Elements of Dynamic Network Analysis: 3. Connecting the dots

John Terrell

Categorical thinking, which I wrote about in the first two posts in this series, may at times be too pat for our own good, but this pragmatic (although potentially knee-jerk) way of dealing with things, people, and events is rarely based solely on nonsense.

Old-fashioned library card catalog [https://www.flickr.com/photos/mamsy/ [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons]
Why not? Because the world is not an entirely unpredictable place. What happens to us, good or bad, is seldom purely random or plain crazy.  Life actually does have patterns that can be real enough, although they can also be far from  clear-cut and hard to see. Even so, patterns can be categorized. Not always successfully (just ask any weather forecaster), but that doesn’t mean we shouldn’t try to do so.

But this is enough about categorical thinking for now. I want to move on and write instead about what I have previously referred to as relational thinking.

Relational thinking

The National Council of Teachers of Mathematics defines this way of thinking as the “mindful application of place value and the properties of number, operations, and equality in solving mathematics problems.” If this confuses you as much as it does me, note this organization adds: “A student with a disposition toward relational thinking has a habit of thinking before acting.”

This seems like an uncommonly low bar. Certainly not the definition I have in mind. Nature‘s online magazine Science of Learning offers an alternative: “At the core of all human learning and  performance  . . .  is the foundational ability to perceive patterns that thread through all of nature, including human nature.”

This isn’t quite it, either. In fact, to me this sounds more like a definition of categorical thinking. So let me give you my own take on what pairing these two words together means:

Categorical thinking assumes that things exist apart from one another, and may then become connected with one another.  

Relational thinking assumes instead that things exist because they are connected.

If my definition sounds too mystical to you, let me offer you several examples of what I mean.

One-sided relationships

It seems likely that no relationship is solely one-sided if looked at closely enough. While granting this likelihood, there is no doubt that relationships can be so out of balance that it is not just a technicality that one side is more influential than the other. Critically, the character and perhaps the very existence of one side in such an imbalanced relationship may depend, maybe entirely, on the relationship it has with the other side.

A classic example of such a one-sided connection is the relationship between the Sun in our solar system and all the other planets (and then some) revolving around it, including Planet Earth.

Even without venturing into the exotic realm of modern cosmological theories about quantum gravity, it is obvious enough nowadays except perhaps to those who believe the Earth truly is flat that if it were not for the gravitational relationship between the planets and our Sun, the Earth would not exist at all and neither would we. Our reliance on the Sun is that one-sided and decisive. There would also be no life at all on our planet without the Sun serving as life’s ultimate source of energy, however otherworldly such a statement may sound.

Technical note: In formal network analysis, a relationship between two things (the two nodes or vertices in the relationship) is said to be dyadic (two-sided). When both are taken together, they are called a dyad. Furthermore, such two-party connections can be either undirected (more or less balanced or symmetrical from the point of view of each), or they can be directed (each party has a different take on the relationship). From this perspective, the relationship between the Earth and the Sun is a directed dyadic relationship, and it is a relationship that is decidedly one-sided.

Photo via Good Free Photos
Two-sided relationshps

It has been said that human beings have an innate sense of fairness and an ingrained willingness to do something for others when they are reasonably confident that a favor, whatever it is, will be returned, if not in kind, at least in some other way having equal value.

This judgment of our willingness to engage with others in two-sided relationships is far too cynical. Available evidence suggests instead that most of us are basically predisposed to be kind, collaborative, and helpful to others. That’s how we have evolved as a social species.

Moreover, humans as a rule are not only ready, willing, and able to forge and maintain relationships with others. We are also remarkably skilled at coming up with playful excuses to do so.

Although jogging, bicycling, and other forms of exercise, for instance, can be done easily enough as solitary tasks, people often find ways of turning even such seemingly self-centered healthy activities into broadly social occasions.

Although a more sedentary activity than a physically healthful one, this observation holds true also for online computer gaming, which is now a major leisure-time social activity for millions around the globe.

Technical note: A racket sport such as tennis is an example of an undirected dyadic relationship (accepting, of course, that only one of the players can win). Yet tennis is also a spectator sport, and as such, creates a directed dyadic relationship between sports fans and players.

Many-sided relationships

It is obvious enough that spectator sports such as tennis or baseball involve more than just simple dyadic relationships between players and spectators. The social complexity of team sports is even more apparent for sports such as soccer and football that call for the coordination of players both within and between the two opposing teams on the field.

A friend in need, 1903 [Public domain, via Wikimedia Commons].

Side note: There seem to be few team sports that call for more than two teams on the playing field at the same time—maybe they should be called “dyadic sports”—although a few examples do come to mind if you are willing to bend the definition of what is a sport: many kinds of card games, many types of board games, some varieties of billiards, some forms of bicycle racing, etc. 

But the many-sided complexity of most human relationships isn’t just obvious while watching  players interact with one another on a playing field. The general complexity of human relationships is more than apparent also among the fans watching the game being played right there before their eyes. Indeed, in the case of some sports, it could  be argued that “most of the action” is actually in the bleachers, not down on field. (You may be able to tell I don’t like baseball, and I am not too fond of football, either.)

Tim Beckham, catcher John Hicks, umpire Roberto Ortiz in a 2017 game [Keith Allison from Hanover, MD, USA (Tim Beckham) [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons
How can we tackle the complexity of human relationships?

Classic definitions of social network analysis as a way of coming to grips with the complexity of human social relationships commonly read like this one from John Scott’s highly successful book Social Network Analysis: A Handbook: “social network analysis is an orientation towards the social world that inheres in a particular set of methods. It is not a specific body of formal or substantive theory” (page 37, 2nd ed., Sage Publications, 2000).

I find such a view naive, however well-intentioned. It is quite impossible to isolate methods from theories and then claim to be doing good science. This is an observation I will explore further in the next posting in this series.

