Journalists' networks: Homophily and peering over the shoulder of other journalists.

Social media plays an important role in how journalists gather and report news. To understand journalists' professional environment, we examine the networks of journalists on Twitter who cover politics for U.S. newspapers in conjunction with a sample of journalists who completed a survey. By combining both their network data and survey responses, we examine the distribution of journalists' ideology (n = 264) and journalistic values (n = 247); and using the network data, we examine the directional relationships between journalists working at large and small papers (n = 4,661). We find that journalists tend to form connections with those who share similar journalistic values. However, we find little evidence that journalists build professional relationships based on similarity in political ideology. Lastly, journalists at larger media outlets are more likely to be central in journalists' Twitter networks, providing evidence that journalists look to other journalists at larger outlets for direction in news coverage. Our evidence provides unique insights into how social media illuminates journalists' professional environment and how that environment may shape news coverage.

Engagement with fact-checked posts on Reddit.

Contested factual claims shared online are of increasing interest to scholars and the public. Characterizing temporal patterns of sharing and engagement with such information, as well as the effect of sharing associated fact-checks, can help us understand the online political news environment more fully. Here, we investigate differential engagement with fact-checked posts shared online via Reddit from 2016 to 2018. The data comprise ∼29,000 conversations, ∼849,000 users, and ∼9.8 million comments. We classified the veracity of the posts being discussed as true, mixed, or false using three fact-checking organizations. Regardless of veracity, fact-checked posts had larger and longer lasting conversations than claims that were not fact-checked. Among those that were fact-checked, posts rated as false were discussed less and for shorter periods of time than claims that were rated as true. We also observe that fact-checks of posts rated as false tend to happen more quickly than fact-checks of posts rated as true. Finally, we observe that thread deletion and removal are systematically related to the presence of a fact-check and the veracity of the fact-check, but when deletion and removal are combined the differences are minimal. Theoretical and practical implications of the findings are discussed.

Examining Homophily, Language Coordination, and Analytical Thinking in Web-Based Conversations About Vaccines on Reddit: Study Using Deep Neural Network Language Models and Computer-Assisted Conversational Analyses.

BACKGROUND: Vaccine hesitancy has been deemed one of the top 10 threats to global health. Antivaccine information on social media is a major barrier to addressing vaccine hesitancy. Understanding how vaccine proponents and opponents interact with each other on social media may help address vaccine hesitancy. OBJECTIVE: We aimed to examine conversations between vaccine proponents and opponents on Reddit to understand whether homophily in web-based conversations impedes opinion exchange, whether people are able to accommodate their languages to each other in web-based conversations, and whether engaging with opposing viewpoints stimulates higher levels of analytical thinking. METHODS: We analyzed large-scale conversational text data about human vaccines on Reddit from 2016 to 2018. Using deep neural network language models and computer-assisted conversational analyses, we obtained each Redditor's stance on vaccines, each post's stance on vaccines, each Redditor's language coordination score, and each post or comment's analytical thinking score. We then performed chi-square tests, 2-tailed t tests, and multilevel modeling to test 3 questions of interest. RESULTS: The results show that both provaccine and antivaccine Redditors are more likely to selectively respond to Redditors who indicate similar views on vaccines (P<.001). When Redditors interact with others who hold opposing views on vaccines, both provaccine and antivaccine Redditors accommodate their language to out-group members (provaccine Redditors: P=.044; antivaccine Redditors: P=.047) and show no difference in analytical thinking compared with interacting with congruent views (P=.63), suggesting that Redditors do not engage in motivated reasoning. Antivaccine Redditors, on average, showed higher analytical thinking in their posts and comments than provaccine Redditors (P<.001). CONCLUSIONS: This study shows that although vaccine proponents and opponents selectively communicate with their in-group members on Reddit, they accommodate their language and do not engage in motivated reasoning when communicating with out-group members. These findings may have implications for the design of provaccine campaigns on social media.

Comparing beliefs in falsehoods based on satiric and non-satiric news.

This article seeks to quantify the extent to which Americans hold beliefs that are consistent with interpreting satiric news literally, and to assess whether factors known to promote misperceptions work differently depending on whether the source of the misperception is satire. We also test the robustness of those factors across a diverse set of real-world falsehoods. The study uses secondary data analysis, relying on data drawn from a 12-wave six-month panel conducted in 2019. Analyses focus on participants' beliefs about 120 falsehoods derived from high-profile political content in circulation before each survey wave, including 48 based on satiric news. A non-trivial number of participants believed claims originating in satire, but it is less than the proportion who believed falsehoods derived from other misleading content. Results also confirm the robustness of established predictors of misperceptions while demonstrating that the associations differ in magnitude between satiric and non-satiric news.

