The role of homophily in the emergence of opinion controversies

Understanding the emergence of strong controversial issues in modern societies is a key issue in opinion studies. A commonly diffused idea is the fact that the increasing of homophily in social networks, due to the modern ICT, can be a driving force for opinion polariation. In this paper we address the problem with a modelling approach following three basic steps. We first introduce a network morphogenesis model to reconstruct network structures where homophily can be tuned with a parameter. We show that as homophily increases the emergence of marked topological community structures in the networks raises. Secondly, we perform an opinion dynamics process on homophily dependent networks and we show that, contrary to the common idea, homophily helps consensus formation. Finally, we introduce a tunable external media pressure and we show that, actually, the combination of homophily and media makes the media effect less effective and leads to strongly polarized opinion clusters.Comment: 24 pages, 10 figure

Fast but multi-partisan: Bursts of communication increase opinion diversity in the temporal Deffuant model

Human interactions create social networks forming the backbone of societies. Individuals adjust their opinions by exchanging information through social interactions. Two recurrent questions are whether social structures promote opinion polarisation or consensus in societies and whether polarisation can be avoided, particularly on social media. In this paper, we hypothesise that not only network structure but also the timings of social interactions regulate the emergence of opinion clusters. We devise a temporal version of the Deffuant opinion model where pairwise interactions follow temporal patterns and show that burstiness alone is sufficient to refrain from consensus and polarisation by promoting the reinforcement of local opinions. Individuals self-organise into a multi-partisan society due to network clustering, but the diversity of opinion clusters further increases with burstiness, particularly when individuals have low tolerance and prefer to adjust to similar peers. The emergent opinion landscape is well-balanced regarding clusters' size, with a small fraction of individuals converging to extreme opinions. We thus argue that polarisation is more likely to emerge in social media than offline social networks because of the relatively low social clustering observed online. Counter-intuitively, strengthening online social networks by increasing social redundancy may be a venue to reduce polarisation and promote opinion diversity.Comment: 9 pages, 6 figures. Comments (e.g. missing references, suggestions, ...) are welcome

The role of homophily in opinion formation among mobile agents

Understanding the evolution and spread of opinions within social groups gives important insight into areas such as public elections and marketing. We are specifically interested in how psychological theories of interpersonal influence may affect how individuals change their opinion through interactions with their peers, and apply Agent-Based Modelling to explore the factors that may affect the emergence of consensus. We investigate the co-evolution of opinion and location by extending the Deffuant–Weisbuch bounded confidence opinion model to include mobility inspired by the psychological theories of homophily and dissonance, where agents are attracted or repelled by their neighbours based on the agreement of their opinions. Based on wide experimentation, we characterize the time it takes to converge to a steady state and the local diversity of opinions that results, finding that homophily leads to drastic differences in the nature of consensus. We further extend our mobility model and add noise in order to check the model's robustness, finding that a number of opinion clusters survive even with high levels of noise

Exploring the foundation of social diversity and coherence with a novel attraction-repulsion model framework

One widely-existed state --``harmony with diversity" in which individuals freely express various viewpoints to sustain integration of social diversity, but at the same time shared values ensure social coherence, can be considered as the foundation of social diversity and coherence, however, which has never attracted research attention. Its formation mechanism still remains unclear. To address this issue, this study proposes an attraction-repulsion model based on the general simple assumption that individuals tend to either reach an agreement with shared opinions or to amplify difference from others with distant opinions. It allows us to take account into the three core parameters: interaction strength, individuals' susceptibility and tolerance to others' opinions. We are concerned with the effect of not only time-varying topology but also fixed interactions imposed by static social network, where the tasks of heterogeneous individuals' attributes are also performed. Remarkably, the simple model rules successfully generate the three above phases except for fragmentation, along with three different transitions and the triple points. We find that sufficient susceptibility, intermediate interaction strength and high tolerance can benefit a balance between repulsive and attractive forces, and thus the emergence of "harmony with diversity". However, fixed interactions can introduce cluster-level self-reinforced mechanism which can unexpectedly promote polarization. Heterogeneous susceptibility or tolerance turns out to be an inhibiting factor, which should be avoided. A method to identify the phase boundaries through computing the maximum susceptibility of entropy and stand deviation of opinions, confirmed by numerical simulations, allows us to build phase diagrams and to locate where the triple points are.Comment: 21 pages, 19 figure