This is Part 3 of a continuing series of posts on dynamic network analysis. Next up: 4. Exploring the 5th dimension.


© 2018 John Edward Terrell. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

Elements of Dynamic Network Analysis: 2. Relativity

John Terrell

In the inaugural posting in this series, I made note of the fact that history shows us time and again that as a species we have decided strengths and obvious weaknesses.

Why it’s good to be human

On the plus side, our kind of animal is outstanding at reshaping and rebuilding the world around us to make the challenges we face as individuals and as a species as humdrum, predictable, and hence as manageable as possible.

Poets, playwrights, philosophers, and scientists may debate the particulars of human motives and intentions, but there is no denying one of the reasons we spend so much time and effort at redoing the conditions under which we live out our days on earth. The more predictable a situation or event is, the easier it is for our brain to cope with it. And if need be, respond more or less appropriately.

Spice Bazaar, Istanbul [personal photograph]
I also argued in the previous post that to avoid becoming overwhelmed by what our body’s senses—classically said to be five in number—are telling us about the state of things and events both inside and outside our skin, our brain ignores much of what it is being told. Instead it mostly relies on the pragmatic strategy of simplifying what it is hearing, both literally and figuratively, by mentally putting things, people, and experiences into separate and seemingly distinct mind boxes—into different categories.

However, there is a fine line between paying too much attention to what our senses are telling us, and too little. (I like to call this the Goldilocks Line after the 19th century children’s story). Failing to pay sufficient attention to what’s happening inside or outside our body can be disastrous, as anyone who has survived the experience can tell us about why they shouldn’t have been texting while driving.

Why it’s bad to be human

As my mother so often liked to say, things can be both good and bad at the same time. However pragmatic and unintentionally self-centered we are as individuals for understandable evolutionary and psychological reasons, the dark side of our human ways cannot be denied.

I wasn’t being cynical in the previous post, therefore, when I remarked that truth may not be as appealing and important—that is, as useful—to us as human beings as the immediate and pragmatic benefits of things and events (and people, too) that are easy, convenient, and predictable.

However, taking the easy way out, the easy answer, the easy job, and so forth can be costly down the road—sometimes sooner rather than later. Doing so can make it difficult for us to notice and pay enough attention to how things, people, and experiences are linked, intertwined, and interrelated. Said more formally, what I called previously “categorical thinking” can lead to “categorical mistakes.”

The power of words

According to more than just a few of us, life’s big question is Why am I here? Others instead see How come I am here? as the mystery to be solved. Conventionally, people turn to theologians, philosophers, psychologists, and their best friends when they are seeking answers to the first question. The second one falls more in the thoughtful arena of pediatricians, scientists, cosmologists, mystics, and priests.

This division of labor, however, is not absolute, and is certainly not as categorical as such a divide implies.  One common thread crossing between these two realms of expertise is the belief or assumption—sometimes up front, sometimes only lurking in the background—that words are both powerful and are usually grounded in reality except, of course, when someone is “making things up” that they know are untrue.

The belief that words can be both truthful and powerful—that by naming things we are not just “putting into words” something already “out there” in the world, but can create something new as if “out of nothing”—is deeply rooted in the antiquity of our species. A classic example would be invoking the word abracadabra during a magic show to lend apparent substance to some clever illusion. But the roots of seeing words as powerfully creative run deeper than this trivial example.

The Almighty. Genesis cap 1 v 16. De Vos [By Phillip Medhurst [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], from Wikimedia Commons]
For instance, consider the opening words of the Book of Genesis in the Hebrew Bible and Old Testament:

IN THE BEGINNING God created the heaven and the earth.
2  And the earth was without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved upon the face of the waters.
3  And God said, Let there be light: and there was light.
4  And God saw the light, that it was good: and God divided the light from the darkness.
5  And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day.
Relational thinking

In my first post I said that I am writing this series about dynamic network analysis because I want to explore with you how a different way of thinking about the world and our place in it can make it easier for us to see and make something out of how widely and how often critically things, people, and events are not separate and distinct in neat categorical ways, but instead are interwoven into relationships that make the whole totality of them, as the saying goes, bigger than the sum of the parts. Since what I want to write about, however, is complicated, I need to proceed step by step.

The next step in this second post is a brief quiz I’d like you to take before we move on to take a closer look in Post #3 at what is called network analysis.

Quiz: How good are you at thinking outside the category?

Please take a piece of printer paper and draw a line down the middle from top to bottom. Near the top of the left-hand column, write the word categorical. Do the same for the right column, except make the word relational. Then write in items under these two headings matching those shown here. Note that the last two rows are blank. In a moment I will be asking what you would add in these two bottom rows resonating with the rows above them.

Here’s the question I want to ask: What makes the items in the right-hand column different from those in the left-hand column? Yes, it is OK to use Google if some of the items seem obscure. And yes, this is a categorical question for sure.

The answers I am looking for

There are many ways to talk about the items in the left-hand column.  #1-2 are often viewed nowadays as wasteful single-use items that pollute the environment; #3 is a famous writer who rejected the virtues of altruism, praised individual rights, and is seen by many as a prophet of selfishness; #4 is an organization dedicated to protecting the rights of individual gun owners; #5 is the day each year when a given individual was born; #6 refers to the belief that all things can be boiled down to singular, individual particles called atoms.

In contrast, paper bags and paper straws are being promoted today as more environmentally friendly than their counterparts in the left column. #3 could be described as the high priest of the relativity rather than the individuality of things in the universe. Without trying to pin them down, the remaining three items are similarly all about things, events, and species that are enmeshed with one another.

Now here’s your job. What would you write in the blank rows at the end of this table? For instance, I myself would be tempted to write in one of these rows the card game solitaire vs. the team sport of boat racing.

By National Library of Ireland on The Commons (Waterford Boat Club) [No restrictions], via Wikimedia Commons [https://commons.wikimedia.org/wiki/File:Waterford_Boat_Club_(8401799848).jpg]
What’s the point I am trying to make?

