The contribution to learning of the learning materials' arousal properties was investigated using degree of interest of the stimulus and response terms as the index of arousal. Words equated on meaningfulness, imagery, and concreteness and rated as high (H), medium (M), and low (L) in interest were used to represent the 3 levels of interest, and served as stimulus and response terms. Ninety students were randomly assigned to one of the 9 treatment conditions consisting of variations in interest on the stimulus and response side. The design called for l0 subjects per cell. The conditions were: H-H, H-M, H-L, M-H, M-M, M-L, and L-H, L-M, L-L. A planned comparison was performed on the response side. The data were also analyzed by trend analysis over 10 trials. The results revealed no significant difference between groups or within groups. The planned comparison suggested that the greatest amount of learning occurred in medium levels of response interest. However, high, medium, and low response effects were not significantly different from each other at conventional levels. The inverted U suggested in this study is in line with certain previous research. (Author)