Abstract
Introduction
Schools are an important developmental context during adolescence, serving as a hub where students encounter their own culture and that of their classmates, socialize with peers, express and challenge their views, and develop social skills essential for their future (Roeser et al., 2024). Students constantly negotiate their identities in this environment while interacting with peers from various cultural and social backgrounds. Hence, schools must be safe and inclusive for all young people (UNESCO, 2016). However, schools reflect broader economic, societal, and political tensions in times of crisis (e.g., Russia’s war in Ukraine), leading to increased conflicts and deteriorating cohesion. One notable issue arising from these current challenges is the increase of hate speech, which can create unsafe and inequitable living and learning environments in schools and negatively impact young people’s well-being (United Nations, 2023; Wachs et al., 2022a). Hate speech can be defined as any form of expression that seeks to humiliate people based on group characteristics (e.g., ethnicity, gender, sexual orientation, or religious affiliation) (Kansok-Dusche et al., 2023) and is a prevalent phenomenon in German schools (Castellanos et al., 2023). Despite its widespread occurence, many teachers feel ill-equipped to address hate speech effectively and cite a lack of access to evidence-based prevention programs (Krause et al., 2023; Seemann-Herz et al., 2022).
More recently, the evaluation of the “HateLess. Together against Hatred” program has shown promise in reducing adolescents’ involvement in hate speech, increasing empathy and self-efficacy (Wachs, 2023b, 2024b; Krause & Wachs, 2024). Questions remain, however, about the mechanisms by which the HateLess achieves increases in empathy and self-efficacy. Given the significance of school environments in positive youth development and success for school-based prevention programs (Low & Van Ryzin, 2014; Wang et al., 2020), the present study, therefore, further examines a) whether participation in HateLess has a positive effect on the classroom climate and b) whether participation in this program indirectly boosts empathy and self-efficacy by strengthening classroom climate.
Description of the HateLess Prevention Program
“HateLess. Together against Hatred” (from here on referred to as HateLess) is a prevention program tailored for adolescents in grades 7 through 9. HateLess is a multilevel program informed by Socio-Ecological Theory (Bronfenbrenner, 1979), integrating activities that develop skills across various levels. At the individual level, it promotes practical skills for intervening in hate speech. At the classroom level, it aims to encourage collaboration to develop anti-hate speech rules and social norms. At the school level, it creates school-wide activities designed to increase awareness of hate speech. At the community level, it involves delivering presentations during parent/guardian nights to extend the program’s impact beyond the school. HateLess employs multiple approaches to tackle hate speech, including knowledge-based interventions (e.g., educating adolescents about hate speech and differences to free speech), intergroup contact interventions (e.g., reading stories and watching films about minority group members and their experiences with hate speech), and individual skill development (e.g., training in empathy, self-efficacy, and collaboration).
HateLess comprises five modules, each delivered over a school week, with six school hours (each lasting 45 min) in a single school day per module. HateLess is designed to prevent online and offline hate speech among adolescents. The program begins with Module 1, which lays the foundational understanding of hate speech. This module includes an introductory session to engage students and prepare them for the topic. The first module helps students identify and comprehend the various forms of hate speech, emphasizing the importance of recognizing it in different contexts. The module then delves into the nuances between hate speech and free speech, encouraging students to analyze the context and intent behind speech acts critically.
Module 2 explores the roots of hate speech. It begins by examining the psychological, social, and cultural factors that drive individuals to engage in hate speech, helping students understand the complex motivations behind such behavior. The module also discusses societal norms and conceptions of normality, illustrating how these standards can perpetuate hate speech. Additionally, it addresses the role of digital mechanisms and online polarization in spreading and normalizing hate speech.
The third module shifts the focus to the consequences of hate speech. It addresses the personal impacts, such as emotional, psychological, and physical harm to individuals. Understanding these personal consequences underscores the severity of hate speech and its damaging effects. The module also examines the broader societal consequences, including social fragmentation, distrust, and conflict. By recognizing these impacts, students can appreciate the importance of combating hate speech. Furthermore, the module teaches coping strategies to help students build resilience and emotional strength in the face of hate speech.
In Module 4, the program presents practical strategies for dealing with hate speech. It begins by encouraging civil courage and active bystander intervention, empowering students to support victims and challenge hate speech perpetrators. This proactive approach fosters a supportive and protective environment. The module also promotes constructive and respectful ways of arguing and debating, emphasizing the value of healthy discourse. Finally, it includes a reflective session on the lessons learned throughout the module, aiming to build class solidarity and a cohesive environment committed to reducing hate speech.
