William G Iacono
Biographic Data
| ID | 376531 |
|---|---|
| NAME | William G Iacono |
| GIVEN NAMES | William G |
| FAMILY NAME | Iacono |
| SIGNATURE | IACONO W G |
| AFFILIATIONS | University of Minnesota |
| ORCID | 0000-0002-3194-3090 |
| VERIFIED | Yes |
| TOTAL WORKS | 67 |
| TOTAL CITATIONS | 321 |
| AUTHOR COUNT | 67 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1974 |
| LATEST PUBLICATION YEAR | 2026 |
| H-INDEX | 10 |
Is Progressive Ideology on the Test? Education and Intelligence in the Development of Nontraditional Attitudes
Enhanced educational attainment and intelligence are consistent correlates of socially liberal, nontraditional attitudes. However, it is unclear how such associations unfold developmentally. Here, we propose an interaction effect between college exposure and intelligence on the development of nontraditional attitudes. Our rationale builds from the fact that a desired learning outcome of college education is to challenge traditional dogma and enco…
Association of Recreational Cannabis Legalization with Frequency of Using Cannabis for Sleep
We examined the association of recreational cannabis legalization (RCL) with frequency of using cannabis, alcohol, and sleep medication for sleep and with co-use of cannabis with other sleep aids. We used linear regression models to examine these associations in a population-based sample of adult twins ( n = 3,141). Participants (M age = 37 (SD = 5)) were primarily White (93%), with 5% Hispanic/Latinx, and female (61%). RCL was associated with us…
Pubertal timing and adolescent outcomes: Investigating explanations for associations with a genetically informed design
BACKGROUND: Psychopathology and risky behaviors increase during adolescence, and understanding which adolescents are most at risk informs prevention and intervention efforts. Pubertal timing relative to same-sex, same-age peers is a known correlate of adolescent outcomes among both boys and girls. However, it remains unclear whether this relation is better explained by a plausible causal process or unobserved familial liability. METHODS: We exten…
Personality and peer groups in adolescence: Reciprocal associations and shared genetic and environmental influences
OBJECTIVE: Peer groups represent a critical developmental context in adolescence, and there are many well-documented associations between personality and peer behavior at this age. However, the precise nature and direction of these associations are difficult to determine as youth both select into, and are influenced by, their peers. METHOD: We thus examined the phenotypic, genetic, and environmental links between antisocial and prosocial peer cha…
The association between saving disposition and financial distress: A genetically informed approach
Educational Attainment and Intergenerational Mobility: A Polygenic Score Analysis
We extend a standard model of parental investment and intergenerational mobility to include a fully specified genetic analysis of skill transmission. The model’s predictions differ substantially from the standard model’s. The coefficient of intergenerational income elasticity (IGE) may be larger than that in the standard model and depends on the distribution of the genotype. The distribution of genetic endowments may be stratified according to in…
Polygenic prediction of educational attainment within and between families from genome-wide association analyses in 3 million individuals
We conduct a genome-wide association study (GWAS) of educational attainment (EA) in a sample of ~3 million individuals and identify 3,952 approximately uncorrelated genome-wide-significant single-nucleotide polymorphisms (SNPs). A genome-wide polygenic predictor, or polygenic index (PGI), explains 12–16% of EA variance and contributes to risk prediction for ten diseases. Direct effects (i.e., controlling for parental PGIs) explain roughly half th…
The clashing nature of rebelliousness: Nontraditional attitudes and counter‐normative behaviors show divergent associations with intelligence
OBJECTIVE: Prior literature indicates that nontraditional attitudes are linked to higher intelligence. However, such attitudes in adolescence often accompany counter-normative, delinquent-type behaviors, which are themselves negatively linked with intelligence. This points to the possibility of suppression in the relationship between intelligence and nontraditional attitudes. METHOD: We analyzed a large community sample of 17 year olds (N = 3330)…
Adolescent Sexual Development and Peer Groups: Reciprocal Associations and Shared Genetic and Environmental Influences
Mechanisms of parent–child transmission of tobacco and alcohol use with polygenic risk scores: Evidence for a genetic nurture effect
Parent-child similarity is a function of genetic and environmental transmission. In addition, genetic effects not transmitted to offspring may drive parental behavior, thereby affecting the rearing environment of the child. Measuring genetic proclivity directly, through polygenic risk scores (PRSs), provides a way to test for the effect of nontransmitted parental genotype, on offspring outcome, termed a genetic nurture effect-in other words, if a…
