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Archaeologist wants to hear the whole song of humans' past, not just individual notes

October 1, 2019

Charles Perreault says material items and behaviors that span beyond individual lifetimes will help uncover large-scale drivers of cultural evolution

Human behavior over time has been extraordinarily complex; that's partly why so many different fields exist to study it. From economics and psychology to sociology and anthropology, each field brings its own set of complementing focuses, methodologies and ranges of study to the larger equation.

But in archaeology specifically, there has been a tendency to study behavior in small pockets — micro time scales shorter than the span of a human lifetime, said Charles Perreault, an assistant professor at Arizona State University’s School of Human Evolution and Social Change.

Assistant Professor

Charles Perreault

This deep vs. broad approach has led to countless fascinating and important discoveries about the human past, he adds, yet leaves a whole lot of lingering questions about the forces that govern human culture.

In his new book “The Quality of the Archaeological Record,” Perreault explains that the field of paleobiology grew significantly in prominence when paleobiologists turned away from studying microevolution in the incomplete fossil record and focused instead on patterns and processes that are revealed only across large scales of time and space. And it’s this type of macro approach that he’s now arguing for more of in his own field.  

 Answers have been edited for length and clarity.

Question: You use the term “macroarchaeology” quite a bit in the book. What is that, and how is it different from what has been done before? 

Answer: We archaeologists tend to view ourselves as ethnographers of the past, meaning it’s our job to clear archaeological sites from the distorting effects of disturbance and preservation processes, fleshing it in with ethnographic or experimental archaeology, in order to reconstruct behavior of a set time, place and people.  

Reconstructed behaviors would then typically be interpreted in terms of cultural anthropology, behavioral ecology, psychology or economics, all fields based on observations made in the present.

This approach has been fruitful, but macroarchaeology tries to do the exact opposite, moving as far away as possible from an ethnographic scale of analysis to a 10,000-mile view of the archaeological record. The goal is to see the types of patterns and processes that become visible only over very large temporal and spatial scales, and well above the hierarchical level of the individual. This could include statistical patterns of abundance, diversity, distributions and rates of change, and their macroscale drivers such as climate change and biogeography. 

Q: What are the parallels between the history of paleobiology and the future of archaeology?

A: Before the 1970s much of paleobiology consisted of reconstructing fossil organisms into what a field biologist would recognize and interpreting the fossil record in terms of microscale evolutionary theory developed by geneticists. But during the 1970s, the agenda of the discipline was transformed, with an emphasis on macroevolution — things observable over geological time scales as opposed to within a human lifespan. This new agenda revitalized the field and augmented its relevance to the biological sciences significantly, and I’d like to see a similar transformation within archaeology.

Q: What kinds of questions can researchers answer using this macro approach?

A: Some of those would be about long-term trends. For instance, Jonathan Paige and Deanna Dytchkowskyj, two graduate students here at ASU, are looking at all the long-term trends in the complexity of stone tool technologies over the last 3 million years.

Archaeologists can also aggregate to measure the expected properties of various aspects of human culture, such as the typical pace of change in technology or the range and duration of stylistic traditions.

In a paper published in 2012, I was able to measure the typical pace of change as seen in the North American record and also compare it to the pace of biological change in the fossil record, and found that culture changes about 50 times faster than biology.

This shows how culture frees humans from generational time constraints and gives us the best of both worlds: We evolve over very short time scales normally accessible only to species with short life spans, but also enjoy the benefits of a long life history, including large bodies, big brains and long childhoods. This information would also be helpful for other disciplines to be able to incorporate in their theories and models.

Q: How would archaeologists go about collecting and analyzing data on a macroscale?

A: The data needed here is a bit different than what you see in a normal archaeology project. First, the program is material culture-centric, and about the archaeological material itself, like a type of arrowhead, rather than about individuals or populations. It needs to have properties measurable at any given point in history, without time-specific, place-specific or technology-specific variables. Examples include temporal ranges, geographic ranges, rates of change and rates of appearance/disappearance.

It’s basically the difference between a zoologist studying bat echolocation systems, a species-specific trait, and a macro ecologist analyzing the geographic range of terrestrial species, something every species has.

