Method

To conduct this systematic review (^{Broome et al., 2006}), we followed the guidelines of the PRISMA statement (^{Page et al., 2021}) for the publication of systematic reviews (^{Moher et al., 2007}). We selected publications reporting results from experimental or quasi-experimental studies evaluating the effect of participation in a deliberative process on various civic competences of adolescents. The research was conducted between July and November, 2022. According to the objectives of this study, the inclusion criteria were:

The search terms were selected based on previous literature on deliberation as a process impacting individuals' civic competences.

The languages in which the search was conducted were Spanish and English, and the search terms used were as follows: (SPA) deliberación; experimento; adolescentes; competencias cívicas / (ENG) deliberation; experiment; adolescents; civic competences. Likewise, the search engines used were: Social Sciences Citation Index, Google Scholar, JSTOR, Scopus, Scielo, and Scispace. We found that these search engines were the most suitable for exploring the state of scientific production within the field of Political Psychology and related Social Sciences. Figure 1 summarizes the articles found and the selection of these based on the inclusion criteria.

Figure 1: Selection of Articles Through the Different Phases of the Systematic Review 

Table 1: Analysis of the Studies Included in the Systematic Review and Their Results 

Results

A small number of studies meeting the inclusion criteria were encountered. Most excluded articles were not experimental or quasi-experimental studies and did not involve adolescents as the study population. Overall, the results of the analysis in this review (Table 1 1a 1b) suggest that deliberation has a positive impact on civic competences in adolescents. However, the effect sizes of these interventions tend to be low. In some cases, null effects were found, and in others, while deliberation was shown to improve observed civic competences, effect sizes were not reported. Thus, while deliberation appears to have a positive effect, not every type of intervention yields significant results.

Dependent Variables

The authors of the studies included in this review analyzed various variables as civic competences. These included deliberative self-efficacy, communicative self-efficacy, and emotional control as individual self-efficacy scales (^{Carlson et al., 2012}); media usage, political cognition, political discussion, deliberative habits, civic identity, and participation as civic engagement variables (^{McDevitt & Kiousis, 2006}); general political knowledge (^{Sampaio & Siqueira, 2013}); disposition and ability for critical thinking (^{Yang & Chung, 2009}); and political interest, political knowledge, democratic values, and political discussion (^{Persson et al., 2019}).

Political knowledge emerged as the primary dependent variable across the analyzed studies. However, its operationalization varied significantly: ^{McDevitt and Kiousis (2006}) and ^{Persson et al. (2019)} both assessed political knowledge through questions pertaining to the political system, such as the electoral process and notable political figures at the local level. McDevitt and Kiousis (2006) integrated this measure within their broader assessment of political cognition, which also considered the integration of political information and issue salience. In contrast, ^{Persson et al. (2019)} categorized their assessment as factual political knowledge, encompassing inquiries about local and international (European Union) formal politics. On the other hand, ^{Sampaio and Siqueira (2013)} devised a more intricate approach to measuring political knowledge. Their methodology involved constructing partial indices concerning knowledge about democracy, legislative institutions, and the ideological spectrum of political parties. These divergent approaches to operationalizing the dependent variable may account for the differing outcomes regarding the positive impact of participation in deliberative processes.

Furthermore, the instruments employed to evaluate political knowledge frequently neglect facets of non-conventional or informal political engagement, which extend beyond the confines of institutional and formal spheres. These realms hold potential significance for political socialization during adolescence (^{Bruno & Barreiro, 2021}). Hence, it becomes pertinent to explore the role of political knowledge using more contextualized and age-appropriate measurements. For instance, inquiries could encompass understanding student politics, gender, or the environment.

Interestingly, in the study by ^{Sampaio and Siqueira (2013)}, political knowledge increased only among adolescents who had reported higher political interest before deliberation. Even in the study with null effects by ^{Persson et al. (2019)}, political knowledge increased by an average of 0.3 more correct responses in the intervention group compared to the control group. While this effect is not statistically significant, this data holds substantial interest in contrast to the result of other variables (^{Persson et al., 2019}).

In studies reporting post-intervention improvements (^{Carlson et al., 2012}; ^{McDevitt & Kiousis, 2006}; ^{Sampaio & Siqueira, 2013}; ^{Yang & Chung, 2009}), the enhanced civic competences were primarily associated with heightened levels of political cognition in adolescents. While this aspect of civic competences received the most attention in these investigations, McDevitt and Kiousis (2006) also examined future political electoral participation intention, volunteering, and university activism as civic competences predominantly linked to political action, albeit with reported effect sizes being small.

