A major challenge in Virtual Reality is to achieve realism at interactive rates. However, the computational time required for realistic image synthesis is significant, precluding such realism in real-time. This paper demonstrates a concept that may be exploited to reduce rendering times substantially without compromising perceived visual quality in interactive tasks. We demonstrate the principle of Inattentional Blindness; when attention is focused on a specific task, items in the scene that are unrelated to the performance of the task literally go unnoticed. Our experiment utilises this principle and varies the rendering quality over the image according to the task at hand. Our results show that observers do not perceive the difference in image quality on objects unrelated to their task. We believe this is due to Inattentional Blindness, as their attention was focused on a task rather than image quality. The difference in rendering was clearly visible when the subjects were asked to pay full attention to spotting the quality differences only. Our results show that Inattentional Blindness may be exploited to reduce rendering times substantially without compromising perceived visual quality in interactive tasks.