The role of the shared environment in college attainment: An adoption study
OBJECTIVE: College attainment is one of the few phenotypes to have substantial variance accounted for by environmental factors shared by reared-together relatives. The shared environment is implicated by the consistently strong parent-to-offspring transmission of college attainment. The mechanisms underlying this relationship remain unclear. We use genetically informative methods with a longitudinal, adoption sample to identify possible environme…
Discrimination and Ethnic-Racial Socialization Among Youth Adopted From South Korea Into White American Families
The current study examined how discrimination relates to adjustment outcomes in a sample of internationally, transracially adopted Korean Americans from the Minnesota Sibling Interaction and Behavior Study (N = 456 adoptees; Mage at T1 = 14.9, Mage at T2 = 18.3, Mage at T3 = 22.3). The moderating roles of ethnic socialization and preparation for bias by parents (i.e., ethnic-racial socialization) were also examined. Results indicated that discrim…
Sexual Development in Adolescence: An Examination of Genetic and Environmental Influences
Sexual development entails many experiences and is a major feature of adolescence. Most relevant behavioral genetic studies, however, focus primarily on sexual behaviors associated with health risks. We took a more normative, developmental perspective by examining genetic and environmental influences on five sexual behaviors ranging from dating to pregnancy in middle (M age = 14.90 years) and late adolescence (M age = 17.85 years) in a sample of …
Personality heterogeneity in adolescents with disruptive behavior disorders
Codevelopment Between Key Personality Traits and Alcohol Use Disorder From Adolescence Through Young Adulthood
OBJECTIVE: Personality traits related to negative emotionality and low constraint are strong correlates of alcohol use disorder (AUD), but few studies have evaluated the prospective interplay between these traits and AUD symptoms from adolescence to young adulthood. METHOD: The Minnesota Twin Family Study (N = 2,769) was used to examine the developmental interplay between AUD symptoms and three personality measures of constraint, negative emotion…
The Developmental Unfolding of Sibling Influences on Alcohol Use over Time
Integrating criminological and mental health perspectives on low self-control: A multi-domain analysis
Numbers Assigned in the Vietnam-Era Selective Service Lotteries Influence the Military Service Decisions of Children Born to Draft-Eligible Men: A Research Note
Previous research has reported correlations between the military service records of parents and their children. Those studies, however, have not determined whether a parent's military service causally influences an offspring's participation in the armed forces. To investigate the possibility of a causal relationship, we examined whether lottery numbers issued to draft-eligible men during the U.S. Vietnam-era Selective Service Lotteries influenced…
Cognitive, Noncognitive, and Family Background Contributions to College Attainment: A Behavioral Genetic Perspective
There is considerable evidence that college attainment is associated with family background and cognitive and noncognitive skills. Behavioral genetic methods are used to determine whether the family background effect is mediated through cognitive and noncognitive skill development. We analyze data from two longitudinal behavioral genetic studies: the Minnesota Twin Family Study, consisting of 1,382 pairs of like‐sex twins and their parents, and t…
Personality Traits Predict the Developmental Course of Externalizing: A Four‐Wave Longitudinal Study Spanning Age 17 to Age 29
The objective of the present study was to determine whether and how personality predicts the developmental course of externalizing problems, including antisocial behavior and substance dependence. In a large, population‐based longitudinal study ( N = 1,252), the 11 personality traits assessed by the Multidimensional Personality Questionnaire were measured at age 17, and DSM diagnoses of adult antisocial behavior, alcohol dependence, and drug depe…
The Gender Risk–Severity Paradox for Alcohol Use Disorder From Adolescence Through Young Adulthood
A large proportion of the public health costs of alcohol use disorder (AUD) can be accounted for by a small percentage of severe cases with a chronic course starting in adolescence and persisting into adulthood. However, chronicity may be a less effective marker of AUD severity in women than men due to a gender risk-severity paradox wherein comparable levels of risk exposure yield more co-occurring problems for women than men with AUD. To model t…
Personality in the age of industry: Structure, heritability, and correlates of personality in middle childhood from the perspective of parents, teachers, and children
