This article is a preview from the Winter 2018 edition of New Humanist
Adam Rutherford is a geneticist, author and broadcaster. His latest book is the “The Book of Humans: the Story of How We Became Us” (Weidenfeld & Nicolson), which explores what sets humans apart in the animal kingdom.
From a scientist’s perspective, how would you define culture?
It includes art, writing and music, but also things like stone tools and pottery. It’s all the extra architecture of our lives.
When did culture evolve?
We began using tools before we were Homo sapiens. The earliest example can be seen in a species called Kenyanthropus platyops, about 3 million years ago. But abstract art, statues, musical instruments and so forth emerged 40,000 years ago.
Are humans unique among all species?
Yes, because we are cultural accumulators. We also pass culture on to people who we are not related to, like we are doing in this interview. There are almost no examples of that activity in non-human animals, with the exceptions perhaps of dolphins or crows. But we do it all the time.
How do biological and cultural evolution relate?
In evolutionary time, culture and biology feed off each other. Culture is based on our biological framework, influencing it as evolution progresses. You need a biological framework on which to build the culture itself. Take, for example, our tool use. We had to have hands to make sophisticated tools.
But in order to articulate them we need to have brains, which are capable of controlling that mode to function. So our evolved biological framework enables us to create cultural artifacts.
What was Charles Darwin’s most significant contribution to evolutionary biology?
He invented it! His books On the Origin of Species (1859) and The Descent of Man (1871) have effectively withstood 150 years of testing. That is incredible for any scientist.
What was so special about these books?
In On the Origin of Species, Darwin really only just teased out the idea that puts us on the same tree of life as every other organism. In The Descent of Man, he clearly placed us as evolved organisms, but at the same time he recognised that we have what he calls “God-like intellect [who] still bear the stamp of our lowly origins”. He also recognised that we are animals, that we evolved, and that we are special.
Darwin also introduced the idea that life is four-dimensional. How does this work?
It means that organisms change through time: that is what evolution is. Darwin gave us the mechanism of evolution, not the concept. The concept predates Darwin. He also came up with the idea that modernity emerges from our sociality: from our ability to teach and to share ideas across populations, due to our changing population structure.
Is violence inherent to nature?
Yes, absolutely, because conflict is inherent to natural selection. Especially with competition relating to resources and access to sexual partners – that is the struggle for existence. Competition is inherent to evolution, and violence is inherent to evolution. We should be wary of using animal behaviour to try and deconstruct or justify human behaviour. Nevertheless, violence is almost universal amongst all animals.
Could you give some examples?
Dolphins engage in infanticide, as do lions and many other organisms. There is also evidence of male chimps going out on patrol on enemy territory, singling out individuals and beating them to death. Still, I don’t think that explains the depths of violence that humankind indulges in.
Are we the most violent species out there?
Through our evolved brains, culture and tool use, humans have turned the application of violence into a fine art. And it appears that we have been engaging in group-level conflict for at least 10,000 years.
You claim that homosexuality presents an evolutionary puzzle.
For a long time, homosexuality was decried in the western churches as being against nature. It’s very clear that it is not against nature and that it’s a universal behaviour between females and females, and between males and males, in literally thousands of species. Some homosexual behaviour fits into well-established evolutionary paradigms. For example, hyenas are part of a matriarchal societal structure that establish hierarchy by licking each other’s clitorises.Around 90 per cent of sexual encounters in giraffes are male-to-male too. But we don’t know why they do that. It’s a scientific puzzle that has yet to be solved.
Is it useful to apply human value judgements to the sexual practices of other animals?
It’s difficult when it comes to issues like coercive sex and rape in the animal world to use human terminology. Because rape, for example, is a legal definition, which relies on consent. We cannot establish what consent means in other animals. With dolphins, for instance, it’s often the case that the option is either sex or death. Therefore it doesn’t seem unreasonable that consent is not being volunteered by the females in those situations. It looks like what amounts to kidnapping, where the female spends all of that time trying to escape, while the males spend their time physically assaulting her and having coercive sex.
In purely scientific terms, is that an evolutionary strategy?
Yes, that is how evolution works. That level of conflict and violence is part of the natural world. It isn’t pleasant or something that you might tell pre-school kids about. But it is biology. The danger is that we look at behaviour like that and say: cute dolphins engage in behaviour that is very similar to rape. By doing that, however, we risk trivialising actual rape and criminal behaviour in humans.
Scientific knowledge about DNA has radically increased in the last few years. What can this new information tell us?
Try and think about DNA as being a sort of logbook of every successful reproductive encounter that your ancestors ever had. Consequently, we have a history of us as individuals, as families, as our species, and the whole of life on earth inside all of us. Because we have got better at extracting that DNA, we can compare DNA between everyone on earth today, and also to people who have been dead for thousands of years. That has enabled us to map out the migration of our species – and earlier versions of our species – all over the world, for the last million years. One of the most powerful revelations coming from this is that we know that all of our ancestors have [in Europe] bred with Neanderthals, and, that we have about one or two per cent Neanderthal in our DNA.
Does science struggle to explain the origins of language?
Yes. It’s a very tricky area for scientists to study. Broadly speaking, evolution tends to go in a tree-like structure, where it simply diverts at every juncture. But we transfer languages all the time. We also adopt languages as people move around, so the evolution of language is a very messy, complicated web.
Are there still some elements of life that science cannot explain, such as love or art?
Over-simplistic explanations for things like love and art tend to deny the fact that we are a cultural species. Such explanations don’t take into account that we have loosened the shackles of natural selection, and do things that don’t appear to have direct intrinsic evolutionary benefit.
I’m an empiricist, so the answer has to be, ultimately, yes, you can explain art and even love using science. But that doesn’t mean it’s going to give you the most interesting answer. And it doesn’t mean it can explain what it’s like to be in love or to create art. There are limits to the use of scientific explanations of things we value.
Does history suggest that migration is intrinsic to the human experience?
We are by definition a species that was born from Africa, and then populated every corner of the globe. But the time scales involved are absurd. We talk about the “out of Africa event”: when 80,000 years ago a population of Homo sapiens left Africa and that became the founding population for the rest of the world. That event probably took five or ten thousand years, and the rate of migration is something like two miles every century. In evolutionary terms, that is migration. The movement of people is a central part of the human story.
