Why the Middle Atlantic?

Although archaeologists debated the boundaries of the Middle Atlantic cultural area for many years (Custer 1994; Hantman and Gold 2002; Kinsey 1971), the region is now generally understood to extend from North Carolina to New York and from the Atlantic Ocean to the Appalachian Mountains (Fig. 1). This paper, with its focus on the Middle Atlantic, arose from the author’s dissertation research, which examined the distribution of Native prehistoric smoking pipes and their relation to prehistoric social networks in the region. An investigation of the history of archaeology in the region revealed that the spatial approaches used to examine and depict Native American cultures and networks were fairly consistent over time and primarily focused on techniques of simplification and generalization. In particular, researchers tended to consistently use cultural areas/complexes and physiographic provinces as the main methods of visualizing Native societies and networks.

This paper expands on the dissertation research by taking a more critical look at maps and their role in research and interpretation. The following sections provide a brief background on the aforementioned cultural territories and how their representations on maps are related to shifts in theoretical paradigms within the archaeological discipline. The review provides context for the investigation of more recent maps that follows in the next section. It is ordered chronologically and begins with the maps of the cultural historians.

Cultural Historians

The goals of anthropologists and archaeologists working in North America during the early 20th-century were primarily framed by the cultural historical paradigm (Trigger 2006; Willey and Sabloff 1974). Many archaeologists conducting research during this period drew from a conception of culture that stressed continuity over wide geographic areas (Binford and Sabloff 1982: 139–140; Driver 1961; Driver and Massey 1957; Holmes 1903; Kroeber 1939; Wissler 1922). Researchers sought to delineate the territories of Native groups by blocking out larger territories based on generalized similarities of linguistic components, cultural traits (e.g. types of subsistence, social organization, economy) and material culture. Areas that exhibited homogeneity in these traits were considered cultural areas. Figure 2, a recreation of a map from Driver and Massey’s 1957 work, Comparative Studies of the North American Indian, is an example of how these areas were illustrated on maps.

To depict cultural areas archaeologists tended to use cartographic techniques of selection and simplification. The majority of maps used in the first half of the 20th-century were small-scale maps with cultural territories delineated by solid boundary lines and areas infilled with different patterns. Boundaries for maps like the one pictured in Figure 2, were drawn based on a lack of similar cultural traits from one area to the next. However, even while endorsing these maps, a number of researchers noted the fluidity of boundaries and how difficult they can be to delineate (Driver 1961: 18; Driver and Massey 1957: 172; Holmes 1914: 414; Kroeber 1939: 6; Wissler 1922). Nevertheless, the shifts between cultural areas were depicted as abrupt and distinct transitions.

It is not surprising that cultural historians primarily employed the cartographic techniques of simplification and selection. These maps emphasized the aspects of Native societies that were important to research. As Driver and Collins (1975: 7) noted the aims of these maps were mostly descriptive, the goal being to depict the most up-to-date inventories of Native American culture traits that anthropologists had identified. Another important consideration when evaluating symbology is the level of measurement of the data. Cultural historians were primarily measuring data on a nominal level, which meant they were limited in what kinds of symbology they could use.

While the culture area paradigm continued to guide archaeological research and interpretation well into the middle of the 20th-century, archaeologists became increasingly interested in moving beyond the description of generalized culture areas to gain a better understanding of the behaviors of prehistoric and historic groups who inhabited these regions and how they changed over time (Guthe 1952: 11; Willey and Sabloff 1974: 133). As a result, a new paradigm was developed, known as processualism.

Processualism

The rise of processual archaeology in the later half of the 20th-century instigated a movement to push pass descriptions of shared traits to investigate cultures as integrated functional systems. With this movement cultural areas fell out of favor as research foci in North American archaeology. Instead, archaeologists became increasingly interested in discerning the dynamic connections between nature and culture. Archaeologists embraced human ecology studies as they centered their attention on the functional systems of prehistoric groups (Willey and Sabloff 1974: 152). This expanded the focus from cultural traits to include settlement patterns and subsistence studies. To depict this change archaeologists altered the ways they illustrated their results. Rather than using small scale qualitative maps, archaeologists started using diagrams and occasionally flow maps (see Table 1) to depict the movement of groups between settlement types during different seasons of the year (Custer 1986; Thomas 1973), or to depict how Native groups moved from different procurement areas to base camps (Custer 1986).

