How much of who we are is hard-wired into our personalities from birth and how much depends on the experiences we go through in our lives? That’s the fundamental question of the age-old nature versus nurture debate. For a long time, people believed that nature mainly provided our physical characteristics, as carried within our genes; and nurture was all-important for just about everything else. The theory was that mostly we become who we are because of the influences that surround us.
While our environments definitely contribute to our personalities, scientists have proven over the past few years that much of the responsibility for who we are actually lies within our DNA. In other words, we are born with a certain personality, and external experiences can only influence it so much. And now, new research has shown that happiness may be one of the aspects of personality that is passed down through our genes — at least to some degree. How much does genetics influence our happiness? Are some of us just born happy?
Researchers from University College, London; Harvard Medical School; the University of California, San Diego; and the University of Zurich teamed up to analyze the data on more than 1,000 pairs of twins involved in a major study on the health of adolescents in the United States.1 They determined that approximately one-third of the variation in one’s general level of happiness may be heritable (or perhaps reincarnatable).
Then, the study was taken a step further: attempting to figure out exactly which gene is in control of our happiness. The gene focused upon was the one that encodes the serotonin-transporter protein, which is a molecule that carries serotonin to various cells. It makes sense to look at serotonin’s involvement, since that is the chemical we produce that helps regulate our moods.
There are two functional variants to the serotonin-transporter gene, a long and a short. The long version produces more transporter-protein molecules than the short version. Everyone has two copies, or alleles, of each gene — one is inherited from each parent. Therefore, some people receive two long alleles, some receive two short alleles, and the remainder receive one of each kind.
The adolescent study volunteers had to report on their level of happiness in life between very satisfied and very dissatisfied. Those possessing two long alleles were the clear winners in the happiness lottery over the people with short alleles. Participants with two long alleles were 17 percent more likely to call themselves very satisfied than those with no long alleles. Participants with one long allele (the other being short) were 8 percent more likely to regard themselves as very satisfied than those with no long alleles. And participants with two short alleles were the least likely to be happy. But again, the result was not automatic. The alleles only shifted the odds of happiness, not the guarantee.
There are so many different ways researchers can break this down and further study this gene. Some are already taking place, such as work on these alleles in the context of race or ethnicity as well as the connection between the short allele variant and mood disorders. Those in this study were all young — it would be interesting to see if as the subjects age other life experiences affect the outcomes of happiness and the genes we inherited.
In fact, a study at Stony Brook University in New York last year found that happiness actually increases as we get older.2 The researchers surveyed 340,847 adults between the ages of 18 and 85, selected at random from a sample of the U.S. population representing various levels of education and income. Respondents were asked to rate their current lives on a scale of zero to ten, with zero being the worst possible life and ten being the best possible life. The scientists found that subjects between the ages of 22 and 25 showed the highest levels of stress, while in people over the age of 50, stress levels decreased dramatically, and the volunteers’ self-ratings reflected this difference. And keep in mind that your alleles don’t change as you age.
So even if you were the recipient of two short alleles and had longer odds for being happy, there is a potentially brighter future ahead. And, since external factors can make a big difference (upwards of 83% it would seem), you can work toward your goals and achieve happiness through doing things you love and enjoying a great quality of life. Or just wait things out and get older. Plus, having good health is an important factor in happiness, so following the Baseline of Health Program will contribute to your overall sense of satisfaction. When you eat well, exercise, and take the right supplements, you can fight off illness and feel good, which will always help you stay happy.
1 De Neve, Jan-Emmanuel. “Functional polymorphism (5-HTTLPR) in the serotonin transporter gene is associated with subjective well-being: evidence from a U.S. nationally representative sample.” Journal of Human Genetics. June 2011. The Japan Society of Human Genetics. 3 November 2011. <http://www.nature.com/jhg/journal/v56/n6/full/jhg201139a.html>.
2 Stone, Arthur A.; Schwartz, Joseph E.; Broderick, Joan E.; and Deaton, Angus. “A snapshot of the age distribution of psychological well-being in the United States.” Proceedings of the National Academy of Sciences of the United States of America. 17 May 2010. National Academy of Sciences. 3 November 2011. <http://www.pnas.org/content/107/22/9985.abstract?sid=454991c6-6769-4c8d-9d90-6393ff08856b>.