Among several theories to explain how different communication media affect task performance, media richness theory(MRT) is one of the most frequently cited. Recent studies related to the use of communication media, however, have raised the question of the effectiveness of the MRT as a predictor of media choices or of individual effectiveness. The objective of this research is to examine the assumptions of the MRT. MRT proposes that the properties of media are objective in other words, they are inherent and physical attributes recognizable by users. This study experiments on the effects of task characteristics and medium experience on the perceived media richness and social presence. The results of this study did not support the assumptions of the MRT. There was an interaction effects of task characteristics and medium experience on both the perceived media richness and social presence. While the inexperienced computer-mediated communication(CMC) group perceives their medium richer for the unequivocal task, the experienced CMC group perceives their medium equally for the equivocal and the unequivocal task.