Jolanta Burke in IFL Science:
The self-help industry is booming, fuelled by research on positive psychology – the scientific study of what makes people flourish. At the same time, the rates of anxiety, depression and self-harm continue to soar worldwide. So are we doomed to be unhappy, despite these advances in psychology?
According to an influential article published in Review of General Psychology in 2005, 50% of people’s happiness is determined by their genes, 10% depends on their circumstances and 40% on “intentional activity” (mainly, whether you’re positive or not). This so-called happiness pie put positive-psychology acolytes in the driving seat, allowing them to decide on their happiness trajectory. (Although, the unspoken message is that if you are unhappy, it’s your own fault.) The happiness pie was widely critiqued because it was based on assumptions about genetics that have become discredited. For decades, behavioural genetics researchers carried out studies with twins and established that between 40% and 50% of the variance in their happiness was explained by genetics, which is why the percentage appeared in the happiness pie.
Behavioural geneticists use a statistical technique to estimate the genetic and environmental components based on people’s familial relatedness, hence the use of twins in their studies. But these figures assumed that both identical and fraternal twins experience the same environment when growing up together – an assumption that doesn’t really hold water. In response to the criticism about the 2005 paper, the same authors wrote a paper in 2019 that introduced a more nuanced approach on the effect of genes on happiness, which recognised the interactions between our genetics and our environment.
Nature and nurture are not independent of each other. On the contrary, molecular genetics, the study of the structure and function of genes at the molecular level, shows that they constantly influence one another. Genes influence the behaviour that helps people choose their environment.
More here.