SAGE CIPS ASSOCIATION FOR PSYCHOLOGICAL SCIENCE Nature and Nurture in Personality Development: The Case of Neuroticism and Extraversion Author(s): Christian Kandler Source: Current Directions in Psychological Science, OCTOBER 2012, Vol. 21, No. 5 (OCTOBER 2012), pp. 290-296 Published by: Sage Publications, Inc. on behalf of Association for Psychological Science Stable URL: https://www.jstor.org/stable/44318598 JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at https://about.jstor.org/terms Sage Publications, Inc. and Association for Psychological Science are collaborating with JSTOR to digitize, preserve and extend access to Current Directions in Psychological Science JSTOR
aps ASSOCIATION FOR PSYCHOLOGICAL SCIENCE Nature and Nurture in Personality Development: The Case of Neuroticism and Extraversion Christian Kandler Bielefeld University Current Directions in Psychological Science 21(5) 290-296 @ The Author(s) 2012 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/0963721412452557 http://cdps.sagepub.com SSAGE Abstract The stability of interindividual differences (i.e., rank-order continuity) in personality traits tends to increase with age until it plateaus in middle adulthood and finally decreases in old age. Rank-order continuity also tends to decrease as the time intervals between occasions of personality assessment increase, irrespective of age. These patterns show that personality development is a lifelong process. Yet the sources of these patterns are unknown. Theories suggest that personality continuity and change may result from environmentally mediated processes of identity development due to age-graded social roles and individual life experiences, but also from biological maturation. Genetically informative longitudinal studies across different age cohorts allow a differentiated picture of genetic and environmental sources. In this article, I give a short overview of the genetic and environmental contributions to rank-order continuity and change in neuroticism and extraversion. Both genetic and environmental factors contribute to personality continuity and change, but genetic factors affect rank-order change only in younger decades of life, whereas environmental influences appear to represent a lifelong source of interindividual differences in personality development. Keywords genetic continuity, environmental continuity, heritability, neuroticism, extraversion The science of behavioral genetics, largely through twin studies, has made a persuasive case that much of our identity is stamped on us from conception; to that extent, our lives seem to be pre-chosen-all we have to do is live out the script that is written in our genes . . . Still, it's confounding to imagine . . . any gardener knows that rather small variations of water and fertilizer and soil acidity affect the development of far less com- plex organisms-are humans so indifferent to the envi- ronment they are planted in? Wright, 1997, pp. 143-148 Personality traits are commonly defined as broad, disposi- tional, and comparative features of psychological individual- ity. The most prominent and extensively studied bipolar personality-trait continua are neuroticism-emotional stability and extraversion-introversion. Compared with more emotion- ally