1. The Heritability of happiness ‘Happiness depends, as Nature shows, less on exterior things than most suppose. ‘ - William Cowper

2. What is ‘happiness’? Studied at various levels and has several parts Positive emotion can be experienced at the same time as negative emotion Subjective happiness Objective happiness ‘Life satisfaction’ ‘Happiness’ – often used interchangeably with ‘subjective well-being’

3. Is happiness heritable? Lykken and Tellegen (1996) – Longitudinal, twin study – Happiness measure: Well Being scale of the Multidimensional Personality Questionnaire (a self- report inventory) – Twins raised together: correlations = 0.44 MZ, 0.08 DZ – Twins separated and reared apart: correlations = 0.52 MZ, -0.02 DZ – Broad heritability of Well Being = 40-50% – Very similar results at Time 2, revealing that stability in happiness is 80% attributable to genetic factors. Lykken and Tellegen (1996). Happiness is a stochastic phenomenon. Psychological Science 7(3), 186-189.

4. Genetic Influences Other studies have found that genetic influences usually account for 35-50% of the variance in happiness measures (Roysamb et al., 2002; Stubbe et al., 2005; Nes et al, 2005, 2006). Genetic influences on happiness and well-being appear to reflect both additive and non-additive genetic effects. The location of the ‘happiness gene’ is still unknown.

5. Happiness and personality: a common genetic background? Edinburgh psychologists Found no genetic effects that were specific to subjective well-being. Instead they identified common genes that result in certain personality traits, which in turn predispose people to happiness. Those who have the right mix of personality genes build an ‘affective reserve’ of happiness. Weiss, Bates & Luciano (2008) Happiness is a personal(ity) thing. Psychological Science, 19(3), 205-210.

6. Environmental influences Non-genetic influences on well-being and happiness mostly reflect non-shared environmental effects. Effects from shared environmental factors appear to be minor or entirely negligible.

7. Implications Evidence for considerable and stable genetic contributions suggests that societal changes and therapeutic interventions may produce mainly transitory or minor effects – This is not true, high heritability does not limit chances for raising happiness. Genes effect long-term happiness, environment affects the here and now.

8. Conclusions Happiness is influenced by genes. Short-term happiness is affected by environmental factors. Long-term happiness is predominantly influenced by genes.