Introduction: This study investigated the effect of cognitive styles on users' information-seeking task performance using a knowledge domain information visualization system called CiteSpace. Method: Sixteen graduate students participated in a user experiment. Each completed an extended cognitive style analysis wholistic-analytic test (the Extended CSA-WA test) on cognitive style, and then conducted eight tasks in the CiteSpace system. Analysis: Users' behaviour and performance data were analysed using statistical techniques to explore the relationships among various measures. The techniques include Pearson Correlation, multivariate analysis of variance, Pearson Chi-squared test and non-parametric tests such as Wilcoxon signed-rank test. Results: Results demonstrated that users' cognitive styles did impact their search performance. The wholistic-analytic ratio obtained from the cognitive test is significantly correlated with result correctness. After dividing the subjects into two groups based on the median wholistic-analytic ratio, analysis showed that subjects with wholistic preference felt significantly more satisfied with results than those with analytic preference. Additionally, subjects with analytic preference found significantly more correct answers than those with wholistic preference. Conclusions: These results indicated that cognitive style is an important factor in the study of information science and human-computer interaction. Research in this area provides valuable indication of future information system design. (Contains 4 figures and 6 tables.)