Kin Altruism: Why We’re Nice to Our Family

What is kin altruism? Where does it come from and why is it an important part of natural selection.

Kin altruism is the idea that we behave more favorably towards those to whom we are related. Proponents of religion claim that without an all-powerful creator, human beings wouldn’t know how to show kindness or affection. But kin altruism may have actually developed as a part of natural selection.

Read more about kin altruism and why it’s an important part of evolution.

The Origins of Kin Altruism

Genes seek to maximize their chances of survival across generations. In that sense, genes are “selfish.” But this does not mean that the human trait of selfishness is itself advantageous in natural selection. In fact, the drive for gene survival provides a powerful incentive for individuals to behave altruistically toward those in their kin group, with whom they share a genetic link.

After all, taking care of your children and ensuring that they grow up strong and healthy enough to have children of their own is one of the best ways to ensure the survival of your own genes. It is easy to see then why natural selection would favor kin altruism as a replicating behavior through generations. And sure enough, kin altruism—caring for those with whom one shares a genetic link—is widely seen not just in humans, but throughout the animal kingdom.

Reciprocity and Mutual Obligation

But even if natural selection can adequately explain kin altruism, creationists ask, what accounts for the kindness and empathy we display toward people we’re not related to? Surely this must be the product of some divine spark within ourselves?

Natural selection, once again, can account for our natural feelings of empathy. Here, the primary evolutionary mechanism is the reciprocity reflex. This tells us to repay others when they do something for us. We do this all the time without even realizing it. When a friend treats you to lunch, you make sure you pick up the check the next time you go out; when your neighbors invite you to a party, you invite them the next time you’re hosting an event.

We are hardwired to repay favors, even from strangers. From an evolutionary perspective, it makes sense because it increases everyone’s chances of survival. The reciprocity reflex causes the other members of the group to help you if you have helped them, creating networks of mutual obligation. 

We are so programmed for kin altruism that we extend it even to people who are unlikely to ever “repay” us for our kind actions. It’s why we are moved by images of war orphans, stateless refugees, or even homeless people we encounter on the street. Their survival has nothing to do with us, can secure us no advantage, and yet the sight of their suffering triggers intense feelings within us. 

Reciprocity is key to the social glue that holds societies together. Especially in early human societies, which would have been small, tight-knit bands of mostly kin, it would be advantageous to cultivate a reputation as being trustworthy and reciprocal. Likewise, it would have been disadvantageous to cultivate a reputation as a selfish free rider—because no one would be willing to help you in your time of need.

(Shortform note: Want to learn more about the reciprocity reflex? Read our summary of Robert Cialdini’s Influence: The Psychology of Persuasion.)

This dynamic would have been enhanced by a key distinguishing feature of human societies—language. In particular, gossip, the sharing of social information about others, would have allowed someone’s reputation as either a generous member of the community or an unscrupulous free rider to spread quickly. 

This sharing of social information was likely an important element in contributing to group survival for early humans, enabling scarce resources to be shared more efficiently and potential threats to be identified more easily. 

Further, it reinforced positive social norms by making our ancestors aware of the misdeeds of people outside the immediate kin group whom they may not have personally known—bolstering both altruism and the reciprocity reflex by ensuring that selfish people didn’t receive cooperation, while altruistic people did.

(Shortform note: To learn more about the role of gossip in fostering early human language, read our summary of Jonathan Haidt’s The Happiness Hypothesis: Finding Modern Truth in Ancient Wisdom.)

Darwinism and Modern Morality

As we mentioned, early kin-based human communities would have strongly favored genetic tendencies toward altruism on the basis of both kin survival and reciprocity. We are thus bred to be altruistic and moral. 

It’s important to note that this does not make the love and compassion we feel toward our fellow human beings any less real or genuine. It simply provides a coherent explanation for why we think and behave as we do. Understanding Darwinism intellectually does not make anyone love their family and friends less, despite what creationists might claim.

Indeed, our modern displays of love and affection might simply be misfirings of our normal evolutionary impulses, just as we saw with religion itself in the previous chapter. For example, the desire for sex comes from a clear Darwinian impulse—to create offspring to pass along your genes. But we still experience lust and desire when there is no chance of procreation—as in same-sex relationships or when a heterosexual couple is using birth control. Sexual desire still exists independently of the original evolutionary impulses that explain it.

Kin Altruism: Why We’re Nice to Our Family

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