It seems that people have always been curious about cultures of the past, but not all of those efforts were purely scientific. Evidence for studying the past goes back at least as far as New Kingdom Egypt when officials preserved monuments from the Old Kingdom. King Nabonidus of Babylon dug into the temples of his predecessors in search of objects belonging to earlier time periods, which we call antiquities. What today would be called pothunting or looting—digging up items for their value rather than as part of a scientific endeavor—was a widespread and accepted practice used for thousands of years to acquire antiques and relics for personal collections.

These excavations began to take on some elements of scientific study as people who were specifically interested in the past began to excavate sites to learn more about past cultures and peoples, but the scientific method was not employed. Such early projects included excavations in 1709 at the ancient Roman town of Herculaneum, where artifacts were collected but not analyzed. Generally, historians focused on past cultures with written histories-  such as the ancient Greeks, Romans, and Egyptians. However, one had to be highly educated to read and translate ancient texts! At the time, individuals (usually men) excavating sites found it difficult to conceive of times and peoples without written records. Some of what we consider to be great historical sites, such as Stonehenge, were attributed to the work of elves, trolls, or witches.

Why did those early excavators attribute their finds to mythological creatures and not to humans? Largely because of their limited frames of reference and perspectives, their paradigms, which guided their research. During this early period of archaeology, researchers and the general public in Western Europe and the United States believed that the Bible was a literal, historical document. Consequently, they understood that humans did not exist before Biblical times (in which Adam and Eve were the first humans), restricting human history to approximately 4,000 years since the earth was believed to be only 6,000 years old. Anything discovered that appeared to be incongruent with this strict interpretation of the Bible, such as “primitive-looking” stone tools and structures, was attributed to non-human sources.

Scientists, however, began to challenge those beliefs with research and data. Geologists, biologists, and botanists discovered evidence that showed that humans had existed far longer than had been interpreted from the Bible. Scientists were also challenging other literal Biblical translations and were drawing new conclusions. Their evidence accumulated, culminating in Charles Darwin’s work on evolution via natural selection, which described how species had changed over time. This became established as part of the realm of science and general public knowledge. Darwin’s work fundamentally changed the study of biology and human history. Researchers tried applying his premises to other fields, including the study of human civilizations.

Herbert Spencer, E.B. Tylor, and William Henry Morgan independently applied Darwin’s principles to the study of civilizations across the globe, developing approaches that collectively became known as Progressive Social Evolutionary Theory (PSET), in which human civilizations were seen as points on a continuum and as having progressed in a linear fashion along this continuum from savagery to barbarism and, ultimately, to enlightened, civilized society. It was assumed that all cultures had originally been primitive and were in the process of becoming more civilized— or “more evolved.” These theorists placed cultures along the continuum using particular diagnostic characteristics that included adoption of agriculture, development of a writing system, tool technologies that relied on metallurgy, and belief systems focused on a single god. Proceeding along the continuum (toward civilization) indicated how “developed” a culture was.

Perhaps it is not surprising that the traits of civilized society essentially described the Western European culture of the theorists and developments made possible by the environmental conditions in those areas. Metallurgy, for example, was possible because Western Europe was endowed with many natural ores. However, the data they collected did not always fit the model. They labeled many early cultures such as the Maya, Aztecs, Incas, and North American tribes as having “devolved”—moved backward on the continuum—because they found evidence that those cultures had possessed “civilized” traits at one time but no longer did.

These and other challenges to the PSET framework were initially ignored, particularly because a large body of research, such as work by Danish archaeologists Christian Thomsen and J.J.A. Worsaae, seemed to support it. Independently, Thomsen and Worsaae had noted that artifacts found in layers in bogs, burials, and village trash collections called middens were deposited in a sequence: stone artifacts at the bottom oldest level, followed by bronze artifacts in the middle level, and iron artifacts in the top youngest level. This ordering of cultural developments became known as the three-age system, and it worked well in places in which early peoples used all three materials over time to make various tools. However, in other parts of the world, such as Africa and North America, people did not use those tool technologies in the same sequence, and some didn’t use one or more of the technologies at all. Many of the historians and researchers at the time chose simply to ignore this problem and even forced the data to fit the theory.

The problems associated with the three-age system and PSET were not addressed by North American theorists and researchers until Franz Boas, now known as the father of American anthropology, rejected theorizing from incomplete data sets and developed what is known as the classificatory-historical paradigm (sometimes called Historical Particularism). Boas demanded that anthropology be conducted in a scientific manner. Therefore, theories could be developed only after precisely collecting, classifying, and analyzing artifacts. He argued that too little was known about the diversity of human cultures—past and present— and that PSET had been formulated too early and was based on too little actual evidence. Boas and others established collection of data as the fundamental task of anthropology (rather than applying a particular explanatory theory), marking the point at which archaeology became a fully scientific endeavor.