Similarly, ^{Yang and Chung (2009}) discovered that implementing a deliberative curriculum on civic education for adolescents positively impacted overall critical thinking scores. However, while inference, interpretation, and evaluation skills, alongside dispositional openness and systematicity, exhibited significant differences between the experimental and control groups, no statistically significant variances were observed in assumption recognition and deduction skills, nor in truth-seeking disposition, analytical capacity, or curiosity.

In this context, deliberation appears to have influenced civic competences associated with cognitive processes more than those related to political action. However, its impact varies depending on the specific political cognition variables under consideration.

Discussion

This review aimed to analyze experimental and quasi-experimental studies investigating the effects of adolescents' participation in deliberative processes on their civic competences, representing the first of its kind to the knowledge of the authors.

One primary finding of this study is the scarcity of experimental research on this topic in adolescent populations, which contrasts with the abundance of evidence available for adult populations. The criteria that led to the exclusion of most initially identified studies were the lack of experimental or quasi-experimental design as well as a lack of focus on adolescent populations. Regarding the former, having experimental evidence is especially relevant as it allows for analyzing the effect of participation in a deliberative process on adolescents' civic competences based on specific and quantifiable data. Additionally, when the methodology is sufficiently detailed, this type of design can be replicated in other settings, enabling comparison of results, validation of findings, and strengthening of identified relationships between variables.

Furthermore, it is worth examining the role of deliberative processes as a tool for political socialization specifically during adolescence, a vital period when individuals begin to become more actively involved in political life. Additionally, it is important to avoid an adult-centric logic of politics that does not recognize young people as active actors in shaping critical citizenship and fostering social transformation (^{Yarema & Kolchinskaya, 2016}).

In summary, the majority of literature exploring the impact of deliberation on adolescents' civic competences consists of theoretical studies (e.g., ^{Avery et al., 2013}; ^{Journell, 2010}; ^{Levine, 2008}), qualitative research (e.g., ^{Crocco et al., 2018}; ^{Eränpalo, 2014}), or non-experimental investigations (e.g., ^{Lee, 2012}; ^{McDevitt & Caton-Rosser, 2009}; ^{Maurissen et al., 2018}; ^{Yunita et al., 2018}). It is worth noting the absence of Spanish-language articles; the sole Latin American study (from Brazil) meeting the selection criteria was the quasi-experiment conducted by ^{Sampaio and Siqueira (2013)}.

Regarding the analyzed studies (n = 5), the prevailing trend indicates positive impacts. Nonetheless, the extent of improvement varied across civic competences, intervention modalities, and research methodologies. Notably, the experimental study with the largest sample size yielded non-significant results (^{Persson et al., 2019}), and the effect size was unreported in the study by ^{Yang and Chung (2009}). In summary, while existing data that suggests that deliberation fosters civic competences, the magnitude of these enhancements appears modest and contingent upon the specific intervention employed. Consequently, certain forms of deliberation may not yield substantial improvements.

The variation in observed effects across studies may be attributed, in part, to differences in political interest. While some studies highlight its pivotal role (^{Sampaio & Siqueira, 2013}), others, such as ^{Persson et al. (2019)}, do not incorporate it. Future investigations should explore the mediating influence of affective or emotional dimensions of political engagement on both interest and political knowledge. These affective labels serve as cognitive shortcuts, significantly influencing the perceived relevance of issues and the allocation of cognitive resources (^{von Scheve, 2013}). Consequently, specific affective labels, combined with existing political knowledge, facilitate the acquisition of new information and guide citizens' decision-making processes (^{Sampaio & Siqueira, 2013}).

As previously noted, the operationalization of the deliberative process varied in terms of duration and context, posing challenges in identifying a consistent pattern underlying the observed positive effects. Consequently, positive outcomes were evident in diverse settings, ranging from specific experiences (^{Sampaio & Siqueira, 2013}) to prolonged exposure to deliberation (^{Carlson et al., 2012}), with the former appearing to yield more pronounced effects. Moreover, both school-based (^{McDevitt & Kiousis, 2006}; ^{Yang & Chung, 2009}) and extracurricular (^{Carlson et al., 2012}; ^{Sampaio & Siqueira, 2013}) deliberative experiences demonstrated similar efficacy. Despite variations in approach and implementation, all deliberative interventions shared the fundamental characteristic of facilitating face-to-face activities aimed at promoting collective participation and civic education through structured tasks. Additionally, adult guidance or participation was consistent across all interventions, whether as facilitators (^{Carlson et al., 2012}), deliberation guides (^{McDevitt & Kiousis, 2006}; ^{Persson et al., 2019}; ^{Yang and Chung, 2009}), or political knowledge instructors (^{Sampaio & Siqueira, 2013}).

