Ten volunteers with normal or corrected visual acuity of 20/20 (four females, six males, 20–30 years of age), who did not participate in Experiment 1, were recruited for the second experiment. The test platform consisted of two personal computers (2.90 GHz, Intel Core i5-2310 CPU, 4 GB DDR3 RAM; Lenovo, Inc.), a 17-inch CRT screen (1024 × 768, 85 Hz/110 MHz; EMC; Proview Technology Co., WuHan, China), a head-mounted display (HMD; Z800 3Dvsior, 800 × 600 resolution, 40° diagonal field of vision; eMagine, Rochester Hills, MI), a microcamera (640 × 480, 30 Hz; Philips Inc., Best, The Netherlands), an eye tracker (View Point EyeTracker; Arrington Research, Inc.), headrest, and a microphone.
One computer was used to show a normal paragraph containing CCs. The other computer ran in-house software written in Visual C++ (Microsoft) to process the images captured by the microcamera (640 × 480, 30 Hz; Philips Inc.) and display the pixelized paragraphs in the HMD.