The fifth module extends the focus to a school-wide approach, aiming to cultivate a hate-free school environment. It outlines comprehensive actions and policies that can be implemented across the school, involving collaboration between students, teachers, administrators, and the broader school community. This module emphasizes the importance of a united effort to create an inclusive and respectful culture within the school.
To enable schools to implement HateLess independently, the program was designed as a stand-alone prevention initiative that required no prior training for teachers. Instead, a comprehensive teacher manual was developed, including a step-by-step guide detailing each activity’s objectives, timing, methods, and learning goals. This approach ensures that schools can integrate the program into their curriculum without relying on external facilitators. To further support implementation, all program materials and resources are freely accessible on the HateLess website (www.hateless.de). This standardized yet flexible protocol enables schools to use HateLess without external support.
Previous HateLess Evaluation Studies
The current study builds on prior findings from two evaluation studies, which primarily focused on the intervention’s effects on adolescents’ involvement in hate speech. The first study focused on the effects of the HateLess program on adolescents’ empathy, self-efficacy, and offline counterspeech (Wachs et al., 2023b). More specifically, this study showed significant increases in offline counterspeech in the intervention group. This study also found that enhanced empathy and self-efficacy partially mediated these improvements in offline counterspeech. The second previous evaluation study examined online hate speech, specifically its perpetration, victimization, and counterspeech. Findings revealed that participation in HateLess significantly reduced online hate speech perpetration and victimization while increasing online counterspeech. These effects were also partially mediated by increased empathy and self-efficacy (Wachs et al., 2024b).
While the current study uses the same sample and overlapping measures (i.e., empathy and self-efficacy) as the previous two studies, it uniquely explores the potential direct effects of HateLess on classroom climate and its role as a mediator of the intervention effects on empathy and self-efficacy. Therefore, the current paper broadens the understanding of group dynamics and learning environments beyond the individual-level effects, which is relevant to understanding hate speech among adolescents (Wachs et al., 2024a).
Potential Effects of HateLess on the Classroom Climate
Classroom climate refers to a classroom’s overall atmosphere and quality of life, including interpersonal relationships, classroom management, the emotional environment, teaching and learning practices, and the physical environment (Loukas, 2007). In the present study, we focus on two facets of classroom climate, namely inclusive classroom climate and classroom cohesion. Though related (Schürer & van Ophuysen, 2022), both facets focus on different aspects of the classroom environment. While an inclusive classroom climate addresses individual student needs and experiences, classroom cohesion looks at group dynamics and collaborative behavior. In particular, an inclusive classroom climate ensures that all students feel valued, respected, and supported, celebrating diversity and promoting equity in participation. It involves fostering positive relationships and creating a safe environment where diverse needs are met. In contrast, classroom cohesion emphasizes the quality of student relationships and teamwork, highlighting solidarity, cooperation, and mutual support. It includes students working well together, supporting each other, and feeling a sense of belonging to a cohesive group with shared norms and values (Margas, 2023).
Previous research showed that in classrooms where students feel supported by their peers, more students defend victims of hate speech, and fewer students contribute actively to hate speech incidents (Ballaschk et al., 2021; Wachs et al., 2024a). In addition, classroom norms play a major role in understanding hate speech dynamics among adolescents (Wachs et al., 2022b). Hence, anti-hate speech programs should consider classroom climate a critical component in targeting hate speech in schools (United Nations, 2023).
Several actions during HateLess might positively influence the classroom climate. HateLess promotes understanding and respect for diversity, crucial components of an inclusive classroom climate. The modules educate students about the nature of hate speech, its roots, and its consequences, fostering a deep understanding of why it is harmful. This awareness encourages students to be more mindful of their language and actions, promoting respect for their peers’ diverse backgrounds and experiences.
Additionally, the program’s use of diverse protagonists helps students identify with characters who reflect the students’ varied social, cultural, and familial backgrounds, fostering empathy and reducing prejudices. By discussing diverse experiences and backgrounds through the program’s protagonists, students will likely develop a deeper appreciation for their peers’ differences, reducing biases and stereotypes. This awareness is crucial in creating a classroom environment where every student feels valued and respected.
