Modelling social agency using diachronic cognition: learning from the Mafia Martin Neumann and Stephen Cowley 1 Abstract. Human cognition is diachronic in that concerted bodily activity links behavior to values that co-evolve with socio-culture: slow historical processes become interlaced with interaction. In principle, therefore, diachronic processes can be placed at the heart of a future socio-cognitive science. In showing how this can be done, we use evidence regarding the historical persistence of Cosa Nostra. In Sicily, the slow processes of a cultural ecosystem, self-maintaining practices, prompt agents to self-configure and make decisions that sustain the mafia. Culture is insinuated into cognitively complex agents who rely on immergence. Having explored how Cosa Nostra self-maintained, we offer a methodology for studying such processes. Agent-based simulation serves to pursue how time-scales are integrated, behavioral patterns sedimented and the effects these have on decision making. Accordingly, we offer a model of cognitively complex agents: these self-configure beliefs, intentions and desires as they engage with social organisations whose rewards demand impersonal conformity. For Cosa Nostra to survive, the ecosystemic power of values like omertà must be sustained as self-configured agents decide how to act. We conclude that effective socio-cognitive modelling offers much to the field of organisational cognition and, above all, the study and management of organisational change. Key words: organisational cognition, distributed language, organisational change, distributed cognition, agent-based modelling, immergence, diachronic cognition 1. Human modes of organizing Recent cognitive science is faced with increasing recognition of the significance of social embedding. In this paper we argue that diachronic cognition is fundamental for socio-cognitive science. In illustration, we turn to agent based simulation for building models that throw new light on the Sicilian Cosa Nostra. As maintained by Vico’s principle of verum factum - truth is verified by creation - modelling permits the experimental investigation of theoretical concepts. This is possible because, using engineering, one program can be embedded in another. In cognitive models, this idea is often used to explore how a world is ‘represented’. However, once one abandons 18 th Century philosophy, one can use the same idea to pursue, not just neural function, but how agents connect actions within embedded systems. Accordingly, we emphasise, not how the social emerges, but rather the immergent processes that drive complex agents to use organisations as they self-configure. Due weight thus falls on how history becomes enmeshed in human cognition. There are good reasons for pursuing this view. First, humans are born into linguistic worlds and, thus, learn from connecting the rapid scales of lived experience with slow ones depending on the slow evolution of external resources. Given their ontogenies, humans both resemble and contrast with social insects. While like bees in drawing on intra-group coordination, human agency is also extended by social and historical organising. People are not totally reliant on factually observable resources –they also draw on what is called society. This is Durkheim’s insight: the social can be used to ground the social. Addressing what is often seen as a paradox, one can link developmental psychology with distributed views of language and cognition to dissolve the seeming paradox. Pursuing this, in a previous paper (Neumann & Cowley 2013), individual rationality is traced to a developmental history that builds on the micro-events of lived co-action. Over time, human agents become users of the resources of reason, language and, most fundamentally, the products of cultural evolution (Hollan, Kirsh& Hutchins, 2000). Enduring cultural products are necessary to diachronic cognition. Not only do they shape the cultural ecologies within which human lives unfold but they self-maintain as biological agents sustain the social world. For example, modern humans use numbers: we trace this to a flow of Shannon information that contributes to cultural 1 Martin Neumann University of Koblenz, Germany Universitaetsstr. 1 56070 Koblenz maneumann@uni-koblenz.de Stephen Cowley University of Southern Denmark Centre for human interactivity cowley@sdu.dk