This paper explores whether the principles of cognitive load and multimedia theory are mediated by cognitive style, gender, and prior knowledge. Participants were 91 children aged 10-11 years (54 boys, 37 girls), each assigned to one of two presentation modes. In Condition 1 children were presented with diagrams supported by printed textual material. In Condition 2 the same diagrams were supported by narrated text. Condition 1 was designed in the conventional manner but Condition 2 was designed to adhere to cognitive load and multimedia theory. Then the children were asked a number of comprehension questions, an outcome measure requiring assimilation of information from both pictures and words. The Cognitive Style Analysis was administered to measure wholist-analytic style and verbal-imagery style. Results from national achievement tests were used as indicators of prior knowledge. Results indicate that outcome is differentiated by style, gender, and prior knowledge, and not just instructional design.