HateLess actively involves students in creating anti-hate speech rules and social norms, which promotes a sense of ownership and collective responsibility. By working together on these initiatives, students develop stronger bonds and a greater sense of unity. The program’s collaborative nature encourages teamwork and mutual support, essential elements of classroom cohesion. In addition, the program includes practical activities (e.g., role-plays) that encourage civic courage and bystander intervention, which can strengthen the social fabric of the classroom as students support each other in standing against hate speech. Similar approaches have been found to be effective in increasing classroom climate in general (Donohoe, 2020; McGiboney, 2023). Besides these direct effects on classroom climate, HateLess might also influence the skills as well as the deployment of skills taught in anti-hate speech programs, such as empathy and self-efficacy, by creating positive learning environments.
Adolescents’ Personal Development Within Positive Classroom Environments
A positive classroom climate fosters student engagement, academic achievement, and social and emotional development, while an adverse climate can hinder learning and contribute to behavioral issues (Wang et al., 2020). Considering that students in the German schooling system typically stay in one classroom together for most of the school day, the significance of classroom climate is even more pronounced in the German context.
Empathy in adolescents is nurtured through positive relationships characterized by warm and supportive interactions within their social environments (Eisenberg et al., 2015). Although adult relationships contribute significantly to developing empathy in young people, a meta-analysis underscored the especially crucial role of peer relationships (Boele et al., 2019). Several ideas support the assumption that the classroom climate positively affects adolescents’ empathy development. First, a positive classroom climate often emphasizes emotional safety, where students feel secure expressing their thoughts and feelings. This environment encourages open communication and understanding of diverse perspectives, which is fundamental to developing empathy (Veldin et al., 2020). Second, classrooms promoting cooperative learning and teamwork can enhance empathetic behavior (Luengo Kanacri et al., 2017; Van Ryzin & Roseth, 2019). When students work together on projects and activities, they learn to appreciate and understand each other’s viewpoints, strengths, and challenges. This collaborative spirit helps build a sense of community and mutual respect, which is essential to empathy (Van Ryzin & Roseth, 2022). Third, peers in a positive classroom climate often model empathetic behavior. When students demonstrate empathy through interactions, they provide a powerful example for their peers to emulate. Observing and experiencing empathy firsthand can reinforce its importance and encourage students to adopt similar behaviors (Miklikowska et al., 2022). Lastly, a positive classroom climate that values inclusivity and diversity can broaden students’ understanding and acceptance of different cultural and social backgrounds. This exposure helps dismantle stereotypes and prejudices, fostering a more empathetic attitude toward individuals who may be different from oneself (Fu et al., 2022). These ideas are also supported by hate speech research, indicating that classroom cohesion is related to adolescents’ empathy for victims of hate speech (Wachs et al., 2023a)
Like empathy, the development of self-efficacy is influenced by significant others, such as parents, siblings, teachers, and peers. During adolescence, peer acceptance and relationships are especially crucial for developing self-efficacy because peers have a significant role in adolescents’ socialization (Schunk & Zimmerman, 2007). Adolescent peers provide each other opportunities to learn from one another and function as role models (Ruggeri et al., 2018). Classrooms, characterized by a positive climate, constitute a meaningful context to develop, exercise, and maintain the skills necessary to engage in self-efficacy (Hong et al., 2021; Zysberg & Schwabsky, 2021). First, a supportive classroom environment often encourages active participation and engagement in social interactions. When students feel comfortable and valued in their classroom, they are more likely to take risks, ask questions, and engage in discussions, all of which contribute to a sense of competence and self-efficacy (Monteiro et al., 2021). Second, a classroom that promotes collaboration allows students to experience success through group efforts. When students work together and achieve common goals, they develop a sense of collective efficacy, which can translate into individual self-efficacy as they recognize their contributions to the group’s success (Lent et al., 2006). Finally, in a positive classroom climate, students are more likely to receive emotional and social support from their peers. This support network can help students navigate challenges and setbacks, reinforcing their belief in overcoming obstacles and succeeding. Indeed, initial research found a positive link between a supportive classroom climate and students’ self-efficacy toward handling bullying (Sjögren et al., 2021). More recently, hate speech research revealed a positive association between classroom cohesion and self-efficacy in intervening in hate speech (Wachs et al., 2023a).
