Happiness, or subjective well-being, was measured on a birth-record-based sample of several thousand middle-aged twins using the Well-Being (WB) scale of the Multidimensional Personality Questionnaire Neither socioeconomic status, educational attainment, family income, marital status, nor an indicant of religious commitment could account for more than about 3% of the variance in WB From 44% to 52% of the variance in WB, however, is associated with genetic variation Based on the retest of smaller samples of twins after intervals of 4 5 and 10 years, we estimate that the heriability of the stable component of subjective well-being approaches 80%

Green, Goldman, and Salovey (1993) challenged the view that “positive affect” and “negative affect” are largely uncorrelated dimensions. On the basis of factor analytic studies of happiness and sadness, and of positive and negative emotional activation (PA and NA), they claimed that a “largely bipolar structure of affect” (p. 1029) emerges when random and nonrandom error are taken into account. A reappraisal of their own findings and confirmatory analysis of additional data do not support this claim. Happiness and sadness form a largely unidimensional bipolar structure, but PA and NA are relatively independent. However, exploratory analyses yield a three-level hierarchy incorporating in one structure a general bipolar Happiness-Versus-Unhappiness dimension, the relatively independent PA and NA dimensions at the level below it, and discrete emotions at the base. We emphasize the heuristic value of a hierarchical perspective.