In this paper we describe a subjective quality assessment experiment conducted to measure the impact of temporal artifacts on video quality and characterize the influence of content motion on perceived quality. We examined the human response to jerkiness and jitter by considering different levels of strength, duration and distribution of the temporal impairments. Using videos with high picture quality, we found that for intermediate and high frame rate values video quality was similar independently from the duration of the frame rate decimation. On the other hand, for very low frame rates, overall video quality decreased as the duration of the impairment increased. The results also show that a reduction of the temporal resolution over the entire video does not necessarily lead to a significant loss of quality. Finally, the results of this study do not confirm the traditional thinking of lower-motion content receiving a higher quality than high-motion content for a given frame rate decimation factor. Using several motion descriptors, we observed that for a given sub-optimum frame rate, perceived quality does not necessarily increase with decreasing motion magnitude. More particularly, we found that perceived quality of head-and-shoulders content is severely affected by frame rate decimation although it is characterized by very low motion. Our results suggest that motion magnitude is not the only factor affecting perception of temporal artifacts.