In the first post in this series, I observed that for entirely understandable reasons each of us is by nature self-centered. Saying this, however, does not have to mean we are also inherently selfish despite the fact that jumping to such a conclusion is unfortunately fairly commonplace even in scholarly circles.  

As we will be exploring in this series, Ayn Rand and others both before and since have been misguided to believe otherwise. The continuing popularity of Rand’s ideas only shows that words can be powerful at least in the limited yet dangerous sense that they can be used to persuade us about what’s real and what’s unreal in the world of yesterday, today, and tomorrow without actual proof.

This is precisely why we need ways of getting outside our heads and dealing directly with the world that force us to “think outside the category.” Why? Because we need ways to confront our hasty impressions, deep-seated desires, wishes, and wants so that we can avoid errors in judgment, however innocent, that tragically can result in the desecration of the world we live in—and if we are not careful, our own extinction as a species.   

This is Part 2 of a continuing series of posts on dynamic network analysis. Next up: 3. Connecting the dots.


© 2018 John Edward Terrell. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

Elements of Dynamic Network Analysis: 1. human nature

JOhn Terrell

Human beings are by nature highly social animals. Despite claims both popular and scientific, we also are not inherently selfish creatures. Yet we often seem self-centered. Why? Short answer: because we are looking out at the world from inside our skulls.

As my mother used to say, this is both good and bad. Let me explain briefly by offering you a few elementary observations about being human.

Your pragmatic brain

A fully functioning human brain is a remarkable compromise. Your senses are constantly feeding you input—lots of it—about what’s happening in the world around you, and also about what’s going on inside your body. If your brain were to pay close attention to all the details it is receiving about the state of things within and beyond you, it would rapidly become overloaded. That, of course, would make it useless to you as an organ dedicated to helping you in an admittedly self-serving fashion navigate your way more or less successfully from the cradle to the grave.

It is perfectly understandable, therefore, why your brain perpetually walks a fine line between paying too much attention to what it is being told by its senses, and too little.

Figure 1. “I swear they came out the box this way | by frankieleon” [https://www.flickr.com/photos/armydre2008/3576170595]
One way the brain accomplishes this delicate balancing act is to put things, people, or events striking it as more or less like one another into the same mind box—that is, into the same mental category. By this I mean what a dictionary says this word means:  “a class or division of people or things regarded as having particular shared characteristics.”

well-known rule of thumb illustrates the point I am trying to make: if it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck. A more colorful example is shown in Fig. 1.

But here’s the rub. What if your brain draws the line between too much and too little in the wrong place? What if it doesn’t pay enough attention to what it is being told by your senses about the animal your brain has concluded must be a duck? More to the point, what if making such a categorical mistake leads to serious consequences? Say, mistaking a friend coming into a darkened room for an intruder. And impulsively you shoot your friend dead?

Clearly having a pragmatic brain lodged inside that bony vault up there on your shoulders can be both good and bad, just as my mother would observe.

A world of our own making

Here’s another observation about how humans deal with the world. If novelty is the spice of life, then from your brain’s pragmatic point of view, predictability is life’s bread & butter.

Put simply, the more predictable a situation or event is, the easier it is for your brain to categorize it. And then, if need be, respond appropriately (or not).

Figure 2. By Crusier [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], from Wikimedia Commons
It is again understandable, therefore, why as a species we humans invest so much of our time and effort (and money) into dumbing down the world around us to make the challenges we face as humdrum, predictable, and therefore categorical as possible.

By “dumbing down” I mean our species is remarkably skilled at remaking the world we live in to be less risky and uncertain than it otherwise would be for us. Said another way, we love to make what’s out there in the world fit into simple, convenient, widely applicable mind boxes, i.e., categories.

Humans are not the only creatures on earth who are predisposed to make the things and events they have to deal with as humdrum as they can make them. Many of the earth’s countless species are similarly committed in their own more limited ways—biochemical, physical, or behavioral—to enhancing their surroundings and creating favorable opportunities for themselves (we are not the only self-centered creatures on earth) by making things more suitable, more accommodating, more predictable. And for them, as well, more categorical.

This last remark is important, as I will be explaining in a later posting in this series. The brain's mind boxes called "categories" may or may not have actual words associated with them that we can use to talk about them. This is often why we may find it hard to put our ideas into words. But with this remark I am getting ahead of what I want to say in this first post. 

Figure 3. Termite mound, Litchfield National Park, Northern Territory, Australia [By brewbooks from near Seattle, USA (Cathedral Termite Mound) [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons]
Classic examples of what other species do to dumb down the world for themselves would be beavers constructing dams to create ponds that help protect them against predators; termites building earthen mounds in Africa, South America, and Australia to live in; birds building nests; and earthworms improving the quality of the soil they move through by eating it and passing it through their bodies, over and over again, generation after generation, thereby making life easier and more fulfilling for the earthworms that take their place in the great circle of life.

Clearly, therefore, we are not alone as a species in being both able and crafty enough to improve our lives and living circumstances by making the world a safer and more predictable place to live in.

Even so, we humans are certifiably the Earth’s champions at the fine and skillful art of redoing the world to suit our needs as well as our fancies, however odd the latter may be (let’s all admit, shall we, that the artificial islands of the exotic tourist resort shown in Fig. 4 are an extreme example of our willingness to redesign the world to suit our fancies and our credit cards).

Figure 4. Palm Island Resort, Dubai, United Arab Emirates [https://commons.wikimedia.org/wiki/File:Dubai_-_The_Palm_Jumeirah_-_panoramio.jpg]
Confronting our pragmatic and often self-centered ways

We have reason, therefore, to be proud of the fact that our species excels all others at creatively dumbing down the world we live in to make the challenges we face humdrum and predictable. But there are genuine risks involved. Why so? Because we are not truly god-like in our powers. We are not all-seeing and wise. We are not always as good as we may think we are at drawing the line between knowing too much about the world and knowing too little.

