How Can Social Networks Ever Become Complex? Modelling the Emergence of Complex Networks from Local Social Exchanges

Small-world and power-law network structures have been prominently proposed as models of large networks. However, the assumptions of these models usually lack sociological grounding. We present a computational model grounded in social exchange theory. Agents search attractive exchange partners in a diverse population. Agent use simple decision heuristics, based on imperfect, local information. Computer simulations show that the topological structure of the emergent social network depends heavily upon two sets of conditions, harshness of the exchange game and learning capacities of the agents. Further analysis show that a combination of these conditions affects whether star-like, small-world or power-law structures emerge.Complex Networks, Power-Law, Scale-Free, Small-World, Agent-Based Modeling, Social Exchange Theory, Structural Emergence

Risk Taking of Executives under Different Incentive Contracts: Experimental Evidence

Classic financial agency theory recommends compensation through stock options rather than shares to induce risk neutrality in otherwise risk averse agents. In an experiment, we find that subjects acting as executives do also take risks that are excessive from the perspective of shareholders if compensated through options. Compensation through restricted company stock reduces the uptake of excessive risks. Even under stock-ownership, however, experimental executives continue to take excessive risks—a result that cannot be accounted for by classic incentive theory. We develop a basic model in which such risk-taking behavior is explained based on a richer array of risk attitudes derived from Prospect Theory. We use the model to derive hypotheses on what may be driving excessive risk taking in the experiment. Testing those hypotheses, we find that most of them are indeed borne out by the data. We thus conclude that a prospect-theory-based model is more apt at explaining risk attitudes under different compensation regimes than traditional principal-agent models grounded in expected utility theory

The Interest Theory of Rights and Rights Attached to Roles

In this essay, I defend the interest theory of rights against the argument that because some agents hold rights grounded in a special role or office, rather than their own interests, the theory is false. I begin by explaining the interest theory and the argument from rights attached to roles against it. I then explore responses to this objection by Kramer and Raz, ultimately rejecting them and proposing a simpler solution of my own. My response stipulates that in cases where people seem to have rights grounded in a special role, it is actually the state or the society that holds those rights. Given that the interest theory can allow collective entities to have rights, this response manages to retain the full explanatory power of the original theory, without introducing additional theoretical conditions for agents holding rights. Based on this, I argue that the argument from rights attached to roles is not sufficient to refute the interest theory

Risk Taking of Executives under Different Incentive Contracts: Experimental Evidence

Classic financial agency theory recommends compensation through stock options rather than shares to induce risk neutrality in otherwise risk averse agents. In an experiment, we find that subjects acting as executives do also take risks that are excessive from the perspective of shareholders if compensated through options. Compensation through restricted company stock reduces the uptake of excessive risks. Even under stock-ownership, however, experimental executives continue to take excessive risks—a result that cannot be accounted for by classic incentive theory. We develop a basic model in which such risk-taking behavior is explained based on a richer array of risk attitudes derived from Prospect Theory. We use the model to derive hypotheses on what may be driving excessive risk taking in the experiment. Testing those hypotheses, we find that most of them are indeed borne out by the data. We thus conclude that a prospect-theory-based model is more apt at explaining risk attitudes under different compensation regimes than traditional principal-agent models grounded in expected utility theory.prospect theory; expected utility theory; risk attitude; executive compensation; reference dependence; experimental finance

A holistic perspective on career development in UK female soccer players: A negative case analysis

Objectives: The purpose of this study was to examine career experiences of UK-based female youth soccer players from a holistic perspective with a view to producing a grounded theory of factors contributing to career/talent development and transitions in UK youth female soccer. Methodology: A Grounded Theory methodology (Corbin & Strauss, 2008) was used. Negative case (Denzin, 1989) former female soccer players (N=13), their best friend (N=13), soccer coaches (N=4), and teachers (N=8) took part in semi-structured interviews about factors associated with talent development and career transitions in female youth soccer. Results: Multiple social agents (players, team-mates, peers, teachers, parents and siblings) need to optimally interact to ensure that an optimal talent development and learning environment is created. This will provide a supportive holistic talent development environment, lead to adaptive player-level changes, and a greater chance of successful athletic and dual career development. Conclusions: This study presents a rich understanding of the dual careers of players who did not make it in female soccer. By considering their perspectives alongside of a range of important social agents, we have been able to construct a substantive grounded theory of factors contributing to career/talent development and transitions in UK youth female soccer. As a result, these findings may contribute to policy and practice development in UK female youth soccer