Genetic evidence of assortative mating in humans
Genetic variants associated with subjective well-being, depressive symptoms, and neuroticism identified through genome-wide analyses
Genome-wide association study identifies 74 loci associated with educational attainment
Perceptions of the Parent-Adolescent Relationship: A Longitudinal Investigation
A self-report measure of conflict and aspects of warmth in the parent-child relationship was completed by 1,330 11-year-old twins, 1,176 of whom completed the inventory again 3 years later. On average, adolescents' perceptions of the quality of the parent-child relationship declined consistently and moderately between age 11 and age 14. Conflict with parents increased, whereas all aspects of warmth decreased; changes were significantly greater fo…
Stability and change in religiousness during emerging adulthood
Understanding the development of religiousness is an important endeavor because religiousness has been shown to be related to positive outcomes. The current study examined mean-level, rank-order, and individual-level change in females' religiousness during emerging adulthood. Genetic and environmental influences on religiousness and its change and stability were also investigated. Analyses were completed with an epidemiological study of 2 cohorts…
Genetic and environmental influences on academic achievement trajectories during adolescence
Most studies have considered the effects of particular characteristics on academic achievement individually, which means that little is known about how they function together. Using the population-based Minnesota Twin Family Study, the authors investigated the effects of child academic engagement (interest, involvement, effort), IQ, depression, externalizing behavior, and family environmental risk on academic achievement (reported school grades) …
Genetic and environmental influences on parent–son relationships: Evidence for increasing genetic influence during adolescence
Genetic evidence of assortative mating in humans
Differential parent-child relationships and adolescent externalizing symptoms: Cross-lagged analyses within a monozygotic twin differences design
Research has indicated that differential parental treatment is linked to differences in externalizing symptomology (EXT) across siblings, even those siblings who are genetically identical. However, the direction of causation and longitudinal significance of this relationship remains unclear. Thus, in the present study, the authors examined 486 monozygotic twin pairs, assessed at ages 11, 14, and 17 years, within a cross-lagged twin differences de…
Genetic and environmental influences on parent-son relationships: Evidence for increasing genetic influence during adolescence
Genetic and environmental influences on self-reported parent-child relationships were examined in a sample of 824 individual male twins and their parents. Cross-sectional comparisons of twin similarity at ages 11 and 17 were undertaken to identify developmental changes in the contribution of genetic and environmental factors to family relationships. Significant genetic influences were found on perceptions of parent-son conflict, regard, involveme…
Genetic and environmental influences on personality trait stability and growth during the transition to adulthood: A three-wave longitudinal study
During the transition to adulthood individuals typically settle into adult roles in love and work. This transition also involves significant changes in personality traits that are generally in the direction of greater maturity and increased stability. Competing hypotheses have been offered to account for these personality changes: The intrinsic maturation hypothesis suggests that change trajectories are endogenous, whereas the life-course hypothe…
Quantifying the association between personality similarity and marital adjustment using profile correlations: A cautionary tale
Nonshared environmental mediation of the association between deviant peer affiliation and adolescent externalizing behaviors over time: Results from a cross-lagged monozygotic twin differences design
It has been argued that peers are the most important agent of adolescent socialization and, more specifically, that this socialization process occurs at the child-specific (or nonshared environmental) level (J. R. Harris, 1998; R. Plomin & Asbury, 2005). The authors sought to empirically evaluate this nonshared environmental peer influence hypothesis by examining the association between externalizing behaviors and deviant peer affiliation in a sa…
Most of the girls are alright, but some aren't: Personality trajectory groups from ages 14 to 24 and some associations with outcomes
Personality traits show normative patterns of development toward maturity during adolescence. Yet individuals follow these normative patterns to differing degrees. This study used growth mixture modeling to characterize personality development patterns and their associations with outcomes in a population-based sample of 1,537 girls aged 14 to 24. The authors used latent class analysis to identify 3 trajectory groups labeled alright (47%), growing…
