current issues, social, political or public interest issues favours participation in political activities (Gil de Zúñiga, Jung & Valenzuela, 2012; Kaye & Johnson, 2002; Scheufele & Nisbet, 2002). On the contrary, fun- or entertainment-oriented uses have no significant effects (Zhang & Chia, 2006). Subsequent studies have developed communication mediation models to explain the effect of informational uses on participation, recently addressing the social media environment. The O-S-R-O-R (Orientation – Stimulus – Reasoning – Orientation – Response) model formulated by Cho et al. (2009) contends that the consumption of political information triggers self-reflective and mental processing processes that are necessary for further political involvement. These cognitive processes in turn tend to be stimulated by expressive behaviours and discussion with others about the revised topics, being contributing factors to political learning. In this regard, the study of Jung et al. (2011) focused on the uses of the internet found that the search and dissemination of hard news indirectly influences the political behaviour of users through the expansion of their knowledge about public affairs, social issues and the political process.

In addition, the compositional efforts demanded by the publication of opinions, as well as the deliberative component of the discussions that can be triggered later, are elements that also contribute to the strengthening of political engagement and knowledge. For Pingree (2007) the political expression is composed of three underlying mechanisms that impact the sender: pre-expression expectation, message composition, and message release effects. Together these stages motivate critical reflection, learning new content, mental elaboration and commitment to the opinions expressed. At this point, social networks generate favourable conditions in terms of costs, scope and immediacy for the development of expressive behaviours. Based on the assumptions of the theoretical model of differential gains, the variety of expressive activities that facilitate social network sites stimulate significant political learning (Yamamoto et al., 2015). This effect is not only because interpersonal communicative contexts promote greater awareness and interest on current events, social issues and the political content discussed, but also motivate users to seek additional information and weigh different perspectives in order to make higher quality arguments, anticipating disagreements that may arise (Eveland, 2004; Pingree, 2007; Shah et al., 2005). Additionally, political learning positively influences individual feelings of political self-efficacy, which in turn stimulates participatory behaviours (Jung et al., 2011; Heiss & Matthes, 2016).

In short, the reported processes are expected to elevate the willingness of users to behave politically. Previous research presents among its findings positive effects on the part of the informational and expressive uses of social media on offline conventional and protest political participation (Conroy, Feezell & Guerrero, 2012; Gil de Zúñiga, Ardevol-Abreu & Casero-Ripollés, 2019; Macafee & De Simone, 2012; Yamamoto et al., 2015; Yoo & Gil de Zúñiga, 2014; Zumárraga-Espinosa, Reyes-Valenzuela & Carofilis-Cedeño, 2017).

3. The moderating role of political group membership and socioeconomic status

Literature increasingly provides insight into the mediating processes that explain the impact of social media on online and offline political participation. However, it remains to be specified the factors that can condition the intensity of the mobilizing effects produced by the political use of these platforms. Empirical research shows that individual variables such as personality traits, civic education, or political values interact with the relationship between general use of social