In 1991, a study was conducted at Riverside City College (RCC), in California, to determine the development of science reasoning among students. A science reasoning test was administered at the beginning and again at the end of fall 1991 to two samples: a college-wide sample of 843 students enrolled in one of 55 courses, and a science-oriented sample of 494 students who took at least one science course at RCC. The study found that, for the college-wide sample, the science curriculum was a positive influence on the development of students' science reasoning ability, with the positive effect of taking science courses on students' science reasoning ability increasing with the number of science units taken. In addition, calculus-based physics courses strongly influenced the development of science reasoning ability, while training in undergraduate psychology also contributed positively. Training in history, however, appeared to be negatively related to science reasoning. Results for the science-oriented sample indicated that a background in college humanities favorably influenced science reasoning ability, with physics courses contributing most to this development. Participation in RCC's introductory chemistry course, however, was found to have a negative impact on science reasoning. The study concluded that high student involvement in the sciences results in an increase in science reasoning ability and that the science curriculum played an important role in community college students' progress in developing reasoning ability. (TGI)