Although the types of maps used during the processual period varied from those used in earlier periods, archaeologists charting Native American material culture in the Middle Atlantic continued to use culture as a basic unit of inquiry, albeit in a different form. A rising interest in human ecology caused the boundaries of these units to shift into alignment with geographic regions called physiographic provinces. A physiographic province is a landform region or area delineated according to similar terrain that has been shaped by a common geologic history. The five physiographic provinces that run north and south through the Middle Atlantic region are, from east to west, the Coastal Plain, the Piedmont, the Blue Ridge Mountains, the Ridge and Valley, and the Appalachian Plateau. The five provinces that pertain to the study area of this project are illustrated in Figure 3.

A number of Middle Atlantic archaeologists tended to portray physiographic provinces as bounded cultural units, especially during the Late Woodland period (Gallivan 2003: 6). The distribution of artifacts and settlement features, such as ceramic temper, lithic raw material, house shape, storage methods, among others, was compared within a province but also across provinces’ borders. It was used to argue that variations in resource availability between the provinces helped foster different cultural units (Custer 1994; Gardner 1987; Mouer 1981). As a result, small-scale maps with solid boundaries continued to be used by archaeologists but the boundaries’ positions replicated physiographic provinces. However, in their symbology, some researchers replaced solid lines with dotted lines around territorial boundaries to indicate uncertainty.

In addition to physiographic provinces, entities known as cultural complexes continued to serve as units of interest to Middle Atlantic archaeologists. Although these complexes were originally meant to serve as units to research archaeological cultures as dynamic and integrated systems, in many ways they simply became smaller versions of culture areas. The continued association of ‘archaeological cultures’ with ‘real’ units encouraged Middle Atlantic archaeologists to focus on classes of material culture that could consistently be tied to a ‘culture.’ Ultimately, as distributions of artifact classes were found to extend outside of ‘cultural’ boundaries, archaeologists extensively pared down the classes of material culture that could be ‘reliably’ used as diagnostic traits. In essence, ceramic forms became the only dependable material cultural class for these types of analyses (Dent 2003; Jirikowic 1995; Kavanagh 1982; Potter 1993). Thus, rather than embracing variation, archaeologists began to eschew variability in favor of consistency or continuity in artifact patterning. As a result, maps depicting Native cultural complexes represented groups that were much like the culture areas of the cultural historians. More importantly, the uncertainty inherent to the archaeological rendering of cultural units disappeared. Researchers used similar symbology to depict these units as areas unified with one color or pattern bounded by solid lines.

Post-processualism: Taking it Apart

Despite the persistence of cultural complexes, within the last few decades, archaeologists have drastically changed their view of Native American cultures. The development of post-processualism has encouraged a number of Middle Atlantic researchers to shift their focus. Drawing from Hodder (1982) and Shennan (1989: 11–24) these archaeologists have questioned the utility of drawing direct relationships between material patterning and particular types of social categories, such as cultures. They suggest that archaeologists have done enough to establish and describe the basic units and should move towards ‘picking things apart’ (Dent 2003; Egloff 1992; Means 2003) and embrace uncertainty.

Additionally there is a growing consensus that archaeologists working in the region should give more consideration to the kind of units they are defining and more attention to the variation within those units. For example, Means (2003) has suggested that the boundaries of cultural complexes are useful analytical tools for looking at variation, but that it is dangerous to perceive them as actual social units. Cultural complexes–while useful for differentiating the spatial and temporal variation of objects–must be explicitly defined as tools: analytical units and not actual representations of Native cultures and communities. Furthermore, there is a growing realization that the depictions of Native culture identified and shared by archaeologists have an impact on the general public and on contemporary Native communities. Thus, illustrating past Native cultures as solely homogeneous and bounded units, rather than dynamic and mobile, suggests Native cultures were static entities in space and time. This has a negative impact on contemporary cultures that are fighting against this kind of stereotype as they work to educate the public about their history and culture.

With the advent of shifting interests in the discipline one might expect maps from more recent years to incorporate different types of symbology or methods of communicating uncertainty in an effort to address the call to break things apart. The next section investigates whether such design changes are actually being incorporated into archaeological interpretation.

Sample

To compose a representative sample of the maps used by Middle Atlantic archaeologists it was necessary to find publications that covered the whole region. Drawing from similar studies of changes in map production over time (Fitzsimons and Turner 2006; Kessler and Slocum 2011) it was deemed preferable to focus on journals as opposed to individually authored books. Ultimately, the Journal of Middle Atlantic Archaeology was chosen as the data source. Two factors ultimately led the author to choose this journal. The first was the interest in focusing on the Middle Atlantic region as much as possible while getting a representative sample of current research topics. One limitation of using this journal, however, is that publication did not begin until 1985. This meant that the journal did not cover as long of a timespan as journals like the Archaeology of Eastern North America, or the Bulletin of the Eastern States Archaeological Federation, which were also considered for the study. However, due to its regional focus, the fact that the journal represents current trends in the region and has had a consistent set of submission guidelines for authors (which could impact whether maps would be included), it was deemed the best possible dataset.

