The Evolutionary Case for Friendship

Learn why friendship has always been necessary for mankind's survival.

Posted Jul 04, 2013

Too many people view friendship as a wonderful yet superficial aspect of life: the cherry on top of the sundae, rather than the sundae itself. But in Friendfluence by Carlin Flora, Carlin explores just how much influence friends can have over our lives, from careers to physical health, and why the importance of friendship is wired into our own DNA. Here, she answers questions about these points and more.

When most people think about the benefits of good friendships, they may think about stress relief or a shoulder to cry on, but there are so many other positive effects. What are some of the more surprising ways that friendship can help us live better lives?

Friendships can spur creativity and innovation, they relieve loneliness even more than siblings and spouses do, and they are the "secret" reason that religious people are happier than others (churches cultivate friendships). Friends know us better than we know ourselves (they are better at guessing our IQs than we are, for instance), and they let us help them (which makes us happier since giving is a mood boost). If you're married, having friends keeps your marriage strong. We don't like to admit this in a supposedly meritocratic society, but friends give jobs and assignments to friends, so having friends who share your career interests and aspirations can get you much farther than you could ever get on your own. Finally, friends at work make you more productive, innovative, happier, and even more satisfied with your paycheck than you'd be if you didn't have pals on the job.

You mention stress relief. It's true that just being with a friend lowers our blood pressure. Other health effects of solid friendships are among the most surprising; friends can help us break bad habits or lose weight, simply because we are so driven to adapt the values and behaviors of those in our social group. Laughing with friends can increase physical pain thresholds by about ten percent. Friends enhance your intelligence (since you're comfortable with them you're more likely to freely share insights until something brilliant surfaces) and they can even save your wits. Elderly people with active social lives are much less likely to experience cognitive decline and dementia than those without.

The ultimate argument for the positive influence of friends is their startling effect on our life spans. One study found that breast cancer patients who were socially isolated had a full 66 percent increased risk of dying compared to women with a supportive circle of friends. Having a spouse did not reduce the patients' chances of dying. According to a meta-study, people with a solid group of friends are 50 percent more likely to survive at any given time than those without one. And here's one of my favorite facts in the book: having few social ties is an equivalent mortality risk to smoking 15 cigarettes a day and even riskier than being obese or not exercising!

Are there periods of life where the need for good friendships is particularly striking?

Friendship is essential to children's social and emotional development. It's through conversations with peers, for example, that kids learn perspective-taking, how to debate and argue, and moral-reasoning. Intimate friendships are intense training grounds that teach kids about conflict resolution and empathy. Children are socialized in a group but ideally gravitate toward friends who help them manage said group while also offering a respite from its limited roles and strict codes.

Of course, friendship is primary for teens. To the average 13-year-old, friends are just as emotionally supportive as parents, and to 17-year-olds, they are more so. It's hard to separate out the influence of friends from the influence of parents (and other factors) but some, such as researcher Judith Rich Harris, argue that other than the genetic material they provide, parents don't influence how their children turn out; rather, their peer group does. Kids tend to rise or fall to the level of their friends, in terms of behaviors and aspirations.

Young adulthood is also a very friend-centered time, particularly as fewer people marry young or at all. Self-esteem, especially for young adults who are grappling with identity issues, doesn't just come from within. It comes from the group of friends to which a young person belongs. That's why it's really important for young adults to receive what researchers call "social identity support" from their friends. Their friends need to reflect their burgeoning identities, and need to see them for who they really want to be, even if they're not there yet.

It's important to have good friends during big life transitions, such as new parenthood, divorce, or loss of a spouse through death. However, those are times when people often lament that they feel disconnected from close friends. Still, if you can manage to meet new friends who are going through the same change that you are going through, the "getting to know you" process can be rapidly accelerated by the exchange of intimate feelings and shared experiences related to the transition. (It's a good reminder to reach out to your own friends when they are navigating a big change. Even if it's a happy circumstance, they need you more than ever as they adjust.)

What about the concept of every-person-for-himself? Or at least every-person-for-their-family? Are humans naturally wired to be able to be good friends?

Yes! From an evolutionary perspective, the urge to make friends is, on the surface, a puzzle: if perpetuating our own genes is life's primary objective, why do we develop such intense non-sexual interest in people who are not related to us? The answer is that we needed to cooperate with and depend on people outside of our families in order to survive.

In our distant ancestors' environments, evolutionary psychologists argue, women tended to leave their families and join their husband's tribe, making it important for them to be able to form ties with non-relatives. Otherwise, they wouldn't be able to secure the help they needed to survive and raise their children successfully. Men would have also needed friendship skills in order to form alliances and obtain power and protection within the tribal hierarchy.

A few other theories build upon this to further explain our unconscious motives for forming particular friendships. John Tooby and Leda Cosmides proposed the "Friend Niche Limitation Model," wherein you have a small number of close friendship slots, and as someone who is trying to survive and avert disaster, you need to fill those slots with people who are capable of helping you out in unforeseen circumstances. Tooby and Cosmides suggest that we evolved to include at least one person with special skills or traits, one person who reads your mind fairly well, and someone who considers you difficult to replace.

Extending the "difficult to replace" notion, Peter DeScioli and Robert Kurzban developed "The Alliance Hypothesis." They've gathered evidence in support of this idea that because we evolved in a time when we really needed one "lifeline," we still become very ruffled when a friend we perceive as our closest pal gets close to someone else. What if she is the new lifeline? Where does that leave us? This really explains why choosing a maid of honor is so fraught -- it's the psychology behind the movie "Bridesmaids."

Many people have stereotypes of the role of friendships for men vs. women. Let's hear some evidence that men should jump on the friendship bandwagon as well.

The amazing benefits of good friendships outlined in my answer to your first question are basically the same for men as they are for women. So therein is all the evidence a man should need to take friendship seriously. (Case in point: As a counterpart to the breast cancer study above, when Swedish men were followed for six years, having a romantic attachment didn't decrease their risk of a heart attack, but friendship did.) While some research has confirmed stereotypes by showing that men are more likely to have "shoulder-to-shoulder" friendships based on shared activities while women have "face-to-face" friendships characterized by exchanging intimacies, other research concludes that the similarities between men's and women's friendships outweigh the differences. Researcher Geoffrey Greif, for instance, has found that men feel quite supported by their friendships, even if they don't tend to open up to their friends as much as women do.

Friendship between the sexes seems to be on the rise. One survey found eighteen- to twenty-four-year-olds are nearly four times as likely as people over fifty-five to have a best friend of the opposite sex. These relationships can be fraught in the beginning, especially if one person wants to turn the friendship into something more romantic and the other one doesn't. Yet if the question of "Where is this going?" is settled or at least kept comfortably on a back burner, these can be particularly rewarding friendships.

To learn even more about the benefits and influence of friendships, pick up Carlin's book Friendfluence today!

Andrea Bonior, Ph.D., is the author of The Friendship Fix and the longtime writer of Baggage Check, the mental health advice column in the Washington Post Express.