Until quite recently, discussions on “polycrystals” have been rather concentrated on or confined to how to realistically evaluate the averaged (macroscopic) stress-strain response, focusing on, e.g., relaxed constraint even with FEM simulations. This chapter discusses new perspectives related to Scale C and the attendant theory and modeling for polycrystalline materials including nanocrystals based on the field theory (they mostly are the latest achievements). Emphasis here is placed on the collective effects brought about by a large number of composing grains on the meso- and macroscopic deformation behavior of polycrystals, in the context of hierarchy of polycrystalline plasticity. For this purpose, a series of systematically designed finite element simulations have been conducted.

Like the previous question about “FCC versus BCC” posed in Chapter 1, here is another interesting question of a very fundamental kind that few might be able to answer clearly and appropriately: What is (are) the substantial distinction(s) between single crystals and polycrystals in terms of plasticity? Of course the secondary and tertiary factors such as the effect of “textures” should be excluded. This question is extensively discussed in this section.

Chapter 4 discusses human swarm problem solving as a distinct subtype of CI with biological antecedents in nest siting among honeybees and flocking behavior. Building on recent biological research, this chapter discusses five mechanisms that are also relevant for human swarm problem solving. These mechanisms are decision threshold methods, averaging, large gatherings, heterogeneous social interaction, and environmental sensing. Studies of collective animal behavior show that they often make decisions that build on statistical rules (e.g. averaging, threshold responses). Even when in a group, individuals will often seek and assess information independently of others with the intention of optimizing decisions through the “many wrongs principle” or the “many eyes principle.” Similarly, human ‘wisdom of the crowd’ studies examine similar statistical rules and principles like the importance of making independent contributions. However, while early research on the wisdom of crowds addressed the importance of independent contributions, newer studies also examine the possible positive influence of dependent contributions. The increasing variety of crowdsourcing studies are in this chapter explained with the framework of different swarm mechanisms. In the summary, four basic characteristics of human swarm problem solving are highlighted: predefined problems, pre-specified problem solving procedures, rapid time-limited problem solving, and individual learning.

Political sociology and social movement studies are closely entwined. Modern scholarship on movements was born in the 1960s, when they were detached from fads, crowds, and other collective behavior, and instead came to be seen as a normal part of politics. Since then scholars have perceived social movements and protest as parallel to (and interacting with) parties and elections, often adopted by groups who are excluded from regular institutional channels as a means to pursue their material and ideal interests. The new paradigm at first focused on formal organizations, material resources, and political structures, and was very much a part of a broader political sociology newly enlivened by comparative and historical methods. Scholars such as Charles Tilly (1975, 1978) and Theda Skocpol (1979, 1992) were equally adept at discussing states and protests, partly because revolutions linked the two.