The purpose of this study was to identify factors responsible for the perceived decline in attitudes toward science observed in an intervention study designed to enhance scientific literacy. The literacy study focuses on a new freshman course in an urban Catholic high school. Negative attitudes toward science were found to be related to the demand characteristics of the scientific literacy course, which emphasized problem solving. Although the course was successful in teaching literacy skills and had a positive effect on general cognitive abilities, there was a sharp decline in attitude toward science between the beginning and end of the course. Factors related to attitude decline are discussed in terms of self-concept, mastery, locus of control and motivation. (TW)