What is a myth, and what are the myths of human evolution? I started giving these questions some thought several years ago when I was approached by the publisher to submit a proposal for a book to be called “50 Great Myths of Human Evolution.” They had already published a book on misconceptions in psychology entitled 50 Great Myths of Popular Psychology and were interested in publishing more books along the same line, focusing on the “50 great myths” of various fields, including human evolution. I was intrigued by the suggestion, as I had been contemplating a general book on human origins and evolution for a while. However, I was a little apprehensive about how to approach the idea of “myths” in human evolution. Like many words, the term “myth” has both narrow and broad meanings. My apprehension stemmed from a narrow interpretation of myth.

A narrow meaning of myth refers to the stories about Greek and Roman gods that I studied in a college mythology class. According to the online version of the Oxford English Dictionary (www.oed.com), a definition that would fit here is “A traditional story, typically involving supernatural beings or forces, which embodies and provides an explanation, etiology, or justification for something such as the early history of a society, a religious belief or ritual, or a natural phenomenon.” This definition does not fit with what I wanted to do with this book as I wanted to go beyond the idea of simply examining stories about human origins, but instead wanted to look at different ideas and misconceptions regarding human evolution and, in particular, illustrate how scientific research often leads us to reject old ideas and consider new ones.

In this book, I use a broader definition of “myth” that is closer to the second definition given in the Oxford English Dictionary: “A widespread but untrue or erroneous story or belief; a widely held misconception; a misrepresentation of the truth.” The myths in this book examine a number of ideas concerning human origins and evolution that fit this broader definition focusing on misconceptions—hence the subtitle of this book.

There are different types of misconceptions that exist when discussing human evolution. Some of these misconceptions are simply not true, but persist over time, such as the popular notion that much of our species’ evolution was influenced by extraterrestrials (Myth 40). Some misconceptions arise from inaccuracies, incomplete data, and/or faulty assumptions, but somehow continue to perpetuate over time. An example from human evolution is the notion that the initial development of agriculture resulted in improved health (Myth 39), an idea possibly resulting from the faulty assumption that technological change in our species’ evolution always results in progress across the board. Another common misconception is the idea that we no longer evolve (Myth 48), a conclusion reached only if we assume that our rapid cultural change completely negates biological change.

Many of the myths deal with topics that are not misconceptions at present, but refer instead to ideas that had once been considered accurate, but were later overturned because of new evidence and insights. Examples here include the idea that our early ancestor Australopithecus was a “killer ape” (Myth 17) and the notion that Neandertals walked bent over (Myth 29). Other myths look at ideas that have been questioned in recent times, but still remain on the table as possible hypotheses, such as the existence of only one species of the genus Homo two million years ago (Myth 21). These ideas are not “myths” in the classic narrow sense, but instead reflect shifts in consensus. Keep in mind that such shifts could in the future change further as new data become available. Ideas change as hypotheses are tested, and so might our conclusions on various myths and misconceptions. Today’s “myth” might be tomorrow’s consensus. It all depends on the evidence and the application of the scientific method.

The dynamic nature of science

Science means different things to people. Sometimes we narrowly equate “science” and “technology” such that recent developments in science often consist of lists of new inventions, drugs, and other important discoveries. This is unfortunate because this narrow definition leaves out many interesting scientific discoveries (particularly those in human evolution) that have no direct or immediate practical benefit, but do inform us about the world and universe that we live in. It is also an unfortunate correspondence because, although science informs technology, that is not its only function or its essential nature.

At its core, science is a way of knowing, specifically a way of knowing about the natural world (including human behavior, as dealt with by the social and behavioral sciences). Although we sometimes think of science in terms of its direct benefits or the total accumulation of knowledge, it is most importantly a process that enables us to learn more about the physical world. Aspects of the scientific method will be described in a later myth, but, for the moment, we can break it down into a process of making observations, developing possible explanations for what we see (hypotheses), and testing them in some manner. Scientific evidence changes over time because this is a dynamic process as we ultimately discard hypotheses that have been rejected. In the general sense, a hypothesis is simply a proposed explanation. Some hypotheses can be supernatural (literally, “above nature”) and invoke forces that we cannot directly perceive. To be a scientific hypothesis, we have to propose an explanation that is rooted in natural processes and is subject to testing.

A key feature of the scientific method is openness to being shown wrong. This does not mean that we like to have our hypotheses rejected (we don’t) or that we don’t resist new ideas and interpretations (we do). It means that ultimately we are open to sufficient evidence showing us that we were wrong, and that there might be a better way to look at things (although we might disagree with what is considered sufficient). In the jargon of the scientific method, we do not prove hypotheses so much as we fail to reject them (sort of like assuming someone is innocent until proven guilty). When a hypothesis is rejected in science, we throw it out and move on, coming up with a new explanation or modifying an old one. This is not always easy to do, as we are all subject to biases and feelings about pet hypotheses, but ultimately we reject or modify rejected hypotheses (or, if we do not, someone else will!).