This also puts archaeologists in a good place to identify some drivers of patterns. For instance, how does geography, such as the shape, size or orientation of continents, affect cultural diversity or complexity? What is the effect of climate on global cultural diversity? These are narrower questions than what you typically see in the field of archaeology, but they are deep questions. 

Q: What other innovations will we see in archaeology over the next 10 years?

A: One would be a greater focus on large historical databases. Archaeologists have produced a wealth of data over time, but it is vastly underutilized. Too often, the results of excavations are used once, to answer whatever particular research question the excavators had in mind, and then it just sits there on the shelves.

To resolve this, we ultimately need to build a global archaeological database that pools together analytical units drawn from the entire archaeological record. That is obviously a very long-term project. But Dytchkowskyj, the ASU graduate student I mentioned before, started collecting from the literature this type of data from the North American archaeological record this fall. This process is important because the archaeological record is a finite resource. For instance, a recent archaeological study has shown that different segments of the record are near depletion, including Upper Paleolithic sites from Europe and monumental sites from the Maya Classic period.

Aaron Pugh

Manager of Marketing and Communications , School of Human Evolution and Social Change


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A first-of-its-kind instrument enables one-of-a-kind student experience

October 1, 2019

What’s better than spending a hot Arizona summer working in a cool basement? Spending a hot Arizona summer in a cool basement, building a scientific instrument expected to be the first of its kind in the world.

Beneath Biodesign Institute building C, five Arizona State University students put their education to work this summer, aiding in the first phase of the compact X-ray free electron laser (CXFEL), a miniaturized high-fidelity X-ray source.

While most free electron lasers are miles long and cost billions to construct, ASU’s CXFEL fits neatly in a traditional lab space at a fraction of its peers’ massive cost. Housed in the Beus Compact X-ray Free Electron Laser Laboratory, the instrument will accelerate electron bunches to nearly the speed of light through a series of three linear accelerators. Powerful magnets will focus and direct the electrons to collide with focused infrared laser pulses. This collision — which generates the power of 100 Hoover Dams, but for only one-millionth of one-millionth of a second — produces X-ray pulses.

This elaborate process will enable scientists to peer into atomic- and molecular-scale structures with unmatched clarity. The CXFEL holds promise to advance discoveries in drug development, medical imaging, materials science, quantum materials and sustainable energy.

The project’s first phase, the compact X-ray light source, is taking shape under the direction of ASU Regents Professor Petra Fromme and Associate Professor Bill Graves, as well as their team in the Biodesign Center for Applied Structural Discovery.

The undergraduate students’ internship was made possible by a $50,000 donation from local philanthropists Bill and Susan Levine to advance the ASU CXFEL. Bill Levine is an investor, real estate developer and founder of Outdoor Systems, an advertising firm. Susan Levine is the director emeritus of Hospice of the Valley and previously served 23 years as the organization’s executive director before retiring in 2016.

“The Levines’ gift created this fantastic opportunity for the undergrads,” said Mark Holl, deputy director of the CXFEL project, who is overseeing the assembly of the instrument and led the student team. “Emphatically, I could not be happier with this team.”

The team’s primary focus over the summer was the physics modeling, design, assembly and testing of the precision thermal control water systems that are used to control the temperature of different CXFEL components. An integral part of the instrument, these systems demand an incredible level of precise water temperature control. One of the three systems requires control within one-hundredth of a degree Celsius, says Holl, who also serves as the chief engineer on the CXFEL.

Two men work with electrical equipment in a lab. The caption reads: Mechanical engineering student Alex Gardeck and engineer Steve Rednour work on an electrical control panel of the Compact X-ray Free Electron Laser.

Mechanical engineering student Alex Gardeck and engineer Steve Rednour work on an electrical control panel of the compact X-ray free electron laser. The students worked alongside the engineering team to bring the first phase of the instrument online. Photo by Andy DeLisle/ASU

The students were smoothly integrated into the team, assembling this system and other instrument components. The work provided them the opportunity to employ their coursework in a professional setting.

