2013-kell.pdf: “Who Rises to the Top?: Early Indicators”, (2013-03-26; ):
Youth identified before age 13 (n = 320) as having profound mathematical or verbal reasoning abilities (top 1 in 10,000) were tracked for nearly three decades. Their awards and creative accomplishments by age 38, in combination with specific details about their occupational responsibilities, illuminate the magnitude of their contribution and professional stature.
Many have been entrusted with obligations and resources for making critical decisions about individual and organizational well-being. Their leadership positions in business, health care, law, the professoriate, and STEM (science, technology, engineering, and mathematics) suggest that many are outstanding creators of modern culture, constituting a precious human-capital resource. Identifying truly profound human potential, and forecasting differential development within such populations, requires assessing multiple cognitive abilities and using atypical measurement procedures.
This study illustrates how ultimate criteria may be aggregated and longitudinally sequenced to validate such measures.
[Keywords: cognitive abilities, creativity, human capital, intelligence, profoundly gifted, STEM]
2010-sabbah.pdf: “The relationships between cognitive ability and dental status in a national sample of USA adults”, Wael Sabbah, Aubrey Sheiham
2010-sturgis.pdf: “Does intelligence foster generalized trust? An empirical test using the UK birth cohort studies”, Patrick Sturgis, Sanna Read, Nick Allum
2011-beaver.pdf: “The association between county-level IQ and county-level crime rates”, Kevin M. Beaver, John Paul Wright
2001-warner.pdf: “The Personal Discount Rate: Evidence from Military Downsizing Programs”, (2001-03; ):
The military drawdown program of the early 1990’s provides an opportunity to obtain estimates of personal discount rates based on large numbers of people making real choices involving large sums. The program offered over 65,000 separatees the choice between an annuity and a lump-sum payment. Despite break-even discount rates exceeding 17%, most of the separatees selected the lump sum—saving taxpayers $2.70$1.72001 billion in separation costs. Estimates of discount rates range from 0 to over 30% and vary with education, age, race, sex, number of dependents, ability test score, and the size of payment.
“Generalized Trust and Intelligence in the United States”, (2014-02-13):
Generalized trust refers to trust in other members of society; it may be distinguished from particularized trust, which corresponds to trust in the family and close friends. An extensive empirical literature has established that generalized trust is an important aspect of civic culture. It has been linked to a variety of positive outcomes at the individual level, such as entrepreneurship, volunteering, self-rated health, and happiness. However, two recent studies have found that it is highly correlated with intelligence, which raises the possibility that the other relationships in which it has been implicated may be spurious. Here we replicate the association between intelligence and generalized trust in a large, nationally representative sample of U.S. adults. We also show that, after adjusting for intelligence, generalized trust continues to be strongly associated with both self-rated health and happiness. In the context of substantial variation across countries, these results bolster the view that generalized trust is a valuable social resource, not only for the individual but for the wider society as well.
2012-hooghe.pdf: “The cognitive basis of trust”, Sofie
General intelligence is an important human quantitative trait that accounts for much of the variation in diverse cognitive abilities. Individual differences in intelligence are strongly associated with many important life outcomes, including educational and occupational attainments, income, health and lifespan. Data from twin and family studies are consistent with a high heritability of intelligence, but this inference has been controversial. We conducted a genome-wide analysis of 3511 unrelated adults with data on 549,692 single nucleotide polymorphisms (SNPs) and detailed phenotypes on cognitive traits. We estimate that 40% of the variation in crystallized-type intelligence and 51% of the variation in fluid-type intelligence between individuals is accounted for by linkage disequilibrium between genotyped common SNP markers and unknown causal variants. These estimates provide lower bounds for the narrow-sense heritability of the traits. We partitioned genetic variation on individual chromosomes and found that, on average, longer chromosomes explain more variation. Finally, using just SNP data we predicted ~1% of the variance of crystallized and fluid cognitive phenotypes in an independent sample (p = 0.009 and 0.028, respectively). Our results unequivocally confirm that a substantial proportion of individual differences in human intelligence is due to genetic variation, and are consistent with many genes of small effects underlying the additive genetic influences on intelligence.
2014-hambrick.pdf: “Deliberate practice: Is that all it takes to become an expert?”, (2014-07; ):
- Ericsson and colleagues argue that deliberate practice explains expert performance.
- We tested this view in the two most studied domains in expertise research.
- Deliberate practice is not sufficient to explain expert performance.
