This study investigates how graphical and content list type overviews with and without navigation restrictions affect the cognitive load experienced by a learner searching for information in a hypertext. The study used a 2x2 between factor design with the factors navigability (restricted vs. non-restricted) and overview format (graphical vs. content list). Participants had to search for information in a hypertext within a specific time limit. Analyses of participants' eye movements revealed that participants' cognitive load was higher in the navigation restricted condition than in the non-restricted condition. Furthermore, a higher cognitive load was experienced with the graphical overview than with the content list type overview. Search efficiency was also higher in the navigation non-restricted condition than in the restricted condition. Furthermore, the better participants represented the hypertext structure the better was their search efficiency. Results of the study indicate that a simple content list type overview that can be directly navigated supports learners best in an information search task.