An exploratory study focused on United States and Japanese college students' perceptions of their communication apprehension, willingness to communicate, and sense of humor in various communication situations. Subjects, 110 students selected from several scientific and technical communication classes at the University of Minnesota and 108 students from a psychology class at Kwansei Gakuin University, completed the Personal Reports of Communication Apprehension (PRCA-24), Willingness to Communicate (WTC) and Sense of Humor (SH) self-report measures. Results indicated significant differences between Japanese college students and United States students on all PRCA-24, WTC, and SH variables. Japanese students have (1) significantly higher PRCA-24 scores for dyadic, group, meeting, and public speaking, and composite variables; (2) significantly lower WTC percentages for dyadic, group, meeting, public speaking, composite, stranger, acquaintance, and friend variables; and (3) significantly higher Sense of Humor scores on liking of humor, sensitivity to humor, and coping humor than United States college students. (Contains 36 references and 6 tables of data.) (Author/RS)