And furthermore let’s be honest. Despite rhetoric to the contrary, truth (spelled with or without a capital “T”) may not actually be as appealing and important—that is, as useful—to us during our journey from the nursery to the grave as the pragmatic benefits and virtues of things and events (and people, too) that are easy, convenient, and predictable.

Here then is what this series of posts at SCIENCE DIALOGUES will be about:

  • Millions of years of evolution have done a skillful job of making us clever, inventive, and remarkably successful beings.
  • As history shows us again and again, however, our reliance as a species on the pragmatic (and generally self-serving) strategy of mentally putting things, people, and experiences into separate and seemingly distinct mind boxes—into different categories—often makes it hard for us to notice and pay sufficient attention instead to how things, people, and experiences are almost always linked and interrelated rather than separate and distinct. 
  • In this series, I will be calling the first brain strategy categorical thinking, and the second one relational thinking.
  • My goal in writing these posts will be to survey for you how the second way of thinking about the world and our place in it makes it easier for us to see and understand how widely and often critically things, people, and events impact one another—sometimes in unexpected and even disastrous ways (for example, see: Fig. 5).

Moral of the story so far: while understandable from an evolutionary and psychological point of view, being self-centered creatures is a handicap we humans need ways to confront and overcome.

Dynamic network analysis is one such way. I hope to convince you it is a good one, too.

Figure 5. The beach at Kanapou Bay collects debris from throughout the Pacific Ocean. [https://www.flickr.com/photos/noaaphotolib/19778606375]
This is Part 1 of a continuing series of posts on dynamic network analysis. Next up: 2. Relativity.
© 2018 John Edward Terrell. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

Prehistory and Plug & Play Genetics

June 2, 2018

As noted earlier this week at SCIENCE DIALOGUES, the popular science monthly Scientific American has now published a lengthy and decidedly critical commentary on current practice in the new field of paleogenetics .

At present it looks like the hype promoting paleogenetics research far exceeds the actual performance.

But who knows what the future will bring once human geneticists realize that there are no simple ways to connect the dots between human genes and the realities of human history.



Elements of Dynamic Network Analysis: a new series

John Terrell

During the second half of 2018 SCIENCE DIALOGUES will be featuring a series of reports on the steps that have been taken at the Field Museum in Chicago since the early 1970s to develop dynamic 4-dimensional (space-time) approaches to networks analysis in the social and historical sciences. 

The goal of these reports is to prepare the way for writing a book about how networks analysis is currently revolutionizing scientific (and hopefully human) thought about the world we live in and our place in it.

The first posting in this new series on human nature is available here along with a link to the second post  now online at SCIENCE DIALOGUES.


Cover art (a fantasy) for the proposed book on networks thinking.

History and Human Genetics: challenges of collaboration

 Writing history is a lot harder than some may realize

John Terrell

UK’s leading archaeology magazine Current Archaeology has taken a  sympathetic look at the often strained relationship between archaeology and human molecular genetics today.

It should come as no surprise to anyone who knows firsthand the challenges of writing history that this brief assessment highlights the concerns some archaeologists have voiced that “aDNA is unable to account for the complexity and subtleties of human behavior.”

This brief published commentary ends on a hopeful note. In the years ahead, collaborations between archaeologists and experts working in other sciences will “becoming stronger and more balanced.”

 “So what? Why should I care?”

This same week in May 2018, Scientific American published my own assessment of  the strengths and weaknesses of paleogenetics today focusing on what is being written about Pacific prehistory by David Reich and others. Reich is the author of an enthusiastic overview of aDNA research around the world published this year by Pantheon.

John Terrell on Teop Island, North Solomons, 1969

Here is what I say at the end of this analysis (somewhat shortened in length):

There are two thoughts I want to leave you with.

My first thought is about scientific responsibility. Pacific Islanders have been dealing with foreigners telling them what to do and how to do it ever since Europeans began sailing around the Pacific in the 16th century. Are we now committed to telling them also what was their history? Why would we want to do this? The days of European colonialism are over, aren’t they? Or are they?

The second thought is this one. Call them “populations” or call them “races,” it makes no difference. As modern molecular genetics has now shown us in remarkable detail, we are all 99.9 percent the same. It may be conventional wisdom to think we humans come in different kinds called races, populations and the like. A statistic like this one, however, ought to be enough to convince anyone willing to listen that we don’t come in kinds whatever you want to call them.

Hence the apparent willingness of more than a few geneticists today to use words like populations, migrations and admixture when they are writing about ancient DNA and the past does more than just misinform the rest of us. As reviews of Reich’s book, both pro and con, have sometimes scoldingly observed, when scientists talk this way, they can sound like they are doing racial profiling. Apparently, it can be hard for some folks to see that what my grandfather called hogwash may not just be something unbelievable. Hogwash can also be words and stories that are socially, politically and, yes, historically misleading. Maybe even dangerous.

6,000-year-old skull could be from the world’s earliest known tsunami victim

Tsunamis spell calamity. These giant waves, caused by earthquakes, volcanic eruptions, and underwater landslides, are some of the deadliest natural disasters known; the 2004 tsunami in the Indian Ocean killed over 230,000 people, a higher death toll than any fire or hurricane. Scientists studying the effects of tsunamis have now shed light on what could be the earliest record of a person killed in a tsunami: an individual who lived 6,000 years ago in what is now Papua New Guinea in the southwest Pacific. This person’s skull was found in geological sediments having the distinctive hallmarks of ancient tsunami activity. This means, scientists posit in a new paper in PLOS One, that this skull could be from the earliest known tsunami victim.

Researchers explaining their project to people hunting for wild pig in Papua New Guinea near the location west of Aitape where the human skull had been discovered. Photo credit: Dr. Ethan Cochrane.

