Communication about socio-emotional issues can come with a range of pleasant or undesirable experiences for those involved. For example, while we might be eager to share with someone the news about our most recent achievement, telling them we will cancel our long-planned trip definitely puts us in a certain distress. In advance of such conversations, people anticipate their course and potential impact, and accordingly pursue communicational strategies that minimize negative and maximize positive experiences and outcomes. One powerful means in this (...) endeavor is the deliberate choice of communication channels that support those strategies. As mediated channels differ from face-to-face conversations in several regards and to varying degrees, they are perceived more or less suited for the pursuit of different communication goals. The present thesis is thus dedicated to the psychological question of why people choose particular channels in socio-emotional situations, how their choices differ between contexts, and how those choices could be influenced. The included set of six studies follows this structure of interrelated research questions. A first qualitative study explored the variety of reasons people refer to when choosing channels for socio-emotional communication and associates them with channel characteristics or contextual factors. Qualitative responses are linked to existing theoretical concepts and further transposed into an integrative model of different reasons behind communication channel choices. Basically, three sets of categories are identified in pragmatic, symbolic, and control-based reasons. Pragmatic reasons comprise choices out of convenience or habit that happen rather casually. Symbolic reasons pertain to choices that occur consciously but are largely predetermined by the respective situation. Control-based reasons are classified as reasons that stem from the intention to deliberately influence the communication process. These control-based reasons are further distinguished into categories of interaction control, i.e., reasons focusing on the synchronicity of channels, and emotion control, i.e., reasons focusing on the richness of channels. These two kinds of control-based reasons represent instances of strategic channel choice, which are the main focus of subsequent studies presented within this thesis. A potential psychological mechanism behind the strategic choice of channels is the intention to utilize their varying degree of subjective buffer, which regulates the interactional and emotional intensity of communication. This buffer effect of channels is defined as their subjective capacity to provide a psychological shield between individuals that mitigates emotional exposure and facilitates deliberate disclosure. Communication channels with a higher buffer effect therefore support face-saving impression management and the pursuit self-presentational goals. Studies 2.1 - 2.4 explored under which contextual circumstances people tend to strategically choose communication channels with higher buffer effects. This occurred when senders were to deliver negative messages and when the socio-emotional issue focused on themselves. The same preferences were shown by receivers, i.e., they chose channels with a higher buffer effect if the message was negative and focused on themselves. I ascribe these tendencies in channel choices to a generally increased salience of self-presentational goals in socio-emotional communication, especially when the issue is negative and revolves around oneself. In close relationships, however, effects of valence were inverted, such that senders chose channels with lower buffer effects in negative situations, while the opposite held true in distant relationships. There was no effect regarding the locus of the issue in either of the relationship conditions. I attribute this moderating effect of interpersonal closeness to the increased relevance of relational goals in close relationships. A general decline in the relevance of self-presentational goals might also explain why people in a work context chose channels with higher buffer effects for communicating negative messages to recipients of a superior or equal hierarchical status, while there was no difference for subordinates. An additional study explored the possibility to influence channel choice without changing the socio-emotional context itself by manipulating an individual’s regulatory focus. Following a regulatory focus induction, people’s channel choices in a potential conflict situation were assessed. The induction of a prevention focus led to the choice of channels with higher buffer effects and to a lower probability of choosing richer communication media, even when controlled for chronic regulatory focus and interpersonal closeness. This exploration constitutes a first example of how communication channel research could advance its implications by not only examining determinants and outcomes of channel choices but also ways to intentionally influence them. Following the overview of empirical studies and their concise summary, I elaborate on how they add to previous research and why widely applied media theories are frequently not suited to predict channel choices in socio-emotional situations. In order to not further the proliferation of theories in the field, I point out how the delivered insights can be integrated into the different stages of the impression management model, on which several of the present studies are predicated on. Subsequently, I present practical implications that may be derived from these works and refer to exemplary technical implementations that can serve as an orientation in this endeavor. This thesis concludes with a discussion of its limitations and directions for future research that go beyond what is already covered by the constituent works. (shrink)