Figure 1.

Experimental setup and design. (A) Center, illustrative image of the experimental setup and visual scenario. Participants donned a head-mounted display (HMD) and viewed the immersive virtual environment in 360° around them. The images on the sides and bottom represent the six types of alterations of the visual aspects employed, at the highest magnitude of alteration shown, for comparison, on a similar section of the virtual room. (B) Trial flow for the experiments. (Top) In Experiment 1, a virtual reality (VR) environment appeared for 2 s, followed by a black screen and then a second VR environment. Subsequently, participants were presented a question screen asking them to report if the two VR environments were identical or not. (Bottom). In Experiment 2, participants viewed a VR environment, which could be altered or unaltered. In each trial, they were required to judge on a continuous scale how ‘real’ the environment felt to them.