The influence of the Doctor Fox effect on student ratings on instruction was examined. The idea for the Doctor Fox effect stemmed from the work of Erving Goffman and his notion that expressive behavior may influence an audience as much or more than substance when there is little time or reason for the audience to evaluate the presentation (1950). Undergraduate subjects compared two lecture segments varying in content and expressiveness. Total rating scores for each paired lecture were analyzed separately, along with a lecture choice variable and an adjective checklist. Results indicate a strong influence on student ratings of instruction by expressive teaching behaviors. Student choice of better lecture presentation and of adjectives to describe the lecturer showed strong relationships with high expressiveness lectures. The validity of the use of student ratings as the sole measure for administrative decisions regarding college teaching is questioned. (SW)