Browsing by Author "Valenzuela, Sebastián"

Now showing 1 - 20 of 61
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    A Downward Spiral? A Panel Study of Misinformation and Media Trust in Chile
    (SAGE PUBLICATIONS INC, 2021) Valenzuela, Sebastián; Halpern, Daniel; Araneda, Felipe
    Despite widespread concern, research on the consequences of misinformation on people's attitudes is surprisingly scant. To fill in this gap, the current study examines the long-term relationship between misinformation and trust in the news media. Based on the reinforcing spirals model, we analyzed data from a three-wave panel survey collected in Chile between 2017 and 2019. We found a weak, over-time relationship between misinformation and media skepticism. Specifically, initial beliefs on factually dubious information were negatively correlated with subsequent levels of trust in the news media. Lower trust in the media, in turn, was related over time to higher levels of misinformation. However, we found no evidence of a reverse, parallel process where media trust shielded users against misinformation, further reinforcing trust in the news media. The lack of evidence of a downward spiral suggests that the corrosive effects of misinformation on attitudes toward the news media are less serious than originally suggested. We close with a discussion of directions for future research.
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    A Meta-Analysis of the Effects of Cross-Cutting Exposure on Political Participation
    (2019) Matthes, Jörg; Knoll, Johannes; Valenzuela, Sebastián; Hopmann, David Nicolas; Von Sikorski, Christian
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    A Self-Righteous, Not a Virtuous, Circle: proposing a new framework for studying media effects on knowledge and political participation in a social media environment
    (2024) Lee, Sangwon; Valenzuela, Sebastián
    To explain the participatory effects of news exposure, communication scholars have long relied upon the “virtuous circle” framework of media use and civic participation. That is, news consumption makes people more knowledgeable, and trustful toward institutions and political processes, making them active and responsible citizens, which then leads them to engage in various political activities. In a social media environment, however, the applicability of the “virtuous circle” is increasingly dubious. A mounting body of empirical research indicates that news consumption via social media does not necessarily yield actual information gains. Instead, it often fosters a false perception of being well-informed and politically competent, thereby stimulating political engagement. Furthermore, selective information consumption and interaction within like-minded networks on social media frequently exacerbate animosity toward opposing political factions, which can serve as a catalyst for political involvement. In light of these findings, we propose replacing the “virtuous circle” framework for a “self-righteous” one. In this new model, social media news users develop a heightened sense of confidence in their knowledge, regardless of its accuracy, and consequently become more inclined to engage in politics by reinforcing the perception that the opposing side is inherently wrong and that achieving victory is imperative.
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    A vaccine against the salmonid pathogen Piscirickettsia salmonis based on recombinant proteins
    (ELSEVIER SCI LTD, 2006) Wilhelm, Vivian; Miquel, Alvaro; Burzio, Luis O.; Rosemblatt, Mario; Engel, Esteban; Valenzuela, Sebastián; Parada, Gustavo; Valenzuela, Pablo D. T.
    We report here the protective effect against piscirickettsiosis elicited in fish by a mixture of recombinant proteins. A comparative genomics strategy was used on a genomic library of Piscirickettsia salmonis in order to select optimal candidates for a recombinant subunit vaccine to protect fish from rickettsial septicaemia (SRS). Based on this information, 15 P. salmonis ORFs encoding heat shock proteins, virulence factors, membrane bound and other surface exposed antigens, were isolated and expressed. Seven of the most promising antigens were formulated in three mixtures (V1-V3) containing two or three recombinant proteins each and injected into salmon to test their protective efficacy. Two of the three formulations (V1, V2) elicited a strong protective response in a challenge against the pathogen, which was coincident with the humoral response against the corresponding recombinant proteins present in each formulation. V I, formulated with recombinant chaperonines Hsp60, Hsp70 and flagellar protein FlgG of P. salmonis achieved the highest level of protection with a relative percent survival (RPS) of 95%. (c) 2006 Elsevier Ltd. All rights reserved.
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    Comparing Disaster News on Twitter and Television: an Intermedia Agenda Setting Perspective
    (2017) Valenzuela, Sebastián; Puente Vergara, María Soledad; Flores, Pablo M.
