This paper aims to show that propaganda and persuasion are underlined by two forms of communication, one aiming at a monologue, and the other aiming at a dialogue, which in practice do often coexist, with one or the other prevailing at a particular time. In order to understand propaganda or persuasion, we need to study them as part of the systems (e.g. institutions, organizations, communication) to which they belong, rather than treat them as decontextualized phenomena. Both propaganda and persuasion involve conscious and unconscious communicative processes. Nevertheless, the majority of social psychology experiments still assume that the experimenter should deal with phenomena only at a conscious level. In dialogical communication, however, latent and unconscious thought, inner dialogue, and ‘the depth of consciousness’, are presupposed to be unavoidable aspects of communication, whether it is concerned with influence processes, persuasion or social representations. They all are established through cultural-historical processes and determine symbolic meanings of social communication of the present and future.