A study examined the effect of humor on the perceived credibility, character, and authority of an advertisement and on the recall of that advertisement. Two groups of subjects each heard two radio spot announcements, one humorous and one serious. Two different products were advertised, so that the first group of subjects, 117 college advertising students, were exposed to a serious commercial for one product and a humorous spot for the other, while the second group, 132 students, heard the opposite. The humorous and serious versions of each advertisement were identical in situation, product information, basic sales appeal, and number of times the product name and slogan were mentioned. Subjects then filled out a questionnaire that solicited information on their perception of the commercials' credibility, authoritativeness, and character, as well as their retention of the message. The results indicated that there was a significant difference between the two groups for each ad on the perceived humor of the message, however, no difference in the subjects' ability to recall copy points was found between the humorous and serious messages. Subjects rated the serious versions more credible than the humorous versions. The results suggest that the use of humor will have little effect on recall, and that a serious message is likely to be judged more credible and to have more authority than a humorous ad. (HTH)