scholarly journals The Personalities of Twins: Just Ordinary Folks

Twin Research ◽  
2002 ◽  
Vol 5 (2) ◽  
pp. 125-131 ◽  
Author(s):  
Wendy Johnson ◽  
Robert F. Krueger ◽  
Thomas J. Bouchard ◽  
Matt McGue
Keyword(s):  
Twin Studies ◽  
Psychological Research ◽  
Effect Sizes ◽  
Large Samples ◽  
Social Closeness ◽  
Twin Registry ◽  
Three Samples ◽  
Males And Females ◽  
Mean Differences ◽  
Mz Twins

AbstractTwin studies have demonstrated that personality traits show moderate genetic influence. The conclusions drawn from twin studies rely on the assumptions that twins are representative of the population at large and that monozygotic and dizygotic twins are comparable in every way that might have bearing on the traits being studied. To evaluate these assumptions, we used Multidimensional Personality Questionnaire (MPQ) data from three samples drawn from the Minnesota Twin Registry (totaling 12,971 respondents) to examine the effect sizes associated with mean differences on the 11 MPQ scales and 3 higher-order MPQ factors for singletons versus twins and MZ twins versus DZ twins. The singletons in the samples were family members of the participating twins. We also used ratios of scale variances to examine the significance of variance differences. The only mean or variance difference replicated across all three samples was greater Social Closeness (about .1 standard deviation) for twins than for singletons. This difference was obtained for both males and females. It would appear that, with respect to personality, twins are not systematically different from other people. Our results also highlight the importance of replication in psychological research because each of our large samples showed differences not replicated in other samples.

scholarly journals Education in Twins and Their Parents Across Birth Cohorts Over 100 years: An Individual-Level Pooled Analysis of 42-Twin Cohorts

2017 ◽  
Vol 20 (5) ◽  
pp. 395-405 ◽  
Author(s):  
Karri Silventoinen ◽  
Aline Jelenkovic ◽  
Antti Latvala ◽  
Reijo Sund ◽  
Yoshie Yokoyama ◽  
...  
Keyword(s):  
Parental Education ◽  
Twin Studies ◽  
Pooled Analysis ◽  
Linear Regression Models ◽  
Birth Cohorts ◽  
Individual Level ◽  
Paternal Education ◽  
Males And Females ◽  
Adult Twins ◽  
Mz Twins

Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ twins in a large pooled dataset. Information was gathered on individual education for 218,362 adult twins from 27 twin cohorts (53% females; 39% MZ twins), and on maternal and paternal education for 147,315 and 143,056 twins respectively, from 28 twin cohorts (52% females; 38% MZ twins). Together, we had information on individual or parental education from 42 twin cohorts representing 19 countries. The original education classifications were transformed to education years and analyzed using linear regression models. Overall, MZ males had 0.26 (95% CI [0.21, 0.31]) years and MZ females 0.17 (95% CI [0.12, 0.21]) years longer education than DZ twins. The zygosity difference became smaller in more recent birth cohorts for both males and females. Parental education was somewhat longer for fathers of DZ twins in cohorts born in 1990–1999 (0.16 years, 95% CI [0.08, 0.25]) and 2000 or later (0.11 years, 95% CI [0.00, 0.22]), compared with fathers of MZ twins. The results show that the years of both individual and parental education are largely similar in MZ and DZ twins. We suggest that the socio-economic differences between MZ and DZ twins are so small that inferences based upon genetic modeling of twin data are not affected.

Adolescent Popularity as a Nonlinear, Two-Dimensional Construct: Convergent Results From Three Large Samples

2021 ◽  
pp. 027243162110160
Author(s):  
Peter E. L. Marks ◽  
Ben Babcock ◽  
Yvonne H. M. van den Berg ◽  
Rob Gommans ◽  
Antonius H. N. Cillessen
Keyword(s):  
Early Adolescents ◽  
Composite Score ◽  
Two Dimensional ◽  
Behavioral Correlates ◽  
Large Samples ◽  
Three Samples ◽  
Peer Nominations

The goal of this study was to advance the conceptualization and measurement of adolescent popularity by exploring the commonly used composite score (popularity minus unpopularity). We used standardized peer nominations from 4,414 early adolescents (ages ≈ 12-14 years) from three samples collected in two countries. Popularity and unpopularity were strongly related, but not linearly; scatterplots of the two variables resembled an L-shaped right angle. Subsequent analyses indicated that either including popularity as a curvilinear term or including both popularity and unpopularity as separate terms explained significantly more variance in social and behavioral correlates than linear, bivariate analyses using popularity, unpopularity, or composite popularity. These results suggest that researchers studying adolescent popularity should either separate popularity and unpopularity or treat composite popularity as curvilinear.

