A study examined instructional television (ITV) to determine the differences in the affect domain existing among three concurrent environments: the face-to-face environment, defined as the site from which the message originates; the on-site location, defined as a location in close proximity to the origin of the message; and the off-site location. Interviews and observational data were collected from both students and professionals enrolled in mechanical engineering courses offered through the PROFNET televised instruction system at San Diego State University during the spring semester of 1989. The face-to-face and on-site settings involved 28 students each, while the off-site classroom included seven participants. Results revealed that five differences did exist in the affect domain between face-to-face sites and mediated sites in ITV: (1) the way in which questions and comments were generated and utilized; (2) the presence of humor; (3) entrance and leave-taking behaviors; (4) the reaction of the observed groups to the content of the message; and (5) the focus of attention of the observed groups. More research into the importance of immediacy, affiliativeness, identification, and other related affective constructs appears to be called for. (Thirty references are attached.) (KEH)