Sentinel node approach to monitoring online COVID-19 misinformation.

Understanding how different online communities engage with COVID-19 misinformation is critical for public health response. For example, misinformation confined to a small, isolated community of users poses a different public health risk than misinformation being consumed by a large population spanning many diverse communities. Here we take a longitudinal approach that leverages tools from network science to study COVID-19 misinformation on Twitter. Our approach provides a means to examine the breadth of misinformation engagement using modest data needs and computational resources. We identify a subset of accounts from different Twitter communities discussing COVID-19, and follow these 'sentinel nodes' longitudinally from July 2020 to January 2021. We characterize sentinel nodes in terms of a linked domain preference score, and use a standardized similarity score to examine alignment of tweets within and between communities. We find that media preference is strongly correlated with the amount of misinformation propagated by sentinel nodes. Engagement with sensationalist misinformation topics is largely confined to a cluster of sentinel nodes that includes influential conspiracy theorist accounts. By contrast, misinformation relating to COVID-19 severity generated widespread engagement across multiple communities. Our findings indicate that misinformation downplaying COVID-19 severity is of particular concern for public health response. We conclude that the sentinel node approach can be an effective way to assess breadth and depth of online misinformation penetration.

Changes in COVID-19 Vaccine Hesitancy Among Black and White Individuals in the US.

Importance: COVID-19 has disproportionately affected Black individuals in the US; however, vaccination rates among Black individuals trail those among other racial groups. This disparity is often attributed to a high level of vaccine hesitancy among Black individuals, but few studies have examined changes in vaccine hesitancy over time. Objectives: To compare changes in vaccine hesitancy between Black and White individuals in the US and to examine mechanisms that might help explain the observed differences. Design, Setting, and Participants: This survey study used 7 waves of data collected using a panel design. A total of 1200 English-speaking adults in the US were recruited from a nonprobability online panel to construct a census-matched sample. Participants were contacted monthly between December 9, 2020, and June 16, 2021. Main Outcomes and Measures: The main outcome of interest was self-reported vaccination intention, measured on a 6-point scale (where 1 indicates extremely unlikely and 6 indicates extremely likely). Beliefs about the safety, effectiveness, and necessity of COVID-19 vaccines were measured on a 5-point Likert scale, with higher scores denoting greater agreement. Results: The baseline data included 1200 participants (693 women [52.0%; weighted]; 921 White individuals [64.0%; weighted], 107 Black individuals [12.2%; weighted]; weighted mean [SD] age, 49.5 [17.6] years). The survey participation rate was 57.0% (1264 of 2218). Black and White individuals had comparable vaccination intentions in December 2020, but Black individuals experienced larger increases in vaccination intention than White individuals relative to baseline in March 2021 (b = 0.666; P < .001), April 2021 (b = 0.890; P < .001), May 2021 (b = 0.695; P < .001), and June 2021 (b = 0.709; P < .001). The belief that the vaccines are necessary for protection also increased more among Black than White individuals in March 2021 (b = 0.221; P = .01) and April 2021 (b = 0.187; P = .04). Beliefs that the vaccines are safe and effective (b = 0.125; P < .001) and necessary (b = 0.405; P < .001) were positively associated with vaccination intention. There was no evidence that these associations varied by race. Conclusions and Relevance: This survey study suggests that the intention of Black individuals to be vaccinated was initially comparable to that of White individuals but increased more rapidly. There is some evidence that this increase is associated with changes in beliefs about the vaccine. Vaccination rates continue to be lower among Black individuals than White individuals, but these results suggest that this might be less likely the result of vaccine hesitancy than other factors.

I am a scientist . . . Ask Me Anything: Examining differences between male and female scientists participating in a Reddit AMA session.

This article investigates interactions between scientists and the online community Reddit. Given that past research on computer-mediated communication between scientists and the public found that male scientists are typically more popular in online spaces than female scientists, we examined differences in popularity as well as potential gendered differences in communication style. Specifically, we examined 269 Reddit "Ask Me Anything" sessions as well as the comments linked with each session (n = 125,580). Overall, we find that male scientists receive more comments on their sessions, but the score an individual comment receives does not differ by gender. Similarly, we find that the message complexity of the comments does not differ by gender. Taken together, these suggest that Reddit AMA sessions might be an effective platform for both male and female scientists to engage with the public.

