1,721,055 research outputs found
Evolution of Risk Preferences
No full textThis paper presents a simulation, made with a genetic algorithm
(GA), in order to shape risk attitudes in a simple environment
of lotteries such as the Machina triangle. An overlapping generations
case is used where only bankrupted agents exit the market at every generation.
The main result is that imposing the simple condition of the
bankruptcy benchmark, with instantaneous wealth as fitness measure, is
enough to induce stochastic dominance. The resulting indifference curves
are shaped graphically, measuring how far they are from the ideal risk
neutral case
Four multi-agents economic models - From evolutionary competition to social interaction
No full textLa pubblicazione è un libro che presenta la tesi di dottorato discussa nel 2007
Eight Degrees of Separation
Full text linkWe present a network formation game whose equilibria are undirected networks. Every
connected couple contributes to the aggregate payoff by a fixed quantity, and the outcome
is split between players according to the Myerson value allocation rule. This setup shows a
wide multiplicity of non-empty equilibria, all of them connected.Weshow that the efficient
equilibria of the game are either the empty network, or a network whose diameter does not
exceed a threshold of 8 (i.e. there are no two nodes with a distance greater than 8)
Public Goods in Networks: A Statistical Mechanics Approach
No full textThe problem of multiple Nash equilibria in games of strategic substitutes on networks is studied.
We consider a general model of public goods provision on network, and analyze in detail the properties of Nash equilibria with particular attention for the subset of equilibria that optimize some
global quantities (optimal equilibria) and to those that are robust to small perturbations (stable
equilibria). We conclude that finding good approximate optimal equilibria is not that difficult, and
we describe the performances of different algorithms. On the other hand, finding stable equilibria
is extremely difficult, by means of naive best-response dynamics as well as using advanced messagepassing algorithms. This is a consequence of the intrinsically different spatial organization of the
two sets of equilibri
Credibility of climate change denial in social media
Full text linkPublic perception about the reality of climate change has remained polarized
and propagation of fake information on social media can be a potential cause. Homophily in
communication, the tendency of people to communicate with others having similar beliefs, is
understood to lead to the formation of echo chambers which reinforce individual beliefs and
fuel further increase in polarization. Quite surprisingly, in an empirical analysis of the effect of
homophily in communication on the level of polarization using evidence from Twitter conversations on the climate change topic during 2007–2017, we find that evolution of homophily over time negatively affects the evolution of polarization in the long run. Among various
information about climate change to which people are exposed to, they are more likely to be
influenced by information that have higher credibility. Therefore, we study a model of
polarization of beliefs in social networks that accounts for credibility of propagating information in addition to homophily in communication. We find that polarization can not increase
with increase in homophily in communication unless information propagating fake beliefs has
minimal credibility. We therefore infer from the empirical results that anti-climate change
tweets are largely not credible
Enhancing Institutional Trust: Evidence from an Experimental Study with Adolescents in Italy
No full textThis study presents a quantitative analysis of a randomized survey experiment with Italian high school students (N = 1,433). It aims to evaluate trust levels in various institutions-healthcare, education, politics, judiciary, and defense-and identify determinants influencing trust in the scientific field, particularly regarding health issues. Using experimental scenarios, potential causal relationships among factors influencing confidence and trust scores are explored. Three distinct experimental scenarios are included in the survey: the first examines the influence of various social media platforms, the second and the third evaluate the impact of doctors, parents, and friends on trust-building among young individuals. Our results indicate a high level of trust in science among adolescents and emphasize high confidence in scientific experts. The study provides policy insights aimed at fostering trust, including recommendations for investments in education, increased involvement of specialists in direct communication, and enhanced transparency measures to mitigate misinformation. © The Author(s), under exclusive licence to Springer Nature B.V. 2025
Paying Positive to Go Negative: Advertisers' Competition and Media Reports
Full text linkThis paper analyzes a two-sided market for news where advertisers may pay a media outlet to conceal negative information about the quality of their own product (paying positive to avoid negative) and/or to disclose negative information about the quality of their competitors' products (paying positive to go negative). We show that whether advertisers have negative consequences on the accuracy of news reports or not ultimately depends on the extent of correlation among advertisers' products.
Specifically, the lower the correlation among the qualities of the advertisers' products, the (weakly) higher the accuracy of the media outlet' reports. Moreover, when advertisers' products are correlated, a higher degree of competition in the market of the advertisers' products may decrease the accuracy of the media outlet's reports
Dynamic opinion updating with endogenous networks
No full textPolarization is a well-documented phenomenon across a wide range of social issues. However, existing theories often treat the evolution of individual opinions and the formation of social networks as separate processes. In this study, we examine how individuals dynamically adjust their opinions while simultaneously forming and dissolving social connections, highlighting the interconnected nature of these behaviors. Our model is based on two key parameters: the direct benefit individuals receive from social connections and their willingness to adapt their opinions to align with their social circle. We identify conditions under which the network fails to achieve full connectivity, leading to persistent polarization of opinions. Additionally, our model demonstrates that polarization can temporarily increase during the transition to consensus, depending on the initial distribution of opinions and network structure. We explore the connection between these scenarios and a critical network metric: the initial diameter, under specific conditions related to the initial distribution of opinions. © 2025 The Author
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