- Other factors must be considered to advance the science of expertise.
Twenty years ago, Ericsson, Krampe, and Tesch-Römer (1993) proposed that expert performance reflects a long period of deliberate practice rather than innate ability, or “talent”. Ericsson et al. found that elite musicians had accumulated thousands of hours more deliberate practice than less accomplished musicians, and concluded that their theoretical framework could provide “a sufficient account of the major facts about the nature and scarcity of exceptional performance” (p. 392). The deliberate practice view has since gained popularity as a theoretical account of expert performance, but here we show that deliberate practice is not sufficient to explain individual differences in performance in the two most widely studied domains in expertise research—chess and music. For researchers interested in advancing the science of expert performance, the task now is to develop and rigorously test theories that take into account as many potentially relevant explanatory constructs as possible.
[Keywords: Expert performance, Expertise, Deliberate practice, Talent]
We developed an analysis pipeline enabling population studies of HARDI data, and applied it to map genetic influences on fiber architecture in 90 twin subjects. We applied tensor-driven 3D fluid registration to HARDI, resampling the spherical fiber orientation distribution functions (ODFs) in appropriate Riemannian manifolds, after ODF regularization and sharpening. Fitting structural equation models ( ) from quantitative genetics, we evaluated genetic influences on the Jensen-Shannon divergence (JSD), a novel measure of fiber spatial coherence, and on the generalized fiber anisotropy (GFA) a measure of fiber integrity. With random-effects regression, we mapped regions where diffusion profiles were highly correlated with subjects’ intelligence quotient (IQ). Fiber complexity was predominantly under genetic control, and higher in more highly anisotropic regions; the proportion of genetic versus environmental control varied spatially. Our methods show promise for discovering genes affecting fiber connectivity in the brain.
2013-mcintosh.pdf: “Polygenic Risk for Schizophrenia Is Associated with Cognitive Change Between Childhood and Old Age”, (2013-05-15; ):
Background: Genome-wide association studies ( ) have shown a polygenic component to the risk of schizophrenia. The disorder is associated with impairments in general cognitive ability that also have a substantial genetic contribution. No study has determined whether cognitive impairments can be attributed to schizophrenia’s polygenic architecture using data from .
Methods: Members of the Lothian Birth Cohort 1936 (LBC1936, n = 937) were assessed using the Moray House Test at age 11 and with the Moray House Test and a further cognitive battery at age 70. To create polygenic risk scores for , we obtained data from the latest of the Psychiatric GWAS Consortium on . polygenic risk profile scores were calculated using information from the Psychiatric GWAS Consortium on Schizophrenia .
Results: In LBC1936, polygenic risk for was negatively associated with IQ at age 70 but not at age 11. Greater polygenic risk for was associated with more relative decline in IQ between these ages. These findings were maintained when the results of LBC1936 were combined with that of the independent Lothian Birth Cohort 1921 (n = 517) in a meta-analysis.
Conclusions: Increased polygenic risk ofis associated with lower cognitive ability at age 70 and greater relative decline in general cognitive ability between the ages of 11 and 70. Common genetic variants may underlie both cognitive aging and risk of .
[Keywords: Aging, cognition, dementia,]
Phenotypic variation in human intellectual functioning shows substantial heritability, as demonstrated by a long history of behavior genetic studies. Many recent molecular genetic studies have attempted to uncover specific genetic variations responsible for this heritability, but identified effects capture little variance and have proven difficult to replicate. The present study, motivated an interest in “mutation load” emerging from evolutionary perspectives, examined the importance of the number of rare (or infrequent) copy number variations (CNVs), and the total number of base pairs included in such deletions, for psychometric intelligence.
Genetic data was collected using the Illumina 1MDuoBeadChip Array from a sample of 202 adult individuals with alcohol dependence, and a subset of these (n = 77) had been administered the Wechsler Abbreviated Scale of Intelligence (WASI). After removing CNV outliers, the impact of rare genetic deletions on psychometric intelligence was investigated in 74 individuals. The total length of the rare deletions statistically-significantly and negatively predicted intelligence (r = −0.30, p = 0.01).
As prior studies have indicated greater heritability in individuals with relatively higher parental socioeconomic status (SES), we also examined the impact of ethnicity (Anglo/White vs. Other), as a proxy measure of ; these groups did not differ on any genetic variable. This categorical variable statistically-significantly moderated the effect of length of deletions on intelligence, with larger effects being noted in the Anglo/White group.
