In the past, shared environmental influences on personality traits have been found to be negligible in behavior genetic studies (e.g., Bouchard and McGue, J Neurobiol 54:4-45, 2003). However, most studies have been based on biometrical modeling of twins only. Failure to meet key assumptions of the classical twin design could lead to biased estimates of shared environmental effects. Alternative approaches to the etiology of personality are needed. In the current study we estimated the impact of shared environmental factors on adolescent personality by simultaneously modeling both twin and adoption data. We found evidence for significant shared environmental influences on Multidimensional Personality Questionnaire Absorption (15 % variance explained), Alienation (10 %), Harm Avoidance (14 %), and Traditionalism (26 %) scales. Additionally, we found that in most cases biometrical models constraining parameter estimates to be equal across study type (twins vs. adoptees) fit no worse than models allowing these parameters to vary; this suggests that results converge across study design despite the potential (sometimes opposite) biases of twin and adoption studies. Thus, we can be more confident that our findings represent the true contribution of shared environmental variance to personality development.
|Original language||English (US)|
|Number of pages||14|
|State||Published - Nov 2013|
Bibliographical noteFunding Information:
Acknowledgments This research was supported in part by USPHS Grants from the National Institute on Alcohol Abuse and Alcoholism (AA09367 and AA11886), the National Institute on Drug Abuse (DA05147, DA13240, and DA024417), and the National Institute on Mental Health (MH066140).
- Method biases
- Shared environment