The Present Study
Schools are critical developmental environments where adolescents interact with diverse peers, negotiate their identities, and develop essential social and emotional skills. Among these dynamics, classroom climate is pivotal in shaping adolescents’ social and emotional development. Empathy flourishes in environments that foster mutual respect and understanding among peers, while self-efficacy is strengthened in classrooms that encourage active participation and collaboration. Despite its importance, limited research has examined how structured anti-hate speech interventions, such as HateLess, directly influence classroom climate and indirectly impact psychosocial outcomes like empathy and self-efficacy through changes in classroom dynamics. The HateLess program aims to foster an inclusive and cohesive classroom climate by promoting understanding and respect for diversity, strengthening social bonds, and encouraging collaborative efforts. These shifts in classroom dynamics are expected to create an environment that nurtures empathy and self-efficacy. To address the scarcity of empirical evidence, the present study examined the direct effects of the HateLess program on classroom inclusivity and cohesion and its indirect effects on students’ empathy and self-efficacy through changes in classroom climate. Given these considerations, the study is guided by four hypotheses:
Hypothesis 1. Participation in HateLess predicts higher levels of inclusive classroom climate.
Hypothesis 2. Participation in HateLess predicts higher levels of classroom cohesion.
Hypothesis 3. Participation in HateLess predicts higher levels of empathy via higher levels of inclusive classroom climate and cohesion.
Hypothesis 4. Participation in HateLess predicts higher levels of self-efficacy via higher levels of inclusive classroom climate and cohesion.
Method
Participants
An a priori power analysis using G*Power (Faul et al., 2007) indicated that a sample of at least 782 participants (α = .05, power = 0.80) was necessary to identify small to medium effects. The sample for this study comprised 820 adolescents aged between 12 and 16 years (
Measures
Inclusive Classroom Climate
Five items were used to measure inclusive classroom climate (e.g., “In my class, one can be different from the others without worry”; Bundeszentrale für politische Bildung, 2013). Responses were given on a scale ranging from “absolutely disagree” (1) to “absolutely agree” (4). The internal consistency of the scale in the current sample was good, Cronbach’s alpha T1 = .85/T2 = .87; McDonald’s omega T1 = .83/T2 = .96. Confirmatory factor analyses (CFAs) confirmed construct validity: CFAT1: χ2 = 29.32,
Classroom Cohesion
Five items were used to measure classroom cohesion (e.g., “In my class, we have a good sense of community”; Bundeszentrale für politische Bildung, 2013). Responses were given on a scale ranging from “absolutely disagree” (1) to “absolutely agree” (4). The internal consistency of the scale in the current sample was good, Cronbach’s alpha T1 = .81/T2 = .82; McDonald’s omega T1 = .80/T2 = .81. CFAs confirmed construct validity: CFAT1: χ2 = 13.71,
Empathy
Six items were used to measure participants’ empathy for victims of hate speech. The instrument, adapted from Knauf et al. (2018), was introduced about hate speech: “When I see classmates being insulted or attacked by other classmates because of their skin color, origin, religion, sexual orientation, or gender. . ..” Participants rated their agreement with the six items (e.g., “I can well imagine how bad it must be for them”) on a scale from “absolutely disagree” (1) to “absolutely agree” (5). The internal consistency of the empathy scale in the current sample was good, Cronbach’s alpha T1 = .89/T2 = .90; McDonald’s omega T1 = .89/T2 = .91. CFAs confirmed construct validity: CFAT1: χ2 = 46.04,
Self-Efficacy
Three items were used to measure participants’ self-efficacy in intervening against hate speech (e.g., “I know that there are things I can do to improve the situation”; Knauf et al., 2018). Responses were rated on a scale from “absolutely disagree” (1) to “absolutely agree” (5). The internal consistency of the self-efficacy scale in the current sample was good, Cronbach’s alpha T1 = .85/T2 = .87; McDonald’s omega T1 = .85/T2 = .88. CFAs confirmed construct validity: CFAT1: χ2= 6.81,
Control Variables
Participants were asked to provide their age and gender, with gender options of male, female, and gender diverse. To determine their immigrant background, participants were questioned if they or their parents were born in a country other than Germany. According to the official German criteria for immigrant background (Statistisches Bundesamt, 2022), participants were classified as having an immigrant background if they or at least one of their parents were born outside of Germany.
