A recent study reported evidence that happiness is contagious, spread through social networks (<citationReference id="cr14-1" rid="c14">Fowler & Christakis, 2008</citationReference>). However, past research with twins (e.g., <citationReference id="cr16-1" rid="c16">Lykken & Tellegen, 1996</citationReference>) concluded that the shared environment has little to no influence on well-being. We used longitudinal data from 615 adoptive and nonadoptive families to address this discrepancy. If happiness is contagious, then family members should have similar levels of happiness even when they are not genetically similar to one another. However, we found that the happiness level of family members was unrelated to the target level of happiness at all assessments when family members were not genetically related. In addition, biometrical modeling produced an estimate of χ2 that was not different from zero.
- behavior genetics
- social network research