Outside In
The Legacy of Disadvantage: Multigenerational Neighborhood Effects on Cognitive Ability
Patrick Sharkey & Felix Elwert
American Journal of Sociology, May 2011, Pages 1934-1981
Abstract:
This study examines how the neighborhood environments experienced over multiple generations of a family influence children's cognitive ability. Building on recent research showing strong continuity in neighborhood environments across generations of family members, the authors argue for a revised perspective on "neighborhood effects" that considers the ways in which the neighborhood environment in one generation may have a lingering impact on the next generation. To analyze multigenerational effects, the authors use newly developed methods designed to estimate unbiased treatment effects when treatments and confounders vary over time. The results confirm a powerful link between neighborhoods and cognitive ability that extends across generations. A family's exposure to neighborhood poverty across two consecutive generations reduces child cognitive ability by more than half a standard deviation. A formal sensitivity analysis suggests that results are robust to unobserved selection bias.
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City living and urban upbringing affect neural social stress processing in humans
Florian Lederbogen et al.
Nature, 23 June 2011, Pages 498-501
Abstract:
More than half of the world's population now lives in cities, making the creation of a healthy urban environment a major policy priority. Cities have both health risks and benefits, but mental health is negatively affected: mood and anxiety disorders are more prevalent in city dwellers and the incidence of schizophrenia is strongly increased in people born and raised in cities. Although these findings have been widely attributed to the urban social environment, the neural processes that could mediate such associations are unknown. Here we show, using functional magnetic resonance imaging in three independent experiments, that urban upbringing and city living have dissociable impacts on social evaluative stress processing in humans. Current city living was associated with increased amygdala activity, whereas urban upbringing affected the perigenual anterior cingulate cortex, a key region for regulation of amygdala activity, negative affect and stress. These findings were regionally and behaviourally specific, as no other brain structures were affected and no urbanicity effect was seen during control experiments invoking cognitive processing without stress. Our results identify distinct neural mechanisms for an established environmental risk factor, link the urban environment for the first time to social stress processing, suggest that brain regions differ in vulnerability to this risk factor across the lifespan, and indicate that experimental interrogation of epidemiological associations is a promising strategy in social neuroscience.
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The evolution of general intelligence
Satoshi Kanazawa
Personality and Individual Differences, forthcoming
Abstract:
Among Richard Lynn's numerous significant contributions to science is his cold winters theory of the evolution of general intelligence. The cold winters of Eurasia presented novel adaptive problems for our ancestors to solve, such as obtaining food by hunting large animals and keeping warm by building clothing, shelter and fire, and they functioned as strong selection pressures for higher intelligence. Empirical analyses support both Lynn's cold winters theory and my evolutionary novelty theory of the evolution of general intelligence. Mean annual temperature and the degree of evolutionary novelty in the environment independently predict the average intelligence of the population. Both theories can also account for the observed race difference in intelligence.
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One-month-old human infants learn about the social world while they sleep
Bethany Reeb-Sutherland et al.
Developmental Science, forthcoming
Abstract:
Although infants display preferences for social stimuli early in their lives, we know relatively little about the mechanisms of infant learning about the social world. In the current set of studies, 1-month-old infants underwent an adapted eyeblink conditioning paradigm to examine learning to both 'social' and non-social cues. While infants were asleep, they were presented with either a 'social' stimulus (a female voice) or one of two non-social stimuli (tone or backward voice) followed by an airpuff presented to the eyelid. Infants in the experimental groups displayed increased learning across trials, regardless of stimulus type. However, infants conditioned to the 'social' stimulus showed increased learning compared to infants conditioned to either of the non-social stimuli. These results suggest a mechanism by which learning about the social world occurs early in life and the power of ecologically valid cues in facilitating that learning.
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Stress Training Improves Performance During a Stressful Flight
Christopher McClernon et al.
Human Factors, June 2011, Pages 207-218
Objective: This study investigated whether stress training introduced during the acquisition of simulator-based flight skills enhances pilot performance during subsequent stressful flight operations in an actual aircraft.
Background: Despite knowledge that preconditions to aircraft accidents can be strongly influenced by pilot stress, little is known about the effectiveness of stress training and how it transfers to operational flight settings.
Method: For this study, 30 participants with no flying experience were assigned at random to a stress-trained treatment group or a control group. Stress training consisted of systematic pairing of skill acquisition in a flight simulator with stress coping mechanisms in the presence of a cold pressor. Control participants received identical flight skill acquisition training but without stress training. Participants then performed a stressful flying task in a Piper Archer aircraft.
Results: Stress-trained research participants flew the aircraft more smoothly, as recorded by aircraft telemetry data, and generally better, as recorded by flight instructor evaluations, than did control participants.
Conclusions: Introducing stress coping mechanisms during flight training improved performance in a stressful flying task.
