likely to have important bearings on social cognition and social behavior. At present, however, little is known about the nature of these models. Here, the authors systematically analyzed American and Japanese participants’ spontaneously produced descriptions of the two emotions and observed, as predicted, that whereas Americans associated positive hedonic experience of happiness with personal achievement, Japanese associated it with social harmony. Furthermore, Japanese were more likely than Americans to mention both social disruption and transcendental reappraisal as features of happiness. As also predicted, unlike happiness, descriptions of unhappiness included various culture-specific coping actions: Whereas Americans focused on externalizing behavior (e.g., anger and aggression), Japanese highlighted transcendental reappraisal and self-improvement.

Brief early exposure to high fat diet changes long term dietary habits

Yet another study of how early environment can cause virtually irreversible changes in later life habits. From Teegarden et al.
Overweight and obesity in the United States continues to grow at epidemic rates in large part due to the overconsumption of calorically-dense palatable foods. Identification of factors influencing long-term macronutrient preferences may elucidate points of prevention and behavioral modification. In our current study, we examined the adult macronutrient preferences of mice acutely exposed to a high fat diet during the third postnatal week. We hypothesized that the consumption of a high fat diet during early life would alter the programming of central pathways important in adult dietary preferences. As adults, the early-exposed mice displayed a significant preference for a diet high in fat compared to controls. This effect was not due to diet familiarity as mice exposed to a novel high carbohydrate diet during this same early period failed to show differences in macronutrient preferences as adults. The increased intake of high fat diet in early exposed mice was specific to dietary preferences as no changes were detected for total caloric intake or caloric efficiency. Mechanistically, mice exposed to a high fat diet during early life exhibited significant alterations in biochemical markers of dopamine signaling in the nucleus accumbens, including changes in levels of phospho–dopamine and cyclic AMP-regulated phosphoprotein, molecular weight 32 kDa (DARPP-32) threonine-75, ΔFosB, and cyclin-dependent kinase 5. These results support our hypothesis that even brief early life exposure to calorically-dense palatable diets alters long-term programming of central mechanisms important in dietary preferences and reward. These changes may underlie the passive overconsumption of high fat foods contributing to the increasing body mass in the western world.

Thursday, September 03, 2009

Weight as an embodyment of importance.

Jostman et al. do some interesting experiments that indicate that our abstract concept of importance is grounded in bodily experiences of weight. This is not a surprise, for weight is a metaphor for importance in many languages. People "weigh" the value of different options before making a decision, they "add weight" to place emphasis on important ideas, and their opinion "carries weight" if they fill an influential position. The experiments suggest that the link between weight and importance exists not only on a linguistic level, but also is an embodied cognition grounded in our bodily experiences of weight.
Participants provided judgments of importance while they held either a heavy or a light clipboard. Holding a heavy clipboard increased judgments of monetary value (Study 1) and made participants consider fair decision-making procedures to be more important (Study 2). It also caused more elaborate thinking, as indicated by higher consistency between related judgments (Study 3) and by greater polarization of agreement ratings for strong versus weak arguments (Study 4). In line with an embodied perspective on cognition, these findings suggest that, much as weight makes people invest more physical effort in dealing with concrete objects, it also makes people invest more cognitive effort in dealing with abstract issues.

Gene variants that correlate with both psychosis and creativity?

Even though a number of studies have discounted an association between creativity and madness, the persistence of the idea may have some basis in fact. Kéri has studied the relationship between a functional promoter polymorphism of the neuregulin 1 gene (SNP8NRG243177/rs6994992; C vs. T) and creativity in 200 healthy participants with high intellectual and academic performance who filled out a creative achievement questionnaire. (Neuregulin 1 - which affects neuronal development, synaptic plasticity, glutamatergic neurotransmission, and glial functioning - is one of the most actively investigated candidate genes for psychosis.) His results suggest that polymorphism of the promoter region TT, T/C, C/C is associated with creativity in people with high intellectual and academic performance. Intriguingly, the highest creative achievements and creative-thinking scores are found in people who carried the T/T genotype, which has been shown to be related to psychosis risk and altered prefrontal activation.

Fleeing from Facebook

Virginia Heffernan writes an interesting piece on the small but noticeable group who are fleeing from Facebook — some of them ostentatiously. Many apparently feel a sense of creeping disillusionment, and that Facebook is stalking them.
Is Facebook doomed to someday become an online ghost town, run by zombie users who never update their pages and packs of marketers picking at the corpses of social circles they once hoped to exploit? Sad, if so. Though maybe fated, like the demise of a college clique.

