This study sought to examine calculus students' mathematical performances and preferences for visual or analytic thinking regarding derivative and antiderivative tasks presented graphically. It extends previous studies by investigating factors mediating calculus students' mathematical performances and their preferred modes of thinking. Data were collected from 183 Advanced Placement calculus students in five high schools. Students' visual preferences were not influenced by gender. Statistically significant differences in visual preference scores were found among high- and low-performing students. Thus, the results suggest that stronger preference for visual thinking was associated with higher mathematical performances. (Contains 3 figures and 4 tables.)