New Research in Personality Theory

Personal Psychology

Describe and discuss the nature-nurture dichotomy as it relates to personality psychology; the key associated areas of research; and the key research findings.

The study of personality progresses in tandem with advances in neuroscience and behavioral studies, fields that reflect the nature-nurture dichotomy of human development. The word dichotomy is misleading in that it describes a division between two mutually exclusive and contradictory elements or conditions. Yet, contemporary research in personality indicates that there is not an actual nature-nurture dichotomy. Instead, experts assert that, "Both genetic and environmental factors are important to personality" (Krueger & Johnson, 2008, p. 287). Indeed, new conceptual and methodological advances have shifted research questions from a focus on which influences are the strongest in personality development and expression to a focus on determining how "genetic and environmental influences actually come together to shape personality" (Krueger & Johnson, 2008, p. 287).

A molecular psychology of personality is being shaped by a perfect storm of innovation in noninvasive brain mapping, molecular biology, and genetics. Brain mapping technology enables neuroscientists "to associate personality traits with individual difference in brain structure and function" through the use of functional magnetic resonance imaging (fMRI), positron emission tomography (PET), and electroencephalograms (Canli, 2008, p. 311). Innovations in molecular biology and genetics enable the identification of genetic variations that can now be mapped through a synergistic new field of study called "imaging genetics" (Canli, 2008, p. 311). Canli asserts that an agentic view of personality -- in which an individual acts to change his or her own environment -- is missing from these new lines of research. Canli's observation is pivotal to the eventual development of psychological thought that does not rest on "the individual as a passive recipient of environmental and genetic input" (2008, p. 323).

Building on the seminal work of researchers who established the Big Five personality constructs, Krueger and Johnson (2004) found that genetic main effects clustered tightly for Extraversion and Neuroticism, but were more diffuse for Agreeableness, Conscientiousness, and Openness. When considering personality in the long-term, researchers have found that genetic factors have a stabilizing effect on personality while environmental factors are associated with changes in personality (Krueger & Johnson, 2008, p. 293). The seeming reciprocity of environmental and genetic influence has some basis in the literature, stemming from the belief that behavior subject to genetic influence tends "to elicit common patterns of responses from the environment, and because people gravitate toward environments that meet their psychological needs and avoid environments that do not" (Krueger & Johnson, 2008, p. 293). Put simply, genetic and environmental influences have been shown to interact and influence personality, and these gene-environment interactions are referred to as G. x E (Krueger & Johnson, 2008, p. 298).

The new molecular perspective examines G. x E. interactions by considering how the expression of genes is moderated by the individual life experiences of people or by environmental variables (Canli, 2008, p. 313). The expression of Extraversion and Neuroticism are believed to be associated with differences in cognitive processes across different individuals, and are particularly tied to the cognitive processing of stimuli that is valenced -- stimuli that have negative or positive value assigned to them by an individual.