The relationship between positive affect and negative affect: A behavioral genetic analysis

For years, researchers have debated the structure of affect. Although many researchers claim positive and negative affect are independent, others present evidence that the two are bipolar. The current study used a behavioral genetic design as a unique way to address this debate. A national sample of 783 sibling pairs, including 117 identical twins, 160 fraternal twins, and 506 full-sibling non-twin pairs provided information on their positive and negative affect over the past month. A sub-sample of 210 twin pairs provided additional information on their positive and negative affect over daily and weekly time frames. Several different analyses indicated that at the phenotypic level, affect demonstrated a bipolar structure. Multivariate behavioral genetic analyses were used to estimate common genetic and environmental factors that influence the relationship between positive and negative affect, as well as the specific genetic and environmental factors that influence each. These analyses indicated that specific genetic and shared environmental factors were not necessary to explain the relationship between positive and negative affect. This pattern of results was consistent with the bipolar viewpoint. The structure of affect looked to be bipolar across differing time frames. No age differences in the structure of affect were found.