Over 400,000 people visited Farnam Street last month to learn how to make better decisions, create new ideas, and avoid stupid errors. With more than 100,000 subscribers to our popular weekly digest, we've become an online intellectual hub. To learn more about what we do, start here.

Survival of the Fittest: Groups versus Individuals

If ‘survival of the fittest’ is the prime evolutionary tenet, then why do some behaviors that lead to winning or success, seemingly justified by this concept, ultimately leave us cold?

Taken from Darwin’s theory of evolution, survival of the fittest is often conceptualized as the advantage that accrues with certain traits, allowing an individual to both thrive and survive in their environment by out-competing for limited resources. Qualities such as strength and speed were beneficial to our ancestors, allowing them to survive in demanding environments, and thus our general admiration for these qualities is now understood through this evolutionary lens.

However, in humans this evolutionary concept is often co-opted to defend a wide range of behaviors, not all of them good. Winning by cheating, or stepping on others to achieve goals.

Why is this?

One answer is that humans are not only concerned with our individual survival, but the survival of our group. (Which, of course, leads to improved individual survival, on average.) This relationship between individual and group survival is subject to intense debate among biologists.

Selecting for Unselfishness?

Humans display a wide range of behavior that seems counter-intuitive to the survival of the fittest mentality until you consider that we are an inherently social species, and that keeping our group fit is a wise investment of our time and energy.

One of the behaviors that humans display a lot of is “indirect reciprocity”. Distinguished from “direct reciprocity”, in which I help you and you help me, indirect reciprocity confers no immediate benefit to the one doing the helping. Either I help you, then you help someone else at a later time, or I help you and then someone else, some time in the future, helps me.

Martin A. Nowak and Karl Sigmund have studied this phenomenon in humans for many years. Essentially, they ask the question “How can natural selection promote unselfish behavior?”

Many of their studies have shown that “propensity for indirect reciprocity is widespread. A lot of people choose to do it.”


Humans are the champions of reciprocity. Experiments and everyday experience alike show that what Adam Smith called ‘our instinct to trade, barter and truck' relies to a considerable extent on the widespread tendency to return helpful and harmful acts in kind. We do so even if these acts have been directed not to us but to others.

We care about what happens to others, even if the entire event is one that we have no part in. If you consider evolution in terms of survival of the fittest group, rather than individual, this makes sense.

Supporting those who harm others can breed mistrust and instability. And if we don’t trust each other, day to day transactions in our world will be completely undermined. Sending your kids to school, banking, online shopping: We place a huge amount of trust in our fellow humans every day.

If we consider this idea of group survival, we can also see value in a wider range of human attributes and behaviors. It is now not about “I have to be the fittest in every possible way in order to survive“, but recognizing that I want fit people in my group.

In her excellent book, Quiet: The Power of Introverts in a World That Can’t Stop Talking, author Susan Cain explores, among other things, the relevance of introverts to social function. How their contributions benefit the group as a whole. Introverts are people who “like to focus on one task at a time, … listen more than they talk, think before they speak, … [and] tend to dislike conflict.”

Though out of step with the culture of “the extrovert ideal” we are currently living in, introverts contribute significantly to our group fitness. Without them we would be deprived of much of our art and scientific progress.

Cain argues:

Among evolutionary biologists, who tend to subscribe to the vision of lone individuals hell-bent on reproducing their own DNA, the idea that species include individuals whose traits promote group survival is hotly debated and, not long ago, could practically get you kicked out of the academy.

But the idea makes sense. If personality types such as introverts aren’t the fittest for survival, then why did they persist? Possibly because of their value to the group.

Cain looks at the work of Dr. Elaine Aron, who has spent years studying introverts, and is one herself. In explaining the idea of different personality traits as part of group selection in evolution, Aron offers this story in an article posted on her website:

I used to joke that when a group of prehistoric humans were sitting around the campfire and a lion was creeping up on them all, the sensitive ones [introverts] would alert the others to the lion's prowling and insist that something be done. But the non-sensitive ones [extroverts] would be the ones more likely to go out and face the lion. Hence there are more of them than there are of us, since they are willing and even happy to do impulsive, dangerous things that will kill many of us. But also, they are willing to protect us and hunt for us, if we are not as good at killing large animals, because the group needs us. We have been the healers, trackers, shamans, strategists, and of course the first to sense danger. So together the two types survive better than a group of just one type or the other.

The lesson is this: Groups survive better if they have individuals with different strengths to draw on. The more tools you have, the more likely you can complete a job. The more people you have that are different the more likely you can survive the unexpected.

Which Group?

How then, does one define the group? Who am I willing to help? Arguably, I’m most willing to sacrifice for my children, or family. My immediate little group. But history is full of examples of those who sacrificed significantly for their tribes or sports teams or countries.

We can’t argue that it is just about the survival of our own DNA. That may explain why I will throw myself in front of a speeding car to protect my child, but the beaches of Normandy were stormed by thousands of young, childless men. Soldiers from World War I, when interviewed about why they would jump out of a trench, trying to take a slice of no man’s land, most often said they did it “for the guy next to them”. They initially joined the military out of a sense of “national pride”, or other very non-DNA reasons.

Clearly, human culture is capable of defining “groups” very broadly though a complex system of mythology, creating deep loyalty to “imaginary” groups like sports teams, corporations, nations, or religions.

As technology shrinks our world, our group expands. Technological advancement pushes us into higher degrees of specialization, so that individual survival becomes clearly linked with group survival.

I know that I have a vested interest in doing my part to maintain the health of my group. I am very attached to indoor plumbing and grocery stores, yet don’t participate at all in the giant webs that allow those things to exist in my life. I don’t know anything about the configuration of the municipal sewer system or how to grow raspberries. (Of course, Adam Smith called this process of the individual benefitting the group through specialization the Invisible Hand.)

When we see ourselves as part of a group, we want the group to survive and even thrive. Yet how big can our group be? Is there always an us vs. them? Does our group surviving always have to be at the expense of others? We leave you with the speculation.