HealthTwiSt: The Berlin Twin Registry for Health Research

2012 ◽  
Vol 16 (1) ◽  
pp. 163-166 ◽  
Author(s):  
Andreas Busjahn
Keyword(s):  
Gene Expression ◽  
Health Research ◽  
Media Coverage ◽  
Collaborative Research ◽  
Twin Studies ◽  
Research Topics ◽  
Private Company ◽  
Intermediate Phenotypes ◽  
Twin Registry ◽  
Scientific Results

The Berlin Twin Registry has its focus on health research. It is operated as a private company, making twin studies available to academic institutions as well as commercial partners in the area of biotechnology and nutrition. Recruitment is based on invitation in the context of mass media coverage of scientific results. Phenotyping in the unselected twin subjects is directed toward intermediate phenotypes that can bear on common diseases. These phenotypes include proteomic approaches and gene expression. Some results are briefly described to give an impression of the range of research topics and related opportunities for retrospective and prospective collaborative research.

Astrocyte Biomarkers in Alzheimer Disease: A Systematic Review and Meta-analysis

Neurology ◽  
2021 ◽  
pp. 10.1212/WNL.0000000000012109
Author(s):  
Bruna Bellaver ◽  
João Pedro Ferrari-Souza ◽  
Lucas Uglione da Ros ◽  
Stephen F Carter ◽  
Elena Rodriguez-Vieitez ◽  
...  
Keyword(s):  
Systematic Review ◽  
Web Of Science ◽  
Meta Analysis ◽  
Effect Sizes ◽  
Significant Progress ◽  
Exclusion Criteria ◽  
Mao B ◽  
Positron Emission ◽  
Registration Number ◽  
Mean Differences

Objective:To perform a systematic review and meta-analysis to determine whether fluid and imaging astrocyte biomarkers are altered in Alzheimer's disease (AD).Methods:PubMed and Web of Science databases were searched for articles reporting fluid or imaging astrocyte biomarkers in AD. Pooled effect sizes were determined with mean differences (SMD) using the Hedge’s G method with random-effects to determine biomarker performance. Adapted questions from QUADAS-2 were applied for quality assessment. A protocol for this study has been previously registered in PROSPERO (registration number: CRD42020192304).Results:The initial search identified 1,425 articles. After exclusion criteria were applied, 33 articles (a total of 3,204 individuals) measuring levels of GFAP, S100B, YKL-40 and AQP4 in the blood and cerebrospinal fluid (CSF), as well as MAO-B, indexed by positron emission tomography 11C-deuterium-L-deprenyl ([11C]-DED), were included. GFAP (SMD = 0.94; 95% CI = 0.71-1.18) and YKL-40 (SMD = 0.76; CI 95% = 0.63-0.89) levels in the CSF, S100B levels in the blood (SMD = 2.91; CI 95% = 1.01-4.8) were found significantly increased in AD patients.Conclusions:Despite significant progress, applications of astrocyte biomarkers in AD remain in their early days. The meta-analysis demonstrated that astrocyte biomarkers are consistently altered in AD and supports further investigation for their inclusion in the AD clinical research framework for observational and interventional studies.

scholarly journals Australian Twin Registry: 30 Years of Progress

2012 ◽  
Vol 16 (1) ◽  
pp. 34-42 ◽  
Author(s):  
John L. Hopper ◽  
Debra L. Foley ◽  
Paul A. White ◽  
Vincent Pollaers
Keyword(s):  
Twin Studies ◽  
Well Being ◽  
Full Potential ◽  
Medical Council ◽  
Twin Registry ◽  
Pair Comparisons ◽  
Baseline Information ◽  
The University ◽  
Health And Well Being ◽  
Online Software