“If we are right about how this person died thousands of years ago, we have dramatic proof that living by the sea isn’t always a life of golden sunsets and great surfing conditions,” says John Terrell, Regenstein Curator of Pacific Anthropology at The Field Museum and one of the study’s authors. “Maybe this individual can help us as scientists to convince sceptics today that all of us on earth must take climate change and rising sea levels seriously as the threats they truly are.”

The skull in question was found deeply buried in the ground in 1929 near the small town of Aitape on the northern Sepik coast of Papua New Guinea about 500 miles north of Australia. Terrell has been doing archaeological and anthropological research in this coastal region of New Guinea, the second largest island in the world, since 1990. As a member of the international team of scientists behind this newly published study, he has long wondered what to make of this tantalizing human find.

“The skull has always been of great archaeological interest because it is one of the few early skeletal remains from the area,” says Mark Golitko of the University of Notre Dame and The Field Museum. “It was originally thought that the skull belonged to Homo erectus until the deposits were more reliably radiocarbon dated to about 5,000 to 6,000 years old. Back then, sea levels were higher and the area would have been just behind the shoreline.”

In 2014 Golitko and others went back to the exact place where this skull had been found to look for new clues about what killed this individual. “We have now been able to confirm what we have long suspected,” says James Goff at the University of New South Wales in Australia, the report’s first author. “The geological similarities between the sediments at the place where the skull was found and sediments laid down during the 1998 tsunami that hit this same coastline have made us realise that human populations in this area have been affected by these massive inundations for thousands of years.”

“Given the evidence we have in hand, we are more convinced than before that this person was either violently killed by a tsunami, or had his or her grave ripped open by one—leading to the head but not the rest of the body being naturally reburied where it then remained undiscovered in the ground for some 6,000 or so years,” explains Professor Goff.

“It is easy to be fooled by the great beauty of the Sepik coast of Papua New Guinea into thinking that surely this part of the world must be as close to paradise-on-earth as anybody could want. This skull is witness to the fact that here as elsewhere natural disasters can suddenly and unexpectedly turn the world upside down,” says Terrell.

This study was contributed to by scientists from the University of New South Wales, l’Université de Bourgogne-Franche-Comté, the University of Notre Dame, the University of Auckland, New Zealand’s National Institute of Water and Atmospheric Research, the University of Papua New Guinea, the Papua New Guinea National Museum and Art Gallery, and The Field Museum.


© 2017 John Edward Terrell. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

Moving past “Systematics Wars”

Beckett Sterner, Arizona State University, and Scott Lidgard, Field Museum of Natural History, have written a new interpretation of a critical period in evolutionary biology leading to how scientists classify organisms: the “Systematics Wars” of the late 1960’s through the 1980’s.

Beckett Sterner (left) and Scott Lidgard (right)

This was a time when prominent biological systematists fought bitterly along partisan lines. They critique philosopher David Hull’s historical account in Science as a Process, which began what later became the common view that one camp, cladistics, straightforwardly “won” over another camp, phenetics.

Hull prioritized theory over practice and the conflicts of a few leading theorists over the less polarized interactions of systematists at large. He treated cultural evolution and biological evolution as forms of the same general process; cladistics and phenetics as holistically opposed theories can only interact by competition to the death.

Sterner and Lidgard instead analyze what systematists actually did in this period, the workflow that they followed, the methods they used, and the common problems that arose and were solved to the benefit of both camps.

They hope this opens a new window of different perspectives on how we classify organisms—the mathematization of systematics.


© 2017 John Edward Terrell. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

Racism, science, and common sense

John Edward Terrell

Five ways to stop sounding like a racist if you aren’t one.

If you think racism isprejudice, discrimination, or antagonism directed against someone of a different race based on the belief that one’s own race is superior,” science has something surprising to tell you.

WHAT A DIFFERENCE A DECADE CAN MAKE. Back in 2006, Angela Davis remarked during a keynote address at the University of Wyoming honoring Martin Luther King Jr.’s birthday: “We have been basically persuaded that we should not talk about racism.”  Following the acquittal of George Zimmerman in the shooting death of African-American teen Trayvon Martin in 2013, the activist movement Black Lives Matter was born. Since then the issue of racism has been front and center in American politics. What remains elusive, however, is why racism however motivated finds such fertile ground in the human psyche.

The Earth is flat

Kyrie Irving, who plays basketball brilliantly for the Cleveland Cavaliers, made headlines in February 2017 for declaring boldly that the Earth is flat. He was perhaps pulling our collective leg.  His stated rationale, however, has more than a little bit of good old common sense to back it up:

“For what I’ve known for as many years and what I’ve come to believe, what I’ve been taught, is that the Earth is round,” he continued. “But if you really think about it from a landscape of the way we travel, the way we move, and the fact that—can you really think of us rotating around the sun and all planets aligned, rotating in specific dates, being perpendicular with what’s going on with these planets?”

Crazy thinking?  Maybe, but then what about this? A poll published two years ago by the U.S. National Science Foundation found that 26% of Americans don’t know that despite appearances to the contrary, the Sun does not go around the Earth.   Perhaps more astonishing, when asked, 52% of Americans evidently don’t agree with the statement that humans evolved from earlier animal species.

You don’t have to be Bill Nye or Neil deGrasse Tyson to see that all these instances of scientific ignorance make perfect sense from a common sense point of view despite being wrong. Furthermore, it wasn’t all that long ago most people on Earth in point of fact were misinformed in precisely these ways: yes, of course, the Earth is flat; yes, it is obvious that the Sun goes around the Earth; and haven’t you heard? Humans were created in their present form by a special act of Divine Will.

. . . and races are real

There are no polls I know of to back up the claim. Even so, it seems likely many people today—maybe even most—would also say they can’t possibly be at all racist because, don’t you know?, they don’t look down upon people in other races (see the dictionary definition reprinted above).

