One of the main theories used by evolutionary psychologists to explain altruism in humans is the kin selection theory, which states that altruistic behavior benefits the genes based on the degree of relatedness. To put it simply, any gene from this generation will essentially be half a gene in the next generation because of recombination, the process of mixing the genes from each parent to form a new gene. Since the publication of The Selfish Gene, it has become widely acknowledged that in a very real way, animals are devices by which genes reproduce. This is the exact opposite of the previous mindset in which animals used genes to reproduce.
With this in mind, kin selection theory predicts that genes ought to program animals to be most prosocial (altruistic) with those individuals who are most likely to share significant amounts of genetic material. This seems straightforward enough, and to a large degree it is. We all know that parents will often sacrifice their own livelihood, happiness, and even their lives for their children, and we would expect that. Both father and mother have a 50% genetic investment in the child, which is the most possible in a sexually reproducing animal*
The thing is, it’s not quite that simple. Parental certainty in humans is asymmetrical. That is, both parents are not equally certain of their parenthood. Females are always certain their child is their own. It literally came from their body as a child, and so there is no doubt.** Males, on the other hand, might be certain that they donated sperm, but they can never be completely certain that some other man didn’t also donate sperm. The ferocious male jealousy we’re all familiar with is largely hypothesized as a genetic adaptation designed to create as much certainty as possible in males. After all, a male who spends all his resources on someone else’s child is not going to pass his own genes on. Those who jealously guard their females after insemination are far more likely to be the father, and therefore, far more likely to have their genes survive.
Given this knowledge, it ought to stand to reason that there would be a hierarchy of investment in offspring. The mother should be the most devoted, and the father should be somewhat prone to abandonment, particularly if there are other indicators that his parenthood is in doubt. Anecdotally, we can all see that this is true. There simply aren’t any movies on Lifetime (Television for Victims) about asshole mothers who abandon their children, leaving their father to work two jobs. “Deadbeat Mom” simply isn’t in our vocabulary, while everyone has heard of “deadbeat dads.” To be sure, there are mothers who abandon their children, but it’s extremely rare compared to the number of males.
Beyond the anecdotal evidence are numerous studies which line up very nicely with the prediction. (Remember, in science, the ability of a theory to make precise predictions is one of the most reliable indicators of its accuracy.) Mothers do invest significantly more in their children than fathers, across all cultures, and across history.*** Fathers are significantly more likely to abandon offspring.
While this is compelling, if the theory of kin selection is true, we ought to see the pattern continue. Grandparents ought to show a marked preference for grandchildren whose parentage is certain. Here is where a certain amount of cognitive dissonance might set in. We all know that if you ask any grandparent, they will tell you that they love all their grandchildren equally. It’s part of the Grandparent’s Handbook. But before we toss the hypothesis to the curb, we need to remind ourselves that our genes don’t care if what we believe about ourselves is true. They only care if what we do is conducive to reproductive success. From the point of view of a gene, it would make sense for a grandparent to believe one thing and do another. For the purpose of social unity and family harmony, the appearance of impartial grandparents would be a great benefit. However, for the purpose of carrying on individual genes, there should be a marked difference in affection and altruism.
A new study by David Bishop, et al, has given new force to this explanation. Interviews with grandparents did indeed give the impression that grandparental investment was equal among all grandchildren. However, when it was examined from the point of view of grandchildren, a clear linear relationship became apparent, and it lined up very nicely with the prediction of kin selection theory. Where parenthood was certain, grandparental prosocial behaviors were the highest. In other words, your mother’s mother is most likely the most altruistic of your grandparents, while your father’s father is the least. (Your mother’s mother is certain that her daughter is hers, and your mother is certain that you are hers. Your father’s father is uncertain that your father is his, and your father is uncertain that you are his.) In fact, the results lined up exactly with the expected progression – MoMo, MoFa, FaMo, FaFa, for Mother’s Mother, Mother’s Father, Father’s Mother, and Father’s Father, respectively. This is precisely the descending line of parental certainty.
Once again, we see with vivid clarity that our concept of free will is not as defensible as it initially seems. Sure, grandparents believe they love their grandchildren equally. Sure, they want to be fair. But they aren’t. Our natures are just as ingrained in us as those of any other animal. All the philosophy in the world can’t change the fact that we believe things about ourselves that simply aren’t true, and we act in accordance with our genes, whether we are aware of it or not.
At this point, clever readers might stumble upon a rather odd notion. Many ad hoc explanations for human morality don’t make a lot of sense when it comes to children’s welfare. Let’s take evolution out of the equation for a moment. We all just take for granted that parents love their own children more than other people’s children, but why should that be so? This is actually a very hard question to even ask, for it is so “obvious” to us that it’s hard for us to step outside the box. Let’s try a thought experiment to see if we can make it more clear. Suppose for a moment that you were going to design a group of self-replicating robots, and your goal was to grant each individual robot the best possible life. (Wouldn’t a loving creator do this?) Suppose you had a hundred robots, and they could each make one copy of themselves in their own lifetime. If you took parentage out of the equation, and designed them so that each of the hundred robots cared equally for all the offspring, you would ensure that there would be no favoritism, and it would be in the best interest of each “parent” to make sure that resources were divided exactly equally among all the “children.” On the other hand, if you made each parent solely responsible for its own offspring, it would pay each parent to acquire as many resources as possible for its own offspring, even if it meant stealing from or even killing rivals to acquire their resources. The result would be great inequality.
Now, can you see how this works for humans? If there is some magical “human morality” that is separate from us, why are we so fiercely loyal to our own children? Why don’t the richest parents give equally to all the other poor children in town? Again, it seems so patently obvious that we love our own children because they’re ours that it never occurs to us to ask why that should even matter! The only answer that makes any sense is that it’s our genetic legacy that matters. In protecting our children, we are literally protecting ourselves, for we are our genes.
What does all this mean? To be honest, I’m finding this a difficult question to answer. It’s one thing to find practical use for some aspects of evolutionary psychology. For this, it’s not as clear cut to me. Perhaps this knowledge could potentially help ease conflict between grandchildren, or between parents who are angry with their inlaws. Maybe it will help some people to come to grips with the discrepancy between the children’s stories and the reality of their lives. I really don’t know. What I do know is that true knowledge is power, and even if we don’t immediately see where it fits into the whole puzzle, it’s better to know than not, and more knowledge is never a bad thing. If nothing else, perhaps it has been helpful to step outside of the human box for a moment and see just how strange some of our most “obvious truths” are when we take our own instincts out of the equation.
* Actually, it’s not. Incest can create a larger than 50% genetic investment in offspring, but the detrimental effects of incest far outweigh the ad hoc benefit of creating greater parental investment, so the point is largely irrelevant.
** Of course, modern medicine has introduced a degree of doubt with various fertilization procedures, but this too is irrelevant to our evolutionary drives, as the incidence of true uncertainty have been so infrequent, and have only occurred within the past several generations — not nearly enough time for evolutionary adaptation.
*** The reader must be cautioned against suggesting that evolutionary anomolies such as enormous harems and baby farms are proof against the hypothesis. Remember that human history spans hundreds of thousands of years, and the most vibrant of these institutions lasted for a few generations.