Networks of Exchange

Lowell Gustafson
President, International Big History Association
Professor of Political Science, Villanova University, USA


Global commercial shipping route density. By Grolltech. CC BY-SA 3.0.

Author’s Note: I am grateful for the comments by Cynthia Brown on an earlier version of this piece. Of course any remaining deficiencies here remain my responsibility.

I grew up in the Chicago area of Illinois, USA. As a boy, I was proud to have come from the same state as Abraham Lincoln, and liked reading about the American Civil War. By college, that interest had developed into a broader one in American and European political and international history. Although I enjoyed my biology and chemistry classes in high school and college, it was not until years after I completed my PhD and had been teaching in a university that I began to appreciate how the natural sciences have revolutionized our understanding of the past – and how we got here. I am now interested in how political science can be understood within the Big History narrative that the natural sciences have made possible. Or, what is the Little Big History of politics?

The natural sciences provide us with an evidence-based account of emergent complexity from the Big Bang through the evolution of humans. The social sciences place their study of humanity within that larger narrative. Here we consider how the idea about networks of exchange may fit within one of the key organizing themes of Big History: emergent complexity. We will look at how relationships among increasingly complex units are facilitated or made possible by different types of networks of exchange.

The History of Trade

World systems theorists analyze networks of exchange over the past 5,000 years; they show the central importance of trade in the development of political and economic complexity.¹ The systematic exchange of goods facilitates the development of specialization. Whether through absolute advantage (when one party has exclusive or highly restricted access to specific goods, such as a rare natural resource) or comparative advantage (where one group is just a bit more skilled at producing an item), networks of exchange establish sustained, usually well-structured relationships among increasing numbers of people. Often, these networks include not just the exchange of goods, but also of ideas and attitudes.

In 2003, William McNeill and his son, John, wrote The Human Web, a history of humanity that focused on the importance of evolving and expanding webs of connections among different human communities. These webs of connections almost always included trade, which were sometimes hard to distinguish from raids. There is evidence that relatively long-distance trade existed in China from the second millennium BCE. As early as 1,800 BCE, the Olmec in Mesoamerica were trading obsidian for other high value goods. In the fifth century BCE, the Royal Road of the Persian Empire covered 1,775 miles, starting just east of the Tigris River to Smyrna, now İzmir in Turkey, on the Aegean Sea. Since the second century BCE, goods were exchanged along the Silk Roads that ran from China to the Levant and even into Europe. I include below just a few sources about the many examples of networks of exchange that have existed at various places and times.

The ever-increasing complexity of these networks has been demonstrated in the process of globalization. Robert Denemark, Christopher Chase-Dunn, Andre Gunder Frank, and others have argued that a core network that began some 5,000 years ago continued to grow in size and inclusiveness ever since. Immanuel Wallerstein and others stressed the importance of the Age of Discovery and then colonialization in the 1500s as a key development in globalization. Others emphasize the role of Great Britain in serving as a lender of last resort in a Pound Sterling area reaching from the UK to India, Africa, and elsewhere in the nineteenth century. And still others mark the end of the Cold War’s division of the world into the First, Second, and Third Worlds in the early 1990s as the greatest period in history of networks of exchange.

During all this time, there have been many periods of decreased networks of exchange as well. One of the most famous was during the Great Depression of the 1930s when world trade dropped by 40 percent. Many believed that the trade wars of the 1930s led to political radicalization and then the military conflicts of the 1940s. Participants at the Bretton Woods conference at the end of WWII thought that re-establishing vigorous networks of exchange was an essential part of the effort to prevent WWIII. Since then, the exchange of goods, capital, and people have become the most extensive in human history. Within the past year especially, there has developed reason to wonder if this 70-year process is about to recede; are we moving into a period of reduced networks of exchange?

A Little Big History of Networks of Exchange?

“Networks of exchange” first bring to mind the history of trade. How can we see networks of exchange as a key part of the Big History narrative? The very notion of complexity is at the heart of these networks. Think of the quarks that emerge almost immediately after the Big Bang. Four types of these almost instantaneously dissolve back into radiation, but two of them, the up and down quarks, form extraordinarily long-lasting relationships within protons and neutrons. There are always two of one type in a network with one of the other type of quark. We might think of their relationship being formed by the constant exchange of gluons between them that mediate the strong force. A single proton is perhaps the most basic network of exchange. We might also think of the electromagnetic force that starts 380,000 years after the Big Bang to form relationships among protons and electrons through the exchange of photons. Each simple hydrogen atom is a profound set of relationships among parts and is itself a network of exchange. The phrase “atomistic society” should not imply individualism and isolation; it would more accurately mean sustained, structured relationships made possible by continuous exchanges.