This is a radical way of thinking about the world. Many times, we use a very different process of making decisions—we start with a conclusion and then pick data to support our established point of view. In an ideal sense, science works in an opposite manner, collecting all available evidence to test a hypothesis rather than assuming it is correct or incorrect beforehand. Of course, we are all human and are thus likely to be swayed by irrelevant information, wishful thinking, and preexisting biases. However, as a process that is practiced by the scientific community, we can work through those sources of bias and error. We have to be willing to be wrong and say we are wrong. This is a difficult stance to make, because we often prize people for being resolute and standing for their convictions—admirable qualities but more appropriate to moral and ethical decisions than for scientific analyses. Imagine, for example, someone were running for elected office and made a statement about subject “X” that “I think that X is correct, but I remain open to the possibility that I am wrong.” I am willing to bet money that this person would not be elected, as we often have little patience for people being on the fence or capable of “flip flops.” In science, however, you have to be open to new evidence and ways of explaining them, provided there is sufficient evidence. As new evidence accumulates, ideas are repeatedly tested and often changed or thrown out. Some of yesterday’s conclusions are now today’s myths. This also means that some of today’s conclusions might be tomorrow’s myths!

In this context, I am always concerned at some of the reaction given to new scientific discoveries that appear to reverse previous ideas and conclusions, be they in human evolution, medicine, astronomy, or some other scientific field. Some people note these changes in a negative light, pointing out previous “errors” in judgment and analysis, and are left wondering why anyone would pay scientists that get things wrong. Well, the truth of the matter is that this is the way science is supposed to work. Our knowledge progresses by making hypotheses and testing them, and then throwing them out when they no longer fit the evidence.

It is in this spirit that I discuss the “myths” of human evolution. To be sure, many of these are completely settled (in my view), but others can change depending on new data and analysis. I try to be clear throughout about my views on current consensus as well as some additional possibilities. A warning, however, is that given the dynamic nature of science, it is quite likely that new evidence will shed further light on many of the topics covered in this book and will become out of date between the time I write these words and you read them. That is what is supposed to happen.

Structure of the book

I have picked 50 “myths” about human evolution that I find useful, particularly in teaching about human origins and evolution. (There are many more that could be discussed, but I accepted the number “50” to be part of the publisher’s “50 Great Myths” series of books.) Each myth is designed to address a broader issue of science and of paleoanthropology (the study of human origins and evolution). I have broken the book into four sections. The first part examines some general myths and misconceptions about the nature of how evolution works. The second part focuses on human origins, examining the fossil record for the time between the initial divergence of African ape and human ancestors and the beginning of the genus Homo, including the evolution of bipedalism (upright walking). The third part continues looking at the fossil record in terms of the genus Homo, those species (including us) with larger brains, smaller faces, and reliance on a stone tool technology. The fourth and final part of the book examines recent (the last 12,000 years), current, and future human evolution, including the history of different human populations. Because evolution is a cumulative process, it is best understood in a linear manner from start to finish. Although I have tried where possible to make some myths independent, everything flows much easier if you read these myths in sequence.

If the idea of reading 50 essays seems daunting, remember that each myth is very short! The purpose of each essay is to use a myth or misconception to introduce a general topic in human evolution and provide some preliminary background and explanation. Each myth starts with a short “status” statement of several sentences that summarizes the thrust of the myth, also indicating if the topic has been settled or if there is still discussion on it. Because each myth is designed to be short, do not expect these to be complete reviews. The topic of every single myth can (and has) filled books. The myths here are designed to be short introductions only.

Although short essays have their purpose, you might find that you want more detail on the overall topic or on some of the specifics, or to read someone else’s take on the issue. I have provided references to the facts and ideas discussed in each myth in a series of endnotes that are listed at the end of each section. A complete list of references is provided at the end of the book. Many of these references are to papers in academic journals that might not be available in many public libraries, but should be available at many colleges and universities. Some are also available for free on the Internet.

In general, I urge people interested in more detail on any of these subjects (or scientific subjects in general) to focus primarily on peer‐reviewed journal papers and books. The peer‐review process means that others in the field have examined the papers in terms of the soundness of the data, analyses, and arguments made. Peer review is a form of quality control and a researcher has to convince his or her peers that they have made the case for a particular conclusion. This is critical in modern times where anything and everything can be distributed on the Internet, often without any review. This does not make things on the Internet necessarily incorrect, but you have no guarantee of accuracy either. Peer review helps, as does looking at web pages that are connected to well‐established scientific journals, magazines, and organizations (unless, of course, you subscribe to the notion that the scientific community consists of individuals involved in conspiracies, in which case I am not sure you will enjoy this book!).