To assess the objective neutrality of the news article, and because user-generated comments can influence individuals' perceptions of news bias, a separate group of 38 individuals (13 men, 25 women: age M = 36.89, SD = 10. 39) who were identified as neither supporting nor opposing the ban, read the news article without any accompanying comments. They indicated how much they thought the news article favored the ban on corporal punishment in grade schools (−5 = Strongly against, +5 = Strongly in favor of) (M = 0.16, SD = 1.00). A one-sample t-test showed that the perceived tone of the news article was not significantly different from the scale midpoint (0.00), t (37) = 0.97, p = .34, attesting to the neutrality of the news article.
To ensure that the valence of the user-generated comments was recognized, participants in the main experiment indicated how much the comments agreed with the statement, “Corporal punishment in grade schools should be banned” (−5 = Strongly disagree, +5 = Strongly agree). An independent-samples t-test showed that the comments that were designed to support the ban (M = 1.63, SD = 2.48) were perceived to be significantly more favorable toward the ban than those designed to oppose it (M = −1.62, SD = 2.17), t (212) = −10.01, p < .001.
H1 predicted that people would infer the general public sentiment from the opinions expressed in user-generated comments. Because it is possible that the participants' pre-existing opinion might interact with the valence of user-generated comments, a 2 (congruent vs. incongruent comments) × 2 (pretest antiban vs. proban opinion) ANOVA was computed on perceived congeniality of public opinion. Results showed that those exposed to other readers' comments congruent with their own opinion believed that public opinion was significantly more congenial (M = 1.52, SD = 1.94) than those presented with the comments countering their stance (M = 0.24, SD = 2.35), F (1, 210) = 17.36, p < .001, ηp2 = .08. No significant interaction was found between comment valence and pre-existing opinion, F < 1. Thus, H1 was supported.
To determine whether perceived congeniality of the public opinion amplifies (H2a) or attenuates HMP (H2b), and if user-generated comments have a direct effect on HMP over and above the indirect effect through perceived public opinion (RQ1), simple mediation tests were conducted (Preacher & Hayes, 2008). First, the indirect effect of comments' congruity with a reader's existing opinion on HMP through readers' assessment of public opinion was statistically significant, b = −0.23, Z = −2.61, p = .009 (95% bias corrected 5000 bootstrap confidence interval: -.486 to -.066). Specifically, exposure to other readers' comments concordant with one's own position led to perceptions of more congenial public opinion, b = 1.29, t = 4.35, p < .001, and the more congenial participants thought that public opinion was, the less hostile their perception of the news story was, b = −0.18, t = −3.23, p = .001. Therefore, H2b was supported. Other readers' comments also had a significant direct effect on HMP, suggesting the possibility of misattribution, b = −0.60, t = −2.40, p = .02. When the same analysis was conducted for perceived impartiality of the news, however, neither the direct effect, b = .25, t = 1.07, p = .29, nor indirect effect was statistically significant, b = 0.08, Z = 1.16, p = .25.
To elucidate how ego-involvement moderates the direct and indirect effects of user-generated comments on perception of the news (RQ2), a moderated mediation test was conducted using the MODMED macro (Preacher, Rucker, & Hayes, 2007). Because safe discussion was previously found to have a significant effect on HMP (Eveland & Shah, 2003), safe and dangerous discussions were included as covariates in the analysis. With no significant interaction between ego-involvement and users' comments on perception of public opinion, b = −0.14, t = −0.69, p = .49, ego-involvement was considered as a potential moderator that affected only the relationship between perceptions of congenial public opinion (the mediator) and HMP (the dependent variable). Results showed a significant interaction between congenial public opinion perception and ego-involvement on HMP, b = −0.06, t = −1.99, p = .048. Specifically, the conditional indirect effect of users' comments on HMP through congenial public opinion perception was statistically significant for more involved individuals (+1 SD from the mean), b = −0.35, Z = −2.95, p = .003, but not for less involved individuals (−1 SD from the mean), b = −0.12, Z = −1.18, p = .24. That is, reading others' comments supporting their own position led the participants to perceive greater public support, which in turn, made them perceive less hostility in the news report, but such effects emerged only for more involved individuals. Meanwhile, safe discussion amplified HMP, b = 0.31, t = 3.17, p = .002, while dangerous discussion attenuated it, b = −0.23, t = −2.38, p = .02.
To better understand the interaction, participants' scores were dichotomized using a median split (n = 105, M = 3.01, SD = 1.02 for the lesser-involvement group; n = 109, M = 5.45, SD = 0.86 for the greater-involvement group) and simple mediation tests were performed for each group, separately. For the less involved group, although the exposure to other readers' comments concordant (vs. discordant) with one's own position induced more congenial perceptions of public opinion, b = 1.10, t = 2.83, p = .006, perceived congeniality of public opinion did not significantly affect HMP, b = −0.13, t = −1.39, p = .17. Not only did others' comments have no significant indirect effects on HMP, b = -0.14, Z = -1.26, p = .21, but they exerted no significant direct effect, b = −0.46, t = −1.23, p = .22. For the more ego-involved group, however, user-generated comments congruent with one's viewpoint induced the perceptions of more favorable public opinion, which in turn, lowered perceived hostility in the news report, b = −0.32, Z = −2.33, p = .02 (see Figure 1). In addition, others' comments had a significant direct effect on HMP, not mediated by perceptions of public opinion.
Figure 1. Direct and Indirect Effects of Readers' Comments on HMP and Perceived News Impartiality: High-Involvement Group
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A moderated mediation test on perceived impartiality of the news story also yielded a significant interaction between ego-involvement and congenial perceptions of public opinion, b = 0.10, t = 3.61, p < .001. The conditional indirect effect of readers' comments on perceived news impartiality was significant for more involved individuals (+1 SD from the mean), b = 0.26, Z = 2.56, p = .01, but not for less involved individuals (−1 SD from the mean), b = −0.14, Z = −1.38, p = .17. To decompose the interaction, simple mediation tests were conducted for greater- and lesser-involvement groups. For the low-involvement group, as was the case for HMP, readers' comments had no significant direct, b = 0.14, t = 0.46, p = .65, or indirect effect, b = −0.12, Z = −1.35, p = .18. By contrast, for the high-involvement group, exposure to congruent comments elicited ratings of greater impartiality of the news, through more congenial public opinion perception, b = 0.27, Z = 2.05, p = .04. Put differently, all readers got a sense of what public opinion was on the basis of what the user-generated comments said, but when readers who considered the news topic to be more important to them inferred from the comments that public opinion was on their side, they saw significantly less bias in the news story. Unlike for HMP, however, there was no significant direct effect of readers' comments on perceived news impartiality. Taken together, the results indicated that the defensive processing mechanism (H2b) and misattribution (RQ1) noted earlier occurred mostly among those with greater ego-involvement in the news topic.