Editorial cartoon showing a Chinese man, surrounded by luggage labeled “Industry”, “Order”, “Sobriety”, and “Peace”, being excluded from entry to the “Golden Gate of Liberty”. The sign next to the iron door reads, “Notice—Communist, Nihilist, Socialist, Fenian & Hoodlum welcome. But no admittance to Chinamen.” At the bottom, the caption reads, “THE ONLY ONE BARRED OUT. Enlightened American Statesman—’We must draw the line somewhere, you know.'” 1882. Source: https://commons.wikimedia.org/wiki/File:The_only_one_barred_out_cph.3b48680.jpg. . . and races are real

This argument may be socially honorable, but if this is what many truly believe, then there are people who need to hear that just like the idea that the Earth is flat, so too, the notion that  human beings come in different kinds that can be labeled as “races” is just plain scientifically wrong.

As the anthropologist Jonathan Marks at the University of North Carolina – Charlotte and many others, too, have been saying for years, human genetic variation around the globe is real. But the same cannot be said for the commonsense claim that the Earth is peopled by separate and distinct human races.

As Marks has observed on numerous occasions, when we try to divide people up into different races, it’s not that we’re reading natural patterns of variation and simply extracting this idea from nature. Instead,

what we’re doing is we’re deciding that certain patterns of variation are less important than others, and certain patterns of variation are more important than others. We decide that the difference between a Norwegian and an Italian is not significant and so we’ll place them in the same category. And we decide that the difference between a Persian and a Somali is important; and so we’ll place them in different categories.

Sinner heal thyself

It is probably true that most human geneticists nowadays recognize that human beings don’t come in kinds—that is, races aren’t real. It is more than unfortunate, therefore, that geneticists today generally still don’t seem to know how to talk about human biological variation from place to place and down through time without using words—the term “population,” for example—that all too easily can mislead others less knowledgeable into believing science still endorses the old commonsense idea that human races exist in the real world to be embraced or savaged depending on one’s personal and moral proclivities.

No wonder, therefore, that dictionary definitions of racism (such as the one at the top of this commentary) can still make it sound like there is nothing wrong with the idea of race provided we don’t use this notion as an excuse for prejudice, discrimination, or antagonism.

The way forward

Most of us don’t believe the Earth is flat. Yet most of us live and act as if it were because this commonsense idea is a seemingly trivial lie that mostly works just fine in everyday life. Similarly, most of us may feel comfortable using the word race for the same reason. Truth be told, however, most of us also know the consequences of doing so can be deadly. Is there a way forward?

Here are 5 recommendations. They have been written specifically with geneticists in mind. But you don’t have to be a professional geneticist to add them to your own personal stock of “best practices.”

  1. Avoid whenever possible using facile concepts and terms such as ancestry, migration, and admixture when writing about human diversity.
  2. Abandon using the outdated concept of a “population,” and replace it with the statistician’s term “sample.”
  3. Stop writing about the “population structure” of this or that species, and instead report on their “genetic structure” as a species.
  4. Develop comparative databases documenting the genetic structure of other species to demonstrate publicly and repeatedly until the truth finally sinks in that geographic variation doesn’t have to be “racial” to be real.
  5. Create mathematical tools and network algorithms to use when mapping, analyzing, and reporting on the genetic structure of a species that unlike current methods (e.g., the popular computer program Structure) are non-categorical.


© 2017 John Edward Terrell. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

Racial migrations and human genetics: The “game changer” in the South Pacific that wasn’t – part 3

John Edward Terrell and Kevin M. Kelly

This is part 3 of a 3 part commentary

How many immigrants does it take to make a migration?

When presented with a sample comprising only 3+1 skulls, both scientific caution and parsimony suggest you should assume that colonists coming ashore back at the beginning of human history in Vanuatu and Tonga were probably more diverse, biologically speaking, than is witnessed by these four—at least until there is further evidence showing they did indeed come not just from a genetically homogeneous place of origin, but also a place where the inhabitants were as sui generis as they appear to be vis-à-vis others on earth (Skoglund et al. 2016: fig. 1b).

Logic such as this is well worth attending to. But in this instance, there is an equally logical way to get around the usual working assumption that people are likely to be more diverse than first appearances may suggest. Given how poorly specified are the two hypotheses under scrutiny here, it is anyone’s guess how big  we are supposed to think the boats must have been that brought early colonists to Vanuatu and Tonga around three thousand years ago. Even granting they may have arrived in more than one canoe, it would be reasonable to assume those arriving were fairly few in numbers. If so, then there is no need to assume blindly that those who came ashore in Vanuatu or Tonga constituted a representative (random) sample of the real human genetic diversity among those back home in the places where they came from, wherever on earth that was (Terrell 1986).

Furthermore, this is not all that might be reasonably assumed when trying to pin down the who, what, where, why, and when behind these four skulls. The number of pioneering colonists arriving  in canoes from elsewhere with them or before them may not only have been relatively few. They may also have been kin, i.e., biologically related to one another. If so, then possibly what makes these crania look sui generis in comparison with other people on earth, living and dead, may just be that we are seeing a “family resemblance” in these human remains (Terrell 1986; Walker and Hill 2014).

“Figure 1 New Guinea’s place in the southwestern Pacific (bathymetry downloaded from http://ingrid.ldeo.columbia.edu/SOURCES/ .WORLDBATH/.bath/based on the ETOPO5 5 · 5 min Navy data base).” Source: Terrell 2006: fig. 1
Homeward bound

For journalists and others, the real mystery of these remains, of course, is where these pioneers or their immediate forebears sailed from when they launched their boats to start a new life elsewhere. What is now known or can be reasonably assumed, therefore, about places to the west where they may have sailed from?

