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Genetic and environmental factors on the development of personality

Abstract 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: This study investigated the patterns and origins of personality trait changes from ages 17 to 29 using 3 waves of Multidimensional Personality Questionnaire data provided by twins.

Results suggest that a trait changes were more profound in the first relative to the second half of the transition to adulthood; b traits tend to become more stable during the second half of this transition, with all the traits yielding retest correlations between.

Overall, these genetically-informed results support a life-course perspective on personality development during the transition to adulthood. The transition to adulthood between the ages of 18 and 30 involves significant psychological development with regard to intimacy, identity, work, and parenthood see Arnett, 20002007. These changes are also accompanied by both stability and change in personality traits e.

Accordingly, the goal of this study was to evaluate genetic and environmental influences on personality stability and change during the transition to adulthood using three waves of personality trait data.

  1. This dimension of personality has been linked to neurobiological markers of attentional focus and other frontal lobe functions Nigg, 2000. My older brother is almost six years older than I am to the very day.
  2. Most notably, although it is widely recognized that multiple wave studies provide the opportunity to employ more sophisticated methodological approaches e. Blonigen and colleagues 2008 used the first two waves of data analyzed in the current report to evaluate genetic and environmental contributions to personality development between the ages 17 and 24.
  3. Or was it a matter of how our personalities developed? This study offers an important extension of the previous report on personality stability and change from this sample Blonigen et al.

First, this transition takes time as individuals negotiate aspects of identity development and gradually assume adult roles and responsibilities Arnett, 2004. Second, on average, more demographic transitions occur during the years between 18 and 30 than any other in the life course Rindfuss, 1991. Thus, by the age of around 30, most individuals have assumed at least one of the major roles of adulthood and therefore the 30s seem to mark the beginning of adulthood proper. Third, there appears to be a considerable amount of variability among individuals in terms of the sequencing of the life transitions between adolescence and adulthood Rindfuss, 1991.

The salient developmental challenges and diversity of experiences people encounter in this phase of the life course suggest that the transition to adulthood represents an important period for research on personality development. Consistent with these trends, personality trait change is generally positive: In light of these trends, Caspi et al. Following this recommendation, we evaluated etiological influences on personality trait stability and change during the transition from adolescence to adulthood.

Specifically, we assessed four broad personality traits assessed by the MPQ. The four factors that appear in more or less all structural models of personality involve negative emotionality or neuroticism NEMagentic positive emotionality or extraversion PEM-Acommunal positive emotionality or agreeableness PEM-Cand constraint CON Caspi et al.

NEM involves a susceptibility to negative emotions as opposed to a tendency to be emotionally placid and adaptable. This domain appears to map onto neurobiological systems governing withdrawal behavior in the context of environmental threats Watson et al.

  1. If he had been forced to walk for hours upon hours through all the isles of T.
  2. A genetic correlation of 1. During the transition to adulthood, age differences in absolute levels of personality traits seem to be well described by the maturity principle of personality development Caspi et al.
  3. Agentic manifestations of this trait i.

PEM generally involves the propensity for positive emotions such as happiness as well as behavioral surgency and vigor. This trait domain is associated with enhanced reward sensitivity Lucas et al. Agentic manifestations of this trait i. Reduced CON is a risk factor for substance use and externalizing problems Krueger et al.

This dimension of personality has been linked to neurobiological markers of attentional focus and other frontal lobe functions Nigg, 2000. Characterizing Personality Stability and Change during the Transition to Adulthood In addition to questions regarding which traits to assess, researchers studying personality development must also consider multiple kinds of personality stability and change Caspi et al. Each of these types of stability involves a different analytic method and interpretive meaning.

The two most commonly studied types are absolute or mean-level stability and differential or rank-order stability. Absolute mean-level stability refers to changes in group averages over time on a genetic and environmental factors on the development of personality trait. Absolute stability can be indexed directly with repeated-measures ANOVA models or growth curve frameworks e.

During the transition to adulthood, age differences in absolute levels of personality traits seem to be well described by the maturity principle of personality development Caspi et al. That is, as individuals mature they become more able to control their impulses and less prone to negative emotions. These kinds of personality changes are concordant with the fulfillment of adult roles and converge well with existing developmental research concerning trends in well-being Galambos et al.

Beyond these mean-level trends there may also be significant variability between individuals in their degree of change i. Importantly, growth curve frameworks allow for the characterization of absolute stability and change in a way that also draws attention to intra-individual differences in change Vaidya et al.

For example in a linear growth model, the fixed effect for the slope describes normative changes in terms of the average increase or decrease for the sample as a whole whereas the random effect indicates the amount of variability around that average trend.

Such variability points to the fact that some individuals increase in absolute trait levels whereas others decrease in absolute trait levels. Differential rank-order stability refers to the degree of consistency in rank-ordering of individuals over time on a given trait. This type of stability is most often indexed by retest correlations. In other words, stability coefficients tend to be lower for adolescent samples than adult samples, a pattern that has been referred to as the cumulative continuity principle of personality development Caspi et al.

