The heterogeneity of today’s classrooms calls for a differentiated instruction that considers students’ different learning conditions. Differentiation means that teachers proactively modify curricula, teaching methods, and learning activities “to address the diverse needs of individual students […] to maximize the learning opportunity for each student in the classroom” (Tomlinson, Brighton, Hertberg et al., 2003, p.121). From a theoretical point of view, different approaches can be considered to explain the necessity of differentiated instruction. In the present study, the focus will be on motivational approaches like the self-determination theory (Deci & Ryan, 1985). According to this theoretical approach, students are mostly motivated when the task allows them to experience their own competence and to work autonomously. This leads to different tasks for different learning levels. Beyond this, the previous knowledge a student brings to the task is one of the most important conditions for the learning process (Krause & Stark, 2006). Differentiated instruction therefore has to consider these different levels of previous knowledge. For a teacher, differentiated instruction means that he or she has to develop different learning materials and adapt tasks for the different achievement levels within a learning group.

The present study is a case study conducted in a German comprehensive school. In this school type, students are normally classified into different courses according to their achievement level. From the seventh grade on, there are so called ‘basic’ and ‘advanced’ courses and changes between the two course levels are possible only at the end of each school year.

The school presented here has changed this model of external differentiation, because most teachers recognised a negative learning atmosphere in the ‘basic courses’ and social problems caused by the change of learning groups after each school year. Therefore, a model of internal differentiation has been introduced where teachers develop different learning material for the different achievement levels within one classroom. Teachers label their students according to their achievement level and students know which level they belong to.

This change of differentiation from an external to an internal model leads to the central research questions of the present study: what effects on students’ motivation, interest and achievement does the external compared with the internal differentiation have? Are there differences between low and high achieving students? Beyond the students’ point of view, we also want to study how teachers deal with the changed model of differentiation. Research questions here are: Does the change of differentiation has an effect on teachers’ perceived stress? How can teachers support each other in putting the internal differentiation into practice? What role does the teacher cooperation play in this process?

Deci, E. L. & Ryan, R. M. (1985). Intrinsic Motivation and Self Determination in Human Behavior. New York: Plenum Publishing Co. Krause, U.-M. & Stark, R. (2006). Vorwissen aktivieren. In H. Mandl & H.-F. Friedrich (Hrsg.), Handbuch Lernstrategien (S. 38-49). Göttingen: Hogrefe. Tomlinson, C. A., Brighton, C., Hertberg, H., Callahan, C. M., Moon, T. R., Brimijoin, K., et al. (2003). Differentiating Instruction in Response to Student Readiness, Interest, and Learning: Profile in Academically Diverse Classrooms: A Review of Literature. Journal of the Education of the Gifted, 27(2/3), 119-145.