Procedure
Sampling Procedure
This study received ethical approval from the data protection officer and the educational authority in the Federal State of Brandenburg and the Federal State of Berlin, Germany. Schools could randomly assign their classes to the intervention conditions to facilitate participation. All participating schools were provided with educational materials and multimedia content to support the implementation of the intervention. We contacted 34 schools via email and phone, detailing the opportunity to be part of the random selection for the study. Nineteen schools declined, citing local spikes in COVID-19 cases, resource constraints, or prior commitments to other prevention initiatives. Four schools did not respond. Ultimately, 11 schools, representing a 32% acceptance rate, agreed to join the study. These schools were selected based on their scheduling flexibility and assurance that they were not concurrently running similar anti-hate speech or anti-bullying programs. Out of the 44 classes initially approached, 7 opted out, resulting in an 84% acceptance rate at the class level (
Data Analysis
Missing Data Analysis
The missing data for each variable were examined using SPSS 29.0 (IBM Corp, 2023). The percentage of missing data ranged from 0.2% (T1 empathy) to 4.9% (T2 self-efficacy). The Little’s missing completely at random (MCAR) test indicated that the data were not likely to be MCAR, χ2 = 365.32,
Preliminary Analysis
We conducted descriptive statistical analyses and bivariate correlations to explore the study’s variables. We conducted independent
Main Analysis
The study’s hypotheses were tested using a two-level multilevel mediation model, which accounts for the nested structure of the data (students within classrooms) and reduces the risk of biased estimates due to clustering effects. The decision to use this model was guided by the intraclass correlation coefficients (ICCs) calculated for each outcome variable, which indicated significant clustering at the classroom level. First, we estimated ICC with a model with only a random intercept. Next, we developed a multilevel mediation model to test the direct effects of being in the intervention versus the control group on T2 inclusive classroom climate (Hypothesis 1), classroom cohesion (Hypothesis 2), empathy, and self-efficacy. Finally, we investigated four indirect pathways: the effect of group assignment on T2 empathy via T2 inclusive classroom climate and classroom cohesion (Hypothesis 3) and the effect of group assignment on T2 self-efficacy through T2 inclusive classroom climate and classroom cohesion (Hypothesis 4). Baseline measures of inclusive classroom climate, classroom cohesion, empathy, and self-efficacy were controlled for, along with demographic variables such as age, gender, and immigration background. These controls were applied to T2 outcomes. All predictors were entered at the student level (Level 1), with no predictors at the classroom level (Level 2). This approach allowed us to simultaneously estimate direct and indirect effects while controlling for baseline measures and demographic variables, ensuring a comprehensive evaluation of the intervention’s impact. The analysis included 37 classes, with an average class size of 22 adolescents, and was conducted using Mplus 8.7 software (Muthén & Muthén, 2021).
Finally, effect sizes were calculated using Cohen’s
where
Once the pooled
where
Results
Descriptive Analysis and Bivariate Correlations
To examine possible baseline differences between the experimental conditions (intervention group vs. control group),
Correlations and Descriptives Among the Study’s Main Variables.
Multilevel Mediation Model
A CFA supported the adequacy of the measurement model, χ2 = 426.50,
Results of the Multilevel Mediation Model.
The multilevel mediation model revealed that adolescents in the intervention group reported higher levels of inclusive classroom climate (

Direct effects of group assignment on inclusive classroom climate, classroom cohesion, empathy, and self-efficacy.
The mediation analysis also identified significant indirect effects. The group assignment intervention had an indirect effect on empathy (T2) through inclusive classroom climate (
The effects of age, gender, and immigrant background were examined. Gender significantly predicted classroom cohesion (
Discussion
This study provides crucial insights into the effectiveness of the HateLess program in enhancing classroom climate and key psychosocial outcomes among adolescents. By directly influencing classroom inclusivity and cohesion, the program creates a supportive environment that fosters empathy and self-efficacy—essential components in combating hate speech (Wachs et al., 2024b). Our findings support all four hypotheses, demonstrating both the direct and indirect positive effects of HateLess on classroom dynamics and individual competencies. These results underscore the multifaceted benefits of implementing structured programs to reduce hate speech within schools.
