The structure, development, and correlates of individual differences in human personality

textHuman personality possesses a complex psychometric structure that changes with maturation and predicts a number of important life outcomes. The current dissertation presents four studies that track the structure, development, and correlates of personality, primarily through a behavioral genetic lens. Study 1 finds that the genetic and environmental structure of personality domains residing over more narrow facets is more complex than can be accounted for by simple, broad domains. Study 2 presents meta-analytic evidence for the differential stability of personality traits across the lifespan, as well as genetic and environmental contributions to stability. Personality traits become more stable with age, and this trend is primarily driven by increasing environmental sources of stability. Study 3 details a transactional model of parental educational expectations, child academic behaviors, and child academic achievement across early development. Finally, Study 4 presents associations between state-level aggregates of personality and the level, timing, and context of fertility across the United States. Together, these studies indicate the importance of understanding personality for individual-level and population-level processes, as well as, the complexities of this goal due to the dynamic nature of gene-environment dependencies that undergird personality development.Psycholog

Hidden heritability due to heterogeneity across seven populations

Meta-analyses of genome-wide association studies, which dominate genetic discovery, are based on data from diverse historical time periods and populations. Genetic scores derived from genome-wide association studies explain only a fraction of the heritability estimates obtained from whole-genome studies on single populations, known as the ‘hidden heritability’ puzzle. Using seven sampling populations (n = 35,062), we test whether hidden heritability is attributed to heterogeneity across sampling populations and time, showing that estimates are substantially smaller across populations compared with within populations. We show that the hidden heritability varies substantially: from zero for height to 20% for body mass index, 37% for education, 40% for age at first birth and up to 75% for number of children. Simulations demonstrate that our results are more likely to reflect heterogeneity in phenotypic measurement or gene–environment interactions than genetic heterogeneity. These findings have substantial implications for genetic discovery, suggesting that large homogenous datasets are required for behavioural phenotypes and that gene–environment interaction may be a central challenge for genetic discovery

Meta-analysis of genome-wide association studies for extraversion:Findings from the Genetics of Personality Consortium

Extraversion is a relatively stable and heritable personality trait associated with numerous psychosocial, lifestyle and health outcomes. Despite its substantial heritability, no genetic variants have been detected in previous genome-wide association (GWA) studies, which may be due to relatively small sample sizes of those studies. Here, we report on a large meta-analysis of GWA studies for extraversion in 63,030 subjects in 29 cohorts. Extraversion item data from multiple personality inventories were harmonized across inventories and cohorts. No genome-wide significant associations were found at the single nucleotide polymorphism (SNP) level but there was one significant hit at the gene level for a long non-coding RNA site (LOC101928162). Genome-wide complex trait analysis in two large cohorts showed that the additive variance explained by common SNPs was not significantly different from zero, but polygenic risk scores, weighted using linkage information, significantly predicted extraversion scores in an independent cohort. These results show that extraversion is a highly polygenic personality trait, with an architecture possibly different from other complex human traits, including other personality traits. Future studies are required to further determine which genetic variants, by what modes of gene action, constitute the heritable nature of extraversion

Achievement relevant personality : relations with the Big Five and validation of an efficient instrument

textA plethora of personality constructs have been proposed, and associated measures developed, to capture behavioral tendencies relevant to academic achievement. For example, individual differences in aspects of motivation, curiosity, studying behaviors and evaluations of the importance of school have been linked with achievement. However, there is little understanding of whether and how different achievement-relevant personality measures (APMs) relate to one another or to broader dimensions of personality. The current project examined the dimensionality of achievement-relevant personality constructs, their associations with the Big Five personality traits, and associations with academic performance. In Study 1, 214 college students were measured on 36 independent APMs along with a well-established, measure of the Big Five traits. Factor analytic results supported the convergent and discriminant validity of five latent dimensions: performance and mastery approaches to learning, self-doubt, effort, and hungry mind. Each factor and the individual scales that composed the factors possessed a distinctive pattern of associations with the Big Five. Conscientiousness, neuroticism, and openness to experience had the most consistent associations with APMs. Based on the results of the first study, we next constructed a more efficient scale of APMs – the Multidimensional Achievement-Relevant Personality Scale (MAPS). In Study 2, we replicated the factor structure of the MAPS and its associations with the Big Five in a sample of 359 individuals. Additionally, we validated the MAPS with four indicators of academic performance. Although the factors assessed by the MAPS overlap somewhat with general indicators of personality, there was some evidence of incremental prediction of achievement.Psycholog

