Explaining Human Diversity

Cultures, Minds, Evolution

Carles Salazar

• Publisher: Routledge
• Year: 2018
• eBook ISBN: 9781351127967
• Edition: 1
• Topic: Sciences sociales
• Subtopic: Anthropologie

Why are humans so different from each other and what makes the human species so different from all other living organisms? This introductory book provides a concise and accessible account of human diversity, of its causes and the ways in which anthropologists go about trying to make sense of it. Carles Salazar offers students a thoroughly integrated view by bringing together biological and sociocultural anthropology and including perspectives from evolutionary biology and psychology.

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BEING HUMAN

Human evolution in the history of life

Imagine a Martian scientist with the job of studying all life forms on planet Earth. In all probability, the first thing she would do would be to classify living organisms according to the species to which they belong. But when she came across the human species, something very odd would immediately catch her eye. The human species seems to be very different indeed from all the others.

In all likelihood, this imaginary alien scientist would not be much impressed by the apparent results of human intelligence – whatever we mean by that and whatever the Martian understood by that. True, some humans are capable of making very spectacular things, such as big buildings. But termites and corals accomplish similar feats and with infinitely smaller brains, or with no brains at all. Furthermore, imagine that the Martian could have – by some sophisticated technological means unknown to us – the whole span of human history in front of her. She would then see that the majority of humans have lived for much of human history in quite humble dwellings, not dissimilar to birds’ nests. Maybe it is the characteristics of the human body that the Martian would find odd. For instance, humans have very big brains. But it so happens that a whale’s brain is seven times bigger than a human brain. It is not even the relationship between the brain weight and the weight of the rest of the body, since in the case of the shrew, the brain weight corresponds to ten per cent of the body weight, whereas for humans it is two per cent. We shall come back to this.

What about culture? That is certainly a good point, as we shall see in more detail below. But the question is: how would the Martian know what ‘culture’ is? Why should we define human buildings as ‘culture’ but not a termite nest, or a beaver’s dam or coral reefs? How would the Martian see what is culture and what is not? Without a doubt, before coming to terms with this somewhat obscure concept 7(and the same applies to the concept of intelligence that we have just mentioned), there is something much simpler and obvious that would draw the Martian’s attention, namely, human diversity. In no other species would she find the diversity characteristic of humans – again, above all if she was able to observe the whole of human history on the spot. That is diversity of ways of life. Any animal of any species leads a way of life practically identical to the way of life of any other member of its own species (setting aside now domesticated animals). The life of a gorilla, ways of feeding, interacting with their environment, with other gorillas or other animals, ways of mating, reproducing, etc. is practically identical with the life of any other gorilla. And the same applies to any other animal. Not only that, the way of life of any member of any species has been practically identical to the way of life of any other member of that same species as far back as the history of the species goes. A gorilla or a chimpanzee has the same way of life now as they had 1,000 years ago, or 100,000 years ago – or at least we have no evidence to suggest that it was not.

The situation with humans is totally different. We not only find diversity in ways of life at any time in history, but if we go back in history we realise that humans’ ways of life have been changing all along. The life of any human being now is very different from the life of his/her ancestors 100 years ago, never mind 1,000 years ago or more. The question is why. What could account for this diversity in the human species? Why are we humans so different from each other as compared with other animals, even with animals genetically very close to us, such as other primates? How do we explain this diversity, which clearly appears as the most distinctive characteristic of the human species?

Now we come to the concept of culture. Anthropologists believe that what makes humans so different from each other – and by making them so different from each other it makes them even more different from all the other species – is something we call ‘culture’. Note that ‘culture’ is a concept. It is not something that we see, it is just an idea. It is something we cannot see and that we use in order to understand something that we can see: human diversity. But there is more than one kind of human diversity. A sub-discipline within anthropology is what is known as physical or biological anthropology, which consists of studying human diversity from a strictly physical or biological point of view. Humans are also different from each other in biological terms. But these differences are no bigger than the same differences that we can find among the members of any other species. In fact, humans are more genetically homogeneous than most other mammalian species. In other words, intra-specific biological differences, though they exist, are not a distinctive characteristic of humans.