Direct Effects of Participation in HateLess on Inclusive Classroom Climate and Cohesion
Consistent with Hypothesis 1 and Hypothesis 2, participating in HateLess significantly enhanced both inclusive classroom climate and cohesion. A possible explanation might be that, by actively involving students in creating anti-hate speech rules and norms, HateLess promoted a sense of ownership and collective responsibility, which is crucial for fostering an inclusive and cohesive environment. The program’s emphasis on recognizing and appreciating diversity likely contributed to a more inclusive atmosphere where students felt valued and respected. The short-term effects on the two classroom climate dimensions were medium to large. Our findings align with the broader literature that shows the significant positive effects of structured interventions on school climate (Charlton et al., 2021). The effect sizes in our study fall within the range observed in other well-regarded interventions, especially those focusing on social and emotional learning (Charlton et al., 2021). This suggests that the HateLess program is similarly effective in enhancing the school environment and social dynamics, even though it explicitly addresses hate speech.
Indirect Effects of Participation in HateLess on Empathy and Self-Efficacy via Inclusive Classroom Climate and Cohesion
The study’s findings support Hypotheses 3 and 4, indicating that the HateLess intervention indirectly increased students’ empathy for victims of hate speech and their self-efficacy toward intervening in such situations through improvements in classroom climate and cohesion. The intervention’s direct and indirect effects on empathy highlight the importance of fostering positive interpersonal relationships and emotional safety within classrooms. The program’s activities, which included discussing diverse experiences and fostering mutual respect, likely facilitated greater understanding and empathy among students. Similarly, the increase in self-efficacy can be attributed to the supportive and collaborative classroom environment promoted by the HateLess program. When students feel supported and valued by their peers, they are more likely to engage actively in social interactions and feel confident intervening in adverse situations. The increases in empathy and self-efficacy reflect the broader literature on social learning, peer influence, and individual development during adolescence (Luengo Kanacri et al., 2017; Schunk & Zimmerman, 2007; Van Ryzin & Roseth, 2019) and initial research on the relationship between classroom climate and adolescents’ empathy for victims of hate speech and self-efficacy toward intervening in hate speech (Wachs et al., 2023a). These effects are particularly important concerning hate speech prevention, given the previous evaluation findings that empathy and self-efficacy play a crucial role in reducing hate speech perpetration and victimization and increasing counterspeech (Wachs et al., 2023b, 2024b).
Practical Implications
The current study’s findings offer several practical implications. First, structured prevention measures have the potential to positively foster classroom climate, as shown in this study by the increase in inclusive classroom climate and cohesion following the HateLess program. Particularly in view of the beneficial effects of a positive classroom climate for students (Wang et al., 2020), such preventive measures should be broadly implemented in schools, which can be supported by integrating them into school-wide policies. Beneficial effects of classroom climate were also found in this study, as inclusive classroom climate and cohesion acted as mediators of the positive impact of the HateLess program on empathy and self-efficacy.
Second, schools should view inclusivity and cohesion as goals and pathways for nurturing empathetic and empowered students. Given the significant role of classroom climate in enhancing empathy and self-efficacy, peer-led initiatives such as mentorship programs or student-led workshops on diversity and hate speech awareness can be particularly impactful. These initiatives could capitalize on peer influence to foster long-term cultural shifts within classrooms. While immediate improvements in classroom climate were evident, sustaining these changes over time requires ongoing effort. Schools should implement long-term strategies, such as continuous monitoring of classroom dynamics, periodic refresher sessions of the HateLess program, and embedding inclusivity as a core school value. Regular assessments of classroom climate can ensure that progress in empathy, self-efficacy, and overall climate is maintained. In addition, scholars who aim to design anti-hate speech interventions should integrate classroom climate-focused modules to address the broader social and emotional dynamics within classrooms and enhance individual behaviors.
Finally, teachers play a pivotal role in fostering inclusive and cohesive classroom environments (Bilz et al., 2024; Wang et al., 2020). Teachers can reinforce inclusivity and mutual respect by incorporating discussions on cultural, social, and personal diversity into their lessons and facilitating activities promoting a sense of belonging (Hymel & Katz, 2019). To equip them for this role, schools should offer ongoing professional development focusing on classroom management, conflict resolution, facilitating sensitive discussions, and effectively managing classroom dynamics. Given that many teachers feel underprepared to address hate speech (Krause et al., 2023), professional development programs should also emphasize how a cohesive, inclusive environment supports empathy and self-efficacy and forms the foundation for such skills, as demonstrated by the findings of this study.
