This paper presents a study investigating the viewing behavior of human subjects for video contents having different frame rates. Frame rate variability arises when temporal video scalability is considered for adaptive video transmission, and the gaze pattern variation due to the frame rate variability would eventually affect the visual perception, which needs to be considered during perceptual optimization of such a system. We design an eye-tracking experiment using several high definition contents having a wide range of content characteristics. By comparing the gaze points for a normal frame rate condition and a low frame rate condition, it is shown that, although the overall viewing pattern remains quite similar, statistically significant difference is also observed for some time intervals. The difference is analyzed in terms of two factors, namely, overall gaze paths and subject-wise variability.