Identity Development in a Transracial Environment: Racial/Ethnic Minority Adoptees in Minnesota
It has been argued that transracial adopted children have increased risk for problems related to self-esteem and ethnic identity development. We evaluated this hypothesis across four groups of transracial adoptees: Asian ( N = 427), Latino ( N = 28), Black ( N = 6), Mixed/Other ( N = 20), and same-race white adoptees ( N = 126) from 357 adoptive families. No mean differences were found in adoptee's ratings of affect about adoption, or of curiosit…
Antisocial peer affiliation and externalizing disorders in the transition from adolescence to young adulthood: Selection versus socialization effects
Prior research has demonstrated both socialization and selection effects for the relationship between antisocial peer affiliation and externalizing problems in adolescence. Less research has evaluated such effects postadolescence. In this study, a cross-lagged panel analysis was used to evaluate the extent of socialization (i.e., the effect of antisocial peer affiliation on subsequent externalizing disorders) and selection (i.e., the effect of ex…
Parental monitoring, personality, and delinquency: Further support for a reconceptualization of monitoring
Parental divorce and adolescent delinquency: Ruling out the impact of common genes
Although the well-documented association between parental divorce and adolescent delinquency is generally assumed to be environmental (i.e., causal) in origin, genetic mediation is also possible. Namely, the behavior problems often found in children of divorce could derive from similar pathology in the parents, pathology that is both heritable and increases the risk that the parent will experience divorce. To test these alternative hypotheses, th…
Adolescent psychopathy features: 6‐Year temporal stability and the prediction of externalizing symptoms during the transition to adulthood
This study investigated the 6‐year stability and predictive validity of adolescent psychopathy features during the transition to young adulthood. It represents one of the longest outcome studies of youth psychopathy to date, and therefore addresses a primary criticism of the research area (i.e., lack of demonstrated associations between child and adult psychopathy features). Recruited participants were 475 males enrolled in the Minnesota Twin and…
Numbers Assigned in the Vietnam-Era Selective Service Lotteries Influence the Military Service Decisions of Children Born to Draft-Eligible Men: A Research Note
Previous research has reported correlations between the military service records of parents and their children. Those studies, however, have not determined whether a parent's military service causally influences an offspring's participation in the armed forces. To investigate the possibility of a causal relationship, we examined whether lottery numbers issued to draft-eligible men during the U.S. Vietnam-era Selective Service Lotteries influenced…
Genetic and environmental influences on affiliation with deviant peers during adolescence and early adulthood
Adolescence and early adulthood is a time when peer groups become increasingly influential in the lives of young people. Youths exposed to deviant peers risk susceptibility to externalizing behaviors and related psychopathology. In addition to environmental correlates of deviant peer affiliation, a growing body of evidence has suggested that affiliation with deviant peers is heritable. This study examined the magnitude of genetic and environmenta…
Genetic influences on the development of grip strength in adolescence
Enhanced physical strength is a secondary sex characteristic in males. Sexual dimorphism in physical strength far exceeds sex differences in stature or total body mass, suggesting a legacy of intense sexual selection. Upper‐body strength is a particularly promising marker of intrasexual competitiveness in young men. Consequently, it is assumed that sex‐influenced gene expression contributes to the development of physical strength. It is unclear, …
Personality in middle childhood: A hierarchical structure and longitudinal connections with personality in late adolescence
Sibling Facilitation Mediates the Association Between Older and Younger Sibling Alcohol Use in Late Adolescence
Previous research has shown adolescent siblings are similar in their alcohol use and that this similarity is largely due to their shared environment. Using a genetically-informed sibling sample (196 full-biological pairs, 384 genetically unrelated pairs), we confirmed that the extent to which older siblings facilitate younger siblings' alcohol use (i.e., help them get alcohol) was one factor contributing to this shared environmental association. …
School performance and genetic and environmental variance in antisocial behavior at the transition from adolescence to adulthood