At one time, it was thought that human diversity could be explained in biological terms, that humans who had different ways of life were biologically different. This was so because, apparently, humans who have very different ways of life from Westerners, the so-called ‘primitive peoples’, happen to be also physically different, they belong to what used to be called a different ‘race’. A race is just a group of individuals, belonging to the same species, who share some, visible, physical characteristics (particularly skin colour, shape of eyes, of the head, body, etc.) believed 8to be inherited, that is, physical characteristics that one gets from his or her parents. Now, it has been widely demonstrated that the so-called racial differences among humans do not explain human diversity of ways of life. What is wrong is not that human differences have nothing to do with human biology, which they do, as we will see, what is wrong is that human differences or human diversity of ways of life is the result of human biological differences.

So how do we explain human diversity? If it is not biology, what is it? Anthropologists believe, and have believed this for a very long time, that human diversity, which is so distinctive and unique to the human species, can only be explained by means of a concept that refers to something also distinctive and unique to the human species, and that is the concept of culture. Anthropology is sometimes also called ‘the science of culture’, and anthropological theories are called ‘culture theories’, even though by rights it should be the science of cultural difference rather than the science of culture. A way of talking about the objectives of this book would be to explore the concept of culture, that is, to understand how culture intervenes in the determination of human behaviour. Now, in the determination of human behaviour many factors intervene (biological, biographical, existential, etc.). Among all these factors there is one we call ‘culture’, the culture factor. And the purpose of this invitation to anthropology is to understand how this works, how the cultural factor intervenes in the determination of human behaviour.

Let us put forward a provisional definition of culture: a system of meanings and symbols in terms of which humans rule their behaviour. Whenever and wherever we see someone behaving in such a way that we can explain that behaviour in terms of a particular system of meanings and symbols, we will call that behaviour ‘cultural behaviour’, we will say that that behaviour has been ‘culturally determined’. Now where does this system of meanings and symbols come from? Why do humans have cultures and other animals do not? Or do they have cultures? How do cultures enter into our heads? How do we ‘understand’ a culture? These are some of the questions we will be looking at in the following pages. As we shall see, cultures have many distinctive characteristics. But there is one of them I would like to underscore right from the beginning: those systems of meanings and symbols that compose human cultures are not innate, that is, they get into human minds as a result of a process of learning. We learn our cultures, we are not born with them, and we learn them as we grow up in a particular society. That is what makes culture different from biology, we are born with our biology (setting aside for now postnatal environmental differences), we are not born with our culture. Since human societies can be very different, and have been very different throughout human history, the cultures that humans learn as members of those societies are also different. Consequently, the behaviours that result from these different cultures are also different. So this is, in a nutshell, the way we anthropologists normally explain human diversity. Humans are different, so different, from each other because the cultures they learn are different.

What we will try to find out now is what makes the human brain susceptible to produce and to learn, to absorb a ‘culture’. Why is it that humans have cultures (and 9hence they are so different from each other) and other animals do not – or if they do, it is always to a much more limited extent than humans? What happened in the process of human evolution that made human brains capable of producing cultures and learning, that is, assimilating, those cultures?

Replicating structures

Let us start the story of human evolution at the very beginning. The process that gave rise to the appearance of the human species is called the process of human evolution. The point I would like to emphasise here is that it was during this long process, which lasted approximately six million years (we will see in a minute why we say that it lasted six million years), that culture came into existence, for the first time in the history of this planet, and, as far as we know, for the only time. So it was a very unique thing to happen in the 3.5 billion years of history of life on earth.

We say that human evolution lasted for six million years because it is reckoned that the last common ancestor of both humans and our closest living species now (chimpanzees) lived six million years ago. This means that if chimpanzees became extinct, then human evolution would have lasted for ten million years instead of six, for that is the time when we would find our last common ancestor with gorillas, which would be our closest living species in the absence of chimpanzees. Correspondingly, if Australopithecus were still alive, then human evolution would be shortened down to two million years. Now, in whatever way we happen to measure the length of human evolution, what cannot be doubted is that something happened during this process that explains the emergence of cultures, something that had never happened before, and that will never happen again afterwards. It does really look like a miracle. But that is not the only ‘miracle’ that took place in the history of our planet. Think of the origins of life itself. Life on earth began 3.5 billion years ago. Our planet is approximately, according to astrophysicists, five billion years old. That is, it came into existence ‘only’ 8.7 billion years after the big bang, which is supposed to be the beginning of the universe. When life began on earth 3.5 billion years ago, pretty much like culture, it did it only once. That explains why all living organisms that exist right now on this planet come from other living organisms, which in turn come from other living organisms and so on and so forth until the very beginning of life, in other words, until the very first living organism that existed on earth, which was not a living organism properly speaking, it was just a sequence of a nucleic acid that started to replicate, that is, to produce copies of itself. This is what goes by the name of LUCA: Last Universal Common Ancestor. We still do not know very well why this thing happened 3.5 billion years ago and it did not happen again after that (and, probably, we will never know for certain). But, again, what we do know is that it was something very unique, that it has happened once in five billion years and has not happened again (or at least it has only happened once on earth).