The exchange of radiation and nutrients from outside the first prokaryote cell and the discharge of waste into the environment is an early ecological form of exchange. The simple cell needs to be in a network of exchange to survive. As biological complexity develops, there is a stunning array of exchanges within the organism of many chemicals. Each one of us is an incredibly complex set of networks of exchange. It is often said that our brains are the most complexly organized matter in the Universe of which we know. A hundred billion neurons connected by a trillion synapses form a three pound (1,300 to 1,400 g) dense network of electrical and chemical exchanges. It is this brain that has permitted the increasingly complex set of exchanges between people over time.

Of course, social networks of exchange are not limited to humans. We see them in many social species, such as bees, ants, and then wolves, elephants, primates, and others. Exchanging grooming sessions builds relationships among baboons. Exchanging food for relational benefits is common among primates.

Once we get to the development of human culture, Big Historians often emphasize flows of energy in new ways of production. As humanity move from scavenging, gathering, and hunting to agriculture, and then to industry and finally our digital era, we see how these energy flows increase. What these increased flows make possible is increasingly complex networks of exchange. Specialized social roles become more pronounced, with one group performing functions in exchange for those performed by others. Even in early villages, we see the increase in specialization and barter, an early form of exchange. As humans became organized into cities, nations, empires, and gradually the globe, networks of exchange became ever more complex.

Staying out of Exchange Networks

Some people seek to stay out of exchange networks; they prefer to be self-sufficient, producing as much as possible of what they need for themselves. They explicitly seek to be “off the grid,” not to be dependent on others. In American political culture, we might think of Henry David Thoreau living at Walden Pond; the Amish avoiding dependence on electricity and gas stations; 1960s communes; or Christopher McCandless going Into the Wild to live as independently as possible. Some prominent political leaders in the United, States, Britain, France, and other nations have called for tighter restrictions on networks of exchange. Many of their supporters feel as though their own economic wellbeing and political identities are harmed by these networks.

In a way, not being part of ever increasingly complex networks of exchange might be seen as the norm within Big History. The emergence of complexity is often the exception, not the rule. Fred Spier reminds us that increasing complexity occurs in small areas, with entropy dumped into the less complex spaces. At each stage of development, many phenomena remain subsequently unchanged. There are still enormous clouds of hydrogen and helium many light years across that have been floating in space virtually unchanged since the Big Bang. These elements are hardly interacting at all. Prokaryote cells, the first form of life from almost 4 billion years ago, are still here in great numbers; those that exist today have not increased their complexity in almost 4 billion years. The process of emergent complexity may be largely the exception. Most of us are quite grateful that we do have evidence of the emergence of ever-greater complexity in certain spots of the Universe, like in our bodies and societies.

Reversing and Voluntarily Increasing Networks of Exchange

We are reminded in our newspapers that a process of emergent complexity and the development of networks of exchanges is not a steady or irreversible one. There have been many periods in history of decreased networks and diminished complexity. I cannot look at this with a sense of detachment, because my very existence is embedded in an extraordinarily long process of increasingly complex networks of exchange. The process of collective learning about what is necessary to sustain networks of exchange has been demanding. We see how easy it is to lose sight of that and instead become part of decreasing levels of complexity.

For me, one of the most pleasant and exciting aspects of Big History is being part of the exchange of knowledge between people from very different disciplines. They are willing to make the effort to transmit their knowledge clearly and intelligibly to nonspecialists. Together, we start to see the relationships between these pieces of evidence and construct an account of what took place so that we can be here now. We are part of the most recent pages of that story. Will those who follow us see what we have done as having contributed positively to their wellbeing?

Being part of the Big History learning community means that all of us are teachers and learners who are in a network of exchanging ideas and data. As we do, we see the relationships between various pieces of evidence. And then we discover how these exchanges have led to networks of relationships among us.

¹See, for example, Denemark, R. A. (2000). World system history: the social science of long-term change. London New York: Routledge; Christian, D., Brown, C. S., & Benjamin, C. (2014). Big history: between nothing and everything. New York, NY: McGraw Hill Education; and Brown, C.S. (2016) Big History, Small World. Great Barrington, MA, Berkshire.


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Has the Scientific Revolution Ended? Debatable.

Jami McLing, BHP Teacher
Idaho, USA

Instinctively, teenagers can be argumentative. They think they’re always right and most don’t shy away from a verbal fight. However, their argument often lacks “bite” and consists of opinions fueled by emotion. The debate activity Has the Scientific Revolution Ended? from Lesson 8.3 provides a terrific opportunity for students to learn how to argue with purpose.


