Participation encompasses a series of activities related to political life, aimed at influencing in a more or less direct - legal, conventional, pacific or contentious - way public decisions. Definitions can vary, depending on whether one focuses on individual or collective actors, on the social or institutional environment, or on the means and procedures of participation (Barnes and Kaase 1979).

On the horizontal axis, we see the shift from individuals to collective aggregates as discussed by the sociology of collective action. A single individual entitled with her own rights, personal means, resources, and identities (Milbrath 1965) is opposed to organized aggregates of people, which can count on organizational resources such as membership, finances, strategic position in the society or in the political system, know-how, better access to information and to channels of expression (Bentley 1908; Olson 1965; Almond and Powell 1966). On the vertical axis, the legislature represents the institutional arena legitimizing the existence of a democratic political system and, in turn, legitimized by the possibility of political participation. Civil society is the arena where economic and social conflicts are developed and then conveyed to the institutional sphere via various forms of participation.

In the ULQ, election represents the classic and most widespread means for an individual to choose freely to participate (or not), by exercising her basic citizenship rights through expressing her own preferences. There is, though, a more elementary and less demanding form of participation, as in the LLQ, through opinions which can be easily changed. Media are the main channel through which opinions can be expressed, but also influenced to the point of manipulation and induced participation. Quite the opposite, the LRQ indicates intense political engagement on contentious issues and through radical forms of mass mobilization, falling within the category of social movements (Tilly and Tarrow 2006; Touraine 1981). The URQ refers to participation within the political system. Organized actors and lobbies play the role of gatekeepers to most institutional resources, usually by building more or less overt coalitions to maintain their monopoly as the power elite in the participatory game (Berger 1981). [Silvia Bolgherini]