Compare the legions of studies published in academic journals to the media coverage of those studies, and the considerable gap between what researchers find and what headlines claim "science says!" becomes abundantly clear. (For anyone who missed it, John Oliver handily illustrated the poverty of accuracy running through so much science coverage.) Sometimes, the truth gets lost in translation when media outlets sloppily aggregate OMG discoveries without bothering to do any sort of fact-checking. Other times, press releases spread misinformation through sticky but wholly inflated claims.
Case in point: Recent news of Dutch scientists locating "happiness genes" for the first time. Yes, "Happiness genes" is as clickworthy a phrase as any. Unfortunately, those genes don't exist. Instead, researchers identified genetic variants associated with “subjective well-being." Not as flashy, but noteworthy nonetheless. Study authors published an accessible FAQ on their work that explains what they actually found and why it matters.
In the FAQ, researchers addressed common misconceptions about claims concerning the genetic basis of behavior, including the notion that personality traits are "determined at birth." Even if genetic factors were entirely responsible for person-to-person differences in subjective well-being (which they aren't), we still wouldn't be born with happiness levels etched into our DNA.
They offer three reasons. Here's one: Genes are subject to environmental factors (over which we may not have control). To use their example, let's say the genetic variant (or SNP, more on that below) that affects our well-being specifically dictates levels of extraversion. And, let's say that, for one person who has the variation, extraversion leads to more friends, and that more friends means more happiness. For that person, the genetic variant indirectly affected happiness. But, let's say another person with the same genetic variant lives in a community where extraversion doesn't lead to more friends, because family status entirely influences social circle. Well, that person might not get the same happiness boost despite having the same genetic variant. Thus, there's no one "happiness gene."
Genetic variants for subjective well-being are not genes that determine whether or not people are happy.
The study is the largest-ever genome-wide association study (GWAS) on behavioral traits. Researchers amassed results from over 100 separate studies and analyzed genetic data, as well as information about personality traits, on 368,890 people. They wanted to find genetic variants — ways in which genomes can differ — shared by people with subjective well-being, depression and neuroticism, but were most interested in subjective well-being.
In the study, researchers analyzed two types of genetic variants, SNPs (pronounced "snips"), the smallest and most common type, and inversion polymorphisms, which are "large segments of the genome that are reversed end to end, or inverted, in some people." Inversion polymorphisms are more exciting because they have a greater influence over traits than tiny, lil' SNPs. But, through analyzing SNPs on a large scale, researchers explained, they can sometimes statistically identify the presence of inversion polymorphisms. As of now, researchers have found very few inversion polymorphisms associated with behavioral traits. In this study, they found:
- Three SNPs associated with subjective well-being (based on analysis of 300,000 people)
- Two SNPs associated with depressive symptoms (based on 180,000 people)
- Nine SNPs and two inversion polymorphisms associated with neuroticism (based on 170,000 people)
- Two SNPs associated with both depressive symptoms and neuroticism
- Most genetic variants associated with depression symptoms and neuroticism are also associated with subjective well-being, and vice versa.
"These findings taken together," researchers wrote, "imply that the genetic influences on these traits result from the cumulative effects of at least thousands (probably millions) of different genetic variants, not just a few."
Furthermore, environment influences our personalities far more than our genes do. Genetic factors do contribute to our emotional and cognitive predilictions, but not a single SNP at a time.
What can we do with the discovery, other than gush over it? At this point, not much.
"Any practical response — individual or policy-level — to this or similar research would be extremely premature," researchers wrote.
It's well-understood, they explained, that genetic variants associated with complex diseases (e.g., Alzheimers) don't carry enough weight to predict anyone's risk of developing that disease. And the effects of the variants identified in the current study "are even smaller and more diffuse."
So, in terms of shaping the people we are, the newly identified SNPs hardly matter. But that doesn't mean the research doesn't. Even if the effect sizes are small, identifying genetic variants can still help scientists glean insights about biological pathways underlying behavioral traits and associated mental disorders. In this case, many of the identified genetic variants (for depression, neuroticism and well-being) are involved in the central nervous system, adrenal glands and pancreas. Researchers don't know why, but mentioned that adrenal glands produce cortisol and other hormones involved in regulating mood and stress. Additionally, some of the identified SNPs are already known as relevant to the personality traits they're studying, including a gene involved in dopamine, the feel-good neurotransmitter. So, these not-yet-understood connections are just something to geek out on for the moment and can guide further research.