The teaching and learning environment in a traditional classroom typically includes a projection screen, a projector, and a computer within a digital interactive table. Instructors may apply multimedia learning materials using various information communication technologies to increase interaction effects. However, a single screen only displays a single teaching view to learners. In this study, we proposed a dual-screen learning environment to present multiple learning contents simultaneously and investigated learning effectiveness and cognitive loads of learners between single- and dual-screen learning environments. We compared different instructional materials in programming language instruction using two types of learning environments with single and dual screens. We designed three types of instructional materials, descriptive material, progressive material, and worked-example material, to arrange the instructional slides of programming language course. The results of this study showed significant differences in learning effectiveness, and the degrees of clarity and difficulty of instructional materials in both learning environments. This study may help explain the learning effects between single- and dual-screen environments, and provide instructors with a better understanding of how a dual-screen learning environment affects learning effectiveness and cognitive loads in programming language instruction. (Contains 1 table and 5 figures.)