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The emergence of social conventions in multi-agent systems has been analyzed mainly in settings where every agent may interact either with every other agent or with nearest neighbours, according to some regular underlying topology. In this note we argue that these topologies are too simple if we take into account recent discoveries on real networks. These networks, one of the main examples being the Internet, are what is called complex, that is, either graphs with the small-world property or scale-free graphs. In this note we study the efficiency of the emergence of social conventions in complex networks, that is, how fast conventions are reached. Our main result is that complex graphs make the system much more efficient than regular graphs with the same average number of links per node. Furthermore, we find out that scale-free graphs make the system as efficient as fully connected graphs.

Since the agent paradigm emerged, agent researchers have faced the challenge of build-ing open societies in which heterogeneous and independently designed entities can work towards similar or different ends. Open societies involve agents that do not necessarily share the same interests, that do not know and might not trust each other, but that can work together and help each other. One of the key omissions in the computational rep-resentation of open societies relates to the need for norms in multi-agent systems, that help to cope with the heterogeneity, the autonomy and the diversity of interests among their members. This also requires agents that can reason about norms because their par-ticipation in a society, rather than predefined, must be voluntary. So, these agents must understand why norms should be adopted and complied with, and why the authority and the power of agents in a society must be respected. This thesis addresses both the in-troduction of norms in systems of autonomous agents, and the modelling of agents that can reason about norms. The thesis makes three main contributions. First, it develops a framework of norma-tive concepts that enables agents to reason about norms and the society in which they participate. Second, it provides the means for agents to identify situations of power, and to use these powers both for the satisfaction of their goals and to understand why the goals of other agents must be satisfied. This is required since agents in an open soci-ety must interact with other agents which are also autonomous, and power represents a means to influence them. Third, this thesis provides models for agents that adopt and comply with norms not as an end, but as the result of a deliberation process in which their goals and motivations are taken into account. This enables agents to voluntarily decide whether participating in a society is important for the achievement of their goals.

The function of a social norm is to coordinate people’s expectations in interactions that possess multiple equilibria. Norms govern a wide range of phenomena, including property rights, contracts, bargains, forms of communication, and concepts of justice. Norms impose uniformity of behavior within a given social group, but often vary substantially among groups. Over time norm shifts may occur, prompted either by changes in objective circumstances or by subjective changes in perceptions and expectations. The dynamics of this process can be modeled using evolutionary game theory, which predicts that some norms are more stable than others in the long run. Social norms are customary rules of behavior that coordinate our interactions with others. Once a particular way of doing things becomes established as a rule, it continues in force because we prefer to conform to the rule given the expectation that others are going to conform (Lewis, 1969). This definition covers simple rules that are self-enforcing at a primary level, such as which hand to extend in greeting or which side of the road to drive on, and more complex rules that trigger sanctions against those who deviate from a first-order rule. (We express outrage if someone cuts in front of someone else in a queue.) The former are sometimes called conventions and the latter norms (Sugden, 1986; Coleman, 1990; Bicchieri, 2006), but in fact there are numerous gradations and levels of response to norm violation that make this dichotomy problematic. Hence I shall use the term ‘norm ’ in its inclusive sense in what follows. David Hume ([1739], 1978) was the first to call attention to the central role that norms play in the construction of social order. Norms define property rights, 1 that is, who is entitled to what. They determine what commodities are accepted as money. They shape our sense of obligation to family and community. They determine the meanings we attach to words. Indeed it is hard to think of a form of interaction that is not governed to some degree by social norms. (For book-

The development of larger technical systems relies on the coordination of autonomous action of a multitude of individuals and organizations. Institutional settings, often neglected in the analysis of technical development, help to achieve such coordination. Our analysis of international technical standardization in telecommunications highlights an institutionalized process aiming at the creation of compatibility standards as the means for coordination. Formal procedural, membership, and decision rules combined with informal sets of expectations constitute the normative basis of the CCITT, the most prominent international standardization organization in telecommunications. Although scientific, political and economic aspects can be equally important for standards, the CCITT selectively legitimizes a technical perspective. Political and scientific reasoning is restricted, an open economic perspective even completely banned, unless they can be "translated" into a technical perspective. This increases the capacity to proceed on a consensusal basis and often facilitates reaching a consensus in a controversy. Standardization of Videotex and Telefax empirically examplifies this, and at the same time demonstrates the limits of pure technical reasoning to resolve genuine political or economic conflicts.