Exploring the direct and indirect effects of elite influence on public opinion.

Political elites both respond to public opinion and influence it. Elite policy messages can shape individual policy attitudes, but the extent to which they do is difficult to measure in a dynamic information environment. Furthermore, policy messages are not absorbed in isolation, but spread through the social networks in which individuals are embedded, and their effects must be evaluated in light of how they spread across social environments. Using a sample of 358 participants across thirty student organizations at a large Midwestern research university, we experimentally investigate how real social groups consume and share elite information when evaluating a relatively unfamiliar policy area. We find a significant, direct effect of elite policy messages on individuals' policy attitudes. However, we find no evidence that policy attitudes are impacted indirectly by elite messages filtered through individuals' social networks. Results illustrate the power of elite influence over public opinion.

Understanding the Relationship Between Official and Social Information About Infectious Disease: Experimental Analysis.

BACKGROUND: Communicating official public health information about infectious diseases is complicated by the fact that individuals receive much of their information from their social contacts, either via interpersonal interaction or social media, which can be prone to bias and misconception. OBJECTIVE: This study aims to evaluate the effect of public health campaigns and the effect of socially communicated health information on learning about diseases simultaneously. Although extant literature addresses the effect of one source of information (official or social) or the other, it has not addressed the simultaneous interaction of official information (OI) and social information (SI) in an experimental setting. METHODS: We used a series of experiments that exposed participants to both OI and structured SI about the symptoms and spread of hepatitis C over a series of 10 rounds of computer-based interactions. Participants were randomly assigned to receive a high, low, or control intensity of OI and to receive accurate or inaccurate SI about the disease. RESULTS: A total of 195 participants consented to participate in the study. Of these respondents, 186 had complete responses across all ten experimental rounds, which corresponds to a 4.6% (9/195) nonresponse rate. The OI high intensity treatment increases learning over the control condition for all symptom and contagion questions when individuals have lower levels of baseline knowledge (all P values ≤.04). The accurate SI condition increased learning across experimental rounds over the inaccurate condition (all P values ≤.01). We find limited evidence of an interaction between official and SI about infectious diseases. CONCLUSIONS: This project demonstrates that exposure to official public health information increases individuals' knowledge of the spread and symptoms of a disease. Socially shared information also facilitates the learning of accurate and inaccurate information, though to a lesser extent than exposure to OI. Although the effect of OI persists, preliminary results suggest that it can be degraded by persistent contradictory SI over time.

Conservatives' susceptibility to political misperceptions.

The idea that U.S. conservatives are uniquely likely to hold misperceptions is widespread but has not been systematically assessed. Research has focused on beliefs about narrow sets of claims never intended to capture the richness of the political information environment. Furthermore, factors contributing to this performance gap remain unclear. We generated an unique longitudinal dataset combining social media engagement data and a 12-wave panel study of Americans' political knowledge about high-profile news over 6 months. Results confirm that conservatives have lower sensitivity than liberals, performing worse at distinguishing truths and falsehoods. This is partially explained by the fact that the most widely shared falsehoods tend to promote conservative positions, while corresponding truths typically favor liberals. The problem is exacerbated by liberals' tendency to experience bigger improvements in sensitivity than conservatives as the proportion of partisan news increases. These results underscore the importance of reducing the supply of right-leaning misinformation.

Eye Movements Predict Large-Scale Voting Decisions.

More than 100 countries allow people to vote directly on policies in direct democracy elections (e.g., 2016 Brexit referendum). Politicians are often responsible for writing ballot language, and voters frequently encounter ballot measures that are difficult to understand. We examined whether eye movements from a small group of individuals can predict the consequences of ballot language on large-scale voting decisions. Across two preregistered studies (Study 1: N = 120 registered voters, Study 2: N = 120 registered voters), we monitored laboratory participants' eye movements as they read real ballot measures. We found that eye-movement responses associated with difficulties in language comprehension predicted aggregate voting decisions to abstain from voting and vote against ballot measures in U.S. elections (total number of votes cast = 137,661,232). Eye movements predicted voting decisions beyond what was accounted for by widely used measures of language difficulty. This finding demonstrates a new way of linking eye movements to out-of-sample aggregate-level behaviors.

Dynamics of social network emergence explain network evolution.

