In the first of two experiments designed to determine whether the use of humor would enhance audience reactions to a speaker without damaging that speaker's ethos (character and authoritativeness), 98 university students were randomly assigned to read one of four versions of the speech, "Why I Chose Psychology." The subjects read speeches that were either humorous or not humorous and ascribed to either a low ethos source (a high school student) or a high ethos source (a university professor). Results of subjects' ratings on ethos, humor, and semantic differential indicated that humor or wit can enhance a speaker's image without damaging the traditional factors of ethos. In a replication of the study, 121 subjects rated a speech, "Why Everyone Should Read the Bible," which used humor rather than the earlier speech's witticisms, and self-deprecation rather than deprecation of the professional field. Although use of humor raised ratings on wittiness and sense of humor, it lowered ratings on authoritativeness. The differences in results may have been related to differences in the type of humor used. The studies suggest that the speaker's use of humor should meet certain standards of taste and appropriateness. (MM)