Besides choosing the journal, it was necessary to determine what kinds of articles to include. In addition to research articles, each volume of JMAA contains introduction pieces, correspondence from the editor, editorials, and book reviews. Book reviews, editorials, news and notes, and any correspondence were not analyzed because spot-checking these types of articles showed they did not contain any maps or non-textual materials. Finally, it should be noted that map data was collected from all the articles in a volume no matter what the subject. Although the primary interest was the use of maps to depict Native culture boundaries, the author anticipated that the number of articles focusing on that topic might be too small of a group to make any meaningful observations. Thus the investigation looks at map use more generally while giving special consideration to those articles that dealt with past Native communities.

Data Collection

In addition to information on maps, data on non-textual elements was collected to provide a more holistic understanding of how maps were used to communicate information in relation to other illustrations. The following non-textual elements were considered in addition to maps: tables, graphs, photographs, diagrams, drawings, paintings, and forms. Roughly the same qualities as those used by Kessler and Slocum (2011: 297) were used to categorize non-textual elements. Tables were considered to be tabular arrangements of data. Graphs were identified as abstract representations of the relationship of two or more sets of numerical data. Diagrams were considered to be illustrations of how something works or directional flow (as in a flow chart). Photographs were images of objects taken using a camera. Items categorized as drawings or paintings were any illustrations in paint, pencil, or ink that represented cultural or natural phenomena. Forms consisted of copies of site’s illustrations or curation forms used in the field or lab.

Maps were divided into two categories: general reference (including locational maps) and thematic maps. A number of sources (Dent 1999: 5; Kessler and Slocum 2011: 297; Muehrcke and Muehrcke 1998; Slocum, McMaster, Kessler and Howard 2005: 2) define general reference maps as maps that provide an overview of a variety of natural and cultural phenomena pertaining to a region with as much locational accuracy as appropriate. In contrast, a thematic map focuses on the distribution of a particular type of social or physical phenomena. It should be noted that the line between these two kinds of maps can be fuzzy (Petchenik 1979) so it was at times difficult to assign a map to one of these two categories. Some maps in the sample seemed to be serving both purposes, i.e. providing an overview of the site or region while showing the distribution of a particular characteristic or attribute. This is not surprising given that authors had limited space. If a map seemed to emphasize one type of phenomena (e.g. the distribution of sites, artifacts, excavation units) even if it provided an overview, it was placed in the thematic category so it could be further studied according to the criteria explained below.

Besides comparing locational and thematic maps, the author was particularly interested in tracking the use of different thematic maps to investigate if the incorporation of post-processual theory increased the diversity in the types of maps archaeologists were using to illustrate cultural and natural phenomena. Within the thematic map category, nine subdivisions were created to capture variation in the types of thematic maps used by archaeologists. The nine categories used were: cartogram, choropleth, dot, flow, graduated symbols, geologic, historic, isarithmic, and qualitative. All of these are either adopted from Kessler and Slocum (2011) and/or are commonly discussed in cartography textbooks (Dent 1999; Slocum, McMaster, Kessler and Howard 2005). The main criteria used to categorize different kinds of maps into these subdivisions are summarized in Table 1. Examples of some of these maps are included in Figures 2, 3, 4a and 4b.

In addition to looking at the use of different kinds of thematic maps, information was collected on the use of different kinds of symbols in thematic maps such as solid or dotted lines, infilling, labeling, and symbolization. The occurrence of these symbols within the selected data was recorded to analyze whether solid lines and infill continued to predominate as an illustrative technique.

Hypotheses

A few hypotheses were developed based on the goals of the study to guide data collection and analysis:

Hypothesis 1: There will be a general increase in the use of maps over time and in relation to other types of non-textual elements due to the introduction of computerized cartography.

Hypothesis 2: There will be an increase in use of different kinds of thematic maps through time as archaeologists try to incorporate ideas from post-processual movement. For example one would expect to see an increase in flow maps or cartograms as opposed to the consistent use of qualitative maps.

