Blueprint summary

The nature versus nurture debate is almost as old as science itself. And for good reason – it is often fiendishly difficult to tell whether any given behavior is a result of our genes or our environment. Unfortunately, social behavior is no different. This begs the question: how can we be sure that the social suite of human behaviors are really inbuilt evolutionary adaptations, rather than spontaneous responses to the situation we find ourselves in?

To know for sure, we would have to conduct life-long experiments in which humans were raised in an environment without any pre-existing society or older people, and see how these unfortunate guinea pigs interacted with one another. Of course, ethical considerations make these sorts of studies impossible. Shipwrecks, however, may provide a close substitute for these experimental conditions. Those who survive shipwrecks, for instance, often find themselves washed up on deserted islands without any trace of established human society or infrastructure. 

What aspects of sexual relationships are universal? Until recently, the author assumed kissing was universal. But it turns out he was wrong about that. The Tsonga people of Mozambique, for example, do not kiss. In fact, upon hearing of this strange practice, the Tsongas questioned why two people would want to share saliva and all its accompanying germs. This got the author thinking: which traits of human sexual relationships are present across all cultures?

The answer, quite simply, is love.

On December 17, 2015, 15-year-old Zavien Dobson was sitting on his porch with three friends in Tennessee, when a car pulled up and opened fire on them. Zavien didn’t hesitate. He threw himself on top of his female companions and died in a hail of bullets. Thanks to his actions that day, each of his friends survived this random and senseless attack. In light of Zavien’s moving sacrifice, the author began wondering: why do we feel such love for our friends? 

Hearteningly, evidence suggests that friendship is a universal feature of nearly all human societies. Furthermore, it seems that the vast majority of cultures share the same core essentials of friendship ⁠⁠– namely, affection, trust and mutual aid. Another universal trait of friendship appears to be the acceptance of our vulnerability. You may not mind being teased by a friend, for instance, because you trust that they mean well. 

In 2005, Amazon launched a software system that enabled them to hire tens of thousands of part-time workers to complete minor online tasks. This massive platform is known as Amazon Mechanical Turk, and its creation allowed the company to recruit workers, record their contribution and pay them accordingly. Before long, social scientists realized they could use the Turk system to set up artificial “communities” of users and see how they responded, individually and as a group, to tasks set by the researchers.

For the author and his laboratory, this vast online apparatus represented an exciting opportunity to explore the social suite of behaviors. He and his team set out to learn whether Turk users would still display these supposedly universal social behaviors online, or whether this brand new environment would prompt them to behave in brand new ways. 

Humans and animals share many similarities. Up until 1964, scientists were stumped as to how to repair damage caused to heart valves by cardiovascular disease. That was until a French surgeon called Alain Carpentier tried replacing them altogether, with valves transplanted from pigs. Incredibly, his technique worked, and is still used today. Clearly then, our organs have a lot in common with those of pigs. But what if animals are similar to us in even more subtle ways?

As science progresses, we are increasingly faced with an uncomfortable truth: that the very same animals we eat and experiment on might share many features of our social suite. Evidence suggests, for example, that elephants have friends, gorillas have their own language, and rats feel empathy. Not convinced? Then just consider the parallels between capuchin monkeys’ social behaviour, and our own. These South American primates put their fingers into other monkeys’ mouths and allow them to gently bite down on them, thus exhibiting the apparently human trait of accepting vulnerability in front of one’s friends.

The human race is scattered across the world. As a species, we’ve made our homes almost everywhere, from the freezing temperatures of the Arctic to the humid Amazonian rainforests. But how exactly have our genetics helped us survive these hugely variable environments? As it turns out, our genes have enabled us to prosper by endowing us with the ability to develop culture.

In an evolutionary sense, culture refers to knowledge that’s transmitted from person-to-person within a group, which then influences individuals’ behavior. Furthermore, culture is an evolutionary adaptation in itself, in that natural selection has equipped us with genes that can create culture. Our genetics give us relatively long lives, for instance, providing plenty of chances for information to be passed on between generations. Humans also have several psychological features that seem tailor-made for culture, like our desire for conformity between individuals and our tendency to mimic the behavior of older individuals. Extremely young children, for example, have been found to regularly copy every action they see an adult performing, no matter how trivial the behavior might be.