The basic purpose of the cooperative research project was to study the level of reasoning skills in junior high school students in Japan and the United States (grades 7, 8, and 9). This study examined the relationships among logical thinking skills, integrated process skills, and attitudes of junior high school students in North Carolina. Students' participation in out-of-school activities as well as teacher background variables were also studied. Nearly 40 teachers from 10 school districts and approximately 3,500 students from North Carolina provided data and a parallel study was simultaneously conducted in Japan. Instrumentation and results are discussed and include the topics of: (1) logical thinking (measuring concrete and formal thinking skills); (2) integrated process skills (examining five subscale skill areas); (3) attitudes (focusing on opinions toward science); (4) student participation (considering in-school and out-of-school activities); and (5) teacher background (obtaining data about teachers' education, experience, and teaching methods). Results in all tested areas are summarized and compared with findings of the Japanese counterparts. Suggestions are offered for improving student reasoning skills. (ML)