This dissertation by Joseph B. Walther explores the effects of time and communication channel (computer conferencing versus face-to-face meetings) on impression development, message personalization, and relational communication in groups. The study aims to test the boundaries of social presence theory and related concepts, which suggest that computer-mediated communication (CMC) is less personal or socioemotional compared to face-to-face communication due to the absence of nonverbal cues. Walther critiques existing CMC research for its limitations, such as chronometry, transcript-only data, contradictory findings, and coding issues. He argues that these weaknesses may be due to the lack of temporal and developmental perspectives in CMC research. The study involves 96 subjects divided into computer conferencing or traditional zero-history groups of three, who complete three tasks over several weeks. The results show that computer-mediated groups exhibit more positive relational dimensions over time, approaching levels similar to face-to-face groups. Walther recommends that the predominant theories of CMC be bounded and suggests future research directions. The dissertation includes a detailed methodology, results, and discussion, with hypotheses testing the effects of time and communication channel on various relational dimensions such as immediacy/affection, similarity/depth, composure/relaxation, formality, dominance/equality, receptivity/trust, and task-social orientation.This dissertation by Joseph B. Walther explores the effects of time and communication channel (computer conferencing versus face-to-face meetings) on impression development, message personalization, and relational communication in groups. The study aims to test the boundaries of social presence theory and related concepts, which suggest that computer-mediated communication (CMC) is less personal or socioemotional compared to face-to-face communication due to the absence of nonverbal cues. Walther critiques existing CMC research for its limitations, such as chronometry, transcript-only data, contradictory findings, and coding issues. He argues that these weaknesses may be due to the lack of temporal and developmental perspectives in CMC research. The study involves 96 subjects divided into computer conferencing or traditional zero-history groups of three, who complete three tasks over several weeks. The results show that computer-mediated groups exhibit more positive relational dimensions over time, approaching levels similar to face-to-face groups. Walther recommends that the predominant theories of CMC be bounded and suggests future research directions. The dissertation includes a detailed methodology, results, and discussion, with hypotheses testing the effects of time and communication channel on various relational dimensions such as immediacy/affection, similarity/depth, composure/relaxation, formality, dominance/equality, receptivity/trust, and task-social orientation.