Genetic influences on personality from infancy to adulthood.

Recent behavior-genetic studies of personality are reviewed. These studies are first organized according to their subjects' age and then interpreted by emphasizing their developmental implications. Although certain discrepancies have arisen from the use of questionnaire versus laboratory assessments and twin studies as opposed to adoption designs, some consensus may be emerging. Research has moved beyond mere demonstration of heritable sources of variation in the great majority of personality measures. This overview of the literature documents (1) the demonstration of genetic bases for stability of certain personality dimensions, (2) evidence suggesting that the most influential environmental sources of variation are those not jointly experienced by family members, and (3) continuing controversy regarding the convergence of genetic results for different assessment strategies and different developmental periods. Clarifying the nature of the interplay between developmental processes and gene action is now a major task for developmental behavioral geneticists who study personality and temperament.