With the spread of computer networks, communication via computer conferences, electronic mail, and computer bulletin boards will become more common in society, but little is known about the social psychological implications of these technologies. One possibility is a change in physiological arousal, feelings, and expressive behavior-that is, affect. These computermediated communication technologies focus attention on the message, transmit social information poorly, and do not have a well-developed social etiquette. Therefore, these technologies might be associated with less attention to others, less social feedback, and depersonalization of the communication setting. In the present study we examined what would happen to feelings and interpersonal behavior in an experiment in which two people met for the first time and discussed a series of questions in order to get to know one another. We measured physiological arousal (pulse and palmar sweat), subjective affect (emotional state and evaluations), and expressive behavior (self-disclosure and uninhibited behavior) in both synchronous computer-mediated and faceto-face discussions. (For comparison purposes, we also examined these effects under high- and low-evaluation anxiety). Communicating by computer did not influence physiological arousal, and it did not change emotions or selfevaluations. However, people who communicated by computer evaluated each other less favorably than did people who communicated face-to-face, they felt and acted as though the setting was more impersonal, and their behavior was more uninhibited. These findings suggest that computer-mediated communication, rather than provoking emotionality per se, elicits asocial or unregulated behavior. Of course, our data are based on a laboratory experiment using just one type of computer-mediated communication, but the results are generally consistent with anecdotal evidence and new field research on how people use computers to communicate in organizations.