the acceptance that the scenario being depicted is actually occurring

Another way of thinking of this illusion is as the automatic and rapid response from the experiencer to the important question: Is this really happening? If the response is ‘no’ then the illusion is broken.

Plausibility illusion (Psi) was put forward by Mel Slater as one of two illusions that contribute to a sense of presence. It is often discussed in conjunction with the Place illusion (Psi):

Psi is determined by the extent to which the system can produce events that directly relate to the participant, and the overall credibility of the scenario being depicted in comparison with expectations.1

…a key component of Psi is that events in the virtual environment over which you have no direct control refer directly to you…2

1. Slater, M. “Place Illusion and Plausibility Can Lead to Realistic Behaviour in Immersive Virtual Environments”Philos Trans R Soc Lond B Biol Sci. 2009 Dec 12; 364(1535): 3549–3557 Pg 1.
2. Slater, M. “Place Illusion and Plausibility Can Lead to Realistic Behaviour in Immersive Virtual Environments”Philos Trans R Soc Lond B Biol Sci. 2009 Dec 12; 364(1535): 3549–3557 Pg 8.