Francesca Giardini

A model for simulating reputation dynamics in industrial districts

Abstract In this work we try to draw an interdisciplinary framework aimed to integrate a socio-cognitive approach with organizational research about industrial clusters, in order to investigate whether and how social evaluations may affect clusters’ dynamics. Industrial districts are sort of “small-worlds” that provide a suitable environment for testing the predictions of our model through multi-agent-based social simulation (MABSS) experiments. Artificial agents will be allowed to exchange products and to transmit social evaluations, and the main features of a cluster will be implemented. The effects of evaluation transmission on products’ quality, partner selection and cheaters’ isolation will be discussed.

Evolution of gossip-based indirect reciprocity on a bipartite network

There are several mechanisms in human societies that help supporting cooperation. Gossiping, for instance, allows to identify defectors who can then be punished via ostracism. However, the evolutionary stability of gossip might be undermined by the fact that it is more error-prone that direct observation, whereas ostracism could be ineffective if the partner selection mechanism is not robust. The aim of this work is to investigate the conditions under which the combination of gossip and ostracism might support cooperation in groups of different sizes. We are also interested in exploring the extent to which errors in transmission might undermine the reliability of gossip as a mechanism for identifying defectors. Our results show that a large quantity of gossip is necessary to support cooperation, and that group structure can mitigate the effects of errors in transmission.

Revenge and Conflict: Social and Cognitive Aspects

Revenge can be conceptualized as an attempt to restore the power balance destroyed by an aggression. It can be risky and costly for the individuals, and it can become completely disruptive at the social and societal level. At the individual level, revenge implies the risk of a counterattack, either coming from the target or from his or her kin and relatives, and it is costly because of the effort it requires. At the social level, a likely and dangerous consequence of revenge is the emergence of feuds, with whole families and groups fighting against each other. Moreover, material resources can get wasted in the conflict, thus further increasing the costs of revenge. Even so, revenge is still part of our behavioral repertoire, humans take revenge continuously, both at a small and at a larger scale. How could have revenge survived if it is costly and dysfunctional? Why do humans still resort to revenge when reacting to a wrong suffered?

Consensus emerging from the bottom-up: the role of cognitive variables in opinion dynamics

The study of opinions − e.g., their formation and change, and their effects on our society − by means of theoretical and numerical models has been one of the main goals of sociophysics until now, but it is one of the defining topics addressed by social psychology and complexity science. Despite the flourishing of different models and theories, several key questions still remain unanswered. The aim of this paper is to provide a cognitively grounded computational model of opinions in which they are described as mental representations and defined in terms of distinctive mental features. We also define how these representations change dynamically through different processes, describing the interplay between mental and social dynamics of opinions. We present two versions of the model, one with discrete opinions (voter model-like), and one with continuous ones (Deffuant-like). By means of numerical simulations, we compare the behaviour of our cognitive model with the classical sociophysical models, and we identify interesting differences in the dynamics of consensus for each of the models considered.The study of opinions − e.g., their formation and change, and their effects on our society− by means of theoretical and numerical models has been one of the main goals of sociophysics until now, but it is one of the defining topics addressed by social psychology and complexity science. Despite the flourishing of different models and theories, several key questions still remain unanswered. Aim of this paper is to provide a cognitively grounded computational model of opinions in which they are described as mental representations and defined in terms of distinctive mental features. We also define how these representations change dynamically through different processes, describing the interplay between mental and social dynamics of opinions. We present two versions of the model, one with discrete opinions (voter model-like), and one with continuous ones (Deffuant-like). By means of numerical simulations, we compare the behaviour of our cognitive model with the classical sociophysical models, showing how consensus is reached in either.

Partner Selection Supports Reputation-Based Cooperation in a Public Goods Game

In dyadic models of indirect reciprocity, the receivers’ history of giving has a significant impact on the donor’s decision. When the interaction involves more than two agents things become more complicated, and in large groups cooperation can hardly emerge. In this work we use a Public Goods Game to investigate whether publicly available reputation scores may support the evolution of cooperation and whether this is affected by the kind of network structure adopted. Moreover, if agents interact on a bipartite graph with partner selection cooperation can thrive in large groups and in a small amount of time.

Group Size and Gossip Strategies: An ABM Tool for Investigating Reputation-Based Cooperation

In an environment in which free-riders are better off than cooperators, social control is required to foster and maintain cooperation. There are two main paths through which social control can be applied: punishment and reputation. Using a Public Goods Game, we show that gossip, used for assortment under three different strategies, can be effective in large groups, whereas its efficacy is reduced in small groups, with no main effect of the gossiping strategy. We also test four different combinations of gossip and costly punishment, showing that a combination of punishment and reputation-based partner selection leads to higher cooperation rates.

Incentivi reputazionali alla cooperazione in un gioco competitivo tra adolescenti: Uno studio sperimentale

Reputation is one of the most effective solutions to the so-called «puzzle of cooperation», but it is usually studied in contexts in which information is not ambiguous and there are no incentives towards strategically using it. In this study, we test wheter the possibility of being evaluated (with a like or a dislike) when giving suggestions about a deal in a competitive game has an effect on truthfulness of suggestions. We designed a computer-mediated experiment and we tested adolescents in a high-school in Italy, with the aim of understanding the development of reputational dynamics and how adolescents deal with competing incentives. Our results show that when reputations introduced, adolescents become more cooperative, both in terms of donations to partners and of suggestions offered. We also observe that reputations, both positive and negative, behave as attractors, thus those of ill-repute receive negative reviews even when they cooperate, and individuals with positive reputations keep on receiving positive evaluations even when misbehaving. Our study adds to the literature on reputation and cooperation by showing how adolescents behave with reputational incentives in a competitive game, but also by investigating the interplay between reputational and material incentives.