Until the Holocene stabilization of sea levels in the southwestern Pacific around 8,000–6,000 years ago, it is likely that much of the northern coastline of New Guinea was steep and uninviting of human settlement (as much of it still is today) except perhaps where favorable local circumstances may have at least temporarily trapped sediment in sandbars, coastal lagoons, and small river deltas. Little is currently known archaeologically about this coastline, which runs east-west for roughly 1,500 miles (2,400 km), and which would logically have been the most likely route between Asia and the farther reaches of the Pacific (Golitko et al. 2016). The best guess at the moment is that few people lived along this coast for the first 35,000–45,000 years of human history in the Pacific (Terrell 2006). In effect, earth and sea conspired to isolate New Guinea, like a sleeping giant, from frequent contact with islanders elsewhere both to the east in what is now popularly called Melanesia, and to the west in Island Southeast Asia (for biological support for this inference, see: Matisoo-Smith 2016: 391).

Following the Holocene stabilization of sea levels, however, coastal areas in Southeast Asia and the Pacific began to develop into rich floodplains, river deltas, and lagoons. By the mid Holocene, it is probable that people in the island realms to the east and west of New Guinea began to deal with one another back-and-forth more often as coastal people began to travel with greater reach along this immense island’s lengthy northern coastline (Torrence and Swadling 2008).

West meets East

Contrary to the notion that there are only two hypotheses about the prehistoric human settlement of the more remote islands in the Pacific east of New Guinea, there are numerous variants not only of those two old ideas but of others, too (for a recent review, see: Matisoo‐Smith 2016). Here we will introduce only one plausible reconstruction (Terrell, in press).

Initial baseline assumptions
  • Archaeologists now think people have been living in Southeast Asia for 50,000 years or so, and perhaps for not quite so long in the islands just east of New Guinea as far as Bougainville in the Northern Solomons.
  • The gradual flooding of the Sunda paleocontinent in what is now Southeast Asia since the Last Glacial Maximum ~21,000 years ago created extensive coastal environments that were ecologically rich and productive (Sathiamurthy and Voris 2006; Hanebuth et al. 2011: fig. 2). Similar extensive flooding did not occur in the area east of New Guinea labeled as Parkinson’s Islands (after the early ethnologist Richard Parkinson) on the map above (Lavery et al. 2016).
  • Due to this environmental advantage, it is probable that there were far more people living in Southeast Asia 6,000 years ago than there were in Parkinson’s Islands.
  • By the mid Holocene—contrary to the prevailing assumption in historical linguistics that doesn’t take this ecological advantage into consideration—it is probable that languages classifiable as Austronesian were widely spoken throughout Wallacea and elsewhere in Southeast Asia even as far north as Taiwan. But not yet in Parkinson’s Islands which had been isolated from Asia by the island of New Guinea.
  • Throughout the Late Pleistocene and early Holocene, Wallacea and Parkinson’s Islands were both areas of the Pacific where the advantages of travel by sea rather than by land nurtured the use of canoes and the development of local navigational methods and skills.
  • Canoes equipped with outriggers and sails were invented in Southeast Asia at some point in the Late Pleistocene or early Holocene. Simple dugout canoes remained the predominant boat type used for travel among coastal communities in Parkinson’s Islands.
Illustration taken from Labillardiere, (1800). Atlas pour servir a la relation du voyage de la recherche de la Perouse. Page Plate 43. Paris. Source: Labillardiere. (1800). Buka Island canoe (Solomon Islands) [digital image]. http://www.dspace.cam.ac.uk/handle/1810/239987 Modeling the relocation of immigrants from Wallacea
“The word proa comes from perahu, the word for “boat” in Malay.” Source: https://commons.wikimedia.org/wiki/File:Proa_(PSF).png
Modeling the relocation of immigrants from Wallacea
  1. A small Austronesian-speaking hamlet or village community left home for some particular local reason or reasons from somewhere in Wallacea—or possibly on the north coast of New Guinea—and made landfall in the Bismarck Archipelago.
  2. It is possible that wherever it was they came ashore, they arrived not as strangers but rather as old friends of some of the local people there in the Bismarcks (Terrell 2015).
  3. Among these immigrants were individuals skilled at pottery-making, and also skilled in the arts and rituals of building and sailing outrigger canoes with sails. Both of these technologies were new to the Bismarcks region. Moreover, such skills may not have arrived at the same time if travel back-and-forth between communities in Wallacea, northern New Guinea, and the Bismarcks became routine at least for awhile.
  4. The local people not only welcomed them, but often also acquired new ways of doing things—such as the art of pottery-making—from their immigrant neighbors, in some instances even their foreign language skills. The reverse may have also been true.
  5. Time passed, generations came and went. For now unknown reasons, it eventually became fashionable, prestigious, or perhaps even necessary for some people in the Bismarcks to set sail for islands yet farther to the south and east in the Pacific, although how many people in how many communities were involved, how often they sailed away, and for how many years this voyaging away from home in the Bismarcks went on are now all unknown and perhaps unknowable. 
  6. Even so, considering the passage of the time between (a) the first arrival of immigrants from the west and (b) the departure of some people generations later to settle down in other (more remote) places to the southeast, there is no reason to insist that these two separate episodes of human resettlement were similarly inspired or motivated (Walker and Hill 2014).
  7. Furthermore, given that both the voyaging technology and navigational skills required to colonize the more remote islands of the Pacific may have been available then only in some communities in the Bismarcks, it is not surprising that early settlers in Vanuatu, Tonga, and elsewhere had similar material culture traits (i.e., the so-called “Lapita cultural complex”).

Because the first immigrants who reached Vanuatu and Tonga were entering a vast and uninhabited part of the Pacific, it is probably not surprising that many nowadays have been seduced by the modern global distribution of Austronesian languages—from Madagascar to Rapa Nui (Easter Island) and from New Zealand to Taiwan—into thinking that such a vast geographic compass could only be the historical product of some kind of massive human migration that was singularly intentional and singularly premeditated from the very moment the first Austronesian-speaking immigrant stepped into the first canoe to sail from somewhere in island Southeast Asia  or on the north coast of New Guinea to the Bismarcks 3,000 and more years ago. It is wise to remember, therefore, that appearances can be deceiving.