When examining the conceptual approach to deliberation, more similarities than differences among the reviewed studies were identified. Both investigations exploring the effects of deliberative school curricula and those assessing the impact of deliberation beyond the educational sphere underscore its significance as a fundamental process for nurturing civic engagement and reinforcing democratic principles from adolescence onward. Consequently, both conceptualizations highlight the interactive and participatory nature of deliberation among peers aimed at reaching a consensus for collective action.

When rigorously comparing the operationalization of deliberation across the reviewed articles, a nuanced variation tailored to each study was discerned, devoid of replicated designs despite occasional similarities, such as the application of deliberative curricula in secondary schools. However, these interventions varied notably in duration, the thematic scope discussed by participants, and the extent of participant involvement. Consequently, it was deduced that deliberative approaches among adolescents exhibit a remarkable diversity. Given the scant number of studies available, it can be assert that this field of study is in infancy, thereby elucidating the heterogeneous nature of operational approaches.

In examining the conceptual approach to civic competences, a striking convergence emerges across the reviewed studies, wherein they uniformly define such competences as essential civic-political skills or knowledge requisite for active citizenship and fortifying democratic governance. However, this conceptual coherence stands in stark contrast to the varied civic competences measured across the studies. For instance, while political knowledge emerged as a recurrent civic competency in most studies, the array of other civic competences varied based on the authors' discretion in each study. This divergence underscores the diversity in conceptualizing and measuring civic competences, albeit with an underlying interplay between practical skills and cognitive predispositions guiding the selection of competences for measurement. This highlights the importance of integrating both dimensions in future investigations on civic competences in adolescents.

Regarding the civic competences that effectively improved after exposure to a deliberative process, political knowledge increased in all studies where this variable was assessed. However, in ^{Sampaio and Siqueira's study (2013)}, political knowledge only increased among individuals who had previous political interest before deliberation. Even in ^{Persson et al. (2019}), where none of the effects were statistically significant, political knowledge was the variable that showed the greatest growth after deliberation. Other variables that increased in some studies were deliberation and interpersonal communication (^{Carlson et al., 2012}; ^{McDevitt & Kiousis, 2006}), attention to political news, electoral attention, integration of information, and issue importance-increasing the degree of importance that adolescents attributed to a particular problem or public controversy- ^{(McDevitt & Kiousis, 2006}).

Substantial differences surfaced in the development of adolescents' civic competences depending on the political deliberation process involved. Both peer-driven political socialization and interaction with adults wield distinct impacts on adolescents' political skill development, each contributing uniquely to their civic education. Across the reviewed studies, adolescent-led deliberation nurtured informal political engagement and activism among peers, thereby nurturing the acquisition of political skills and attitudes. Conversely, political deliberations involving adults, within familial or scholastic settings, adopted a more formalized approach, encompassing media utilization, cognitive processes, and conventional political participation. Such engagements augmented adolescents' propensity to engage in political dissent while nurturing endeavors to comprehend the significance and essence of newfound political information.

While these findings hold significance, they also raise certain methodological concerns that warrant attention in forthcoming research endeavors. Primarily, the political knowledge assessments predominantly targeted facets of formal politics, such as voting, sidelining themes and institutions more intertwined with adolescents' daily experiences. It is necessary to understand that adolescent populations may be less engaged with these issues compared to political themes and institutions that are more part of their daily lives (^{Quintelier & Hooghe, 2013}). A measurement of political knowledge for this population should be able to include them. Secondly, most studies focused on dimensions of political cognition while overlooking those pertinent to political action. Future investigations should strive to ascertain whether these competences manifest in concrete political engagement and activity.

In addition to the limitations identified in the reviewed studies, this study also has important constraints. Firstly, the scarcity and diversity of literature in this field impede the drawing of definitive conclusions regarding the impact of deliberation on adolescents' civic competences and the potential mediating factors influencing these effects. Furthermore, the presence of publication bias warrants consideration: there is a greater likelihood of articles reporting significant effects being published compared to those that do not report any effects. Consequently, it would be pertinent to undertake further inquiries aimed at accessing unpublished findings by reaching out to researchers actively engaged in this area of study. Collectively, while the evidence amassed is generally promising, it remains inconclusive at this juncture.

The practical implications of this study prompt the question of whether implementing deliberative interventions on a larger scale among adolescents to promote or enhance their civic competences is viable. The answer is that further experimentation is warranted. This article marks the initial endeavor to investigate and analyze the impacts of deliberative experimental studies on adolescents, addressing a notable gap in Latin American academic literature. Deliberative experimental studies provide individuals with hands-on experience in civic participation, a crucial component for nurturing their civic engagement. Consequently, it is imperative to delve deeper into the study of civic competences, particularly during their formative stages, to uncover avenues for their cultivation. By doing so, we may mitigate levels of political apathy and disinterest stemming from the current crisis in the democratic system.