Overall, these results suggest that rare deletions (between 5% and 1% population frequency or less) adversely affect intellectual functioning, and that pleiotropic effects might partly account for the association of intelligence with health and mental health status. Substantial limitations of this research, including issues of generalizability andmeasurement, are discussed.
2013-zuckerman.pdf: “The Relation Between Intelligence and Religiosity: A Meta-Analysis and Some Proposed Explanations”, (2013-08-06; ):
A meta-analysis of 63 studies showed a significant negative association between intelligence and religiosity. The association was stronger for college students and the general population than for participants younger than college age; it was also stronger for religious beliefs than religious behavior. For college students and the general population, means of weighted and unweighted correlations between intelligence and the strength of religious beliefs ranged from −.20 to −.25 (mean r = −.24). Three possible interpretations were discussed. First, intelligent people are less likely to conform and, thus, are more likely to resist religious dogma. Second, intelligent people tend to adopt an analytic (as opposed to intuitive) thinking style, which has been shown to undermine religious beliefs. Third, several functions of religiosity, including compensatory control, self-regulation, self-enhancement, and secure attachment, are also conferred by intelligence. Intelligent people may therefore have less need for religious beliefs and practices.
2004-gottfredson.pdf: “2004fundamentalcause.pdf”, gottfredson
2014-carl.pdf: “Verbal intelligence is correlated with socially and economically liberal beliefs”, Noah Carl
Libertarians are an increasingly prominent ideological group in U.S. politics, yet they have been largely unstudied. Across 16 measures in a large web-based sample that included 11,994 self-identified libertarians, we sought to understand the moral and psychological characteristics of self-described libertarians. Based on an intuitionist view of moral judgment, we focused on the underlying affective and cognitive dispositions that accompany this unique worldview. Compared to self-identified liberals and conservatives, libertarians showed (1) stronger endorsement of individual liberty as their foremost guiding principle, and weaker endorsement of all other moral principles; (2) a relatively cerebral as opposed to emotional cognitive style; and (3) lower interdependence and social relatedness. As predicted by intuitionist theories concerning the origins of moral reasoning, libertarian values showed convergent relationships with libertarian emotional dispositions and social preferences. Our findings add to a growing recognition of the role of personality differences in the organization of political attitudes.
2017-ruffle.pdf: “Clever enough to tell the truth”, Bradley J. Ruffle, Yossef Tobol
2010-wennerstad.pdf: “Associations between IQ and cigarette smoking among Swedish male twins”, Karin Modig Wennerstad, Karri Silventoinen, Per Tynelius, Lars Bergman, Jaakko Kaprio, Finn Rasmussen
1984-hunter.pdf: “Validity and Utility of Alternative Predictors of Job Performance”, (1984; ):
Meta-analysis of the cumulative research on various predictors of job performance shows that for entry-level jobs there is no predictor with validity equal to that of ability, which has a mean validity of 0.53. For selection on the basis of current job performance, the work sample test, with mean validity of 0.54, is slightly better. For federal entry-level jobs, substitution of an alternative predictor would cost from $9.32$3.121984 billion (job tryout) to $47.49$15.891984 billion per year (age). Hiring on ability has a utility of $46.65$15.611984 billion per year, but affects minority groups adversely. Hiring on ability by quotas would decrease this utility by 5%. A third strategy—using a low cutoff score—would decrease utility by 83%. Using other predictors in conjunction with ability tests might improve validity and reduce adverse impact, but there is as yet no data base for studying this possibility.
2000-colquitt.pdf: “Toward an integrative theory of training motivation: A meta-analytic path analysis of 20 years of research”, (2000-01-01; ):
This article meta-analytically summarizes the literature on training motivation, its antecedents, and its relationships with training outcomes such as declarative knowledge, skill acquisition, and transfer. statistically-significant predictors of training motivation and outcomes included individual characteristics (eg., locus of control, conscientiousness, anxiety, age, cognitive ability, self-efficacy, valence, job involvement) and situational characteristics (eg., climate). Moreover, training motivation explained incremental in training outcomes beyond the effects of cognitive ability. Meta-analytic path analyses further showed that the effects of personality, climate, and age on training outcomes were only partially mediated by self-efficacy, valence, and job involvement. These findings are discussed in terms of their practical importance and their implications for an integrative theory of training motivation.