Antisocial behavior increases in adolescence, particularly among those who perform poorly in school. As adolescents move into adulthood, both educational attainment and the extent to which antisocial behavior continues have implications for adolescents' abilities to take on constructive social roles. The authors used a population-representative longitudinal twin study to explore how links among genetic and environmental influences at ages 17 and …
The association between saving disposition and financial distress: A genetically informed approach
The Developmental Unfolding of Sibling Influences on Alcohol Use over Time
Adolescent personality moderates genetic and environmental influences on relationships with parents
In contrast with early theories of socialization that emphasized the role of parents in shaping their children's personalities, recent empirical evidence suggests an evocative relationship between adolescent personality traits and the quality of the parent-adolescent relationship. Research using behavior genetic methods suggests that the association between personality and parenting is genetically mediated, such that the genetic effects on adoles…
Relationship between "strength of the nervous system" and the need for stimulation
Guilty knowledge
A measure of the 'sick' label in psychiatric disorder and physical illness
Genetic and environmental influences on parent-son relationships: Evidence for increasing genetic influence during adolescence
Genetic and environmental influences on self-reported parent-child relationships were examined in a sample of 824 individual male twins and their parents. Cross-sectional comparisons of twin similarity at ages 11 and 17 were undertaken to identify developmental changes in the contribution of genetic and environmental factors to family relationships. Significant genetic influences were found on perceptions of parent-son conflict, regard, involveme…
Genetic and environmental influences on parent–son relationships: Evidence for increasing genetic influence during adolescence
The structure of self-concept in female preadolescent twins: A behavioral genetic approach
Two hundred and forty-three female monozygotic (MZ) and 164 female dizygotic (DZ) twin pairs, aged 11 and 12 years, who participated in the ongoing Minnesota Twin Family Study, completed six specific scales of the Piers-Harris Children's Self-Concept Scale (P-H). Model-fitting analyses yielded three major conclusions. First, approximately 30% of the variance in specific self-concepts in female preadolescents was due to genetic factors, with the r…
A Behavioral Genetic Analysis of the Relationship Between the Socialization Scale and Self‐Reported Delinquency
This investigation examined the genetic (A), and shared (C) and nonshared (E) environmental variance contributions to the relationship of self‐reported delinquency (as measured by the “Delinquent Behavior Inventory” [DBI; Gibson, 1967]) to the Socialization (So) scale of the California Psychological Inventory using univariate and bivariate structural equation models. The scales were administered to 222 male (145 monozygotic; 77 dizygotic) and 159…
Assessing the validity of amnesia in dissociative identity disorder: A dilemma for the DSM and the courts
Assessing the validity of amnesia in dissociative identity disorder: A dilemma for the DSM and the courts
Etiologic connections among substance dependence, antisocial behavior and personality: Modeling the externalizing spectrum.
A hierarchical biometric model is presented of the origins of comorbidity among substance dependence, antisocial behavior, and a disinhibited personality style. The model posits a spectrum of personality and psychopathology, united by an externalizing factor linked to each phenotype within the spectrum, as well as specific factors that account for distinctions among phenotypes within the spectrum. This model fit self-report and mother-report data…
Childhood externalizing and internalizing psychopathology in the prediction of early substance use
Aims To examine the prospective relationships between childhood externalizing and internalizing disorders and substance use in early adolescence. Design Longitudinal, community‐based study of twins (aged 11 at intake; aged 14 at follow‐up). Setting and participants The sample was composed of twins participating in the Minnesota Twin Family Study, an epidemiological sample of twins and their families representative of the state population of Minne…
Perceptions of the Parent-Adolescent Relationship: A Longitudinal Investigation
A self-report measure of conflict and aspects of warmth in the parent-child relationship was completed by 1,330 11-year-old twins, 1,176 of whom completed the inventory again 3 years later. On average, adolescents' perceptions of the quality of the parent-child relationship declined consistently and moderately between age 11 and age 14. Conflict with parents increased, whereas all aspects of warmth decreased; changes were significantly greater fo…
The essential role of behavioral genetics in developmental psychology: Reply to Partridge (2005) and Greenberg (2005)
