The development of spatial abilities and mental imagery is one of the primary aims in geometric education in primary schools. There are hopes that the new media have an especially great potential when it comes to the development of spatial awareness and abilities in children at primary school age. However, not much research has been done yet to find out whether this claim holds true. This is the motivation for the present study.Ideas and concepts from philosophy, psychology and the field of mathematics education and didactics helped to form a detailed understanding of the notions of spatial abilities and mental imagery. They refer back to mental models and formed the starting point for this work.The focal point of the study is the investigation of the effect and impact of the use of computer animations on the development of mental imagery of primary school learners. Therefore, computer animation programmes were analysed with regard to their design and their potential for learning. Afterwards learners were observed when using the computer animations. Subsequently, they were interviewed and asked to evaluate the impact of the computer animations on their learning. The video data was analysed using basic principles of the ‘qualitative content analysis and ‘objective hermeneutics. Three prototypical patterns of behaviour could be observed. These are illustrated by three learners, ‘Michi, ‘Jan and ‘Johannes. Michi and Jan represent two extreme poles on a spectrum whereas the case of Johannes functions as an example of the prototypical learner situated in the middle.In the analysis of the learners, ‘Cognitive Load emerged as one of the determining factors for the interpretation of individual behaviour patterns.