Photo courtesy of Jami McLing

Our students love the activity because it’s an excuse for them to practice their argumentation skills, and in the context of a juicy question. They’re challenged to think critically about questions that have seemingly obvious answers (like, “what counts as science?”) and consider their role in historical narratives.

This is the first time many of our students have debated so we are careful about how we set it up:

  1. Ask Questions: After introducing the debate question, groups answer a set of questions.
    a. How do you define a scientific revolution?
    b. What counts as science?
    c. What is a revolution?
    d. How do we know if we are in the midst of a revolution?
    e. How do we know when something in history began and ended?
  2. Research: Students spend a day gathering evidence to support their position using BHP’s claim testers—authority, evidence, logic, and intuition. We check in with each group frequently to remind and encourage them to support their claims with concrete evidence from the Big History site or by using credible outside sources. This is always a fun step because preconceived notions about a position can be changed, much to a student’s surprise.
  3. Debate: Each group gets 5 minutes to present their opening statement, rebuttal, and closing statement. Because this is the first time most of our students have been exposed to debating, we modify the debate format presented in Unit 8. Instead of giving 5-15 minutes for rebuttals, we give 20-25 minutes.
  4. Reflection: After the debate, students vote on which side made the best argument and write up a short reflection on why that side “won” and how they could’ve made their argument even stronger.

Not only does this activity help develop a student’s argumentative, research, and presentation skills, but it also provides an exciting opportunity for them to go head-to-head with their peers and battle it out. After all, who doesn’t love a good dose of healthy competition.

About the author: Jami McLing has been teaching history at her middle school in Idaho Falls, Idaho, since 2007. She has been teaching Big History since 2013. She teaches the year-long BHP course to eighth graders in two 50-minute classes per day.


Kathy Hays, Big History Teacher
Arizona, USA

STRIVE FOR FIVE! That’s our new motto each time we initiate a Unit Investigation. BHP Score has transformed how I teach writing, and how my students approach the writing process. I used to spend weeks grading the Investigations, and by the time they were returned, students had completely forgotten everything about it—my feedback on their writing was shoved into a backpack, never to be seen again. BHP Score, on the other hand, returns constructive feedback much faster and on a more detailed level than I could ever manage with more than 120 students. Since the Investigation writing prompt is still fresh in my students’ minds when they get their Score reports, they have a vested interest in revising and improving their work.


Sample BHP Score class report

My students have now received BHP Score reports for Investigations 2 and 6. In both cases, I’ve built lessons around the reports. After receiving reports for the Unit 2 Investigation, we went over the comments as a class. As students worked on their revisions, I conducted individual meetings to review their modifications. After a peer exchange and review, students wrote final drafts. It was the first time I had taken students through the entire writing process, allowing them to see the progress from first draft to final copy.

As we approached Unit 6, I wanted to craft a lesson that would build even more student investment in the BHP Writing Rubric, and prime them for making revisions to their writing. I was also curious to see how student evaluations of Investigations would compare to those of the BHP Score evaluators. After students submitted Investigation 6 (and were waiting for BHP Score reports to be returned), I printed off a batch of essays (names removed) for students to grade against the BHP Writing Rubric. A few days later, we received the BHP Score evaluations of the same essays. I had students compare their evaluations with the BHP Score ones—it turns out the scores were pretty close! Some students were confused as to why an essay had received a score of “3” when they thought it should receive a “4.” We took time to address questions and ensure everyone was on the same page before I turned them loose to craft a final version of Investigation 6. Using the feedback from BHP Score allowed students to produce quality final drafts.

At some point during the writing process of Investigation 6, we decided to “Strive for Five” on future writing assignments. Advice provided by the BHP Score team in the monthly Writing Exchange in the BHP Online Teacher Community has helped equip me with valuable teaching strategies to help my students. We incorporated the new strategies into the Unit 8 Investigation and saw scores improve significantly. I highly recommend joining the ASU Writing Exchange on Yammer for the monthly words of wisdom.

As we approach Investigation 9, everyone is anxious to “Strive for Five”! Thanks to BHP Score, students now have a vested interest in their writing.

About the author: Kathy Hays has been teaching for 30 years, and this year is her second teaching Big History. She teaches five BHP classes a year, and so reaches about 130 ninth-grade students. Her school is on a semester schedule with daily 52-minute periods. Kathy’s favorite thing about teaching Big History is the opportunity to learn with her students!