The Australian Twin Registry (ATR) is a national volunteer resource of twin pairs and higher-order multiples willing to consider participating in health, medical, and scientific research. The vision of the ATR is ‘to realize the full potential of research involving twins to improve the health and well-being of all Australians’. The ATR has been funded continuously by the National Health and Medical Council for more than 30 years. Its core functions entail the recruitment and retention of twin members, the maintenance of an up-to-date database containing members’ contact details and baseline information, and the promotion and provision of open access to researchers from all institutes in Australia, and their collaborators, in a fair and equitable manner. The ATR is administered by The University of Melbourne, which acts as custodian. Since the late 1970s the ATR has enrolled more than 40,000 twin pairs of all zygosities and facilitated more than 500 studies that have produced at least 700 peer-reviewed publications from classical twin studies, co-twin control studies, within-pair comparisons, twin family studies, longitudinal twin studies, randomized controlled trials, and epigenetics studies, as well as studies of issues specific to twins. New initiatives include: a Health and Life Style Questionnaire; data collection, management, and archiving using a secure online software program (The Ark); and the International Network of Twin Registries. The ATR's expertise and 30 years of experience in providing services to national and international twin studies has made it an important resource for research across a broad range of disciplines.

The Unique Contribution of Twin Studies to the Elucidation of Nongenetic Factors in Personality Development and Psychopathogenesis

1970 ◽  
Vol 19 (1-2) ◽  
pp. 299-302
Author(s):  
William Pollin
Keyword(s):  
Matched Control ◽  
Personality Development ◽  
Methodological Issue ◽  
Twin Studies ◽  
Birth Size ◽  
Unique Contribution ◽  
Genetic Studies ◽  
Personality Differences ◽  
Multidisciplinary Study ◽  
Mz Twins

Our Section in Bethesda is primarily engaged in studies of schizophrenia and personality formation. I will summarize a number of our ongoing studies, and then briefly focus on a methodological issue: the possibility of twin studies moving beyond their heretofore almost constant, very useful tie to genetic studies.We have previously reported an elaborate multidisciplinary study of a series of MZ twins discordant for schizophrenia, a smaller number of appropriately matched control twin pairs, and their families, aimed at studying nongenetic factors in the pathogenesis of schizophrenia (Pollin et al, 1965, 1966). We have described three interacting groups of variables which consistently differentiated the schizophrenic and nonschizophrenic twins in the discordant pairs (Pollin and Stabenau, 1965). These included an initial set of nongenetic constitutional differences, including birth size, vigor, and physiological competence; consequent different parental perceptions of, and relationships to, each of the twins in a given pair; and subsequent biological and life history differences, based on evolving personality differences, such as in fearfulness, competence, independence, initiative and the like, differentiating the schizophrenic index and the nonschizophrenic cotwins.

scholarly journals Deconstruction of Vulnerability to Complex Diseases: Enhanced Effect Sizes and Power of Intermediate Phenotypes

2007 ◽  
Vol 7 ◽  
pp. 124-130 ◽  
Author(s):  
David Goldman ◽  
Francesca Ducci
Keyword(s):  
Effect Size ◽  
Complex Disease ◽  
Complex Diseases ◽  
Effect Sizes ◽  
Complex Disorders ◽  
Large Samples ◽  
Intermediate Phenotypes ◽  
Genome Association ◽  
Whole Genome Association ◽  
Disease Loci

The deconstruction of vulnerability to complex disease with the help of intermediate phenotypes, including the heritable and disease-associated endophenotypes, is a legacy of Henri Begleiter. Systematic searches for genes influencing complex disorders, including bipolar disorder, have recently been completed using whole genome association (WGA), identifying a series of validated loci. Using this information, it is possible to compare effect sizes of disease loci discovered in very large samples to the effect sizes of replicated functional loci determining intermediate phenotypes that are of essential interest in psychiatric disorders. It is shown that the genes influencing intermediate phenotypes tend to have a larger effect size. Furthermore, the WGA results reveal that the number of loci of large effect size for complex diseases is limited, and yet multiple functional loci have already been identified for intermediate phenotypes relevant to psychiatric diseases, and without the benefit of WGA.

scholarly journals A Reassessment of ANOVA Reporting Practices: A Review of Three APA Journals

