The web radically changed the dissemination of information and the global spread of news. In this study, we aim to reconstruct the connectivity patterns within nations shaping news propagation ...globally in 2022. We do this by analyzing a dataset of unprecedented size, containing 140 million news articles from 183 countries and related to 37,802 domains in the GDELT database. Unlike previous research, we focus on the sequential mention of events across various countries, thus incorporating a temporal dimension into the analysis of news dissemination networks. Our results show a significant imbalance in online news spreading. We identify news superspreaders forming a tightly interconnected rich club, exerting significant influence on the global news agenda. To further investigate the mechanisms underlying news dissemination and the shaping of global public opinion, we model countries' interactions using a gravity model, incorporating economic, geographical, and cultural factors. Consistent with previous studies, we find that countries' GDP is one of the main drivers to shape the worldwide news agenda.
Social media platforms heavily changed how users consume and digest information and, thus, how the popularity of topics evolves. In this paper, we explore the interplay between the virality of ...controversial topics and how they may trigger heated discussions and eventually increase users' polarization. We perform a quantitative analysis on Facebook by collecting ∼57M posts from ∼2M pages and groups between 2018 and 2022, focusing on engaging topics involving scandals, tragedies, and social and political issues. Using logistic functions, we quantitatively assess the evolution of these topics finding similar patterns in their engagement dynamics. Finally, we show that initial burstiness may predict the rise of users' future adverse reactions regardless of the discussed topic.
Users Volatility on Reddit and Voat Di Marco, Niccolo; Cinelli, Matteo; Alipour, Shayan ...
IEEE transactions on computational social systems,
2024
Journal Article
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Social media platforms behave like giant arenas where users can rely on different content and express their opinions through likes, comments, and shares. However, do users welcome different ...perspectives or only listen to their preferred narratives? This article examines how users explore the digital space and allocate their attention among communities on two social networks, Voat and Reddit. By analyzing a massive dataset of about 215 million comments posted by about 16 million users on Voat and Reddit in 2019, we find that most users tend to explore new communities at a decreasing rate, meaning they have a limited set of preferred groups they visit regularly. Moreover, we provide evidence that preferred communities of users tend to cover similar topics throughout the year. We also find that communities have a high turnover of users, meaning that users come and go frequently showing a high volatility that strongly departs from a null model simulating users' behavior.
Many recent studies have shown that Fractal Dimension (FD), a ratio for figuring out the complexity of a system given its measurements, can be used as an useful index to provide information about ...certain brain disease. Our research focuses on the Alzheimer’s disease changes in white and grey brain matters detected through the FD indexes of their contours. Data used in this study were obtained from the Alzheimer’s Disease (AD) Neuroimaging Initiative database (Normal Condition,
N
= 57, and Alzheimer’s Disease,
N
= 60). After standard preprocessing pipeline, the white and grey matter 3D FD indexes are computed for the two groups. A statistical analysis shows that only grey matter 3D FD indexes are able to differentiate healthy and AD subjects. Although white matter 3D FD indexes do not, it is remarkable that their presence enhance the separation capability of previous ones. In order to valuate the classification capability of these indexes on healthy and AD subjects, we define several Neural Networks models. The performances of these models vary according to the statistical analysis and reach their best performances when each 3D FD input index is changed into a sequence of 2D FD indexes of (a subset of) the horizontal slices of the white and grey matter volumes.
The benefits of an information ecosystem based on social media platforms came at the cost of the rise of several antisocial behaviours, including the use of toxic speech. To assess the aspects that ...concur with the formation of toxic conversations, we provide a multi-platform comparison on Twitter and YouTube between the 2022 Italian Political Elections, representing a potentially polarising topic, and the Italian Football League, a topic close to the country's popular culture. We first probe structural and conversational toxicity differences by analyzing 257 K conversations (3.7 M posts, 1 M users) on both platforms. Then, we provide a machine learning approach that, by leveraging the previous features, identifies the presence of the following toxic comment in different stages of conversations. We show that football tends to exhibit lower toxicity levels than politics, with the latter producing more extended conversations that attract a broader audience and consequently fostering the polarization phenomenon. The implemented classifiers resulting from the conversation stage-based approach achieve state-of-the-art performances despite a restricted set of features. Furthermore, our cross-topic comparison shows that models trained on a divisive topic can be applied to other discussions without causing a degradation of their performance.
Given a 3-uniform hypergraph
H
having a set
V
of vertices, and a set of hyperedges
T
⊂
P
(
V
)
, whose elements have cardinality three each, a
null labelling
is an assignment of
±
1
to the hyperedges ...such that each vertex belongs to the same number of hyperedges labelled
+
1
and
-
1
. A sufficient condition for the existence of a null labelling of
H
(proved in Di Marco et al. Lect Notes Comput Sci 12757:282–294, 2021) is a Hamiltonian cycle in its 2-intersection graph. The notion of 2-intersection graph generalizes that of intersection graph of an (hyper)graph and extends its effectiveness. The present study first shows that this sufficient condition for the existence of a null labelling in
H
can not be weakened by requiring only the connectedness of the 2-intersection graph. Then some interesting properties related to their clique configurations are proved. Finally, the main result is proved, the NP-completeness of this characterization and, as a consequence, of the construction of the related 3-hypergraphs.
Given a 3-uniform hypergraph H, its 2-intersection graph G has as vertex set the hyperedges of H and ee′ is an edge of G whenever e and e′ have exactly two common vertices in H. Di Marco et al. prove ...in Di Marco et al. (2023) that deciding whether a graph G is the 2-intersection graph of a 3-uniform hypergraph is NP-complete. Following this result, we study the class of claw-free graphs. We show that the recognition problem remains NP-complete for that class, but becomes polynomial if we consider triangulated claw-free graphs.
Growing concern surrounds the impact of social media platforms on public discourse
and their influence on social dynamics
, especially in the context of toxicity
. Here, to better understand these ...phenomena, we use a comparative approach to isolate human behavioural patterns across multiple social media platforms. In particular, we analyse conversations in different online communities, focusing on identifying consistent patterns of toxic content. Drawing from an extensive dataset that spans eight platforms over 34 years-from Usenet to contemporary social media-our findings show consistent conversation patterns and user behaviour, irrespective of the platform, topic or time. Notably, although long conversations consistently exhibit higher toxicity, toxic language does not invariably discourage people from participating in a conversation, and toxicity does not necessarily escalate as discussions evolve. Our analysis suggests that debates and contrasting sentiments among users significantly contribute to more intense and hostile discussions. Moreover, the persistence of these patterns across three decades, despite changes in platforms and societal norms, underscores the pivotal role of human behaviour in shaping online discourse.
Given a 3-uniform hypergraph H, its 2-intersection graph G has for vertex set the hyperedges of H and ee' is an edge of G whenever e and e' have exactly two common vertices in H. Di Marco et al. ...prove that deciding wether a graph G is the 2-intersection graph of a 3-uniform hypergraph is NP-complete. The main problems we study concern the class of claw-free graphs. We show that the recognition problem remains NP-complete when G is claw-free graphs but becomes polynomial if in addition G is triangulated.