Wednesday, September 02, 2009

Woodland Peace

Predicting child temperament - genes, brain and behavior

Work from Schmidt et al. on correlations between frontal EEG asymmetry, variations in a dopamine receptor gene, and later temperament:
Gene-environment interactions involving exogenous environmental factors are known to shape behavior and personality development. Although gene-environment interactions involving endogenous environmental factors are hypothesized to play an equally important role, this conceptual approach has not been empirically applied in the study of early-developing temperament in humans. Here we report evidence for a gene-endoenvironment (i.e., resting frontal brain electroencephalogram, EEG, asymmetry) interaction in predicting child temperament. The dopamine D4 receptor (DRD4) gene (long allele vs. short allele) moderated the relation between resting frontal EEG asymmetry (left vs. right) at 9 months and temperament at 48 months. Children who exhibited left frontal EEG asymmetry at 9 months and who possessed the DRD4 long allele were significantly more soothable at 48 months than other children. Among children with right frontal EEG asymmetry at 9 months, those with the DRD4 long allele had significantly more difficulties focusing and sustaining attention at 48 months than those with the DRD4 short allele. Resting frontal EEG asymmetry did not influence temperament in the absence of the DRD4 long allele. We discuss how the interaction of genetic and endoenvironmental factors may confer risk and protection for different behavioral styles in children.

Multitasking - bad for the brain?

From the random samples section of the Aug. 28 issue of Science, reporting unsettling news from one of the first-ever studies of chronic multitaskers:
A team headed by psychologist Eyal Ophir compared 19 "heavy media multitaskers" (HMMs), identified by questionnaires on media use, with 22 "light media multitaskers" (LMMs). They tested how well the subjects could filter relevant information from the environment, filter relevant information in their memories, and quickly switch cognitive tasks. One filtering test, for example, required viewers to note changes in red rectangles while ignoring blue rectangles in the same pictures.

HMMs did worse than LMMs across the board. Surprisingly, says co-author Clifford Nass, "they're bad at every cognitive control task necessary for multitasking." Nass, a sociologist, says the study has "disturbing" implications in an age when more and more people are simultaneously working on computers, listening to music, surfing the Web, and texting or talking on a phone. Also troubling, he notes, is that "people who chronically multitask believe they're good at it." The findings are reported this week in the Proceedings of the National Academy of Sciences.

The team hopes to investigate whether multitasking really scrambles brains or whether people with poor filtering and attentional abilities are more attracted to it to begin with. Psychologist Anthony Wagner suspects that media multitasking offers instant rewards that reinforce "exploratory" behavior at the expense of the ability to concentrate on a particular task.

Five second touch sufficient to convey emotion.

Bakalar reports on work of Herenstein and others who show the sophistication and rapidity of our human ability to communicate emotions such as anger, fear, happiness, sadness, disgust, love, gratitude or sympathy with a brief touch.

Our sense of smell is binaral.

When different images are presented to each of our two eyes, or different sounds to each of our two ears, our perception usually switches back and forth between the two alternatives. Now Zhou and Chen have found that the same applies to two odors separately presented to each nostril. This binaral rivalry involves both cortical and peripheral (olfactory receptor) adaptations. (If one of two odors is first presented to a nostril, and then after a brief interval it is again presented to the nostril while a second odor of equal initial power is presented to the other nostril, the second odor is predominantly sensed.)

Tuesday, September 01, 2009

Get aroused and be stronger.

From Schmidt et al.:
Effort magnitude is commonly thought to reflect motivation, but little is known about the influence of emotional factors. Here, we manipulated the emotional state of subjects, via the presentation of pictures, before they exerted physical effort (squeezing a hand grip) to win money. After highly arousing pictures, subjects produced more force and reported lower effort sensation, regardless of monetary incentives. Functional neuroimaging revealed that emotional arousal, as indexed by postscan ratings, specifically correlated with bilateral activity in the ventrolateral prefrontal cortex. We suggest that this region, by driving the motor cortex, constitutes a brain pathway that allows emotional arousal to facilitate physical effort.

Figure - The emotional incentive force task. Successive screens displayed in every trial are shown from left to right, with durations in milliseconds. Emotional pictures that could be neutral or arousing (with positive or negative valence) were shown before physical effort. Effort was triggered by simultaneously showing the amount of money at stake, materialized as coin images (1 cent, 10 cents, or 1 {euro}), and a thermometer in which fluid level represented the force exerted on the hand grip. Subjects knew that the top of the thermometer corresponded to the monetary incentive, such that the more they squeezed the hand grip, the more money they would win. The last screen informed subjects about the cumulative total of monetary earnings.

Oxytocin Increases Envy and Schadenfreude (Gloating)

Work from Shamay-Tsoory et al. suggests that oxytocin plays a role in a wider range of social emotion-related behaviors than just positive pro-social behaviors.
Fifty-six participants participated in a double-blind, placebo-controlled, within-subject study. Following the administration of oxytocin or a placebo, participants played a game of chance with another (fake) participant who either won more money (envy manipulation), lost more money (schadenfreude manipulation), or won/lost equal amounts of money. In comparison with the placebo, oxytocin increased the envy ratings during unequal monetary gain conditions involving relative loss (when the participant gained less money than another player). Oxytocin also increased the ratings of gloating during relative gain conditions (when the participant gained more money than the other player). By contrast, oxytocin had no effect on the emotional ratings following equal monetary gains nor did it affect general mood ratings.

