Cognitive Acceleration through Science Education (CASE) is an intervention programme conducted during Years 7 and 8 in the United Kingdom (aged 11-13 years), which has reported remarkable success in enhancing cognitive development and in raising academic achievement. Critics, however, have questioned whether a purely cognitive mechanism can explain the differential cognitive gains made by participants. One suggestion is that differences in motivational style might provide an explanation. This paper will present findings from a longitudinal study that addresses this matter. Utilising a goal theory approach to motivation, the motivational orientation, related beliefs, and self-concepts of approximately 1600 secondary students attending nine schools, five of whom were delivering the CASE intervention, were assessed before and at the end of the programme. Analyses of these data suggested that students exhibit six different motivational styles or world-views. These will be characterised. Change in motivation can be gauged by examining changes in world-view over the time-span of the research (the first 2 years of secondary schooling). Differences in the change of motivation of students for students attending CASE and control schools will be inspected. Finally, the relationship between motivation and cognitive gain, which turns out to be complex, will be presented. The implications of these findings, including whether world-view can explain differential cognitive acceleration effects, will be discussed. Supplementary Data Tables are appended. (Contains 7 figures, 13 tables, and 5 notes.)