The Thinking Aloud method is about the verbalization of one's own thinking. Users are asked to express their thoughts while performing a task. This provides direct information on thinking and problem solving processes. The method makes it possible to obtain information about the cognitions and emotions that occur during interaction with a product. Qualitative information can be obtained, which also provides information about the mental models of the users. However, the method has an impact on the processing time of tasks, so that a simultaneous, undistorted measurement of processing times is difficult.