This paper presents human visual perception experiment results for a computer graphics rendering technique introduced in ACSC'05. In order to achieve a good immersive virtual reality experience, it is necessary to have at least 60 frames per second to ensure smooth motion. It is also necessary to have low end-to-end latency so that user interaction does not suffer from perceptible delays in images presented to the eyes. The Address Recalculation Pipeline (ARP) architecture reduces end-to-end latency in immersive Head Mounted Display (HMD) virtual reality systems. By using the ARP in conjunction with priority rendering, different sections of the scene are updated at different rates. This reduces the overall rendering load and allows for more complex and realistic scenes. Large object segmentation in conjunction with priority rendering further reduces the overall rendering load. However, scene tearing artefacts can emerge when different object segments are updated at different times. Region warping was devised to hide such tearing artefacts. In compensating for the tearing, region warping introduces slight distortions to the scene. Immersive virtual reality systems have humans as integral parts of the system. While researchers do thorough measurements and evaluation of hardware and software performance, the human experience and perception of the system is often neglected. This paper addresses this important issue. We describe our human visual perceptual experimental methodology in detail and present some initial results. Initial experiments in human visual perception of region warping distortions show interesting characteristics which lead us to propose further experimental investigations to clarify their significance.