Previous research on the attentional influence of new objects and new motion in the environment has focused on studying these two visual features in isolation. In the present study, we examined new objects and new motion when they co-occurred within one scene. In addition, we evaluated the extent to which low-level luminance changes can contribute to the attention-capturing properties of each of these dynamic events. Results suggest that new objects have a larger impact on the allocation of attention than new motion and, under certain circumstances, the appearance of new objects may suppress the attentional benefit typically afforded to new motion. Lastly, our findings indicate that low-level factors account for some, but not all, of the attentional effects observed for new objects and new motion.