Hypothesis 3: There will be increased variation in the symbols used in later time periods with introduction of computerized mapping and the incorporation of ideas from post-processualism. For example, the use of solid boundary lines and infill will be minimal.

Results

A total of 310 articles from the JMAA were analyzed to examine how maps were used and if their use changed through time. To analyze change over time, the journal articles were divided into six different periods, each containing five years. The only exception was the last group, which had four instead of five years. The interval of five years was chosen because it divided the articles in the 29 volumes into fairly even groups. These six groups were used as the primary units for analysis. Table 2 shows the number of articles contained within each five-year interval, which ranges from 45 to 61. It also shows the percentage of articles in each period that contained maps, which did not immediately seem to fluctuate in a consistent manner.

The next step was to analyze the data and evaluate the three hypotheses. All analyses were conducted in R (R Development Core Team 2014) and Figures 5 through 9 were created with R’s ggplot2 package (Wickham 2009). The first analysis examined if the number of maps used in journal articles changed through time. Figure 5 is a histogram that shows the distribution of maps within each time period. The histograms show that maps were consistently used in the JMAA through time. It is notable that most articles had four or fewer maps. This is likely due to the fact that authors had to keep their papers to reasonable lengths although some contributors did include as many as 11 maps. However, in contrast to the proposed hypothesis there is no indication of a clear trend of maps increasing through time. Instead the histogram suggests that from 1990–2005 the frequency of articles without maps increased.

The decrease in map use through time suggested by the histogram was reinforced when the percentage of articles with maps was compared with the use of non-textual elements in the text (Fig. 6). The graph shows that maps were consistently used during all six periods, but there is a marked downward trend in their use from 1990-2005. In contrast, during the same time span, the percentage of articles using tables and graphs increased. However, it should be noted that at the lowest point, maps were still used in 44% of articles.

The downward trend in map use from 1990–2005 is interesting given that computerized mapping software was becoming more widely available during this period. A look back at the volumes published shows that at least one focused on a topic that does not necessarily lend itself to mapping: Volume 21 published in 2005 focused on curation. But the focus in one volume certainly does not explain the overall downward trend. A closer look at the volumes published in this 15-year period provided some possible explanations. A number of articles focused on the classification of artifacts, which does not necessarily have a spatial component. Other researchers looked at ethnohistory, and still others dealt with more theoretical topics. If nothing else, this data shows the variety of elements archaeologists use to illustrate their results and their interpretations, and the diversity of topics covered in JMAA.

Besides looking at general trends in the use of maps, the author was curious about the different kinds of maps used by archaeologists. Figure 7 is a comparison of the two types of maps classified in the study, referential/locational maps and thematic maps. The graph illustrates that thematic maps were used consistently and in a higher percentage of articles than referential maps. This is interesting because it indicates that referential maps were not as important for illustrating or situating archaeological arguments as thematic maps. However, it should be noted that when a map seemed to fulfill the criteria for both referential and thematic it was classified as thematic. Thus, the higher percentage of thematic maps could be due to the way referential vs. thematic maps were categorized.

The next analysis centered on the second hypothesis and considered the use of different types of thematic maps. With the advent of post-processualism, one might expect to see increased variation in the types of thematic maps used over time as archaeologists diversified the types of social phenomena they were interested in. However, as illustrated in Figures 8 and 9, the use of different kinds of thematic maps did not change over time. Instead the frequency of thematic maps’ use remained fairly consistent and broke down into two distinct divisions. One division included three kinds of maps: historic, dot, and qualitative which typically were used in 20–60% of articles containing maps. The other five types of maps (cartogram, choropleth, flow, graduated symbols, and isarithmic) consistently comprised less than 20% (in all but one case less than 10%) of the maps used in each period.

Given the persistent use of qualitative maps the final analysis focused on whether the symbology had changed over time. This examination focused on depictions of Native cultures. Out of the 169 thematic maps contained in the dataset, 17 were used to illustrate Native American cultures or linguistic areas. Four maps used solid lines, three used dotted lines, and nine had an area infilled with a pattern with no boundary lines. Although it is a small sample, it is encouraging that the majority of maps (70%) did not use solid lines and indicated that the boundaries of the territories were not discrete or abrupt. However, it is somewhat surprising that qualitative maps continue to be so popular given that there are other methods for mapping territories available.