“It's been an incredible experience working on this project, because it's been a direct application of everything that I've learned in my undergraduate career,” said Alex Gardeck, a mechanical engineering student in the Ira A. Fulton Schools of Engineering. “Really, we’re just living the everyday life of engineers, encountering problems and figuring out creative ways to solve them.”

Gardeck’s responsibilities included assembling and testing components for the instrument, some of which he 3D modeled using SolidWorks, a computer-aided design and engineering program.

“Hands-on assembly experience will help my designs in the future. When I'm doing a 3D model, everything lines up perfectly, but until I'm starting to torque these wrenches I don’t always see the reality of it,” he said while working on the instrument’s cooling system.

The project also provided students with an opportunity to learn from fellow interns.

Engineering students Brett Liebich and Brandon Cook, who work as electromechanical research technicians at the center, brought a wealth of experience they were able to pass along to the rest of the team. Veterans of the U.S. Navy, Liebich and Cook had previously served on nuclear submarines as a machinist’s mate and electrician's mate, respectively.

“After a decade in the Navy, we were able to get a skill set that you really don't see in a lot of interns or college students,” said Liebich. “Working with some guys who haven't done any of this, we get to not only mentor them a little bit, but also learn from the project engineers. We're engineering students, so the more eyes we can get looking at different things that we might end up doing, it's all good experience.” 

While moving from working on nuclear submarines to constructing complex scientific instrumentation isn’t exactly a one-to-one transition, the former sailors nevertheless found similarities between the two jobs. 

“The attention to detail, procedural compliance and problem solving that we learned in the nuke program is just being applied in a different fashion here,” said Cook.

Two young men peer at an array of scientific components. The caption: Students Alex Gardeck and Brandon Cook examine the precision thermal trim unit water systems that controls the temperature of components in the radiography/fluoroscopy room.

Students Alex Gardeck and Brandon Cook examine the precision thermal control water systems that regulate the temperature of components in the radiography/fluoroscopy room of the Beus Compact X-ray Free Electron Laser Laboratory. Photo by Andy DeLisle/ASU

Physics students Dakota King and Albert Wang also spent their summer working on the CXFEL. 

“This opportunity is rewarding because it's really hands-on and applied,” said King, who graduated in spring 2019 with his bachelor’s degree. “Physics is a lot of theory. It's cool getting into the engineering side of things.”

“When we’re taught about an instrument or experiment in class, it’s easy to understand why we’re talking about it or the outcomes that made it important,” said Wang, who had previously worked with CXFEL Science Director Graves. “With the CXFEL, it’s almost surreal to work on something that is on the forefront of science. We’re on the precipice of so many possibilities, and while it’s a challenging project, it’s a great opportunity for growth.”

Gardeck, King and Wang were instrumental in the developing both 3D and mathematical physics models of the precision thermal trim unit water systems, according to Holl. 

“Initially, we only had a control resolution on the order of one-fourth of a degree Celsius,” said Holl. This was a far cry from the one-hundredth required from the system.

Following the team’s modeling work, they were able to identify the right water flow regulating valves and actuators needed to achieve the precise temperature requirement.

“The students completed the full engineering process, from specifications to modeling the system physics incorporating the properties of real components,” said Holl. “This is a perfect example of an integrated project team with engineering and physics skills brought to bear on a challenging problem. That integration allowed us to achieve a critical need for this accelerator.”

Four of five of the students have remained working on the instrument through the fall semester, contributing as their academic schedules allow. Gardeck, who expects to graduate in the spring, is basing his honor’s thesis on the thermal trim water system.

“I’ve been obsessed with accelerators since I was a kid and I first learned of the Large Hadron Collider,” says Gardeck. “So to be able to work on the CXFEL is a dream come true, and I’m extremely grateful to the Levines for the opportunity.”

Top photo: Alex Gardeck, a mechanical engineering student, examines one of the precision thermal trim unit water systems that is used to control the temperature of various components of the compact X-ray free electron laser, or CXFEL. Photo by Andy DeLisle/ASU

Pete Zrioka

Managing editor , Knowledge Enterprise