Furthermore, today we know nothing about marriage (or sexual) practices in the Pacific in the prehistoric past. Although it is stating the case too simply, we do know that the basic building block of human genetic relatedness is the gene. Anyone who knows about the birds and the bees knows that genes can travel far and wide through sexual intercourse even if the people carrying them may only get as far away from home during their time on earth as the next village or two down the road. Consequently, there is no a priori reason to assume that race = language = culture. Or that genes necessarily traveled the Pacific millennia ago as the exclusive and enduring “property” of a massive and self-contained ethnic or ethnolinguistic migration that was able to keep its collective act together over thousands of miles and for hundreds, even thousands, of years. As some anthropologists like to say it, we need models of Pacific prehistory to work with that are “on the ground,” not “pie in the sky.”

Although we have been talking here almost exclusively about the Pacific Islands, the issue at stake is a global one. It is not just worrisome to find that even scientists may sometimes be unaware of the intellectual racism hidden in the conviction that the story of our species is a tale about ancestry, ancient migrations, and admixture. Commonsense ideas like these can be more than misleading. They can lend credence to other notions and old prejudices that can be harmful and sometimes deadly.  


We thank Ethan Cochrane, Mark Golitko, Tyrone Lavery, Lisa Matisoo-Smith, and Robin Torrence for assistance in the preparation of this 3-part commentary.


Bellwood, Peter. 2011. Holocene population history in the Pacific region as a model for worldwide food producer dispersals. Current Anthropology 52: S363–S378.

Gibbons, Ann. 1994. Genes point to a new identity for Pacific pioneers. Science 263: 32–33, p. 32.

Gibbons, Ann. 2001. The peopling of the Pacific. Science 291: 1735–1737.

Golitko, Mark, Ethan E. Cochrane, Esther M. Schechter, and Jason Kariwiga. 2016. Archaeological and Palaeoenviromental Investigations Near Aitape, Northern Papua New Guinea, 2014. Journal of Pacific Archaeology 7: 139–150.

Green, Roger C. 2003. The Lapita horizon and traditions – signature for one set of oceanic migrations. In C. Sand (ed.), Pacific Archaeology: Assessments and Prospects. Le Cahiers de l’Archéologie en Nouvelle-Calédonie 15. Nouméa: Service de Musées et du Patrimoine de Nouvelle-Calédonie, pp. 95-120.

Hanebuth, Till JJ, Harold K. Voris, Yusuke Yokoyama, Yoshiki Saito, and Jun’ichi Okuno. 2011. Formation and fate of sedimentary depocentres on Southeast Asia’s Sunda Shelf over the past sea-level cycle and biogeographic implications. Earth-Science Reviews 104: 92-110.

Lavery, Tyrone H., Andrew D. Olds, Jennifer M. Seddon, and Luke K‐P. Leung. 2016. The mammals of northern Melanesia: speciation, ecology, and biogeography.” Mammal Review 46: 60–76.

Matisoo-Smith, Elizabeth A. 2016. Human biology and population histories in the Pacific–Is there such thing as a Lapita people?. In: The Routledge Handbook of Bioarchaeology in Southeast Asia and the Pacific Islands, edited by M. Oxenham and H. Buckley, pp. 389–408. Routledge, London.

Sathiamurthy, E. V. H. K., and Harold K. Voris. 2006. Maps of Holocene sea level transgression and submerged lakes on the Sunda Shelf. The Natural History Journal of Chulalongkorn University, Supplement 2: 1-43.

Skoglund, Pontus, Cosimo Posth, Kendra Sirak, Matthew Spriggs, Frederique Valentin, Stuart Bedford, Geoffrey R. Clark, et al. 2016. Genomic insights into the peopling of the Southwest Pacific. Nature 538: 510–513.

Specht, Jim, Tim Denham, James Goff, and John Edward Terrell. 2014. Deconstructing the Lapita cultural complex in the Bismarck Archipelago. Journal of Archaeological Research 22: 89-140.

Specht, Jim, Chris Gosden, Carol Lentfer, Geraldine Jacobsen, Peter J. Matthews, and Sue Lindsay. 2016. A pre-Lapita structure at Apalo, Arawe Islands, Papua New Guinea. The Journal of Island and Coastal Archaeology: 1-22.

Terrell, John. 1986. Causal pathways and causal processes: Studying the evolutionary prehistory of human diversity in language, customs, and biology. Journal of Anthropological Archaeology 5: 187-198.

Terrell, John Edward. 2006. Human biogeography: Evidence of our place in nature. Journal of Biogeography 33: 2088-2098.

Terrell, John Edward. 2015. A Talent for Friendship. Oxford University Press.

Terrell, John Edward. In press. Understanding Lapita as history. In Oxford Handbook of Prehistoric Oceania, edited by Ethan Cochrane and Terry Hunt. Oxford University Press.

Terrell, John Edward, John Edward, Terry L. Hunt, and Chris Gosden. 1997. The dimensions of social life in the Pacific: Human diversity and the myth of the primitive isolate. Current Anthropology 38: 155–195.

Terrell, John Edward, Kevin M. Kelly, and Paul Rainbird. 2001. Foregone conclusions: In search of “Austronesians” and “Papuans.” Current Anthropology 42: 97–124.

Torrence, Robin, and Pamela Swadling. 2008. Social networks and the spread of Lapita. Antiquity 82: 600–616.

Walker, Robert S., and Kim R. Hill. 2014. Causes, consequences, and kin bias of human group fissions. Human Nature 25: 465-475.

© 2017 John Edward Terrell and Kevin M. Kelly. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.