What do you think you´re doing? Measuring perception in fish tank virtual reality

Fish tank virtual reality (FTVR) systems use eye tracking to present perspective projections to a user that are tailored to his or her view position. These perspective views can create the illusion of a world behind the display screen-a virtual fish tank. However, the illusion is not perfect “users do not feel that the virtual objects are real. Despite this, users clearly are getting some indication of depth. What exactly are they perceiving? We review previous work in FTVR and identify key differences between the virtual world and the real world. We show that we still have an incomplete understanding of perception in fish tank virtual reality and that some important questions may be impossible to answer