2018 ◽  
Vol 8 (1) ◽  
pp. 3-19 ◽  
Author(s):  
Yuanyuan Zhou ◽  
Susan Troncoso Skidmore
Keyword(s):  
Counseling Psychology ◽  
Research Question ◽  
Psychological Research ◽  
Effect Sizes ◽  
Applied Psychology ◽  
Primary Research ◽  
Primary Analysis ◽  
P Values ◽  
Comprehensive Review ◽  
Reporting Practices

Historically, ANOVA has been the most prevalent statistical method used in educational and psychological research and today ANOVA continues to be widely used.  A comprehensive review published in 1998 examined several APA journals and discovered persistent concerns in ANOVA reporting practices.  The present authors examined all articles published in 2012 in three APA journals (Journal of Applied Psychology, Journal of Counseling Psychology, and Journal of Personality and Social Psychology) to review ANOVA reporting practices including p values and effect sizes.  Results indicated that ANOVA continues to be prevalent in the reviewed journals as a test of the primary research question, as well as to test conditional assumptions prior to the primary analysis.  Still, ANOVA reporting practices are essentially unchanged from what was previously reported.  However, effect size reporting has improved.

scholarly journals Reduction in Physical Match Performance at the Start of the Second Half in Elite Soccer

2011 ◽  
Vol 6 (2) ◽  
pp. 174-182 ◽  
Author(s):  
Matthew Weston ◽  
Alan M. Batterham ◽  
Carlo Castagna ◽  
Matthew D. Portas ◽  
Christopher Barnes ◽  
...  
Keyword(s):  
High Speed ◽  
Analysis Data ◽  
Effect Sizes ◽  
Match Analysis ◽  
Warm Up ◽  
Total Distance ◽  
Mean Differences ◽  
English Premier League ◽  
Opening Phase ◽  
Physical Match

Purpose:Soccer referees’ physical match performances at the start of the second half (46–60 min) were evaluated in relation to both the corresponding phase of the first half (0–15 min) and players’ performances during the same match periods.Methods:Match analysis data were collected (Prozone, UK) from 12 soccer referees on 152 English Premier League matches during the 2008/09 soccer season. Physical match performance categories for referees and players were total distance, high-speed running distance (speed >5.5 m/s), and sprinting distance (>7.0 m/s). The referees’ heart rate was recorded from the start of their warm-up to the end of the match. The referees’ average distances (in meters) from the ball and fouls were also calculated.Results:No substantial differences were observed in duration (16:42 ± 2:35 vs 16:27 ± 1:00 min) or intensity (107 ± 11 vs 106 ± 14 beats/min) of the referees’ preparation periods immediately before each half. Physical match performance was reduced during the initial phase of the second half when compared with the first half in both referees (effect sizes—standardized mean differences—0.19 to 0.73) and players (effect sizes 0.20 to 1.01). The degree of the decreased performance was consistent between referees and players for total distance (4.7 m), high-speed running (1.5 m), and sprinting (1.1 m). The referees were closer to the ball (effect size 0.52) during the opening phase the second half.Conclusion:Given the similarity in the referees’ preparation periods, it may be that the reduced physical match performances observed in soccer referees during the opening stages of the second half are a consequence of a slower tempo of play.

New Effect Sizes for Tests of Categorical Moderation and Differential Prediction

2016 ◽  
Vol 20 (4) ◽  
pp. 639-664 ◽  
Author(s):  
Christopher D. Nye ◽  
Paul R. Sackett
Keyword(s):  
Effect Size ◽  
Past Research ◽  
Well Being ◽  
Psychological Research ◽  
Effect Sizes ◽  
Categorical Variables ◽  
Differential Prediction ◽  
Large Sample ◽  
Additional Information ◽  
Large Databases

Moderator hypotheses involving categorical variables are prevalent in organizational and psychological research. Despite their importance, current methods of identifying and interpreting these moderation effects have several limitations that may result in misleading conclusions about their implications. This issue has been particularly salient in the literature on differential prediction where recent research has suggested that these limitations have had a significant impact on past research. To help address these issues, we propose several new effect size indices that provide additional information about categorical moderation analyses. The advantages of these indices are then illustrated in two large databases of respondents by examining categorical moderation in the prediction of psychological well-being and the extent of differential prediction in a large sample of job incumbents.

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