The purpose of this study was two-fold. One was to investigate the role of field dependent-independent cognitive style in the development of causal and social reasoning, and the other was to investgate common vertical structure and common horizontal structure across domains in Korean students. The study was based on a neo-Piagetian theory of intellectual development. The sample for this study consisted of 120 subjects. This included 20 girls, 20 boys from each of grade 6., 8 and 11. Half of the subjects in each grade and sex were field dependent and the other half were field independent. The Balance Beam Task, Marini’s Personality Diagnosis Task were used to assess the development of causal and social reasoning. The findings of the present study were as follows: 1. Field independent students scored significantly higher than field dependent subjects on the Balance Beam Task. 2. Many students did not function at the same level, across two structurally equivalent tasks. But the significant effect of split(not functioning at the same level on both tasks)was not attained. Also the significant effect of cognitive style in the percentage of split was not attained. 3. It was found that the percentage of students succeeding on the two tasks decreased as the level of task complexity increased. And the results showed that students were performing at similar levels, but they were performing at low rates These findings have showed the linkage of cognitive style with neo-Piagetian tasks. Also these results suggest that there are common vertical and common horizontal structure across domains in Korean students.