Logic of Justified Beliefs Based on Argumentation

This manuscript presents a topological argumentation framework for modelling notions of evidence-based (i.e., justified) belief. Our framework relies on so-called topological evidence models to represent the pieces of evidence that an agent has at her disposal, and it uses abstract argumentation theory to select the pieces of evidence that the agent will use to define her beliefs. The tools from abstract argumentation theory allow us to model agents who make decisions in the presence of contradictory information. Thanks to this, it is possible to define two new notions of beliefs, grounded beliefs and fully grounded beliefs. These notions are discussed in this paper, analysed and compared with the existing notion of topological justified belief. This comparison revolves around three main issues: closure under conjunction introduction, the level of consistency and their logical strength.acceptedVersio

A learning model of community collaboration in West Virginia

This study tested a grounded theory model, Getting it Together: A Learning Model of Community Collaboration, developed during a six-year study (2004-2010) of a statewide substance abuse prevention program funded by the Substance Abuse and Mental Health Services Administration (SAMHSA) and the Center for Substance Abuse Prevention (CSAP). The model features the perceptions and experiences of those who were active in community-based collaborative and educational work in West Virginia focused on substance abuse prevention. The study revisited community coalitions from three counties that were part of the original ethnographic research used to develop the community collaboration theory. The grounded theory model was used as the lens through which to examine what the three community coalitions experienced in the subsequent years. The findings from this collective case study support the grounded theory model and its key components—the “right” people, collaborative engagement, shared commitments, and financial resources, bound together by a focus on learning. Further, findings suggest theory modifications related to the importance of: 1) youth members and paid staff; 2) coalitions’ community presence and reputation; 3) evolving shared commitments within the coalition as well with other community groups; 4) continuity in supportive fiscal agents; and 5) the quality of learning opportunities for coalitions. In effect, new information advanced knowledge about key factors related to the effectiveness and sustainability of community coalitions

How Natural Selection Can Create Both Self- and Other-Regarding Preferences, and Networked Minds

Biological competition is widely believed to result in the evolution of selfish preferences. The related concept of the `homo economicus' is at the core of mainstream economics. However, there is also experimental and empirical evidence for other-regarding preferences. Here we present a theory that explains both, self-regarding and other-regarding preferences. Assuming conditions promoting non-cooperative behaviour, we demonstrate that intergenerational migration determines whether evolutionary competition results in a `homo economicus' (showing self-regarding preferences) or a `homo socialis' (having other-regarding preferences). Our model assumes spatially interacting agents playing prisoner's dilemmas, who inherit a trait determining `friendliness', but mutations tend to undermine it. Reproduction is ruled by fitness-based selection without a cultural modification of reproduction rates. Our model calls for a complementary economic theory for `networked minds' (the `homo socialis') and lays the foundations for an evolutionarily grounded theory of other-regarding agents, explaining individually different utility functions as well as conditional cooperation

Preservation of Semantic Properties during the Aggregation of Abstract Argumentation Frameworks

An abstract argumentation framework can be used to model the argumentative stance of an agent at a high level of abstraction, by indicating for every pair of arguments that is being considered in a debate whether the first attacks the second. When modelling a group of agents engaged in a debate, we may wish to aggregate their individual argumentation frameworks to obtain a single such framework that reflects the consensus of the group. Even when agents disagree on many details, there may well be high-level agreement on important semantic properties, such as the acceptability of a given argument. Using techniques from social choice theory, we analyse under what circumstances such semantic properties agreed upon by the individual agents can be preserved under aggregation.Comment: In Proceedings TARK 2017, arXiv:1707.0825