Sensation seeking and impulsive traits as personality endophenotypes for antisocial behavior: Evidence from two independent samples

Sensation seeking and impulsivity are personality traits that are correlated with risk for antisocial behavior (ASB). This paper uses two independent samples of twins to (a) test the extent to which sensation seeking and impulsivity statistically mediate genetic influence on ASB, and (b) compare this to genetic influences accounted for by other personality traits. In Sample 1, delinquent behavior, as well as impulsivity, sensation seeking and Big Five personality traits, were measured in adolescent twins from the Texas Twin Project. In Sample 2, adult twins from the Australian Twin Registry responded to questionnaires that assessed individual differences in Eysenck's and Cloninger's personality dimensions, and a structured telephone interview that asked participants to retrospectively report DSM-de- fined symptoms of conduct disorder. Bivariate quantitative genetic models were used to identify genetic overlap between personality traits and ASB. Across both samples, novelty/sensation seeking and impulsive traits accounted for larger portions of genetic variance in ASB than other personality traits.We discuss whether sensation seeking and impulsive personality are causal endophenotypes for ASB, or merely index genetic liability for ASB

Multiplexed Nanoflares: mRNA Detection in Live Cells

We report the development of the multiplexed nanoflare, a nanoparticle agent that is capable of simultaneously detecting two distinct mRNA targets inside a living cell. These probes are spherical nucleic acid (SNA) gold nanoparticle (Au NP) conjugates consisting of densely packed and highly oriented oligonucleotide sequences, many of which are hybridized to a reporter with a distinct fluorophore label and each complementary to its corresponding mRNA target. When multiplexed nanoflares are exposed to their targets, they provide a sequence specific signal in both extra- and intracellular environments. Importantly, one of the targets can be used as an internal control, improving detection by accounting for cell-to-cell variations in nanoparticle uptake and background. Compared to single-component nanoflares, these structures allow one to determine more precisely relative mRNA levels in individual cells, improving cell sorting and quantification

Supplemental Material, SPPS784890_suppl_mat - Genetic and Environmental Associations Between Child Personality and Parenting

<p>Supplemental Material, SPPS784890_suppl_mat for Genetic and Environmental Associations Between Child Personality and Parenting by Mona Ayoub, Daniel A. Briley, Andrew Grotzinger, Megan W. Patterson, Laura E. Engelhardt, Jennifer L. Tackett, K. Paige Harden, and Elliot M. Tucker-Drob in Social Psychological and Personality Science</p

Hidden heritability due to heterogeneity across seven populations

Meta-analyses of genome-wide association studies (GWAS), which dominate genetic discovery are based on data from diverse historical time periods and populations. Genetic scores derived from GWAS explain only a fraction of the heritability estimates obtained from whole-genome studies on single populations, known as the 'hidden heritability' puzzle. Using seven sampling populations (N=35,062), we test whether hidden heritability is attributed to heterogeneity across sampling populations and time, showing that estimates are substantially smaller from across compared to within populations. We show that the hidden heritability varies substantially: from zero (height), to 20% for BMI, 37% for education, 40% for age at first birth and up to 75% for number of children. Simulations demonstrate that our results more likely reflect heterogeneity in phenotypic measurement or gene-environment interaction than genetic heterogeneity. These findings have substantial implications for genetic discovery, suggesting that large homogenous datasets are required for behavioural phenotypes and that gene-environment interaction may be a central challenge for genetic discovery