Communication medium can influence how people develop and maintain status in groups and relationships. However, such status effects of communication medium are often complicated by the evolving features of communication technologies and the changing practices of mediated communication. This dissertation explores theoretical principles behind the apparently myriad possibilities of effects of communication medium on status development in problem-solving groups. This is approached from different angles with two laboratory studies. The first study (Chapter 2) examines the medium effects on group members’ perception of each other’s expertise, with respect to how they match each other’s language use (i.e., linguistic accommodation) in group interactions. The findings suggest that linguistic accommodation channels people’s hidden confidence about task performance into interpersonal perception of performance (i.e., rankings of expertise). This language-based process can be affected by medium features that modulate the salience of confidence cues and language use (e.g., text-chat vs face-to-face discussion). The second study (Chapter 3) focuses on individuals’ selective attention—a prevalent issue of technology design. The study particularly examines selective attention to task objects and social objects in group interactions, along with two behavioral mechanisms—performance expectation and physiological stress—of status differentiation. The study found selective attention interplays with physiological stress in predicting the status outcome (i.e., deference and resistance to social influence). Thus, the findings suggest that effects of communication medium on status development can be partly understood through the technological modulation of selective attention and the subsequent effects on certain behavioral mechanisms of status differentiation.