A challenge of student modeling in adaptive virtual learning environments is to get enough information about the learner. Information about the learner such as the domain competence, the learning style or the cognitive traits of a learner is very important for an adaptive environment to achieve its main aim, namely to adapt to the learners' needs. In this paper we investigate the interaction between learning styles, in particular the Felder-Silverman learning style model, and working memory capacity, a cognitive trait. As a result we demonstrate some relationships between learners with high working memory capacity and a reflective, intuitive, and sequential learning style whereas learners with low working memory capacity tend to prefer an active, sensing, visual, and global learning style. These interactions make it possible to improve student models.