Genetic and environmental influences on academic achievement trajectories during adolescence
Most studies have considered the effects of particular characteristics on academic achievement individually, which means that little is known about how they function together. Using the population-based Minnesota Twin Family Study, the authors investigated the effects of child academic engagement (interest, involvement, effort), IQ, depression, externalizing behavior, and family environmental risk on academic achievement (reported school grades) …
Differential parent-child relationships and adolescent externalizing symptoms: Cross-lagged analyses within a monozygotic twin differences design
Research has indicated that differential parental treatment is linked to differences in externalizing symptomology (EXT) across siblings, even those siblings who are genetically identical. However, the direction of causation and longitudinal significance of this relationship remains unclear. Thus, in the present study, the authors examined 486 monozygotic twin pairs, assessed at ages 11, 14, and 17 years, within a cross-lagged twin differences de…
Risk for recurrence in depression
Obituary: David T. Lykken (1928-2006)
Adolescent psychopathy features: 6‐Year temporal stability and the prediction of externalizing symptoms during the transition to adulthood
This study investigated the 6‐year stability and predictive validity of adolescent psychopathy features during the transition to young adulthood. It represents one of the longest outcome studies of youth psychopathy to date, and therefore addresses a primary criticism of the research area (i.e., lack of demonstrated associations between child and adult psychopathy features). Recruited participants were 475 males enrolled in the Minnesota Twin and…
Construct Validity of Adolescent Antisocial Personality Disorder
Most of the girls are alright, but some aren't: Personality trajectory groups from ages 14 to 24 and some associations with outcomes
Personality traits show normative patterns of development toward maturity during adolescence. Yet individuals follow these normative patterns to differing degrees. This study used growth mixture modeling to characterize personality development patterns and their associations with outcomes in a population-based sample of 1,537 girls aged 14 to 24. The authors used latent class analysis to identify 3 trajectory groups labeled alright (47%), growing…
The Mental Health of US Adolescents Adopted in Infancy
OBJECTIVE: To determine whether adopted adolescents are at excess risk for clinically relevant behavioral and emotional problems. DESIGN: We examined whether adopted and nonadopted adolescents differed on quantitative indicators of mental health and the prevalence of childhood disorders and whether differences exist between internationally and domestically placed adoptees. SETTING: Assessments occurred at the University of Minnesota from December…
Stability and Change in Personality Traits From Late Adolescence to Early Adulthood: A Longitudinal Twin Study
We conducted a longitudinal‐biometric study examining stability and change in personality from ages 17 to 24 in a community sample of male and female twins. Using Tellegen's (in press) Multidimensional Personality Questionnaire (MPQ), facets of Negative Emotionality (NEM) declined substantially at the mean and individual levels, whereas facets of Constraint (CON) increased over time. Furthermore, individuals in late adolescence who were lowest on…
The Heritability of Personality Is Not Always 50: Gene‐Environment Interactions and Correlations Between Personality and Parenting
Twin studies of personality are consistent in attributing approximately half of the variance in personality to genetic effects, with the remaining variance attributed to environments that make people within the same families different. Such conclusions, however, are based on quantitative models of human individual differences that estimate genetic and environmental contributions as constants for entire populations. Recent advances in statistical …
Personality in middle childhood: A hierarchical structure and longitudinal connections with personality in late adolescence
Stability and change in religiousness during emerging adulthood
Understanding the development of religiousness is an important endeavor because religiousness has been shown to be related to positive outcomes. The current study examined mean-level, rank-order, and individual-level change in females' religiousness during emerging adulthood. Genetic and environmental influences on religiousness and its change and stability were also investigated. Analyses were completed with an epidemiological study of 2 cohorts…
Psychology (61 works) · Developmental psychology (48 works) · Social Psychology (29 works) · Child and Adolescent Psychosocial and Emotional Development (26 works) · Cognitive Abilities and Testing (26 works) · Clinical Psychology (22 works) · Personality (21 works) · Genetics (19 works) · Genetics (17 works) · Biology (16 works)