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The Evolutionary Origins of Friendship

The emergence of this crucial kind of relationship relied on the ability to recognize the unique benefits others have to offer

As awful as 2020 was, its ability to reveal the genuine strengths and weaknesses of our relationships was an unexpected boon. When severe trouble strikes, whether it be a death in the family, divorce, lost fortune, public cancellation or global crisis, true friends rise above the posers.  

Strange as it might sound, severe downturns are watershed moments. They enable us to discern fair-weather friends from friends tried and true. Flush times, when all is going well, do not provide the clarifying moments that enable us to see who will come to our aid when the chips are down. In fact, the ironic implication is that during times of good fortune, we might be less certain of who our friends really are and only glean this insight during times of hardship. Indeed, over the past year, I’ve experienced the gratifying strengthening of relationships with people not previously in close orbit, but also the distressing unraveling of relationships I had thought beyond question. Some relationships can withstand intense stress; others break like brittle bones.

As an evolutionary psychologist, I have conducted research on social relationships and emotions for over 20 years. Friendships are an important class of relationships that evolved in response to the benefits of having additional people beyond family invested in one’s welfare. But how do we make other people care—that is, redirect their time, money and social benefits to us instead of themselves or their kin?


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The answer: we make ourselves valuable.

The evolution of friendships relied on the ability to recognize the unique benefits other people have on offer. Benefits can include the usual suspects of prestige, status and attractiveness, but there are myriad reasons why you might value another person: they are of the same political party, they like the same kinds of foods, they like to golf, surf or play chess, or they enjoy talking endlessly about Star Wars. Friendships tend to begin when one individual perceives value in another and performs a beneficent act: “You can borrow my phone if you need to make a call”; “Can I help you carry that?” These actions serve as a fishing line, cast out to see if the target individual might be in the market for a new friend. Signals of their gratitude are promising indicators of a bite; anger and annoyance are indicators of a lost lure.

What begins as a mere platitude, though, can snowball into a deep engagement. If I demonstrate that I value you, then, all else equal, it pays for you to value me in return. Your increased valuation of me can then lead me to care more about you, and so forth. To the extent we can make ourselves valuable to each other, we will have a vested interest in keeping each other around, which comes in handy during times of misfortune.

The talk of value and benefits on offer sounds calculated and coldhearted. It is. But this jargon refers to the rationale behind why the thoughts and feelings we experience exist. You do not consciously calculate the likelihood that a person values you or the downstream benefits that could result from a relationship—instead the algorithms doing these calculations generate outputs, which percolate up from the unconscious as “liking.” Have you ever met someone, talked for hours, and left feeling like you’ve found a long-lost brother, sister, or soulmate? Chances are, you noticed similarities and evaluated the kinds of benefits future interactions might yield, which generated a sense of immediate closeness. Mutual valuation, when intense, can create storybook relationships.

But the tricky part is deciphering which individuals merely say they value us versus those who would be inclined to stand by our side during hardship. Talk is cheap and promises easily spoken: “I’d totally help you out in a pinch”; “You can ask me for money anytime”; “Feel free to stay at my place.” Promises cost nothing when friends don’t need help, money or a place to stay. As they say, actions speak louder than words. The pandemic has therefore been an unexpected (albeit unwanted) opportunity to test the tensile strength of our relationships.

As 2020 retreats farther into the rearview, it is as good a time as any to take stock of our relationships and to apply the old adage to ourselves and to others: friends in need are friends indeed.