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Nature connectedness: Associations with well-being and mindfulness
Andrew Howell et al.
Personality and Individual Differences, July 2011, Pages 166-171
Abstract:
Wilson's (1984) biophilia hypothesis predicts that people's psychological health is associated with their relationship to nature. Two studies examined associations among nature connectedness, well-being, and mindfulness in samples of undergraduate students while socially desirable responding was controlled. Significant associations emerged among measures of nature connectedness and indices of well-being (in Study 1 and Study 2) and mindfulness (in Study 2). Results are discussed in relation to possible mediators and moderators of the association between nature connectedness and mental health.
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The Effect of Education on Cognitive Ability
Torberg Falch & Sofia Sandgren Massih
Economic Inquiry, July 2011, Pages 838-856
Abstract:
This paper analyzes whether schooling increases intelligence measured by intelligence quotient (IQ). We use a longitudinal dataset where the individuals have conducted IQ tests both at ages 10 and 20. We estimate the effect of schooling on IQ at age 20 conditional on IQ at age 10 and other measures of early cognitive ability to account for selection into noncompulsory schooling. Ordinary least squares estimates indicate that 1 year of schooling increases IQ by 2.9-3.5 points (about 0.2 SD deviations), and instrumental variables estimates are similar.
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Joseph Ferrie, Karen Rolf & Werner Troesken
NBER Working Paper, June 2011
Abstract:
Assessing the impact of lead exposure is difficult if individuals select on the basis of their characteristics into environments with different exposure levels. We address this issue with data from when the dangers of lead exposure were still largely unknown, using new evidence on intelligence test scores for male World War Two U.S. Army enlistees linked to the households where they resided in 1930. Higher exposure to water-borne lead (proxied by urban residence and low water pH levels) was associated with lower test scores: going from pH 6 to pH 5.5, scores fell 5 points (1/4 standard deviation). A longer time exposed led to a more severe effect. The ubiquity of lead in urban water systems at this time and uncertainty regarding its impact mean these effects are unlikely to have resulted from selection into locations with different levels of exposure.
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Ellen Beate Hansen Sandseter & Leif Edward Ottesen Kennair
Evolutionary Psychology, June 2011, Pages 257-284
Abstract:
This theoretical article views children's risky play from an evolutionary perspective, addressing specific evolutionary functions and especially the anti-phobic effects of risky play. According to the non-associative theory, a contemporary approach to the etiology of anxiety, children develop fears of certain stimuli (e.g., heights and strangers) that protect them from situations they are not mature enough to cope with, naturally through infancy. Risky play is a set of motivated behaviors that both provide the child with an exhilarating positive emotion and expose the child to the stimuli they previously have feared. As the child's coping skills improve, these situations and stimuli may be mastered and no longer be feared. Thus fear caused by maturational and age relevant natural inhibition is reduced as the child experiences a motivating thrilling activation, while learning to master age adequate challenges. It is concluded that risky play may have evolved due to this anti-phobic effect in normal child development, and it is suggested that we may observe an increased neuroticism or psychopathology in society if children are hindered from partaking in age adequate risky play.
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Premotor functional connectivity predicts impulsivity in juvenile offenders
Benjamin Shannon et al.
Proceedings of the National Academy of Sciences, 5 July 2011, Pages 11241-11245
Abstract:
Teenagers are often impulsive. In some cases this is a phase of normal development; in other cases impulsivity contributes to criminal behavior. Using functional magnetic resonance imaging, we examined resting-state functional connectivity among brain systems and behavioral measures of impulsivity in 107 juveniles incarcerated in a high-security facility. In less-impulsive juveniles and normal controls, motor planning regions were correlated with brain networks associated with spatial attention and executive control. In more-impulsive juveniles, these same regions correlated with the default-mode network, a constellation of brain areas associated with spontaneous, unconstrained, self-referential cognition. The strength of these brain-behavior relationships was sufficient to predict impulsivity scores at the individual level. Our data suggest that increased functional connectivity of motor-planning regions with networks subserving unconstrained, self-referential cognition, rather than those subserving executive control, heightens the predisposition to impulsive behavior in juvenile offenders. To further explore the relationship between impulsivity and neural development, we studied functional connectivity in the same motor-planning regions in 95 typically developing individuals across a wide age span. The change in functional connectivity with age mirrored that of impulsivity: younger subjects tended to exhibit functional connectivity similar to the more-impulsive incarcerated juveniles, whereas older subjects exhibited a less-impulsive pattern. This observation suggests that impulsivity in the offender population is a consequence of a delay in typical development, rather than a distinct abnormality.
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Zdeňa Op de Macks et al.