Alternative Views of Space and Place

Historic accounts indicate that Western explorers were not the only people creating maps in the early Middle Atlantic. In fact, Native peoples drew or provided the data for many of the earliest maps that illustrated parts of North America (Lewis 1998; Norona 1950; Vorsey 1992; Waselkov 2006). Unfortunately most of these maps were often drawn on ground surfaces or organic materials, such as deerskins, and have not survived. The few surviving examples, however, demonstrate that Native people had extensive cartographic capabilities. Furthermore, these maps indicate that Native people used their own cartographic symbology. Researchers have noted that Native maps could provide an extremely accurate bird’s eye view of tertian and geographic locales (Lewis 1998). On the other hand, some maps tended to ignore geographic distance and used size and distance as an indicator of cultural factors, such as political influence or the strength of a relationship between two groups (Waselkov 2006). Additionally, the use of simple symbols and a ‘variable scale’ are also important components of Native cartography.

The research into indigenous mapmaking, and the acceptance of the fact that Native peoples had their own informed and complex view of natural and social topo­graphy, has encouraged historians, cartographers, anthropologists and archaeologists to rethink the symbology and themes used in their mapping. While differences in artifacts can be used to show differences and boundaries, they also embody similarities that are material evidence of relationships. Perhaps the most appropriate maps to illustrate relationships are cartograms. Cartograms give up geographic and topographic accuracy by using a variable scale to depict relationships, territories, and networks and travel routes. No cartograms were used in JMAA. Yet their incorporation into research might provide an interesting expansion of the ways archaeologists depict space and place in the past.

Mapping Mobility and Social Networks

Research into Native cartography has demonstrated that many individuals in Native communities were extremely knowledgeable about the geography of their immediate area and, in some instances, of areas well beyond their immediate vicinity. Material culture studies of Native lithics and ceramics have also shown that individuals or groups would travel long distances to procure necessary or important resources. While communities had home territories they were also on the move and created relationships that traversed cultural and even linguistic boundaries. Native people were clearly mobile and this should be taken into account when creating maps.

In addition to movement, social and exchange networks were an important part of Native culture. Ethnohistorical evidence from maps created in large part from Native informants even suggests that Native people used solid boundaries to delineate territories to illustrate the networks that bound them together (Lewis 1998; Waselkov 2006). Thus, networks were just as important as boundaries.

Flow maps provide a means of illustrating or depicting movement. Recent developments in mapping programs, such as ArcGIS, have made it easier to depict networks and movement of goods and people using flow maps (Gegit 2013). A total of 11 flow maps were present in the JMAA dataset and Figure 8 demonstrates that their use increased slightly in the last five years. Cross’s (2012) article in particular demonstrates that new applications, such as cost path analyses, can help researchers determine which pathways Native peoples most likely used while also illustrating them for readers. Again, cartograms can also be employed to illustrate relationships or networks. Finally, the recent development of visualization programs like Neatline software allows archaeologists to create animations that can help audiences to actually visualize the movement of past individuals and groups through landscape. These types of illustrations help reinforce the idea that Native peoples were dynamic and mobile, not static cultural entities.

Depicting Uncertainty

Perhaps one of the most difficult aspects of depicting social landscapes is the uncertainty of any social entity’s boundaries. Archaeology is not the only discipline to struggle with the depiction of uncertainty (MacEachren, Robinson, Hopper, Gardner, Murray, Gahegan and Hetzler 2005). Geographers, geologists, and cartographers have also struggled to communicate this concept on maps in an effective way for centuries. MacEachern (1992) and Slocum, McMaster, Kessler and Howard (2005) have suggested that transparency, crispness, and differing resolution provide ways of illustrating uncertainty to map-readers. By thinking of cultural and linguistic boundaries as smooth continuous phenomena and delineating interaction or uncertainty with transparency one can communicate a more nuanced view of Native cultures and community boundaries.

Figure 10 provides an example of depiction of uncertainty. Using the ring buffer tool in ArcGIS, the boundaries of Middle Atlantic cultural complexes can be depicted as ‘fuzzy’, indicating uncertain boundaries. Adding transparency to the buffer lines also allows them to overlap without canceling each other out. This is just one way for archaeologists to communicate or illustrate the spatial dimensions of our analytic units but also show that Native cultures were not bound entities.

In conclusion, this article has sought to better understand how archaeologists have used and continue to use maps. It has demonstrated that the cartographic decisions used in making maps are impacted by the introduction of different theoretical paradigms in the discipline. Despite the introduction of post-processualism, the types of maps used by archaeologists have not necessarily changed. Hopefully the ideas presented here will encourage fellow archaeologists to be aware of how the units and symbols have a broader impact and to experiment with different kinds of maps to communicate ideas.