This research addresses three important issues regarding interpersonal expectancy effects and communication across various modalities. The phenomena of behavioral confirmation and disconfirmation were tested in an original experiment involving 148 participants using computer-mediated communication (CMC). First, this study tested a boundary condition asserted by previous theorists about whether or not confirmation and disconfirmation could occur in communication channels without nonverbal communication. Secondly, it shed light on an important causal variable of perceived malleability of interpersonal expectancies in a novel, simultaneous test of confirmation and disconfirmation. Lastly, it verified the hyperpersonal model of CMC by demonstrating behavioral confirmation, and extended the model by specifying when disconfirmation occurs online.