More on "Running helps your knees?" and exercise

I received an email from Dan Peterson, reacting to my comment in my Aug. 27 post that I "feel strange if I have missed a day of going to the university gym to swim, run, or do weights." He had just done a story on a study by Robin Kanarek of Tufts University on the endorphin-fueled addictive qualities of running/exercise in rats. Here is Peterson's blog.

Monday, August 31, 2009

Monday musical offering - "Gade" from the lyrical pieces

The power of the press.

Chin, in the Editor's choice section of Science, notes work from Gerber et al. on the effects of newspapers:
A common belief in the United States is that the media exhibit a liberal bias, which generally aligns them with Democratic programs and politicians, in their reporting of the news and in their selection of what news to report on. In fact, one study estimates the effect of Fox News Channel, which was launched about a decade ago and is generally more conservative than other television outlets, as having increased the Republican share of the vote by half a percentage point.

One month before the November 2005 gubernatorial election in Virginia, Gerber et al. carried out a randomized field study in which several thousand households that did not already receive a daily newspaper were given trial subscriptions to either the Washington Post (liberal) or the Washington Times (conservative). Post-election telephone interviews established that receiving either newspaper had little impact on factual knowledge (such as Harriet Miers being a Supreme Court nominee) or political attitudes (such as President Bush's approval rating). What was affected was voter turnout (as measured by administrative records) and, surprisingly, actual voter choice, with both sets of newspaper-receiving households favoring the Democratic candidate by about seven percentage points.

Genes predicting our individual differences in exploration and exploitation

In the face of uncertainty, how do we choose between maintaining our current strategy or trying new strategies? A study From Frank et al. shows that a gene controlling prefrontal dopamine function is predictive of uncertainty-driven exploration:
The basal ganglia support learning to exploit decisions that have yielded positive outcomes in the past. In contrast, limited evidence implicates the prefrontal cortex in the process of making strategic exploratory decisions when the magnitude of potential outcomes is unknown. Here we examine neurogenetic contributions to individual differences in these distinct aspects of motivated human behavior, using a temporal decision-making task and computational analysis. We show that two genes controlling striatal dopamine function, DARPP-32 (also called PPP1R1B) and DRD2, are associated with exploitative learning to adjust response times incrementally as a function of positive and negative decision outcomes. In contrast, a gene primarily controlling prefrontal dopamine function (COMT) is associated with a particular type of 'directed exploration', in which exploratory decisions are made in proportion to Bayesian uncertainty about whether other choices might produce outcomes that are better than the status quo. Quantitative model fits reveal that genetic factors modulate independent parameters of a reinforcement learning system.

Friday, August 28, 2009

The biological residue of low early life social class.

A fascinating and sobering piece from Miller et al in the new issue of Proc. Nat. Acad. Sci.:
Children reared in unfavorable socioeconomic circumstances show increased susceptibility to the chronic diseases of aging when they reach the fifth and sixth decades of life. One mechanistic hypothesis for this phenomenon suggests that social adversity in early life programs biological systems in a manner that persists across decades and thereby accentuates vulnerability to disease. Here we examine the basic tenets of this hypothesis by performing genome-wide transcriptional profiling in healthy adults who were either low or high in socioeconomic status (SES) in early life. Among subjects with low early-life SES, there was significant up-regulation of genes bearing response elements for the CREB/ATF family of transcription factors that conveys adrenergic signals to leukocytes, and significant down-regulation of genes with response elements for the glucocorticoid receptor, which regulates the secretion of cortisol and transduces its antiinflammatory actions in the immune system. Subjects from low-SES backgrounds also showed increased output of cortisol in daily life, heightened expression of transcripts bearing response elements for NF-κB, and greater stimulated production of the proinflammatory cytokine interleukin 6. These disparities were independent of subjects' current SES, lifestyle practices, and perceived stress. Collectively, these data suggest that low early-life SES programs a defensive phenotype characterized by resistance to glucocorticoid signaling, which in turn facilitates exaggerated adrenocortical and inflammatory responses. Although these response patterns could serve adaptive functions during acute threats to well-being, over the long term they might exact an allostatic toll on the body that ultimately contributes to the chronic diseases of aging.

