Scientific research is complicated because the world is complicated. Let’s say you’re in a bad mood when you get home, and, you want to find out why. Sometimes, it’s hard to determine what leads to your conclusion. Was it that huge report assigned by your boss? How about the annoying coworker who does not pull his weight? It could even be something that you wouldn’t immediately think of, for example, the donut that you had on your break.
All of these different factors are variables. In science, you want at least one variable in an experiment. But, you want to exclude others to make a definite conclusion. For example, let’s say you want to determine whether eating donuts can sour a person’s mood. A demanding boss, lazy coworker, and a rude driver should be excluded as possibilities.
For most science that’s done in a lab, cutting out extra variables is relatively easy. Samples are all prepared the same way, kept at the same temperature, and checked after the same amount of time. Usually, only one thing is different. For example, different samples may undergo different drug treatments to see if the drugs affect cell growth. With humans, though—and with humans in romantic situations, in particular—we cannot control all of the variables. There are just too many, and it’s unreasonable to find a group of people who are homogenous in ways that tend to influence partnerings like race, age, and religion and throw them into the same temperature- and condition-controlled room for decades until the experiment is complete. This is why psychology experiments are so difficult to carry out—we cannot ethically control our subjects.
Unless, of course, people happen to control the extra variables for us. While studying the correlation between diverse HLA genes (the genes tied to attraction) and partnering, Dr. Carole Ober focused on an unusually homogenous group of people to use as her subjects. She did this by surveying the Hutterites, which is a group of North Americans of European ancestry, all of whom share a communal lifestyle, culture, geography, and religion.
Moreover, each one out of the hundreds of study subjects had only one of a limited five different combinations of HLA genes, likely due to the limited ancestry and tendency to remain within the community when mating. This was smart of Dr. Ober. Because there were only a limited number of HLA gene sets, the likelihood that people would marry a person with a different or similar HLA set could be easily calculated. Moreover, because significant factors like religion, culture, and region were all held constant, the fact that someone would choose one person over another could be more confidently ascribed to that which was different: HLA genes.
“…big factors like religion, culture, and region were all held constant…”
After studying 411 different Hutterite couples, Ober found that those who married DID choose mates with varying HLA genes significantly more frequently than would be expected by chance. As we have been saying all along, genetics do contribute to attraction and long-term relationship happiness.
Most of us aren’t part of defined communities where different fundamental lifestyle choices and beliefs are held constant. That said, when you combine logical and emotional decisions—using Pheramor’s data-based algorithm or even just thoughtful questions during dates—with biological tendencies, then you are setting yourself up for a truly magnificent partnership.
An important note: As with all scientific journalism, this article is necessarily a simplification of the research. Be wary of any articles that cannot cite their sources, and be sure to check out the source material to reach your conclusions about the study or delve more deeply into something that interests you! Dr. Ober has an extensive body of exciting research, but this particular post focuses on the work mentioned in HLA and Mate Choice in Humans.