Change is inevitable, but some changes and transformations are more dramatic and fraught with suffering than others. Resilience theory suggests the concept of a “rigidity trap” as an explanation for these differences. In rigidity traps, a high degree of connectivity and the suppression of innovation prolong an increasingly rigid state, with the result that the eventual transformation is harsh. Three archaeological cases from the U.S. Southwest (Mimbres, Mesa Verde, and Hohokam) and new methods for assessing transformations and rigidity are used to evaluate this concept. They reveal the expected association between the severity of transformation and degree of rigidity, suggesting that a rigidity trap contributed to the Hohokam decline, which included significant human suffering. Possible causes of rigidity, with implications for today's world, are explored.

The late pre-Hispanic period in the US Southwest (A.D. 1200-1450) was characterized by large-scale demographic changes, including long-distance migration and population aggregation. To reconstruct how these processes reshaped social networks, we compiled a comprehensive artifact database from major sites dating to this interval in the western Southwest. We combine social network analysis with geographic information systems approaches to reconstruct network dynamics over 250 y. We show how social networks were transformed across the region at previously undocumented spatial, temporal, and social scales. Using well-dated decorated ceramics, we track changes in network topology at 50-y intervals to show a dramatic shift in network density and settlement centrality from the northern to the southern Southwest after A.D. 1300. Both obsidian sourcing and ceramic data demonstrate that long-distance network relationships also shifted from north to south after migration. Surprisingly, social distance does not always correlate with spatial distance because of the presence of network relationships spanning long geographic distances. Our research shows how a large network in the southern Southwest grew and then collapsed, whereas networks became more fragmented in the northern Southwest but persisted. The study also illustrates how formal social network analysis may be applied to large-scale databases of material culture to illustrate multigenerational changes in network structure.archaeology | North American Southwest | spatial analysis | network visualization | regional interaction

This paper identifies rare climate challenges in the long-term history of seven areas, three in the subpolar North Atlantic Islands and four in the arid-to-semiarid deserts of the US Southwest. For each case, the vulnerability to food shortage before the climate challenge is quantified based on eight variables encompassing both environmental and social domains. These data are used to evaluate the relationship between the "weight" of vulnerability before a climate challenge and the nature of social change and food security following a challenge. The outcome of this work is directly applicable to debates about disaster management policy.anaging disasters, especially those that are climate-induced, calls for reducing vulnerabilities as an essential step in reducing impacts (1-8). Exposure to environmental risks is but one component of potential for disasters. Social, political, and economic processes play substantial roles in determining the scale and kind of impacts of hazards (1,(8)(9)(10)(11)(12). "Disasters triggered by natural hazards are not solely influenced by the magnitude and frequency of the hazard event (wave height, drought intensity etc.), but are also rather heavily determined by the vulnerability of the affected society and its natural environment" (ref. 1, p. 2). Thus, disaster planning and relief should address vulnerabilities, rather than returning a system to its previous condition following a disaster event (6).Using archaeologically and historically documented cultural and climate series from the North Atlantic Islands and the US Southwest, we contribute strength to the increasing emphasis on vulnerability reduction in disaster management. We ask whether there are ways to think about climate uncertainties that can help people build resilience to rare, extreme, and potentially devastating climate events. More specifically, we ask whether vulnerability to food shortfall before a climate challenge predicts the scale of impact of that challenge. Our goal is both to assess current understandings of disaster management and to aid in understanding how people can build the capability to increase food security and reduce their vulnerability to climate challenges.We present analyses of cases from substantially different regions and cultural traditions that show strong relationships between levels of vulnerability to food shortage before rare climate events and the impact of those events. The patterns and details of the different contexts support the view that vulnerability cannot be ignored. These cases offer a long-term view rarely included in studies of disaster management or human and cultural well-being (for exceptions, see refs. 13 and 14). This long time frame allows us to witness changes in the context of vulnerabilities and climate challenges, responding to a call for more attention to "how human security changes through time,

In social network analysis, brokerage refers to the processes through which individuals or larger groups mediate interactions between actors that would otherwise not be directly connected. Brokers occupy key intermediate positions that have alternately been interpreted as sources of social capital or potential disadvantages.Recent empirical studies suggest that the relationship between brokerage and rewards or risks varies considerably depending on the nature of interactions in a given setting. In this study, we use a large settlement and ceramic database including sites across the western U.S. Southwest (C.E. 1200-1400) to identify settlements that likely filled brokerage roles in ceramic networks. We develop a new structural measure of brokerage and compare long-term outcomes for settlements characterized by varying degrees of brokerage. We argue that brokerage was not a major source of social capital in our study area, as interactions instead favored the formation of discrete groups over such intermediate positions. [U.S. Southwest, social network analysis, brokerage, social capital, archaeology] RESUMEN En el análisis de redes sociales, intermediación se refiere a los procesos a través de los cuales individuos o grupos más grandes sirven de mediadores en interacciones entre actores que podrían de otra manera no estar directamente conectados. Los intermediadores ocupan posiciones intermedias importantes que alternativamente han sido interpretadas como fuentes de capital social o potenciales desventajas. Estudios empíricos recientes sugieren que la relación entre intermediadores y recompensas o riesgos varia considerablemente dependiendo de la naturaleza de las interacciones en un contexto dado. En este estudio usamos un asentamiento grande y una base de datos de cerámicas incluyendo sitios a través del sur del Suroeste de los Estados Unidos (1200-1400 E.C.) para identificar asentamientos que llenaron los papeles de intermediarios en redes de cerámica. Desarrollamos una nueva medida estructural de intermediación y comparamos resultados de largo plazo para poblaciones caracterizadas por diferentes grados de intermediación. Argüimos que la intermediación no fue una fuente mayor de capital social en nuestraárea de estudio en la medida en que interacciones en cambio favorecieron la formación de grupos discretos en vez de tales posiciones intermedias. [Suroeste de Estados Unidos, análisis de redes sociales, capital social, arqueología] Matthew A. Peeples Archaeology Southwest, Tucson, AZ 85701, mpeeples@archaeologysouthwest.org http://www.mattpeeples.net

The value of "diversity" in social and ecological systems is frequently asserted in academic and policy literature. Diversity is thought to enhance the resilience of social-ecological systems to varied and potentially uncertain future conditions. Yet there are trade-offs; diversity in ecological and social domains has costs as well as benefits. In this paper, we examine social diversity, specifically its costs and benefits in terms of decision making in middle range or tribal societies, using archaeological evidence spanning seven centuries from four regions of the U.S. Southwest. In these nonstate societies, social diversity may detract from the capacity for collective action. We ask whether as population density increases, making collective action increasingly difficult, social diversity declines. Further, we trace the cases of low diversity and high population density across our long-temporal sequences to see how they associate with the most dramatic transformations. This latter analysis is inspired by the claim in resilience literature that reduction of diversity may contribute to reduction in resilience to varied conditions. Using archaeological data, we examine social diversity and conformity through the material culture (pottery styles) of past societies. Our research contributes to an enhanced understanding of how population density may limit social diversity and suggests the role that this association may play in some contexts of dramatic social transformation.