Networked systems emerge and subsequently evolve. Although several models describe the process of network evolution, researchers know far less about the initial process of network emergence. Here, we report temporal survey results of a real-world social network starting from its point of inception. We find that individuals' ties undergo an initial cycle of rapid expansion and contraction. This process helps to explain the eventual interactions and working structure in the network (in this case, scientific collaboration). We propose a stylized concept and model of "churn" to describe the process of network emergence and stabilization. Our empirical and simulation results suggest that these network emergence dynamics may be instrumental for explaining network details, as well as behavioral outcomes at later time periods.

Testing of a (Spiritual) Self-Assessment Tool ((S)SAT) in a Community Hospital Setting.

The (Spiritual) Self-Assessment Tool Study was designed to test the novel engagement tool's effectiveness. Providing the (Spiritual) Self-Assessment Tool Study to newly admitted medical patients led to few instances where the tool was completed. Nevertheless, the (Spiritual) Self-Assessment Tool Study patient questionnaire generated significant secondary findings: a third of responding patients consider their hospital care incomplete without their care team having access to (Spiritual) Self-Assessment Tool data. Nursing staff also desire this data, but are unable to access it without the (Spiritual) Self-Assessment Tool or an equivalent source.

Low-cost, high-impact altruistic punishment promotes cooperation cascades in human social networks.

Theoretical models and experiments suggest that social networks may significantly impact the emergence and stability of cooperation in humans. Similarly, theoretical models and experiments have shown that punishing behavior can significantly increase cooperative behavior in individuals. However, how punishing impacts the effects of social networks on cooperation is not yet understood. Here, I examine a set of laboratory experiments in which participants choose to cooperate or defect under differing punishment arrangements. Through analysis of the experiment as a network, I evaluate how institutional arrangements affect the degree to which social networks promote cooperative behavior. The results show that cooperative behavior spreads from person-to-person in all versions of the game, but that in versions of the game with low-cost, high-impact punishment the influence both endures for more rounds and spreads further in the network. These results show that the extent to which cooperative behavior cascades is affected by the institutional arrangements that govern game play.

Social influence and political mobilization: Further evidence from a randomized experiment in the 2012 U.S. presidential election.

A large-scale experiment during the 2010 U.S. Congressional Election demonstrated a positive effect of an online get-out-the-vote message on real world voting behavior. Here, we report results from a replication of the experiment conducted during the U.S. Presidential Election in 2012. In spite of the fact that get-out-the-vote messages typically yield smaller effects during high-stakes elections due to saturation of mobilization efforts from many sources, a significant increase in voting was again observed. Voting also increased significantly among the close friends of those who received the message to go to the polls, and the total effect on the friends was likely larger than the direct effect, suggesting that understanding social influence effects is potentially even more important than understanding the direct effects of messaging. These results replicate earlier work and they add to growing evidence that online social networks can be instrumental for spreading offline behaviors.

Temporal Dynamics of Rituals in Obsessive Compulsive Disorder.

Obsessive-compulsive disorder (OCD) is characterized by obsessions, defined as intrusive and persistent thoughts, and compulsions, defined as repetitive ritualistic behaviors that attempt to neutralize the anxiety associated with the obsessions. The present study investigated the patterns of symptoms as they occur over time in order to generate new insights about the triggers to symptoms. Fourteen adult participants who met the DSM-5 criteria for OCD completed 7-day logbooks of daily activities including the times when they engaged in compulsive rituals. Orbital Decomposition (ORBDE) was used to extract symptom patterns and revealed a wide range of symptom cycle lengths, some of which were hierarchically organized in time and some were not. Furthermore the results of the ORBDE analysis were logically consistent with those of a previously reported nonlinear regression analysis. Both analytic techniques supported a turbulence model for OCD onset: Combinations of cognition, emotion, and behavioral responses that would occur randomly for nonclinical samples self-organize into deterministic and chaotic patterns for clinical samples. It is speculated that knowledge of the individuals' temporal dynamics could inform effective treatment strategies, allowing a therapist to develop an individualized yet empirically supported treatment plan.

The Contagious Spread of Violence Among US Adolescents Through Social Networks.

