In recent years, the technology of adaptive hypermedia in learning has received increased attention. Adaptive hypermedia systems can offer a richer learning experience by giving more attention to personalization to learning and cognitive styles. Most approaches to adaptive hypermedia were based around acquiring and representing user’s knowledge. While this is crucial for user modelling in general adaptive hypermedia, it is very limited for e-learning because it does not address the far more fundamental problem which is “students learn in different ways, different learning styles and different cognitive styles”. The design of adaptive hypermedia system in this work is based on quantitative and qualitative research; the adaptive rules are deduced from the results of a psychological and pedagogical questionnaire. Pedagogical activities are the outcome of a series of deductions; the final activity sets are manifested in adaptive hypermedia. In order to assess the positive effect and validity of adaptation on the basis of users' cognitive and learning styles, this study presents two subsequent experiments. The first experiment explores the relationship of cognitive style and pedagogical activities to validate this specific psychological construct in the context of educational hypermedia. The second experiment presents the effect of a set of human factors (cognitive style, learning style) in an adaptive educational system.