Comments on "Proust was a Neuroscientist"

I have been reading, in fits and starts, Jonah Leher's "Proust was a Neuroscientist," and just came across a review by Jonathan Bates that is consonant with my own opinions of the book:
The book is an elegant collection of essays—like Davis's extended essay, written in partial homage to William James—in which a range of 19th and early 20th century artists are shown to have discovered truths about the human mind ‘that science is only now rediscovering’ (pvii). Thus we get Walt Whitman on the ’embodied‘ nature of emotion (anticipating Antonio Damasio's work, which is so inspiring to scholars on the humanist side of the two cultures divide), Escoffier on the essence of taste, Cézanne on the process of sight, Gertrude Stein on the structure of language and so on. The focus is very much on the innovations of modernism. It would have been equally possibly to write a series of studies based on earlier anticipations—Wordsworth rather than Proust on memory, Keats rather than Whitman on the body—but that does not diminish the sharpness of the insights.

The book is worth its price for the chapter on Proust alone. This begins with some fairly obvious points, for instance that Proust was right to suppose that taste and smell are more powerful triggers for memory than sight, hearing and the self-conscious work of trying to remember something because they are ‘the only senses that connect directly to the hippocampus, the centre of the brain's long-term memory’ (p80). This explains the effect of the famous madeleine dipped into a cup of tea in Du côté de chez Swann. But Lehrer rapidly moves on to the much more interesting question of memory's fallibility. The key to A la Recherche du Temps Perdu is that past time is forever lost and that the search for it will always end in failure because of the fallibility of memory.

Lehrer contends that Proust intuited something that experimentation has now confirmed:

‘A memory is only as real as the last time you remembered it. The more you remember something, the less accurate the memory becomes ... every time we remember anything, the neuronal structure of the memory is delicately transformed, a process called reconsolidation ... So the purely objective memory, the one ‘true’ to the original taste of the madeleine, is the one memory you will never know. The moment you remember the cookie's taste is the same moment you forget what it really tasted like’ (p85).

Lehrer backs up this proposition with a fascinating account of some experiments on rats at New York University (Nader et al., 2000Go, 2004). Admittedly, this begs the question of the degree to which human memories work like rat memories. But the evidence does seem to support the profoundly Proustian idea that a memory is not like a photograph stored somewhere in the brain. Rather, ‘every memory is inseparable from the moment of its recollection: there simply is no way to describe the past without lying. Our memories are not like fiction. They are fiction’ (p88). This was a thought that Wordsworth got to before Proust: in his great autobiographical poem The Prelude, he wrestled with the question of the degree to which the feelings associated with his memories were invented by the very act of remembering.

Lehrer reminds us that the average half life of a brain protein is only 14 days. ‘The mind is in a constant state of reincarnation’ (p91). If the brain is constantly being reconstituted out of new cells, how do memories last? The chapter concludes with a tentative answer from Kausik Si's hypothesis that the ‘synaptic mark’ of memory is to be found in the cyptoplasmic polyadenylation element binding protein, which behaves very like a prion (Si et al., 2003Go). As is well-known from the huge challenge of research on mad cow disease, prions are virtually indestructible and ‘display an astonishing amount of plasticity’ (p93). Si's work remains controversial but it is, Lehrer claims, ‘the first hypothesis that begins to explain how sentimental ideas endure’. And the model is indeed remarkably Proustian.

....whilst there are new things about Shakespeare and Proust to be learnt by humanities scholars from brain science, so there are old things which Shakespeare and Proust can teach to brain scientists.

The poor payoff of pleasure postponed.

An interesting article describing work of Harvard Business School assistant professor Anat Keinan, in collaboration with Columbia Business School professor Ran Kivetz.
Keinan and Kivetz set out to see if they could observe, in formal studies, people overestimating discipline’s payoff and underestimating future feelings of having missed out. Time after time, when subjects were asked to recall situations in which they had to choose between work and pleasure, their responses emulated those of the Columbia doctoral students. More of the subjects who’d chosen play over work recently expressed regret, but those numbers reversed for choices made in the distant past. For instance, college students said they’d spent too much time relaxing during a recent winter break, but when they considered the previous year’s break, they said they’d spent too much time studying and working.

They call the habit of overestimating the benefits one will receive in the future from making responsible decisions now "hyperopia" - the name, drawn from ophthalmology, means “farsightedness.” It works to our detriment by driving people to underconsume precisely those products and experiences that they enjoy the most.

Thursday, August 27, 2009

Guilt and atonement in child development.

Tierney does an interesting piece on work by Kochanska and colleagues showing how guilt in children, which usually appears during their second year, develops along side effortful self-control to inhibit impulsive behaviors that might hurt themselves or others. A deficit in either can be compensated by increased strength of the other, but a deficit in both guilt behavior and self-control increases the probability of sociopathic behaviors. To prevent guilt over a particular bad event from generalizing into shame (which has repeatedly been found to be unhealthy, as in "I'm a bad person"), it is important to have some sort of atonement process to round off the process. The article gives interesting examples of this process.