Developmental Cognitive Neuroscience, forthcoming
Abstract:
Risk taking is an integral part of learning and development, particularly during adolescence the prevalence of risky behaviors peak. It is hypothesized that the tendency to take risks is related to pubertal maturation, where there is interplay between gonadal hormones, the neural mechanisms that underlie affective (e.g., reward) processing, and risky behavior. To test this hypothesis, fifty healthy adolescents (aged 10-16 years; 33 girls, 17 boys) at different stages of puberty performed a gambling task while lying in the MRI scanner, and provided saliva samples for hormone assessment. Gonadal hormone levels were correlated with the neural response to receiving a monetary reward. Results showed that testosterone level correlated positively with activation in the striatum for both boys and girls, suggesting that individual differences in hormones at puberty are related to the way adolescents respond to reward, which can ultimately affect risk-taking behavior.
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General intelligence predicts reasoning ability even for evolutionarily familiar content
Scott Barry Kaufman et al.
Intelligence, forthcoming
Abstract:
The existence of general-purpose cognitive mechanisms related to intelligence, which appear to facilitate all forms of problem solving, conflicts with the strong modularity view of the mind espoused by some evolutionary psychologists. The current study assessed the contribution of general intelligence (g) to explaining variation in contextualized deductive reasoning. One hundred and twelve participants solved 70 contextualized reasoning problems in a computerized version of the Wason Card Selection Task that recorded both accuracy and reaction time. Consistent with prior research, in the sample as a whole, precautionary and social exchange reasoning problems were solved more frequently and more quickly than reasoning problems about arbitrary rules. At the individual-differences level of analysis, however, performance on all reasoning tests was significantly correlated and loaded on a single deductive-reasoning accuracy factor. Further, this factor was significantly correlated with g. There was no relation, however, between g and the speed of arriving at the correct answer for any form of deductive reasoning. We discuss the implications of these findings for evolutionary psychology, intelligence, and reasoning.
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Mindfulness training for smoking cessation: Results from a randomized controlled trial
Judson Brewer et al.
Drug and Alcohol Dependence, forthcoming
Background: Cigarette smoking is the leading cause of preventable death in the world, and long-term abstinence rates remain modest. Mindfulness training (MT) has begun to show benefits in a number of psychiatric disorders, including depression, anxiety and more recently, in addictions. However, MT has not been evaluated for smoking cessation through randomized clinical trials.
Methods: 88 treatment-seeking, nicotine-dependent adults who were smoking an average of 20 cigarettes/day were randomly assigned to receive MT or the American Lung Association's freedom from smoking (FFS) treatment. Both treatments were delivered twice weekly over 4 weeks (eight sessions total) in a group format. The primary outcomes were expired-air carbon monoxide-confirmed 7-day point prevalence abstinence and number of cigarettes/day at the end of the 4-week treatment and at a follow-up interview at week 17.
Results: 88% of individuals received MT and 84% of individuals received FFS completed treatment. Compared to those randomized to the FFS intervention, individuals who received MT showed a greater rate of reduction in cigarette use during treatment and maintained these gains during follow-up (F = 11.11, p = .001). They also exhibited a trend toward greater point prevalence abstinence rate at the end of treatment (36% vs. 15%, p = .063), which was significant at the 17-week follow-up (31% vs. 6%, p = .012).
Conclusions: This initial trial of mindfulness training may confer benefits greater than those associated with current standard treatments for smoking cessation.
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Elizabeth Broadbent et al.
Brain, Behavior, and Immunity, forthcoming
Abstract:
Psychological stress has been shown to impair wound healing, but experimental research in surgical patients is lacking. This study investigated whether a brief psychological intervention could reduce stress and improve wound healing in surgical patients. This randomised controlled trial was conducted at a surgical centre. Inclusion criteria were English-speaking patients over 18 years booked to undergo elective laparoscopic cholecystectomy; exclusion criteria were cancellation of surgery, medical complications, and refusal of consent. 75 patients were randomised and 15 patients were excluded; 60 patients completed the study (15 male, 45 female). Participants were randomised to receive standard care or standard care plus a 45-minute psychological intervention that included relaxation and guided imagery with take-home relaxation CDs for listening to for three days before and seven days after surgery. In both groups ePTFE tubes were inserted during surgery and removed at seven days after surgery and analysed for hydroxyproline as a measure of collagen deposition and wound healing. Change in perceived stress from before surgery to seven-day follow-up was assessed using questionnaires. Intervention group patients showed a reduction in perceived stress compared with the control group, controlling for age. Patients in the intervention group had higher hydroxyproline deposition in the wound than did control group patients (difference in means 0.35, 95% CI 0.66 to 0.03; t(43)=2.23, p = 0.03).Changes in perceived stress were not associated with hydroxyproline deposition. A brief relaxation intervention prior to surgery can reduce stress and improve the wound healing response in surgical patients.The intervention may have particular clinical application for those at risk of poor healing following surgery.