Computational and Simulation Modeling of Political Attitudes: the 'Tiger' Area of Political Culture Research

In almost one century long history, political attitudes modeling research has accumulated a critical mass of theory and method. Its characteristics and particularities have often suggested that political attitude approach to political persuasion modeling reveals a strong theoretical autonomy of concept which entitles it to become a new separate discipline of research. Though this did not actually happen, political attitudes modeling research has remained the most challenging area - the "tiger" - of political culture modeling research. This paper reviews the research literature on the conceptual, computational and simulation modeling of political attitudes developed starting with the beginning of the 20th century until the present times. Several computational and simulation modeling paradigms have provided support to political attitudes modeling research. These paradigms and the shift from one to another are briefly presented for a period of time of almost one century. The dominant paradigmatic views are those inspired by the Newtonian mechanics, and those based on the principle of methodological individualism and the emergence of macro phenomena from the individual interactions at the micro level of a society. This period of time is divided in eight ages covering the history of ideas in a wide range of political domains, going from political attitudes to polity modeling. Internal and external pressures for paradigmatic change are briefly explained

Opinion disparity in hypergraphs with community structure

The division of a social group into subgroups with opposing opinions, which we refer to as opinion disparity, is a prevalent phenomenon in society. This phenomenon has been modeled by including mechanisms such as opinion homophily, bounded confidence interactions, and social reinforcement mechanisms. In this paper we study a complementary mechanism for the formation of opinion disparity based on higher-order interactions, i.e., simultaneous interactions between multiple agents. We present an extension of the planted partition model for uniform hypergraphs as a simple model of community structure and consider the hypergraph SIS model on a hypergraph with two communities where the binary ideology can spread via links (pairwise interactions) and triangles (three-way interactions). We approximate this contagion process with a mean-field model and find that for strong enough community structure, the two communities can hold very different average opinions. We determine the regimes of structural and infectious parameters for which this opinion disparity can exist and find that the existence of these disparities is much more sensitive to the triangle community structure than to the link community structure. We show that the existence and type of opinion disparities are extremely sensitive to differences in the sizes of the two communities.Comment: 14 pages, 8 figure

Stance Polarity in Political Debates: a Diachronic Perspective of Network Homophily and Conversations on Twitter

[EN] In the last decade, social media gained a very significant role in public debates, and despite the many intrinsic difficulties of analyzing data streaming from on-line platforms that are poisoned by bots, trolls, and low-quality information, it is undeniable that such data can still be used to test the public opinion and overall mood and to investigate how individuals communicate with each other. With the aim of analyzing the debate in Twitter on the 2016 referendum on the reform of the Italian Constitution, we created an Italian annotated corpus for stance detection for automatically estimating the stance of a relevant number of users. We take into account a diachronic perspective to shed lights on users' opinion dynamics. Furthermore, different types of social network communities, based on friendships, retweets, quotes, and replies were investigated, in order to analyze the communication among users with similar and divergent viewpoints. We observe particular aspects of users' behavior. First, our analysis suggests that users tend to be less explicit in expressing their stances after the outcome of the vote; simultaneously, users who exhibit a high number of cross-stance relations tend to become less polarized or to adopt a more neutral style in the following phase of the debate. Second, despite social media networks are generally aggregated in homogeneous communities, we highlight that the structure of the network can strongly change when different types of social relations are considered. In particular, networks defined by means of reply-to messages exhibit inverse homophily by stance, and users use more often replies for expressing diverging opinions, instead of other forms of communication. Interestingly, we also observe that the political polarization increases forthcoming the election and decreases after the election day.The work of Viviana Patti and Giancarlo Ruffo was partially funded by the Fondazione CRT under research project the Hate Speech and Social Media (2016.0688), and the "Progetto di Ateneo/CSP 2016" under research project "Immigrants, Hate and Prejudice in Social Media" (S1618_L2_BOSC_01). The work of Paolo Rosso was partially funded by the Spanish MICINN under the research project "MISMIS-FAKEnHATE on Misinformation and Miscommunication in social media: FAKE news and HATE speech" (PGC2018-096212-B-C31).Lai, M.; Tambuscio, M.; Patti, V.; Ruffo, G.; Rosso, P. (2019). Stance Polarity in Political Debates: a Diachronic Perspective of Network Homophily and Conversations on Twitter. Data & Knowledge Engineering. 124:1-20. https://doi.org/10.1016/j.datak.2019.101738S12012