[{"id":358093,"last_updated":"2023-07-03 11:45:24","id_people":481807,"institutes":["ILC"],"type":"journal_article","type_order":0,"type_people":"article","title":"The Role of Argument Strength and Informational Biases in Polarization and Bi-Polarization Effects","year":2023,"authors_people":"Proietti, Carlo; Chiarella, Davide","authors_cnr":["Chiarella, Davide","Proietti, Carlo"],"authors_cnr_id":["15601","18841"],"authors_cnr_institute":[""],"authors":["Proietti, C.","Chiarella, D."],"abstract":"This simulation research explores the informational causes of polarization and bi-polarization of opinions within groups. We define 'polarization' here as a uniform change of the opinion of the whole group in the same direction, whereas 'bi-polarization' indicates a split of two subgroups towards opposite directions. For our purposes, we have expanded the model of the Argument Communication Theory of Bi-polarization. This is an argument-based multi-agent model of opinion dynamics inspired by Persuasive Argument Theory. The original model accounts for polarization as an outcome of pure informational influence and reproduces bipolarization effects by postulating an additional mechanism of homophilous selection of communication partners. The expanded model adds two dimensions: i.e., argument strength and more sophisticated protocols of informational influence (argument communication and opinion update). Adding the first dimension, allows us to investigate whether and how the presence of stronger or weaker arguments in a discussion influences polarization and bi-polarization dynamics, as suggested by the original framework of Persuasive Arguments Theory. The second feature allows us to test whether other mechanisms related to confirmation bias and epistemic vigilance can act as a driving force of bi-polarization. For the first issue, our simulations showed that argument strength has a measurable effect. For the second, our results would indicate that, in absence of homophily, only very strong types of informational bias can lead to bi-polarization.","keywords":["Argumentation","Argument Communication Theory","Polarization","Bi-Polarization","Epistemic Vigilance","Opinion dynamics"],"pages":"25","url":"https:\/\/www.jasss.org\/26\/2\/5.html","volume":"26","doi":"10.18564\/jasss.5062","editors_people":"","editors":[""],"published":"JASSS (Guildf.)","publisher":"SimSoc Consortium ([Guildford], Regno Unito)","issn":"1460-7425","isbn":"","conference_name":"","conference_place":"","conference_date":""},{"id":132449,"last_updated":"2022-02-03 16:40:15","id_people":454043,"institutes":["ILC"],"type":"journal_article","type_order":0,"type_people":"article","title":"Dynamic epistemic logics for abstract argumentation","year":2021,"authors_people":"Proietti Carlo Yuste-Ginel Antonio","authors_cnr":["Proietti, Carlo"],"authors_cnr_id":["18841"],"authors_cnr_institute":[""],"authors":["Proietti, C.","Yuste Ginel, A."],"abstract":"This paper introduces a multi-agent dynamic epistemic logic for abstract argumentation. Its main motivation is to build a general framework for modelling the dynamics of a debate, which entails reasoning about goals, beliefs, as well as policies of communication and information update by the participants. After locating our proposal and introducing the relevant tools from abstract argumentation, we proceed to build a three-tiered logical approach. At the first level, we use the language of propositional logic to encode states of a multi-agent debate. This language allows to specify which arguments any agent is aware of, as well as their subjective justification status. We then extend our language and semantics to that of epistemic logic, in order to model individuals' beliefs about the state of the debate, which includes uncertainty about the information available to others. As a third step, we introduce a framework of dynamic epistemic logic and its semantics, which is essentially based on so-called event models with factual change. We provide completeness results for a number of systems and show how existing formalisms for argumentation dynamics and unquantified uncertainty can be reduced to their semantics. The resulting framework allows reasoning about subtle epistemic and argumentative updates--such as the effects of different levels of trust in a source--and more in general about the epistemic dimensions of strategic communication.","keywords":["Abstract argumentation","Dynamic epistemic logic","Awareness logics","Multi-agent argumentation frameworks","Persuasion","Strategic Argumentation"],"pages":"1-60","url":"https:\/\/link.springer.com\/article\/10.1007\/s11229-021-03178-5#citeas","volume":"","doi":"10.1007\/s11229-021-03178-5","editors_people":"","editors":[""],"published":"Synthese (Dordr., Online)","publisher":"Kluwer (Dordrecht, Paesi Bassi)","issn":"1573-0964","isbn":"","conference_name":"","conference_place":"","conference_date":""},{"id":132484,"last_updated":"2022-02-15 17:20:06","id_people":463554,"institutes":["ILC"],"type":"conference_article","type_order":5,"type_people":"conferenceObject","title":"Measuring bi-polarization with argument graphs","year":2021,"authors_people":"Carlo Proietti, Davide Chiarella","authors_cnr":["Chiarella, Davide","Proietti, Carlo"],"authors_cnr_id":["15601","18841"],"authors_cnr_institute":[""],"authors":["Proietti, C.","Chiarella, D."],"abstract":"Multi-agent models play a significant role in testing hypotheses about the unfolding of opinion dynamics in complex social networks. The model of the Argument Communication Theory of Bi-polarization (ACTB), developed by Maes and Flache (2013), shows that simple circulation of arguments among individuals in a group can determine strong differentiation of opinions (bi-polarization effects) even with a small degree of homophily. The ACTB model and similar ones have nevertheless one limitation: given a topic of discussion, only direct pro and con arguments for it are considered. This does not allow to account for the topology of a more complex debate, where arguments may also interact indirectly with the topic at stake. This gap can be filled by using Quantitative Bipolar Argument Frameworks (QBAF). More specifically, by applying measures of argument strength for QBAFs in order to calculate the agents' opinion. In the present paper we generalize the ACTB measure of opinion strength to acyclic bipolar graphs and compare it with other measures from the literature. We then present a revised version of the ACTB model, where the agents' knowledge bases are structured as subgraphs of an underlying global knowledge base (described as a QBAF). We first test that the predictions of the ACTB model are confirmed when the underlying QBAF contains only direct pro and con arguments for a topic. We then explore more complex topologies of debate with two additional batches of simulations. Our first results show that changing the topology, while keeping the same number of pro and con arguments, has no significant impact on bi-polarization dynamics.","keywords":["bi-polarization","abstract argumentation","opinion dynamics","multi-agent modelling"],"pages":"13","url":"https:\/\/publications.cnr.it\/doc\/463554","volume":"","doi":"","editors_people":"","editors":[""],"published":"Advances in Argumentation in Artificial Intelligence 2021","publisher":"M. Jeusfeld c\/o Redaktion Sun SITE, Informatik V, RWTH Aachen (Aachen, Germania)","issn":"1613-0073","isbn":"","conference_name":"20th International Conference Italian Association for Artificial Intelligence-5th Workshop on Advances in Argumentation in Artificial Intelligence","conference_place":"Milano","conference_date":"29\/11\/2021"}]