Understanding the user and customizing the interface to augment cognition and usability are goals of human computer interaction research and design. Yet, little is known about the influence of individual visual-verbal information presentation preferences on visual navigation and screen element usage. If consistent differences in visual navigation can be detected and measured, these differences could be used to augment cognition or customize views appropriately as eye tracking and other monitoring devices improve. This dissertation research investigates: (1) the relationship between the measured visual-verbal preferences and the participant's eye movements during different types of problem-solving tasks; (2) performance on text, text plus diagram, diagrammatic reasoning problems and selection of problem representation; and (3) whether different levels of cognitive load are observed in eye movement patterns while solving reasoning problems of differing difficulty. A visual-verbal preference questionnaire adapted from several established instruments was administered to 140 university students in a variety of fields. The responses to this questionnaire were analyzed to understand overall tendencies toward visual and verbal preferences by field of study, gender and other factors. Twelve participants (six verbal and six visual, balanced by gender) were recruited from those scoring in the extreme 20% of the pool, either more visual than verbal or more verbal than visual, to complete an eye tracking experiment. Each participant completed 3 practice problems and 15 reasoning problem tasks (6 text-plus-diagram, 6 text-only, and six diagram-only). The results showed a strong trend for the verbal group to perform better on problems with diagrams than without, while the visual group only performed slightly better with a diagram. The visual group performed better than the verbal group on the text-only and diagram-only problems. The visual group spent more time on blank areas of the screen than the verbal, possibly indicating internal visualization. Different strategies were found between the two groups and among individuals. These differences are analyzed in terms of one's awareness of their visual processing and the importance of specific task requirements. The results are important to the use and customization of representations in interface design, education, marketing and diagrammatic communication for problem solving. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]