Limitations and Future Research
While the current study offers valuable insights into the effects of the HateLess program, several limitations should be acknowledged. First, the study relied on self-reported measures for assessing outcomes such as inclusive classroom climate, cohesion, empathy, and self-efficacy. Self-reports are subject to biases such as social desirability and recall bias, which could affect the validity of the findings. Future research could benefit from incorporating a multi-method approach, including teacher observations, peer assessments, or objective behavioral measures, to provide a more comprehensive assessment of classroom dynamics and individual behaviors.
Second, due to the limitation of the selected two measurement points, there are still remaining questions regarding (a) the temporal sequencing between mediators and outcome variables, (b) long-term sustainability and effects, and (c) bidirectional associations between classroom climate and critical outcomes. Both the mediators (inclusive classroom climate and cohesion) and the outcome variables (empathy and self-efficacy) were measured at the same time point (T2). However, prevention science emphasizes the importance of measuring mediators and outcomes at different time points to understand better the temporal pathways through which interventions exert their effects (Kraemer et al., 2002). Along the same line, bidirectional associations between classroom climate and critical outcomes such as empathy and self-efficacy should be examined, as improvements in a supportive classroom environment may not only foster prosocial skills but also be reinforced by students’ growing sense of empathy and self-efficacy, creating a positive feedback loop that strengthens both the climate and individual development over time (Luengo Kanacri et al., 2017). Lastly, prevention science also highlights the importance of examining long-term sustainability and effects, especially as the full impact of interventions may take time to manifest. However, the present study focused on short-term outcomes 1 month after the intervention. Follow-up studies with additional measurement points over more extended periods can address these issues.
Third, the quasi-experimental design limits the ability to make strong causal inferences. Although the intervention and control groups were well-matched, random assignment was not feasible in this study. This limitation can introduce selection bias, where unmeasured pre-existing differences between groups may have influenced the results. Future studies should consider employing randomized controlled trial designs to strengthen the causal claims of anti-hate speech prevention programs like HateLess.
Fourth, the findings are based on adolescents from German schools shaped by unique cultural and educational contexts. While this provides valuable insights, the results may not fully generalize to countries or regions with different approaches to hate speech, varying levels of ethnic and cultural diversity, or alternative educational systems. For example, classrooms in more socially homogeneous or heterogeneous settings may exhibit dynamics that could influence the program’s effectiveness, such as differing intergroup interaction or inclusion practices. In addition, the program’s impact on typical target groups of hate speech, such as students with immigrant backgrounds, LGBTQIA+ students, or those with special educational needs (Castellanos et al., 2023), warrants further exploration. These currently underrepresented or marginalized groups may have unique experiences and challenges related to classroom climate and hate speech, making it essential to test whether HateLess addresses their specific needs effectively. Understanding these nuances could provide valuable insights into how interventions like HateLess can be tailored to promote inclusivity and equity more broadly.
Finally, the focus on classroom climate as a mediating factor underscores the importance of environmental contexts in shaping individual outcomes. However, the study could further explore other potential mediators, such as teacher-student relationships or the broader school climate, which may interact with classroom dynamics to influence program effectiveness. Prevention science advocates for comprehensive, multilevel models considering interactions across individual, relational, and systemic levels (Gradinger & Strohmeier, 2018). Including these additional factors in future research could provide deeper insights into the mechanisms that drive HateLess’s success.
Conclusion
The present study extends prior research on the HateLess program by demonstrating its effectiveness in improving classroom climate and fostering essential social outcomes. Participation in the HateLess program significantly improved both inclusive classroom climate and classroom cohesion. These enhancements, in turn, were positively associated with students’ empathy and self-efficacy, underscoring the critical role that structured educational interventions can play in promoting positive social outcomes within schools. By creating supportive and collaborative classroom environments, schools can empower adolescents to take a proactive stance against hate speech. In addition, the findings contribute valuable insights into the design and implementation of educational interventions, emphasizing the importance of comprehensive approaches to cultivating inclusive and supportive learning spaces for all students. While the study provides robust evidence for the immediate impacts of the HateLess program, further research is needed to evaluate the long-term sustainability of these improvements and their broader influence on adolescents’ social development. Additionally, exploring the program’s adaptability across different cultural and educational contexts could provide valuable insights for scaling such interventions. Continued exploration of classroom-based interventions remains essential for developing inclusive, equitable, and supportive educational environments that empower students to challenge hate speech and foster respect and collaboration.