OBJECTIVES: To test the hypothesis that violence among US adolescents spreads like a contagious disease through social networks. METHODS: Participants were a nationally representative sample of 90 118 US students aged 12 to 18 years who were involved in the National Longitudinal Study of Adolescent Health. Violence was assessed by having participants report the number of times in the preceding 12 months they had been involved in a serious physical fight, had hurt someone badly, and had pulled a weapon on someone. RESULTS: Participants were 48% more likely to have been involved in a serious fight, 183% more likely to have hurt someone badly, and 140% more likely to have pulled a weapon on someone if a friend had engaged in the same behavior. The influence spread up to 4 degrees of separation (i.e., friend of friend of friend of friend) for serious fights, 2 degrees for hurting someone badly, and 3 degrees for pulling a weapon on someone. CONCLUSIONS: Adolescents were more likely to engage in violent behavior if their friends did the same, and contagion of violence extended beyond immediate friends to friends of friends.

CD14(+) macrophages that accumulate in the colon of African AIDS patients express pro-inflammatory cytokines and are responsive to lipopolysaccharide.

BACKGROUND: Intestinal macrophages are key regulators of inflammatory responses to the gut microbiome and play a central role in maintaining tissue homeostasis and epithelial integrity. However, little is known about the role of these cells in HIV infection, a disease fuelled by intestinal inflammation, a loss of epithelial barrier function and increased microbial translocation (MT). METHODS: Phenotypic and functional characterization of intestinal macrophages was performed for 23 African AIDS patients with chronic diarrhea and/or weight loss and 11 HIV-negative Africans with and without inflammatory bowel disease (IBD). AIDS patients were treated with cotrimoxazole for the prevention of opportunistic infections (OIs). Macrophage phenotype was assessed by flow cytometry and immuno-histochemistry (IHC); production of proinflammatory mediators by IHC and Qiagen PCR Arrays; in vitro secretion of cytokines by the Bio-Plex Suspension Array System. Statistical analyses were performed using Spearman's correlation and Wilcoxon matched-pair tests. Results between groups were analyzed using the Kruskal-Wallis with Dunn's post-test and the Mann-Whitney U tests. RESULTS: None of the study participants had evidence of enteric co-infections as assessed by stool analysis and histology. Compared to healthy HIV-negative controls, the colon of AIDS patients was highly inflamed with increased infiltration of inflammatory cells and increased mRNA expression of proinflammatory cytokine (tumour necrosis factor (TNF)-α, interleukin (IL)-1ß, IFN-γ, and IL-18), chemokines (chemokine (C-C motif) ligand (CCL)2 and chemokine (C-X-C) motif ligand (CXCL)10) and transcription factors (TNF receptor-associated factor (TRAF)6 and T-box (TXB)21). IHC revealed significant co-localization of TNF-α and IL-1ß with CD68(+) cells. As in IBD, HIV was associated with a marked increase in macrophages expressing innate response receptors including CD14, the co-receptor for lipopolysaccharide (LPS). The frequency of CD14(+) macrophages correlated positively with plasma LPS, a marker of MT. Total unfractionated mucosal mononuclear cells (MMC) isolated from the colon of AIDS patients, but not MMC depleted of CD14(+) cells, secreted increased levels of proinflammatory cytokines ex vivo in response to LPS. CONCLUSIONS: Intestinal macrophages, in the absence of overt OIs, play an important role in driving persistent inflammation in HIV patients with late-stage disease and diarrhea. These results suggest intensified treatment strategies that target inflammatory processes in intestinal macrophages may be highly beneficial in restoring the epithelial barrier and limiting MT in HIV-infected patients.

Aperiodic deterministic structure of OCD and the familial effect on rituals.

A dynamical disease is one in which the symptoms appear and disappear over time in a deterministic pattern that could be chaotic. By determining the dynamic structure of the temporal pattern it would be possible to gain some insight into the triggers for symptoms if not the disease process as a whole. The present study investigated whether obsessive-compulsive disorder (OCD) could be considered a dynamical disease because of the intermittent outbursts of ritual behaviors. One-week diaries were collected from 17 clinical cases with 16 matched controls to record both the occurrence of rituals as they transpired over time and the influence the family may have had upon the spatiotemporal structure of symptoms. Comparisons of nonlinear regression parameters and Lyapunov exponents revealed that OCD exhibited a low-dimensional deterministic structure. The average nonlinear model (R2 = 0.32) explained more than 10 times the variance of its linear counterpart (R2 = 0.03). Family reactions and emotional responses accounted for only a very modest increase in the variance explained by the nonlinear regression model or in the amount of turbulence. Family reactions and emotional responses do little to make the rituals go away, but instead may strengthen the dynamics. Finally, significant rank order correlations were found between the R2 for the time series for each logbook and Lyapunov exponents with symptom severity and family reactions.