In the late 1960s, population geneticist George Price developed a mathematical theory of altruism. The theory goes that in a species like ours, in which two parents reproduce, we’re more likely to show altruism to each other the more similar we are genetically, the most likely being parents, siblings, and children.
I first heard about this theory listening to an episode of the podcast “Radiolab,” and it was explained like this: Imagine a family gathering full of siblings, aunts, uncles, and cousins that has been overtaken by a flood. You have the choice, let’s say, between saving your brother and your first cousin. Since you share 1/2 of your genes with your brother and only 1/8 of your genes with your cousin, your instinct to save your brother is theoretically four times stronger.
I was thinking about sibling relationships a lot this weekend with my brother in town from Denver, the bonds that tie us, and how those relationships are simply like no other.
My brother and I share a lot of the same interests, talents, and perspectives. We’re both graphic designers, we share similar artistic and stylistic aesthetics (I chalk up many of mine to his influences early in life); we’re captivated with the natural world (thanks, Dad), and fascinated with the complexities of human relationships and interactions (thanks, Mom). Eddie is perceptive and observant and endlessly curious, asking of everything around him: How and why? Because of this, and because we’ve never known life without the other in it, we’ll never get bored of one another. After all, there isn’t anyone else I’d watch “Glengarry, Glen Ross” with for the 15th time. There’s no one else I have as many inside jokes with or whom I can make laugh harder. There isn’t anyone else I could spend six hours with playing cornhole at Lemon Reservoir, drinking beer, grilling and eating a whole pack of hot dogs, and steadily destroying a couple bags of chips.
Over the weekend – walking the town Friday, catching happy hour at Steamworks, attending an art opening, standing stage-side for a set of my friends playing music – I had a chance to introduce my brother to people I know. People’s faces lit up when I said, “This is my brother, Eddie,” in ways they wouldn’t have if I said, “This is my good friend, Eddie, from back East.” Because he’s my brother. Because we’ve experienced our entire lives together. Because we look unmistakably similar. Because they know he knows things about me no one else does. These people care about me, and because of the genetic makeup I share with Eddie, part of them cares about him that much more without knowing anything about him.
I had a similar excitement in introducing him around as well. This is not only someone I think my friends would like, but because I am saying to them, essentially: This is me. The guy you know and like here in Durango? A lot of it has to do with this guy. I admire and respect my brother so much I want my friends to see the legend in person.
The weekend wasn’t without its quarrels and tense discussions. Some of it was brotherly squabbling, some more serious and existential in nature and how we relate to one another and to other people in our lives. But such discussions are different with my brother. We engage because we care about the other, we are invested in the other’s short- and long-term well-being. We participate in conflict that would be so easy to walk away from if it were just a friend, because you can’t simply walk away from a sibling. I don’t know what could break that bond.
I may have had friends over the years I felt closer to, or been in romantic relationships with people I knew more intimately or experienced life with more thoroughly on a day-to-day basis. But there’s nothing like my relationship with my brother. Perhaps it’s the half of our genes we share, the genes that tell us instinctively, “No matter what happens, I’ll always be here. I’m never going away.”