In this study, the authors examine rapidly spreading CMC (Computer-Mediated Communication) from a social psychological point of view and investigate the differences between CMC and FTF (Face-to-Face) communication modes through an experiment based on the conditions of both modes. Subjects were randomly assigned into three-person groups and then answered a series of choice dilemma problems involving risk decision-making. We defined a concept of“interpersonal pressure”that illustrates the idea of some tensions or psychological burdens brought by others into the communication situation. It was found that the interpersonal pressure decreased significantly in CMC and the authors suggest that the phenomenon of status equalization in CMC can be explained by such a decrease in interpersonal pressure. However, group polarization was also observed in CMC. Comparing CMC with FTF, the subjects in CMC had a tendency to make more risky decisions. Furthermore, a first advocated statement effect was also examined in the study.