Mental Contents in Interacting with a Multiobjective Optimization Program

User psychology aims at understanding human-machine interaction from a psychological point of view. Its ultimate goal is to provide knowledge about human psychological properties for interaction designers. In this article, we are particularly interested in applying the theoretical concepts of mental contents (i.e., the information contents of users’ mental representations), in studying interaction with professional software. The immediate motivation for adopting such an approach arises from problems met in designing interaction processes in multiobjective optimi�ation software. These types of software are meant to support complex thought and decision-making processes and this is why interaction design has to meet a number of theoretical problems, which do seldom arise in simpler interaction types. In four experiments, we investigated the types of knowledge required when developing ones’ capability of working with such a thought tool. We observed that in interaction design it is essential to take into account domain, professional and software specific mental content structures.