This new paradigm recognized that observation must be the first step to inform the scientific method since it allows one to formulate relevant questions to pursue in subsequent steps. Theory does not start the process of scientific inquiry but rather comes out of extensive study of the natural world. Boas and his successors realized that the anthropological technique of ethnography, which involved careful observation of living peoples and their cultures, could be applied to cultures of the past via archaeology.

Frustrated by the limits of the classificatory-historical paradigm, archaeologists began to introduce a third paradigm, processual archaeology, in the 1960s. It is also sometimes referred to as the New Archaeology. They wanted to examine human behavior more broadly rather than just recover artifacts, so the primary idea underlying processual archaeology is that artifacts and data can be used to explain the past, not just describe it.

Since the focus of processual archaeology was on theoretical interpretations of data, several theoretical approaches developed over time that made explicit the connection between the specifics of archaeological data and the broad theoretical applications.

• Middle range theory (MRT), for example, was based on the idea that linking archaeological data to theories is a matter of linking artifacts or features within a site made by people to the behaviors that created the items.
• American archaeologist Kent Flannery advocated use of systems theory, which was designed to help researchers see the complex whole as a series of smaller subsystems that could be pulled apart and analyzed independently along with the whole.

Ultimately, processual theoretical applications were found to be suitable only in some situations and to be too broad to have general scientific value. Actual data didn’t always fit within a specific theory.

This meant that archaeologists could now shift their focus in pretty substantial ways. Look at the following fictitious examples to see how this shift worked:

Example 1: Food on the coast of Oregon

• Question under Culture History: What were people eating on the coast of Oregon during a specific time period?
• Questions under Processual Archaeology: Why did people on the coast of Oregon rely upon seals and other aquatic mammals for their food during one time period, but stop eating them completely in the following time period?

Example 2: Ceramics in Southeast Asia

• Question under Culture History: What kinds of ceramics did this culture make?
• Questions under Processual Archaeology: Why did this culture make this specific kind of ceramics, and why did their ceramic styles change over time? Was it because of access to certain materials? Was it because of pressures in a trade market? Was it because their diet changed so they needed a different kind of vessel to store or cook a different kind of food?

Lewis Binford, an American archaeologist who is often cited as the father of processual archaeology, advocated for the importance of theory in interpreting human behaviors. He implemented some new techniques. Ethnoarchaeology is a subfield of archaeology that involves observing contemporary people to better understand the archaeological record. Basically, an archaeologist can use use the same ethnographic techniques used by cultural anthropologists. They could then compare the observed behavior of living peoples with the artifacts and features found within archaeological sites. Binford, for example, accompanied Inuit hunters and studied the debris they left behind at hunting stands. He then used that contemporary data to predict what Inuit hunting stands of the past would have looked like and to interpret hunting artifacts found in Inuit excavations.

Researchers always realized that they could also use ethnographic analogy, or interpreting the archaeological record based on similarities observed in already described cultures. This is particularly useful if traditional lifeways are no longer the primary way of doing things in our contemporary world.

Another method that grew of processual archaeology is experimental archaeology. This involve conducting controlled experiments to replicate both the human modified objects and past skills or behaviors that made those items. An example would be to manufacture flaked stone tools. Archaeologists make stone tools using the same tools ancient people used. Not only can they understand the process of manufacturing a certain style or type of stone tool, they can record the lithic (stone) debris (debitage) left behind from making the tool which is often found in the archaeological record. Furthermore, they can take the tools they made and use them on various materials, like plants, meat, bone, etc.. By carefully documenting these patterns of use that remain on the stone tool,  looking at the wear patterns under a microscope, they can create a catalog of use wear. These patterns can be compared with patterns of use on ancient artifacts. This is called use wear analysis.

At the same time, new technologies such as computing and absolute dating techniques were providing researchers with new kinds of data and analytical capabilities that simply did not exist before. Archaeologists could process, analyze, and curate more data than ever before. We could securely date artifacts in ways never possible before.

Processual archaeology is still actively used today. Processual archaeology’s lasting contribution is its use of data and scientific methods to support theoretical applications and analysis, and some of the theoretical approaches proposed (such as predictive human behavioral models), continue to be used to interpret past human behavior.

Many archaeologists viewed processual archaeology as having limited value, and beginning in the late 1970s, in the midst of the feminist and postmodern movements in other disciplines, began formulating a new approach called post-processual archaeology. This paradigm stressed the potential for multiple interpretations of the archaeological record and recognized that every interpretation is affected to some degree by researchers’ biases. Its proponents argued that something as complex as human behavior could not be investigated by testing hypotheses. Instead, their goal was to obtain as broad a perspective of the past as possible by interpreting the data from various vantage points and trying to see the artifacts and data from an “insider’s” (emic) perspective . The post-processual paradigm also placed a greater emphasis on obtaining information about a culture’s religion, symbolism, world view, and iconography from the archaeological record. Post-processual archaeology brought a stronger focus on the role of women, children, and minorities in the past because it encouraged archaeologists to analyze data that previously would have been ignored.