Moreover, personality maturity is temporally linked with increases in differential stability such that individuals who are lower in negative affectivity and higher in constraint in adolescence tend to show more differential stability during the transition to adulthood Roberts et al, 2001and individuals with borderline personality disorder show less differential stability over time Hopwood et al.

The most active area of disagreement involves the explanation of personality maturation i. One perspective argues that biologically-based intrinsic processes underlie changes in personality in young genetic and environmental factors on the development of personality e. Genetically informed cross-sectional studies have made important contributions to personality psychology by demonstrating that higher order traits are substantially and similarly heritable but also influenced by non-shared environmental factors those environmental factors that make siblings within the same family different, e.

However, longitudinal behavior genetic designs are needed to assess the genetic and environmental underpinnings of personality stability and change. In one such study, McGue et al. Blonigen and colleagues 2008 used the first two waves of data analyzed in the current report to evaluate genetic and environmental contributions to personality development between the ages 17 and 24. Both of these studies reported results consistent with the maturity hypothesis and found that genetic and environmental factors accounted for personality changes.

These studies also provide consistency of results across ages, samples, and methods in support of the maturity hypothesis. However, this emerging behavioral genetic literature on personality development is limited in several ways. Most notably, although it is widely recognized that multiple wave studies provide the opportunity to employ more sophisticated methodological approaches e.

In fact, most phenotypic studies of personality development during the transition to adulthood have relied on 2-wave studies but see Vaidya et al. For example, such approaches can be used to test the adequacy of linear models of absolute growth and identify individual differences in absolute change. Twin studies that use this analytic approach are particularly important as they can be used to decompose the origins of individual differences in change into genetic and environmental components.

In light of these advantages, the work of Bleidorn and colleagues 2009 represents a seminal contribution as the first multi-wave behavior genetic study of personality trait stability. Nonetheless, this study assessed a relatively small sample of individuals who varied widely in age at first assessment. Thus, this work was limited in its ability to specifically characterize personality stability and change during the transition to adulthood.

Genetics vs. Environmental Influences on Personality

By comparison, the Minnesota Twin Family Study MTFS data, which sampled twins during this period, are well-suited to address such issues and can potentially resolve contrasting views regarding on the origins of personality stability and change. The Present Study The present study was designed to address these gaps in current knowledge about the influences on personality change during the transition to adulthood. This study offers an important extension of the previous report on personality stability and change from this sample Blonigen et al.

This additional wave allows tests regarding the linearity of personality change during the transition to adulthood, such as whether more changes occur during the peak of emerging adulthood e.

Moreover, this additional wave allows the application of analytic techniques used by Bleidorn et al. Unlike Bleidorn et al. Accordingly, the results can more specifically adjudicate among intrinsic and lifespan perspectives on the underlying impetus for personality maturation during the transition to adulthood.

Zygosity was determined by parent and MTFS staff reports on physical resemblance and an algorithm which uses ponderal and cephalic indices and fingerprint ridge counts to assess similarity. When these estimates did not agree a serological analysis was performed to confirm twin status. Exclusion criteria included living more than a 1-day drive from the data collection site or serious cognitive or genetic and environmental factors on the development of personality disabilities which would preclude participation.

Twins were reassessed at the average ages of 24 and 29. Attrition analyses suggested that the baseline trait scores between those who continued versus those who dropped out at each follow-up were less than.

As in Blonigen et al. Analyses Phenotypic Analyses Test-retest coefficients were used to indicate the degree of differential stability of personality traits over time. Growth curve analyses were used to estimate the degree of mean-level change in traits across the three waves, as well as individual variability in rates of change following procedures outlined in Kashy, Donnellan, Burt, and McGue 2008 for working with twin data. These models were fit using maximum likelihood estimation in AMOS 17.

Slope paths were fixed to 0 for the baseline assessment, 1 for the third assessment, and were estimated from the data for the second assessment i. This allows the model to estimate the extent to which change occurred during the first or second intervals given that an empirical value close to. Intercept paths were fixed to 1 for each measurement occasion so that the intercept represents scores at the first assessment. Residuals were freely estimated at each wave but fixed to the same value for each twin and we specified a twin correlation between these residuals within measurement occasions.

Twins were constrained to have genetic and environmental factors on the development of personality intercept and slope parameters. MZ and DZ twin correlations are compared to estimate the relative contributions of additive genetic effects a2shared environmental effects c2and non-shared environmental effects plus measurement error e2 to the variance within observed behaviors or characteristics i.

Any differences in the MZ and DZ correlations are thus assumed to be due to differences in the genetic similarity of the corresponding twins. To evaluate the origins of differential stability, we fitted a Cholesky decomposition model. Within a triangular, or Cholesky decomposition, model see Figure 1the variance within and the covariance between personality traits across each assessment were decomposed into their genetic and environmental components.

In this model, the genetic, shared, and non-shared environmental covariances can be standardized on their respective variances to produce genetic, shared environmental, and non-shared environmental correlations. These statistics reveal the extent to which a specific effect e. A genetic correlation of 1.

This model thus enabled us to explicitly estimate the extent to which genetic and environmental influences contribute to the differential or rank-order stability of personality over time.