Both the appearance of life on earth and the appearance of the human species, that is, the process of human evolution with this very idiosyncratic and unique 10characteristic (which is that it is a cultural species, strictly speaking, not the only cultural species that has ever existed but undoubtedly the most cultured), are both facts so unique and mysterious in themselves, that we still do not have a clear explanation as to why this was so. All this makes creationist explanations look rather attractive, both for the origins of life and for the origins of the human species. Creationism is the doctrine according to which neither the origins of life nor the origins of the human species – nor the origins of any other species for that matter – can be explained without resorting to some sort of external (divine) intervention. Needless to say, this is not the point of view taken in this book. No matter how attractive creationism might be – and it certainly is, given all we have said, given all these mysteries and uncertainties concerning the origins of life and of our species – it is not a scientific hypothesis because it takes as a premise something that cannot be proven: either the existence of supernatural beings or of any other being to whom we can attribute creation powers.

Here we are not concerned with the origins of life as such (not directly concerned, at least) but with the origins of the human species, and with what is so distinctive about the human species, what makes this species so different from all the other species that have existed on this planet. Still, I think it is important to keep all of these temporalities, these huge time dimensions, in mind while we think about the origins of our species. The following panel aims to be a concise summary of the history of life on earth:

What we see in Figure 1.1 is what Darwin called ‘the tree of life’. This very simple graph shows that all living organisms, humans included, share a common ancestor and this was that ancestral acid strip that came into existence 3.5 billion years ago. Let us take a very quick look at how this process of the evolution of life took place. This a well-known story so I do not claim any originality for what follows. My interest is just to emphasise a few particular aspects that will be relevant for what we will see later on.

We shall begin with the very concept of life itself. What is a living thing? A living thing is a structure that replicates itself, that is, that is capable of producing copies of itself. Nowadays we know of only one substance that is capable of doing this, it is a molecular chain called DNA. All living organisms contain DNA. Now this DNA is, in turn, made of what we call nucleotides. There are four of these nucleotides: adenine, cytosine, guanine and thymine. In a DNA molecule what we have is a long strip made of a sequence of these nucleotides arranged in a particular order:

ACGTGGTAAGCTAACTGGA, etc.

So this is the substance of life, what life is made of. These DNA strips are the structures that reproduce themselves. What is the purpose of these DNA strips? Why do they have to be ordered in particular sequences? Because, together with other chemical processes that do not concern us now, these particular sequences of DNA allow for the synthesis of another chemical, another substance that constitutes the bricks, as it were, with which the body of any living organism can be built. These are the proteins. The body of any living thing, ourselves included, is made out of proteins – plus other components such as fats, water, etc. Important differences between one organism and another originate in the type of proteins of which organisms are made. That is why DNA, ordered in specific sequences, is so important for life. DNA is like the alphabet and proteins are the words that can be made with the letters of this alphabet: the letters are always the same, but the words are different, hence the bodies of those living organisms are also different.

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FIGURE 1.1 The tree of life

Now, what makes life such a unique phenomenon it is not so much the substance it is made of (DNA and proteins) but the power of this substance, the power to produce copies of itself. Remember that a living thing is just a structure that can produce copies of itself. How does this process of reproduction take place? In two different ways. The most simple and earliest way of reproducing a living organism is by cloning, which consists merely of that organism producing a copy of itself, which we call a clone. But approximately 1,000–1,200 million years ago a new form of reproduction came into existence among the euk...

Table of contents

• Cover
• Title Page
• Copyright Page
• Contents
• List of figures
• Acknowledgements
• Introduction
• 1. Being human
• 2. A new form of knowledge
• 3. Theories of difference
• 4. Cultural evolution
• 5. Summary and conclusions
• Index