Abstract. The social laws paradigm represents an important approach to the co-ordination of behaviour in multi-agent systems. In this paper we examine the relationship between social laws and rational behaviour, by which we mean behaviour that can be justified by a defensible argument. We describe how social laws have previously been defined and used within the context of Action-Based Alternating Transition Systems (AATS). We then show how an account of argumentation for practical reasoning in agent systems, also based on AATS, can be used to determine what is rational for the agents to do in the absence and presence of such laws. The reasoning involved is both of a practical and epistemic nature: agents need to make decisions about what to do based upon the assumptions that they make about the states they find themselves in, and crucially, they also need to reason about what the other agents in the scenario will do. What is rational for the agents to do has implications for the need for social laws, the ways in which social laws can help the situation, the form the social laws should take, and the likelihood of compliance with the social laws. This paper demonstrates how we can think about social laws and rational behaviour in a single framework, so as to identify these implications in particular scenarios, and so frame social laws accordingly. 1

HAYEK’S WORKS WOULD SEEM to be divided into two distinct parts that cannot be logically combined (Wilhelm 1972, p. 179f.). On the one rules ” (Gray 1980) on whose basis a spontaneous order arises in the form of individuals ’ interaction (Hayek 1960, pp. 148ff.). This framework must fulfill certain criteria in order to guarantee a maximum of individual freedoms: its rules must be universal, abstract, open, and certain in order to discern equal private spheres for each individual. On the other hand, these criteria would appear to contradict Hayek’s concept of the “twin ideas of evolution and of the spontaneous formation of order ” (Hayek 1991b, p. 81): not only is the social order—the entirety of individuals ’ spontaneous interactions as determined by a framework of a liberal order—the unintended result of evolutionary processes, but so is the framework itself. 1 According to Hayek, a decisive feature of these processes is their uncertain outcome. Therefore, a rule formed in an evolutionary process does not necessarily have the characteristics mentioned above, nor secure individual freedom (Hayek 1973, pp. 88f.). Thus, rules ensuring a liberal order are by no means necessarily identical with those evolved over time. 2

This paper is copyright © 1999 Ian Watson. It may be used for non-commercial personal In 1919, 104 of the world’s territories drove on the left and 104 on the right. Between 1919 and 1986, 34 of the keep-left territories changed to keep-right. No territories shifted in the opposite direction. This paper tests and largely sustains the counterintuitive hypothesis that the reason all changes were in one direction was less that there was any difference between keep-left and keepright as rules, and more that the geographical position of many keep-left territories happened to put them under pressure to change from keep-right neighbors. This paper also discusses six other potential explanations of change, most of which played some role as well. Finally, it shows that the rule of the road is an example of standardization and convention. The explanations of change proposed for the rule of the road are familiar from many other cases of standardization. 2

Nonconsciously activated goals and consciously set goals produce the same outcomes by engaging similar psychological processes (Bargh, 1990; Gollwitzer & Bargh, 2005). However, nonconscious and conscious goal pursuit may have diVerent effects on subsequent affect if goal pursuit aVords an explanation, as nonconscious goal pursuit occurs in an explanatory vacuum (i.e. cannot be readily attributed to the respective goal intention). We compared self-reported aVect after nonconscious versus conscious goal pursuit that either violated or conformed to a prevailing social norm. When goal-directed behavior did not require an explanation (was norm-conforming), aVective experiences did not differ after nonconscious and conscious goal pursuit. However, when goal-directed behavior required an explanation (was norm-violating), nonconscious goal pursuit induced more negative affect than conscious goal pursuit.

Constitutional economics is essentially about the examination and evaluation of the foundational rules of social order. The constitutional perspective suggests that in our pursuit for social improvement changes in rules ought to be the principal means. The paper suggests that the consistency of constitutional perspective as well as its applicability to the business firm may benefit from introducing conventions within its realm. The extended constitutional perspective of the paper attempts to provide a consistently subjectivist framework to help us to understand the linkage between rational constructivist and spontaneous elements in the business firm’s constitutional dynamics.} 1 1