A lot of things undermine physical health, like poor diet, lack of exercise, and not enough sleep. Did you know that dysfunctional relationships — those characterized by lots of conflict and poor communication — also contribute to poor health? For example, when couples are “hostile” toward one another, there’s a good chance that any recent wounds (even everyday cuts and abrasions) will take longer to heal than if partners maintain a more civil and responsive tone with one another during disagreements or other conversations.1 On the other hand, good relationships, and not just those we have with our romantic partners, generally benefit our overall health. But why?
The prevailing wisdom is that being connected to others, and enjoying positive relations with those others, helps us confront stress in life and promotes overall physical functioning, which leads to a longer, healthier life. But what if the story is more complicated than that? What if our genetic makeup (you know, chromosomes and stuff) dictates how the quality of our relationships affects us to varying degrees, for better or for worse? Researchers refer to such an idea as a gene BY environment interaction — such that different environments work in tandem with our genes to lead to various outcomes. For example, you have a combination of genes in your DNA that makes you genetically-predisposed to a certain level of aggression (generally speaking). But whether you ultimately become an aggressive person depends on whether you grew up in an environment that “triggered” the aggressive gene.2 Thus, you may have an “anger gene” that may never “turn on,” so to speak, if you grow up in a happy, supportive household. But if your upbringing involved lots of screams for “Serenity Now,” then your “anger gene” may be on overdrive.
Recently, researchers applied this idea of gene BY environment interactions to the link between marriage and health.3 The researchers took advantage of a very large sample of twins, all of whom were married (not to each other, obviously) from the Midlife in the United States (MIDUS) study. The sample of twins included both identical twins (i.e., monozygotic twin pairs) and fraternal twins (i.e., dizygotic twin pairs). In addition to knowing each set of twins’ genetic overlap (identical = more, fraternal = less), the researchers focused on individual twins’ reports of marital satisfaction (a general measure of the quality of their marriages) and self-reported health that asks participants to indicate their overall health, from “the worst possible” to “the best possible” health. And then, through the magic of statistical analyses (biometric modeling, to be exact), the researchers determined the extent to which individuals’ genetics influenced health, their marital quality, or some combination of the two.
Consistent with the results of past studies, people in happier marriages were also healthier. No shock there. It’s the genetic analysis where things get really interesting. Specifically, the researchers found evidence for what the gene-BY-environment research world refers to as an orchid effect. Genetics contributed to overall health at the highest and lowest levels of marital satisfaction. In other words, married individuals’ genetic codes affect their health the most in the weakest and strongest marriages. Or, put another way, really bad marriages are capable of turning on (and even amplifying) any genetic predispositions one might have to experiencing poor health. But really good marriages may help “good health” genes thrive moreso than they would have otherwise.
Why is it called an “orchid effect”? Well, orchids are notoriously difficult to raise — they require very specific humidity levels, fertilization, and light (as I can attest to firsthand). Trying to grow an orchid in a bad environment will destroy the confidence of even the most experienced green thumb; but, in an ideal environment, orchids will flourish. This research suggests that there are some people out there that are, essentially, like orchids. Put them in the wrong environment — a bad marriage — and their health will especially suffer. But put them in the right environment — a good marriage — and they’ll reap the benefits far beyond what the typical person might.
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*Thanks to Susan South for her feedback on how to describe the orchid effect.
1Kiecolt-Glaser, J. K., Loving, T. J., Stowell, J. R., Malarkey, W. B., Lemeshow, S., Dickinson, S., & Glaser, R. (2005). Hostile marital interactions, proinflammatory cytokine production, and wound healing. Archives of General Psychiatry, 62, 1377-1384.
2Merjonen, P., Pulkki-Råback, L., Lipsanen, J., Lehtimäki, T., Rontu, R., Viikari, J., & … Keltikangas-Järvinen, L. (2011). Development of adulthood hostile attitudes: Childhood environment and serotonin receptor gene interactions. Personal Relationships, 18(2), 184-197.
3South, S. C., & Krueger, R. F. (in press). Marital satisfaction and physical health: Evidence for an Orchid Effect. Psychological Science.
Dr. Tim Loving – Science of Relationships articles | Website/CV
Dr. Loving’s research addresses the mental and physical health impact of relationship transitions (e.g., falling in love, breaking up) and the role friends and family serve as we adapt to these transitions. He’s a former Associate Editor of Personal Relationships and his research has been funded by the National Institute of Child Health and Human Development.