Abstract: In this experiment,we examined the characteristics of visual smooth pursuit under different direction conditions. Three major findings were noted. First,a significant difference was observed between horizontal and vertical pursuit. This difference was shown in almost all eye movement indices. Second,differences were also observed between the "toward left" and the "toward right" and between the up and the down conditions. These differences were registered only in data structures of pursuits. Third,we found that the distance of saccades was the most sensitive index of eye movement. In addition to these findings,we also noted that the effects of different direction conditions might be registered differently by different eye movement indices. This observation,which points to the complexity of visual pursuit research,warrants further investigation. The spectral analysis used to analyze eye movement in this study provides an alternative method that we believe is more effective than some of the traditional methods.

Key words: eye movements, visual pursuit, smooth movement, spectral analysis