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    Contagio moral en redes sociales : cómo la emoción moral transmite mensajes y polariza diferentes tipos de conversaciones en Twitter
    (2020) Donoso Ariztía, Francisco de Paula; Bargsted, Matías; Valenzuela, Sebastián; Pontificia Universidad Católica de Chile. Instituto de Sociología
    La masificación de Internet y la Web 2.0 ha significado un cambio radical en la manera en que nos expresamos, particularmente en referencia a cuestiones políticas. La interacción, con barreras de entrada teóricamente inexistentes, entre usuarios de todo el mundo ha permitido un intercambio de ideas y visiones jamás visto en la historia humana. Para muchos, se trata de un signo de esperanza en la construcción de sociedades más democráticas y deliberativas. Para otros, más recientemente se han constituido una amenaza para el diálogo civil y la estabilidad política y social. Recientes avances en las ciencias cognitivas nos indican que muchos de los fenómenos derivados del acceso a estas tecnologías son solamente expresión de nuestros mecanismos de procesamiento mental desarrollados durante milenios de evolución. En cualquiera de los casos, se trata de un fenómeno importante de estudiar. Aunque las investigaciones sobre el comportamiento de usuarios en redes sociales ha explotado en los últimos años, lamentablemente (1) su desarrollo se ha enfocado principalmente en el componente metodológico y no ha visto demasiada elaboración teórica desde las ciencias sociales, y (2) estas investigaciones se han realizado fundamentalmente en sociedades anglófonas, quedando otros lenguajes muy relegados del estado del arte de la investigación. Esta tesis pretende ser un aporte en ambas carencias, ofreciendo un diseño de investigación anclado en la teoría social y cognitiva, al día en los métodos de análisis de textos y aplicado a un estudio de caso en Chile. Los resultados indican que, a grandes rasgos, es posible reconocer dinámicas de polarización amplificadas por la transmisión de emoción moral y contextos altamente politizados, algo que se puede observar también en la literatura similar. Implicancias empíricas y futuras líneas de investigación son planteadas en la sección de discusión.
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    Counter a reactive media system
    (2021) Shah, Dhavan; Zhang, Yini; Pevehouse, Jon; Valenzuela, Sebastián
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    Del testimonio al testimonial : propuesta de conceptualización del Contenido Generado por Usuario de carácter testimonial (CGUt) en Twitter aplicada al caso de las protestas contra el impeachment de Dilma Rousseff.
    (2018) Santos, Marcelo Luis Barbosa; Condeza, Ana Rayén; Valenzuela, Sebastián; Condeza, Ana Rayén; Valenzuela, Sebastián; Pontificia Universidad Católica de Chile. Facultad de Comunicaciones
    La tesis conceptualiza y operacionaliza empíricamente (cuantitativa y cualitativamente) el concepto de Contenido Generado por Usuario de carácter testimonial, o CGUt. El caso seleccionado para aplicar dicho concepto fue el impedimento de la expresidenta de Brasil Dilma Rousseff, tal como observado a partir de los tuits emitidos con el #ForaTemer durante dos protestas en el contexto de su juicio final: 31/08/2016 y el 04/09/2016. El trabajo empírico utilizómétodos mixtos para: identificar contenidos testimoniales; caracterizarlos individualmente según atributos vía análisis de contenido; y apreciar su proceso de creación como apropiación social de TICs a través de entrevistas en profundidad con una selección de 10 usuarios. Los resultados muestran diferentes patrones de generación de contenido testimonial por usuarios ordinarios, siendo los principales CGUt Político, CGUt Periodístico y CGUt Expresivo. Los patrones cuantitativos de creación y consumo de CGUt varían significativamente tanto en diferentes contextos (días diferentes) como en un mismo día (etapas de la protesta) y, desde una perspectiva cuantitativa, no parecen muy relevantes en términos de alcance (visualizaciones y retweets), por lo que el CGUt como táctica efectiva de protesta pareciera ser más bien una posibilidad más teórica que concreta, la menos en el caso estudiado. Las entrevistas muestran una fuerte convergencia en la creación de CGUt, vinculada a la percepción de cobertura sesgada por los medios tradicionales, generando una especie de inteligencia colectiva, además de, por un lado, una satisfacción de cumplimiento del deber cívico mermada, por el otro, por la frustración de la ineficacia de las protestas en el ámbito político. Se plantea que tUGC es un concepto interdisciplinario y puede ser aplicado a otras áreas de conocimiento como desastres, entretención y otros.
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    Detection and impact estimation of social bots in the Chilean Twitter network
    (2024) Mendoza Rocha, Marcelo; Providel, Eliana; Santos, Marcelo; Valenzuela, Sebastián
    The rise of bots that mimic human behavior represents one of the most pressing threats to healthy information environments on social media. Many bots are designed to increase the visibility of low-quality content, spread misinformation, and artificially boost the reach of brands and politicians. These bots can also disrupt civic action coordination, such as by flooding a hashtag with spam and undermining political mobilization. Social media platforms have recognized these malicious bots’ risks and implemented strict policies and protocols to block automated accounts. However, effective bot detection methods for Spanish are still in their early stages. Many studies and tools used for Spanish are based on English-language models and lack performance evaluations in Spanish. In response to this need, we have developed a method for detecting bots in Spanish called Botcheck. Botcheck was trained on a collection of Spanish-language accounts annotated in Twibot-20, a large-scale dataset featuring thousands of accounts annotated by humans in various languages. We evaluated Botcheck’s performance on a large set of labeled accounts and found that it outperforms other competitive methods, including deep learning-based methods. As a case study, we used Botcheck to analyze the 2021 Chilean Presidential elections and discovered evidence of bot account intervention during the electoral term. In addition, we conducted an external validation of the accounts detected by Botcheck in the case study and found our method to be highly effective. We have also observed differences in behavior among the bots that are following the social media accounts of official presidential candidates.
