The study was conducted in context of the Fernstudent-project. Part of this research has been funded by the LMU Quality Teaching Fund (Fonds zur Förderung der guten Lehre) and the DFG-project PerforM—Personalities for Machinery in Personal Pervasive Smart Spaces (425412993) in context of the Priority Program "Scalable Interaction Paradigms for Pervasive Computing Environments" (SPP 2199).