2007-berry.pdf: “Revisiting Interview-Cognitive Ability Relationships: Attending To Specific Range Restriction Mechanisms In Meta-Analysis”, (2007-11-13; ):
This study revisits the relationship between interviews and cognitive ability tests, finding lower magnitudes of correlation than have previous meta-analyses; a finding that has implications for both the construct and incremental validity of the interview. Our lower estimates of this relationship than previous meta-analyses were mainly due to (a) an updated set of studies, (b) exclusion of samples in which interviewers potentially had access to applicants’ cognitive test scores, and (c) attention to specific range restriction mechanisms that allowed us to identify a sizable subset of studies for which range restriction could be accurately accounted. Moderator analysis results were similar to previous meta-analyses, but magnitudes of correlation were generally lower than in previous meta-analyses. Findings have implications for the construct and incremental validity of interviews, and meta-analytic methodology in general.
1996-lynn-dysgenics.pdf: “DYSGENICS: Genetic Deterioration in Modern Populations”, Lynn
1991-arthur.pdf: “Prediction of Vehicular Accident Involvement: A Meta–Analysis”, (1991; ):
Previous attempts to summarize the vehicular accident involvement literature have been non-quantitative. Outcomes of these reviews have also reflected the equivocalness of research in this area. In an attempt to synthesize the diverse research findings into a collective result, aprocedure that controlled for sampling error was used.
4 classes of variables were identified as predictors of vehicular accident involvement. These were information-processing, cognitive ability, personality, and demographic/biographical variables. Moderate-to-marginally favorable overallresults were obtained for selective attention, regard for authority, locus of control, and cognitive ability as predictors of vehicular accident involvement.
Suggestions and directions for future research are discussed.
1992-bourhis.pdf: “Meta-analysis of the relationship between communication apprehension and cognitive performance”, (1992; ):
Although numerous studies have examined the relationship between communication apprehension (CA) and cognitive performance (eg., IQ grade point averages, course grades, assignment grades, and test scores), the findings are equivocal.
One area of findings suggests that students in the traditional educational environment experiencing high CA are at a distinct disadvantage when compared to their low or moderate counterparts. A second area of findings suggests that no statistically-significant relationship exists. A third area indicates that the nature of the instructional environment is a statistically-significant mediating variable that moderates the effects of CA on cognitive performance.
In the present study, awas conducted of 23 manuscripts containing information on 30 experiments that examined CA and cognitive performance. Results confirmed a statistically-significant negative correlation between CA and cognitive performance.
Implications for future research and classroom instruction are discussed.
“Premorbid IQ in Schizophrenia: A Meta-Analytic Review”, (2008-05-01):
Objective: Over the past three decades, there have been substantial changes in the diagnostic criteria for schizophrenia as well as changes in measurement of IQ. The last quantitative review of the literature on premorbid IQ inwas published more than two decades ago. Since that time, there have been many published studies of data sets pertaining to this issue. The purpose of the present review was to provide an updated meta-analysis of premorbid IQ in individuals who later develop schizophrenia.
Method: The authors performed a systematic literature search, which yielded 18 studies that met criteria for the. Inclusion criteria were 1. premorbid psychometric measures of IQ in subjects who were later diagnosed with , schizoaffective disorder, or schizophreniform disorder, 2. similar comparison data, and 3. sufficient data for calculation of an effect size. The analogue to the analysis of method was used to model between-study due to key study-design features.
Results: Overall, effect sizes was minimal and almost exclusively the result of one study. Methodological differences, such as diagnostic criteria, type of IQ measure, sample ascertainment, and age at premorbid testing, contributed minimally to the effect size variance. A cross-sectional analysis of all studies by age and a descriptive review of studies that used repeated measures of IQ in a single sample did not support the presence of a relative decline in IQ during the premorbid period in individuals with schizophrenia. However, all studies with pre-onset and post-onset testing within the same sample suggested that a [substantial] decline in the IQ of individuals with , relative to comparison subjects, was associated with the onset of frank psychosis.samples demonstrated a reliable, medium-sized impairment in premorbid IQ. The heterogeneity of
Conclusions: Years before the onset of psychotic symptoms, individuals with, as a group, demonstrate mean IQ scores approximately one-half of a standard deviation below that of healthy comparison subjects.
2017-keyes.pdf: “Association of Fluid Intelligence and Psychiatric Disorders in a Population-Representative Sample of US Adolescents”, American Medical Association