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    (Don’t) Stop Believing: A Signal Detection Approach to Risk and Protective Factors for Engagement with Politicized (Mis)Information in Social Media
    (2024) Winter, Stephan; Valenzuela, Sebastián; Barbosa Santos, Marcelo Luis; Schreyer, Tobias; Iwertowski, Lena; Rothmund, Tobias
    Prior misinformation research often lacks comparisons with the processing of true information and specifically focuses on the dangers of right-wing or conservative misinformation. By employing a signal detection framework, this research addresses the ability to discern between true and false (discrimination sensitivity) as well as the tendency to prefer belief-congruent messages (confirmation bias) and reject belief-incongruent messages (disconfirmation bias), regardless of veracity, and aims to provide a comprehensive view on the ideological and cognitive factors that promote or inhibit engagement with politicized (mis)information across the political spectrum. In apre-registeredonline experiment (N = 992), participants evaluated 16 social media posts (true vs. false, supporting left-wing vs. right-wing views) with regard to perceived credibility. Results identified the dark factorof personality and social media usage as risk factors that were connected to lower discrimination sensitivity. With regard to political orientation, bias occurred on both sides of the political spectrum: Rightists exhibited a stronger confirmation bias, while leftists were more likely to reject belief-incongruent messages even if they were true (higher disconfirmation bias).These findings highlight the relevance of unpacking (mis)information-related behavior into a more nuanced approach.
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    Engaging with the news : incivility, disagreement, and deliberation in Chilean news comments
    (2020) Rosenberg Benadretti, Andrés Alejandro; Valenzuela, Sebastián; Saldaña Villa, Magdalena Carolina; Pontificia Universidad Católica de Chile. Facultad de Comunicaciones
    Although it is not a novel issue, uncivil attitudes and expressions have been at the center of communication research. Most specifically, the amount and extension of online incivility has been pointed as being detrimental to democratic values such as engaging in disagreement and deliberation without insulting others. Unfortunately, the idea that online spaces for citizens to discuss about pubic issues, such as news comments, have not delivered promising results, and incivility is pointed as one of the main handicaps. This dissertation studies three key variables related to online discussion: incivility, disagreement, and deliberation. Previous research has focused on relating either incivility with deliberation, or incivility with disagreement. However, disagreement and deliberation are closely related; with disagreement described as being either a consequence or an antecedent of deliberation. Therefore, I expect to have a more holistic understanding of how online discussion between strangers takes place when important social and political issues are at stake. To better respond to hypotheses and questions related to these three variables and how they affect online discussion, I divided this thesis into a two-step design with two different quantitave techniques: Study 1 sees a content analysis of news comments related to a Chilean presidential election in December 2017, while Study 2 brings an experiment embedded into a survey with a representative sample of Chilean population. While the first study focused on the frequency of each variable and how they relate to each other, the second analyzed two possible outcomes from the exposition of different levels of (in)civility and (dis)agreement: negative emotions and online participation. Results from the first study saw a whopping 41% of online incivility, when previous research conducted in the Global North usually average 30%. Moreover, disagreement was four times as common as deliberation, suggesting that at least in this sample disagreement is neither an antecedent nor a consequence of deliberation. Finally, uncivil disagreement is more common than civil disagreement, which reaffirms the notion that manifesting a disagreement would be the intended outcome, while the civility of the message is more related to the way in which the comment is presented. The experiment served the purpose of proving that uncivil disagreement comments produce negative emotions. In fact, both of the groups that were exposed to uncivil comments (with or without disagreement,) experienced an arousal of negative emotions such as anger and anxiety, in comparison to the groups that read either civil agreement or civil disagreement comments. One of positive outcomes that is usually mentioned in the literature when discussing incivility was also tested, so participants were expected to be more willing to participate in online actions such as putting a like/dislike in the comment, or posting another comment, after reading an uncivil post. However, this thesis was not supported as there was no association between the levels of incivility and willingness to further participate online. Among different explanations, a third variable like social trust could be mediating the relationship between the exposure to uncivil comments and willingness to online participation (e.g. users low in social trust putting less trust in others at the forum.) This dissertation matters in a context where democratic societies wonder if it is possible to have spaces for citizens to engage in public discussion without an important amount of incivility. Upon reading this thesis, I hope the reader would take a more comprehensive way of how political issues are being discussed online in a context accustomed to little-to-none moderation, and how these forums do not only involve the users who actively participate on them, but also can have detrimental effects on readers wanting to learn the opinion of their peers on issues that are important to them.
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    Explicating the Values-Issue Consistency Hypothesis through Need for Orientation
    (2016) Valenzuela, Sebastián; Chernov, Gennadiy
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