Ressive commentors have nothing to hide: they stand up for higher-order moral ideals and principles. The goal of norm enforcement can be reached most effectively if sanctions are forwarded non-anonymously because they are credible, create awareness, support, and offer benefits. The descriptive statistics show that only 29.2 of all commenters prefer to remain anonymous. Anonymity of commenters is thus aPLOS ONE | DOI:10.1371/journal.pone.0155923 June 17,13 /Digital Norm Enforcement in Online FirestormsFig 2. Online aggression dependent on controversy and anonymity (random-effects). Predictions of Table 1, Model 2. doi:10.1371/journal.pone.0155923.gcharacteristic feature of social media; however, a vast majority still U0126MedChemExpress U0126-EtOH comments under their real names. The results in Tables 1 and 2, Model 1, show the impact of commenters’ anonymity to predict online aggression in comments. In line with Hypothesis 4, both the random-effects and fixed-effects models show that more online aggression is obtained by non-anonymous commenters and not by anonymous commenters. Exemplarily, we present three of the most aggressive comments by non-anonymous commenters: “Silly, fake, inhuman and degrading, racist, defamatory and ugly theses like those of Sarrazin (author’s note: a former German politician) have no place in this world, let alone in the SPD (author’s note: Social democratic party). Sarrazin certainly has no business in the Social democratic party and should try his luck with the Nazis” (ID352216); “HC Strache (author’s note: Austrian politician) has an evil, inhuman character, he lies and tries to persuade other people of wrong ideas.” (ID284846); “These authorities are mostly no people, but ���and regulatory machines! I detest authorities ith my 67 years’ life experience after all!” (ID418089). Figs 6 and 7 illustrate the size of the effect as predicted in the random- and fixed-effects regressions. The average effect of anonymity on aggression becomes sharper in the fixed-effects model. The random-effects model additionally illustrates that many of the very aggressive commenters appear non-anonymously. Overall, the effect size is small. However, the data clearly show that social norm enforcement, and not as popularly assumed, the risks of detection, seems the major motivation for aggression in social media because persons often aggress under their real names. If norm enforcement is indeed the major motivation for aggression in social media, the highest amount of non-anonymous U0126MedChemExpress U0126 negative word-of-mouth should be obtained in situationsPLOS ONE | DOI:10.1371/journal.pone.0155923 June 17,14 /Digital Norm Enforcement in Online FirestormsFig 3. Online aggression dependent on scandal and anonymity (random-effects). Predictions of Table 1, Model 2. doi:10.1371/journal.pone.0155923.gthat offer selective incentives and for intrinsically motivated actors. Model 2, in Tables 1 and 2, tests this assumption by introducing interaction effects between the anonymity of commenters and the presence of selective incentives and their intrinsic motivation. The results give preliminary support for Hypotheses 5 and 6. The highest amount of non-anonymous aggression is observed if a petition is accompanied by a highly controversial debate, is connected with a scandal in news media, and if persons are motivated by fairness concerns. By introducing these interaction effects, the main effect of anonymity on online aggression becomes insignificant, and thus suggests that the underlying r.Ressive commentors have nothing to hide: they stand up for higher-order moral ideals and principles. The goal of norm enforcement can be reached most effectively if sanctions are forwarded non-anonymously because they are credible, create awareness, support, and offer benefits. The descriptive statistics show that only 29.2 of all commenters prefer to remain anonymous. Anonymity of commenters is thus aPLOS ONE | DOI:10.1371/journal.pone.0155923 June 17,13 /Digital Norm Enforcement in Online FirestormsFig 2. Online aggression dependent on controversy and anonymity (random-effects). Predictions of Table 1, Model 2. doi:10.1371/journal.pone.0155923.gcharacteristic feature of social media; however, a vast majority still comments under their real names. The results in Tables 1 and 2, Model 1, show the impact of commenters’ anonymity to predict online aggression in comments. In line with Hypothesis 4, both the random-effects and fixed-effects models show that more online aggression is obtained by non-anonymous commenters and not by anonymous commenters. Exemplarily, we present three of the most aggressive comments by non-anonymous commenters: “Silly, fake, inhuman and degrading, racist, defamatory and ugly theses like those of Sarrazin (author’s note: a former German politician) have no place in this world, let alone in the SPD (author’s note: Social democratic party). Sarrazin certainly has no business in the Social democratic party and should try his luck with the Nazis” (ID352216); “HC Strache (author’s note: Austrian politician) has an evil, inhuman character, he lies and tries to persuade other people of wrong ideas.” (ID284846); “These authorities are mostly no people, but ���and regulatory machines! I detest authorities ith my 67 years’ life experience after all!” (ID418089). Figs 6 and 7 illustrate the size of the effect as predicted in the random- and fixed-effects regressions. The average effect of anonymity on aggression becomes sharper in the fixed-effects model. The random-effects model additionally illustrates that many of the very aggressive commenters appear non-anonymously. Overall, the effect size is small. However, the data clearly show that social norm enforcement, and not as popularly assumed, the risks of detection, seems the major motivation for aggression in social media because persons often aggress under their real names. If norm enforcement is indeed the major motivation for aggression in social media, the highest amount of non-anonymous negative word-of-mouth should be obtained in situationsPLOS ONE | DOI:10.1371/journal.pone.0155923 June 17,14 /Digital Norm Enforcement in Online FirestormsFig 3. Online aggression dependent on scandal and anonymity (random-effects). Predictions of Table 1, Model 2. doi:10.1371/journal.pone.0155923.gthat offer selective incentives and for intrinsically motivated actors. Model 2, in Tables 1 and 2, tests this assumption by introducing interaction effects between the anonymity of commenters and the presence of selective incentives and their intrinsic motivation. The results give preliminary support for Hypotheses 5 and 6. The highest amount of non-anonymous aggression is observed if a petition is accompanied by a highly controversial debate, is connected with a scandal in news media, and if persons are motivated by fairness concerns. By introducing these interaction effects, the main effect of anonymity on online aggression becomes insignificant, and thus suggests that the underlying r.
